Merge branch 'greybus' into staging-testing

This merges the greybus branch into staging-testing.  It contains the
drivers/staging/greybus/ subsystem and related drivers and has passed
the 0-day bot tests so no builds should break.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

89 files changed, 37600 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 1b654772cc2e..24b07f746919 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5290,6 +5290,23 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/aeroflex/
 
+GREYBUS SUBSYSTEM
+M:	Johan Hovold <johan@kernel.org>
+M:	Alex Elder <elder@kernel.org>
+M:	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+S:	Maintained
+F:	drivers/staging/greybus/
+
+GREYBUS PROTOCOLS DRIVERS
+M:	Rui Miguel Silva <rmfrfs@gmail.com>
+S:	Maintained
+F:	drivers/staging/greybus/sdio.c
+F:	drivers/staging/greybus/light.c
+F:	drivers/staging/greybus/gpio.c
+F:	drivers/staging/greybus/power_supply.c
+F:	drivers/staging/greybus/spi.c
+F:	drivers/staging/greybus/spilib.c
+
 GSPCA FINEPIX SUBDRIVER
 M:	Frank Zago <frank@zago.net>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index 5ebaf0028a10..9c0339c53fe0 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -102,4 +102,6 @@ source "drivers/staging/i4l/Kconfig"
 
 source "drivers/staging/ks7010/Kconfig"
 
+source "drivers/staging/greybus/Kconfig"
+
 endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index 29a1672820e6..6952aaf3114b 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -40,3 +40,4 @@ obj-$(CONFIG_WILC1000)		+= wilc1000/
 obj-$(CONFIG_MOST)		+= most/
 obj-$(CONFIG_ISDN_I4L)		+= i4l/
 obj-$(CONFIG_KS7010)		+= ks7010/
+obj-$(CONFIG_GREYBUS)		+= greybus/
diff --git a/drivers/staging/greybus/Documentation/firmware/authenticate.c b/drivers/staging/greybus/Documentation/firmware/authenticate.c
new file mode 100644
index 000000000000..ab0688ad1e37
--- /dev/null
+++ b/drivers/staging/greybus/Documentation/firmware/authenticate.c
@@ -0,0 +1,139 @@
+/*
+ * Sample code to test CAP protocol
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "../../greybus_authentication.h"
+
+struct cap_ioc_get_endpoint_uid uid;
+struct cap_ioc_get_ims_certificate cert = {
+	.certificate_class = 0,
+	.certificate_id = 0,
+};
+
+struct cap_ioc_authenticate authenticate = {
+	.auth_type = 0,
+	.challenge = {0},
+};
+
+int main(int argc, char *argv[])
+{
+	unsigned int timeout = 10000;
+	char *capdev;
+	int fd, ret;
+
+	/* Make sure arguments are correct */
+	if (argc != 2) {
+		printf("\nUsage: ./firmware <Path of the gb-cap-X dev>\n");
+		return 0;
+	}
+
+	capdev = argv[1];
+
+	printf("Opening %s authentication device\n", capdev);
+
+	fd = open(capdev, O_RDWR);
+	if (fd < 0) {
+		printf("Failed to open: %s\n", capdev);
+		return -1;
+	}
+
+	/* Get UID */
+	printf("Get UID\n");
+
+	ret = ioctl(fd, CAP_IOC_GET_ENDPOINT_UID, &uid);
+	if (ret < 0) {
+		printf("Failed to get UID: %s (%d)\n", capdev, ret);
+		ret = -1;
+		goto close_fd;
+	}
+
+	printf("UID received: 0x%llx\n", *(long long unsigned int *)(uid.uid));
+
+	/* Get certificate */
+	printf("Get IMS certificate\n");
+
+	ret = ioctl(fd, CAP_IOC_GET_IMS_CERTIFICATE, &cert);
+	if (ret < 0) {
+		printf("Failed to get IMS certificate: %s (%d)\n", capdev, ret);
+		ret = -1;
+		goto close_fd;
+	}
+
+	printf("IMS Certificate size: %d\n", cert.cert_size);
+
+	/* Authenticate */
+	printf("Authenticate module\n");
+
+	memcpy(authenticate.uid, uid.uid, 8);
+
+	ret = ioctl(fd, CAP_IOC_AUTHENTICATE, &authenticate);
+	if (ret < 0) {
+		printf("Failed to authenticate module: %s (%d)\n", capdev, ret);
+		ret = -1;
+		goto close_fd;
+	}
+
+	printf("Authenticated, result (%02x), sig-size (%02x)\n",
+		authenticate.result_code, authenticate.signature_size);
+
+close_fd:
+	close(fd);
+
+	return ret;
+}
diff --git a/drivers/staging/greybus/Documentation/firmware/firmware-management b/drivers/staging/greybus/Documentation/firmware/firmware-management
new file mode 100644
index 000000000000..7918257e5b3b
--- /dev/null
+++ b/drivers/staging/greybus/Documentation/firmware/firmware-management
@@ -0,0 +1,333 @@
+
+Firmware Management
+-------------------
+ Copyright 2016 Google Inc.
+ Copyright 2016 Linaro Ltd.
+
+Interface-Manifest
+------------------
+
+All firmware packages on the Modules or Interfaces are managed by a special
+Firmware Management Protocol. To support Firmware Management by the AP, the
+Interface Manifest shall at least contain the Firmware Management Bundle and a
+Firmware Management Protocol CPort within it.
+
+The bundle may contain additional CPorts based on the extra functionality
+required to manage firmware packages.
+
+For example, this is how the Firmware Management part of the Interface Manifest
+may look like:
+
+	; Firmware Management Bundle (Bundle 1):
+	[bundle-descriptor 1]
+	class = 0x16
+
+	; (Mandatory) Firmware Management Protocol on CPort 1
+	[cport-descriptor 2]
+	bundle = 1
+	protocol = 0x18
+
+	; (Optional) Firmware Download Protocol on CPort 2
+	[cport-descriptor 1]
+	bundle = 1
+	protocol = 0x17
+
+	; (Optional) SPI protocol on CPort 3
+	[cport-descriptor 3]
+	bundle = 1
+	protocol = 0x0b
+
+	; (Optional) Component Authentication Protocol (CAP) on CPort 4
+	[cport-descriptor 4]
+	bundle = 1
+	protocol = 0x19
+
+
+Sysfs Interfaces - Firmware Management
+--------------------------------------
+
+The Firmware Management Protocol interacts with Userspace using the character
+device interface. The character device will be present in /dev/ directory
+and will be named gb-fw-mgmt-<N>. The number <N> is assigned at runtime.
+
+Identifying the Character Device
+================================
+
+There can be multiple devices present in /dev/ directory with name gb-fw-mgmt-N
+and user first needs to identify the character device used for
+firmware-management for a particular interface.
+
+The Firmware Management core creates a device of class 'gb_fw_mgmt', which shall
+be used by the user to identify the right character device for it. The class
+device is created within the Bundle directory for a particular Interface.
+
+For example this is how the class-device can be present:
+
+/sys/bus/greybus/devices/1-1/1-1.1/1-1.1.1/gb_fw_mgmt/gb-fw-mgmt-0
+
+The last name in this path: gb-fw-mgmt-0 is precisely the name of the char
+device and so the device in this case will be:
+
+/dev/gb-fw-mgmt-0.
+
+Operations on the Char device
+=============================
+
+The Character device (gb-fw-mgmt-0 in example) can be opened by the userspace
+application and it can perform various 'ioctl' operations on the device. The
+device doesn't support any read/write operations.
+
+Following are the IOCTLs and their data structures available to the user:
+
+/* IOCTL support */
+#define GB_FW_LOAD_METHOD_UNIPRO		0x01
+#define GB_FW_LOAD_METHOD_INTERNAL		0x02
+
+#define GB_FW_LOAD_STATUS_FAILED		0x00
+#define GB_FW_LOAD_STATUS_UNVALIDATED		0x01
+#define GB_FW_LOAD_STATUS_VALIDATED		0x02
+#define GB_FW_LOAD_STATUS_VALIDATION_FAILED	0x03
+
+#define GB_FW_BACKEND_FW_STATUS_SUCCESS		0x01
+#define GB_FW_BACKEND_FW_STATUS_FAIL_FIND	0x02
+#define GB_FW_BACKEND_FW_STATUS_FAIL_FETCH	0x03
+#define GB_FW_BACKEND_FW_STATUS_FAIL_WRITE	0x04
+#define GB_FW_BACKEND_FW_STATUS_INT		0x05
+#define GB_FW_BACKEND_FW_STATUS_RETRY		0x06
+#define GB_FW_BACKEND_FW_STATUS_NOT_SUPPORTED	0x07
+
+#define GB_FW_BACKEND_VERSION_STATUS_SUCCESS		0x01
+#define GB_FW_BACKEND_VERSION_STATUS_NOT_AVAILABLE	0x02
+#define GB_FW_BACKEND_VERSION_STATUS_NOT_SUPPORTED	0x03
+#define GB_FW_BACKEND_VERSION_STATUS_RETRY		0x04
+#define GB_FW_BACKEND_VERSION_STATUS_FAIL_INT		0x05
+
+
+struct fw_mgmt_ioc_get_intf_version {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u16 major;
+	__u16 minor;
+} __attribute__ ((__packed__));
+
+struct fw_mgmt_ioc_get_backend_version {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u16 major;
+	__u16 minor;
+	__u8 status;
+} __attribute__ ((__packed__));
+
+struct fw_mgmt_ioc_intf_load_and_validate {
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+	__u8			load_method;
+	__u8			status;
+	__u16			major;
+	__u16			minor;
+} __packed;
+
+struct fw_mgmt_ioc_backend_fw_update {
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+	__u8			status;
+} __packed;
+
+#define FW_MGMT_IOCTL_BASE			'S'
+#define FW_MGMT_IOC_GET_INTF_FW			_IOR(FW_MGMT_IOCTL_BASE, 0, struct fw_mgmt_ioc_get_intf_version)
+#define FW_MGMT_IOC_GET_BACKEND_FW		_IOWR(FW_MGMT_IOCTL_BASE, 1, struct fw_mgmt_ioc_get_backend_version)
+#define FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE	_IOWR(FW_MGMT_IOCTL_BASE, 2, struct fw_mgmt_ioc_intf_load_and_validate)
+#define FW_MGMT_IOC_INTF_BACKEND_FW_UPDATE	_IOWR(FW_MGMT_IOCTL_BASE, 3, struct fw_mgmt_ioc_backend_fw_update)
+#define FW_MGMT_IOC_SET_TIMEOUT_MS		_IOW(FW_MGMT_IOCTL_BASE, 4, unsigned int)
+#define FW_MGMT_IOC_MODE_SWITCH			_IO(FW_MGMT_IOCTL_BASE, 5)
+
+1. FW_MGMT_IOC_GET_INTF_FW:
+
+   This ioctl shall be used by the user to get the version and firmware-tag of
+   the currently running Interface Firmware. All the fields of the 'struct
+   fw_mgmt_ioc_get_fw' are filled by the kernel.
+
+2. FW_MGMT_IOC_GET_BACKEND_FW:
+
+   This ioctl shall be used by the user to get the version of a currently
+   running Backend Interface Firmware identified by a firmware-tag. The user is
+   required to fill the 'firmware_tag' field of the 'struct fw_mgmt_ioc_get_fw'
+   in this case. The 'major' and 'minor' fields are set by the kernel in
+   response.
+
+3. FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE:
+
+   This ioctl shall be used by the user to load an Interface Firmware package on
+   an Interface. The user needs to fill the 'firmware_tag' and 'load_method'
+   fields of the 'struct fw_mgmt_ioc_intf_load_and_validate'. The 'status',
+   'major' and 'minor' fields are set by the kernel in response.
+
+4. FW_MGMT_IOC_INTF_BACKEND_FW_UPDATE:
+
+   This ioctl shall be used by the user to request an Interface to update a
+   Backend Interface Firmware.  The user is required to fill the 'firmware_tag'
+   field of the 'struct fw_mgmt_ioc_get_fw' in this case. The 'status' field is
+   set by the kernel in response.
+
+5. FW_MGMT_IOC_SET_TIMEOUT_MS:
+
+   This ioctl shall be used by the user to increase the timeout interval within
+   which the firmware must get loaded by the Module. The default timeout is 1
+   second. The user needs to pass the timeout in milliseconds.
+
+6. FW_MGMT_IOC_MODE_SWITCH:
+
+   This ioctl shall be used by the user to mode-switch the module to the
+   previously loaded interface firmware. If the interface firmware isn't loaded
+   previously, or if another unsuccessful FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE
+   operation is started after loading interface firmware, then the firmware core
+   wouldn't allow mode-switch.
+
+
+Sysfs Interfaces - Authentication
+---------------------------------
+
+The Component Authentication Protocol interacts with Userspace using the
+character device interface. The character device will be present in /dev/
+directory and will be named gb-authenticate-<N>. The number <N> is assigned at
+runtime.
+
+Identifying the Character Device
+================================
+
+There can be multiple devices present in /dev/ directory with name
+gb-authenticate-N and user first needs to identify the character device used for
+authentication a of particular interface.
+
+The Authentication core creates a device of class 'gb_authenticate', which shall
+be used by the user to identify the right character device for it. The class
+device is created within the Bundle directory for a particular Interface.
+
+For example this is how the class-device can be present:
+
+/sys/bus/greybus/devices/1-1/1-1.1/1-1.1.1/gb_authenticate/gb-authenticate-0
+
+The last name in this path: gb-authenticate-0 is precisely the name of the char
+device and so the device in this case will be:
+
+/dev/gb-authenticate-0.
+
+Operations on the Char device
+=============================
+
+The Character device (/dev/gb-authenticate-0 in above example) can be opened by
+the userspace application and it can perform various 'ioctl' operations on the
+device. The device doesn't support any read/write operations.
+
+Following are the IOCTLs and their data structures available to the user:
+
+#define CAP_CERTIFICATE_MAX_SIZE	1600
+#define CAP_SIGNATURE_MAX_SIZE		320
+
+/* Certificate class types */
+#define CAP_CERT_IMS_EAPC		0x00000001
+#define CAP_CERT_IMS_EASC		0x00000002
+#define CAP_CERT_IMS_EARC		0x00000003
+#define CAP_CERT_IMS_IAPC		0x00000004
+#define CAP_CERT_IMS_IASC		0x00000005
+#define CAP_CERT_IMS_IARC		0x00000006
+
+/* IMS Certificate response result codes */
+#define CAP_IMS_RESULT_CERT_FOUND	0x00
+#define CAP_IMS_RESULT_CERT_CLASS_INVAL	0x01
+#define CAP_IMS_RESULT_CERT_CORRUPT	0x02
+#define CAP_IMS_RESULT_CERT_NOT_FOUND	0x03
+
+/* Authentication types */
+#define CAP_AUTH_IMS_PRI		0x00000001
+#define CAP_AUTH_IMS_SEC		0x00000002
+#define CAP_AUTH_IMS_RSA		0x00000003
+
+/* Authenticate response result codes */
+#define CAP_AUTH_RESULT_CR_SUCCESS	0x00
+#define CAP_AUTH_RESULT_CR_BAD_TYPE	0x01
+#define CAP_AUTH_RESULT_CR_WRONG_EP	0x02
+#define CAP_AUTH_RESULT_CR_NO_KEY	0x03
+#define CAP_AUTH_RESULT_CR_SIG_FAIL	0x04
+
+
+/* IOCTL support */
+struct cap_ioc_get_endpoint_uid {
+	__u8			uid[8];
+} __attribute__ ((__packed__));
+
+struct cap_ioc_get_ims_certificate {
+	__u32			certificate_class;
+	__u32			certificate_id;
+
+	__u8			result_code;
+	__u32			cert_size;
+	__u8			certificate[CAP_CERTIFICATE_MAX_SIZE];
+} __attribute__ ((__packed__));
+
+struct cap_ioc_authenticate {
+	__u32			auth_type;
+	__u8			uid[8];
+	__u8			challenge[32];
+
+	__u8			result_code;
+	__u8			response[64];
+	__u32			signature_size;
+	__u8			signature[CAP_SIGNATURE_MAX_SIZE];
+} __attribute__ ((__packed__));
+
+#define CAP_IOCTL_BASE			'C'
+#define CAP_IOC_GET_ENDPOINT_UID	_IOR(CAP_IOCTL_BASE, 0, struct cap_ioc_get_endpoint_uid)
+#define CAP_IOC_GET_IMS_CERTIFICATE	_IOWR(CAP_IOCTL_BASE, 1, struct cap_ioc_get_ims_certificate)
+#define CAP_IOC_AUTHENTICATE		_IOWR(CAP_IOCTL_BASE, 2, struct cap_ioc_authenticate)
+
+
+1. CAP_IOC_GET_ENDPOINT_UID:
+
+   This ioctl shall be used by the user to get the endpoint UID associated with
+   the Interface.  All the fields of the 'struct cap_ioc_get_endpoint_uid' are
+   filled by the kernel.
+
+2. CAP_IOC_GET_IMS_CERTIFICATE:
+
+   This ioctl shall be used by the user to retrieve one of the available
+   cryptographic certificates held by the Interface for use in Component
+   Authentication. The user is required to fill the 'certificate_class' and
+   'certificate_id' field of the 'struct cap_ioc_get_ims_certificate' in this
+   case. The other fields will be set by the kernel in response. The first
+   'cert_size' bytes of the 'certificate' shall be read by the user and others
+   must be discarded.
+
+3. CAP_IOC_AUTHENTICATE:
+
+   This ioctl shall be used by the user to authenticate the Module attached to
+   an Interface.  The user needs to fill the 'auth_type', 'uid', and 'challenge'
+   fields of the 'struct cap_ioc_authenticate'. The other fields will be set by
+   the kernel in response.  The first 'signature_size' bytes of the 'signature'
+   shall be read by the user and others must be discarded.
+
+
+Sysfs Interfaces - Firmware Download
+------------------------------------
+
+The Firmware Download Protocol uses the existing Linux Kernel's Firmware class
+and the interface provided to userspace are described in:
+Documentation/firmware_class/.
+
+
+Sysfs Interfaces - SPI Flash
+----------------------------
+
+The SPI flash is exposed in userspace as a MTD device and is created
+within the Bundle directory. For example, this is how the path may look like:
+
+$ ls /sys/bus/greybus/devices/1-1/1-1.1/1-1.1.1/spi_master/spi32766/spi32766.0/mtd
+mtd0    mtd0ro
+
+
+Sample Applications
+-------------------
+
+The current directory also provides a firmware.c test application, which can be
+referenced while developing userspace application to talk to firmware-management
+protocol.
+
+The current directory also provides a authenticate.c test application, which can
+be referenced while developing userspace application to talk to
+component authentication protocol.
diff --git a/drivers/staging/greybus/Documentation/firmware/firmware.c b/drivers/staging/greybus/Documentation/firmware/firmware.c
new file mode 100644
index 000000000000..ff9382401030
--- /dev/null
+++ b/drivers/staging/greybus/Documentation/firmware/firmware.c
@@ -0,0 +1,262 @@
+/*
+ * Sample code to test firmware-management protocol
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "../../greybus_firmware.h"
+
+#define FW_DEV_DEFAULT		"/dev/gb-fw-mgmt-0"
+#define FW_TAG_INT_DEFAULT	"s3f"
+#define FW_TAG_BCND_DEFAULT	"bf_01"
+#define FW_UPDATE_TYPE_DEFAULT	0
+#define FW_TIMEOUT_DEFAULT	10000;
+
+static const char *firmware_tag;
+static const char *fwdev = FW_DEV_DEFAULT;
+static int fw_update_type = FW_UPDATE_TYPE_DEFAULT;
+static int fw_timeout = FW_TIMEOUT_DEFAULT;
+
+static struct fw_mgmt_ioc_get_intf_version intf_fw_info;
+static struct fw_mgmt_ioc_get_backend_version backend_fw_info;
+static struct fw_mgmt_ioc_intf_load_and_validate intf_load;
+static struct fw_mgmt_ioc_backend_fw_update backend_update;
+
+static void usage(void)
+{
+	printf("\nUsage: ./firmware <gb-fw-mgmt-X (default: gb-fw-mgmt-0)> <interface: 0, backend: 1 (default: 0)> <firmware-tag> (default: \"s3f\"/\"bf_01\") <timeout (default: 10000 ms)>\n");
+}
+
+static int update_intf_firmware(int fd)
+{
+	int ret;
+
+	/* Get Interface Firmware Version */
+	printf("Get Interface Firmware Version\n");
+
+	ret = ioctl(fd, FW_MGMT_IOC_GET_INTF_FW, &intf_fw_info);
+	if (ret < 0) {
+		printf("Failed to get interface firmware version: %s (%d)\n",
+			fwdev, ret);
+		return -1;
+	}
+
+	printf("Interface Firmware tag (%s), major (%d), minor (%d)\n",
+		intf_fw_info.firmware_tag, intf_fw_info.major,
+		intf_fw_info.minor);
+
+	/* Try Interface Firmware load over Unipro */
+	printf("Loading Interface Firmware\n");
+
+	intf_load.load_method = GB_FW_U_LOAD_METHOD_UNIPRO;
+	intf_load.status = 0;
+	intf_load.major = 0;
+	intf_load.minor = 0;
+
+	strncpy((char *)&intf_load.firmware_tag, firmware_tag,
+		GB_FIRMWARE_U_TAG_MAX_SIZE);
+
+	ret = ioctl(fd, FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE, &intf_load);
+	if (ret < 0) {
+		printf("Failed to load interface firmware: %s (%d)\n", fwdev,
+			ret);
+		return -1;
+	}
+
+	if (intf_load.status != GB_FW_U_LOAD_STATUS_VALIDATED &&
+	    intf_load.status != GB_FW_U_LOAD_STATUS_UNVALIDATED) {
+		printf("Load status says loading failed: %d\n",
+			intf_load.status);
+		return -1;
+	}
+
+	printf("Interface Firmware (%s) Load done: major: %d, minor: %d, status: %d\n",
+		firmware_tag, intf_load.major, intf_load.minor,
+		intf_load.status);
+
+	/* Initiate Mode-switch to the newly loaded firmware */
+	printf("Initiate Mode switch\n");
+
+	ret = ioctl(fd, FW_MGMT_IOC_MODE_SWITCH);
+	if (ret < 0)
+		printf("Failed to initiate mode-switch (%d)\n", ret);
+
+	return ret;
+}
+
+static int update_backend_firmware(int fd)
+{
+	int ret;
+
+	/* Get Backend Firmware Version */
+	printf("Getting Backend Firmware Version\n");
+
+	strncpy((char *)&backend_fw_info.firmware_tag, firmware_tag,
+		GB_FIRMWARE_U_TAG_MAX_SIZE);
+
+retry_fw_version:
+	ret = ioctl(fd, FW_MGMT_IOC_GET_BACKEND_FW, &backend_fw_info);
+	if (ret < 0) {
+		printf("Failed to get backend firmware version: %s (%d)\n",
+			fwdev, ret);
+		return -1;
+	}
+
+	printf("Backend Firmware tag (%s), major (%d), minor (%d), status (%d)\n",
+		backend_fw_info.firmware_tag, backend_fw_info.major,
+		backend_fw_info.minor, backend_fw_info.status);
+
+	if (backend_fw_info.status == GB_FW_U_BACKEND_VERSION_STATUS_RETRY)
+		goto retry_fw_version;
+
+	if ((backend_fw_info.status != GB_FW_U_BACKEND_VERSION_STATUS_SUCCESS)
+	    && (backend_fw_info.status != GB_FW_U_BACKEND_VERSION_STATUS_NOT_AVAILABLE)) {
+		printf("Failed to get backend firmware version: %s (%d)\n",
+			fwdev, backend_fw_info.status);
+		return -1;
+	}
+
+	/* Try Backend Firmware Update over Unipro */
+	printf("Updating Backend Firmware\n");
+
+	strncpy((char *)&backend_update.firmware_tag, firmware_tag,
+		GB_FIRMWARE_U_TAG_MAX_SIZE);
+
+retry_fw_update:
+	backend_update.status = 0;
+
+	ret = ioctl(fd, FW_MGMT_IOC_INTF_BACKEND_FW_UPDATE, &backend_update);
+	if (ret < 0) {
+		printf("Failed to load backend firmware: %s (%d)\n", fwdev, ret);
+		return -1;
+	}
+
+	if (backend_update.status == GB_FW_U_BACKEND_FW_STATUS_RETRY) {
+		printf("Retrying firmware update: %d\n", backend_update.status);
+		goto retry_fw_update;
+	}
+
+	if (backend_update.status != GB_FW_U_BACKEND_FW_STATUS_SUCCESS) {
+		printf("Load status says loading failed: %d\n",
+			backend_update.status);
+	} else {
+		printf("Backend Firmware (%s) Load done: status: %d\n",
+				firmware_tag, backend_update.status);
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int fd, ret;
+
+	if (argc > 1 &&
+	    (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))) {
+		usage();
+		return -1;
+	}
+
+	if (argc > 1)
+		fwdev = argv[1];
+
+	if (argc > 2)
+		sscanf(argv[2], "%u", &fw_update_type);
+
+	if (argc > 3) {
+		firmware_tag = argv[3];
+	} else if (!fw_update_type) {
+		firmware_tag = FW_TAG_INT_DEFAULT;
+	} else {
+		firmware_tag = FW_TAG_BCND_DEFAULT;
+	}
+
+	if (argc > 4)
+		sscanf(argv[4], "%u", &fw_timeout);
+
+	printf("Trying Firmware update: fwdev: %s, type: %s, tag: %s, timeout: %d\n",
+		fwdev, fw_update_type == 0 ? "interface" : "backend",
+		firmware_tag, fw_timeout);
+
+	printf("Opening %s firmware management device\n", fwdev);
+
+	fd = open(fwdev, O_RDWR);
+	if (fd < 0) {
+		printf("Failed to open: %s\n", fwdev);
+		return -1;
+	}
+
+	/* Set Timeout */
+	printf("Setting timeout to %u ms\n", fw_timeout);
+
+	ret = ioctl(fd, FW_MGMT_IOC_SET_TIMEOUT_MS, &fw_timeout);
+	if (ret < 0) {
+		printf("Failed to set timeout: %s (%d)\n", fwdev, ret);
+		ret = -1;
+		goto close_fd;
+	}
+
+	if (!fw_update_type)
+		ret = update_intf_firmware(fd);
+	else
+		ret = update_backend_firmware(fd);
+
+close_fd:
+	close(fd);
+
+	return ret;
+}
diff --git a/drivers/staging/greybus/Documentation/sysfs-bus-greybus b/drivers/staging/greybus/Documentation/sysfs-bus-greybus
new file mode 100644
index 000000000000..2e998966cbe1
--- /dev/null
+++ b/drivers/staging/greybus/Documentation/sysfs-bus-greybus
@@ -0,0 +1,275 @@
+What:		/sys/bus/greybus/devices/greybusN
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The "root" greybus device for the Greybus device tree, or bus,
+		where N is a dynamically assigned 1-based id.
+
+What:		/sys/bus/greybus/devices/greybusN/bus_id
+Date:		April 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The ID of the "root" greybus device, or bus.
+
+What:		/sys/bus/greybus/devices/N-M
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		A Module M on the bus N, where M is the 1-byte interface
+		ID of the module's primary interface.
+
+What:		/sys/bus/greybus/devices/N-M/eject
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Writing a non-zero argument to this attibute disables the
+		module's interfaces before physically ejecting it.
+
+What:		/sys/bus/greybus/devices/N-M/module_id
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The ID of a Greybus module, corresponding to the ID of its
+		primary interface.
+
+What:		/sys/bus/greybus/devices/N-M/num_interfaces
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The number of interfaces of a module.
+
+What:		/sys/bus/greybus/devices/N-M.I
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		An Interface I on the bus N and module N-M, where I is the
+		1-byte interface ID.
+
+What:		/sys/bus/greybus/devices/N-M.I/current_now
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Current measurement of the interface in microamps (uA)
+
+What:		/sys/bus/greybus/devices/N-M.I/ddbl1_manufacturer_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Unipro Device Descriptor Block Level 1 manufacturer ID for the
+		greybus Interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/ddbl1_product_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Unipro Device Descriptor Block Level 1 product ID for the
+		greybus Interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/interface_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The ID of a Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/interface_type
+Date:		June 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The type of a Greybus interface; "dummy", "unipro", "greybus",
+		or "unknown".
+
+What:		/sys/bus/greybus/devices/N-M.I/power_now
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Power measurement of the interface in microwatts (uW)
+
+What:		/sys/bus/greybus/devices/N-M.I/power_state
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		This file reflects the power state of a Greybus interface. If
+		the value read from it is "on", then power is currently
+		supplied to the interface. Otherwise it will read "off" and
+		power is currently not supplied to the interface.
+
+		If the value read is "off", then writing "on" (or '1', 'y',
+		'Y') to this file will enable power to the interface and an
+		attempt to boot and possibly enumerate it will be made. Note
+		that on errors, the interface will again be powered down.
+
+		If the value read is "on", then writing "off" (or '0', 'n',
+		'N') to this file will power down the interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/product_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Product ID of a Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/serial_number
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Serial Number of the Greybus interface, represented by a 64 bit
+		hexadecimal number.
+
+What:		/sys/bus/greybus/devices/N-M.I/vendor_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Vendor ID of a Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I/voltage_now
+Date:		March 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Voltage measurement of the interface in microvolts (uV)
+
+What:		/sys/bus/greybus/devices/N-M.I.ctrl
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Abstract control device for interface I that represents the
+		current mode of an enumerated Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I.ctrl/product_string
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Product ID string of a Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I.ctrl/vendor_string
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Vendor ID string of a Greybus interface.
+
+What:		/sys/bus/greybus/devices/N-M.I.B
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		A bundle B on the Interface I, B is replaced by a 1-byte
+		number representing the bundle.
+
+What:		/sys/bus/greybus/devices/N-M.I.B/bundle_class
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The greybus class of the bundle B.
+
+What:		/sys/bus/greybus/devices/N-M.I.B/bundle_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The interface-unique id of the bundle B.
+
+What:		/sys/bus/greybus/devices/N-M.I.B/gpbX
+Date:		April 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The General Purpose Bridged PHY device of the bundle B,
+		where X is a dynamically assigned 0-based id.
+
+What:		/sys/bus/greybus/devices/N-M.I.B/state
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		A bundle has a state that is managed by the userspace
+		Endo process.  This file allows that Endo to signal
+		other Android HALs that the state of the bundle has
+		changed to a specific value.  When written to, any
+		process watching the file will be woken up, and the new
+		value can be read. It's a "poor-man's IPC", yes, but
+		simplifies the Android userspace code immensely.
+
+What:		/sys/bus/greybus/devices/N-svc
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The singleton SVC device of bus N.
+
+What:		/sys/bus/greybus/devices/N-svc/ap_intf_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The AP interface ID, a 1-byte non-zero integer which
+		defines the position of the AP module on the frame.
+		The interface positions are defined in the GMP
+		Module Developer Kit.
+
+What:		/sys/bus/greybus/devices/N-svc/endo_id
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The Endo ID, which is a 2-byte hexadecimal value
+		defined by the Endo layout scheme, documented in
+		the GMP Module Developer Kit.
+
+What:		/sys/bus/greybus/devices/N-svc/intf_eject
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		Write the number of the interface that you wish to
+		forcibly eject from the system.
+
+What:		/sys/bus/greybus/devices/N-svc/version
+Date:		October 2015
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		The version number of the firmware in the SVC device.
+
+What:		/sys/bus/greybus/devices/N-svc/watchdog
+Date:		October 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		If the SVC watchdog is enabled or not.  Writing 0 to this
+		file will disable the watchdog, writing 1 will enable it.
+
+What:		/sys/bus/greybus/devices/N-svc/watchdog_action
+Date:		July 2016
+KernelVersion:	4.XX
+Contact:	Greg Kroah-Hartman <greg@kroah.com>
+Description:
+		This attribute indicates the action to be performed upon SVC
+		watchdog bite.
+
+		The action can be one of the "reset" or "panic". Writing either
+		one of the "reset" or "panic" will change the behavior of SVC
+		watchdog bite. Default value is "reset".
+
+		"reset" means the UniPro subsystem is to be reset.
+
+		"panic" means SVC watchdog bite will cause kernel to panic.
diff --git a/drivers/staging/greybus/Kconfig b/drivers/staging/greybus/Kconfig
new file mode 100644
index 000000000000..89c49767d247
--- /dev/null
+++ b/drivers/staging/greybus/Kconfig
@@ -0,0 +1,219 @@
+menuconfig GREYBUS
+	tristate "Greybus support"
+	depends on SYSFS
+	---help---
+	  This option enables the Greybus driver core.  Greybus is an
+	  hardware protocol that was designed to provide Unipro with a
+	  sane application layer.  It was originally designed for the
+	  ARA project, a module phone system, but has shown up in other
+	  phones, and can be tunneled over other busses in order to
+	  control hardware devices.
+
+	  Say Y here to enable support for these types of drivers.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called greybus.ko
+
+if GREYBUS
+
+config GREYBUS_ES2
+	tristate "Greybus ES3 USB host controller"
+	depends on USB
+	---help---
+	  Select this option if you have a Toshiba ES3 USB device that
+	  acts as a Greybus "host controller".  This device is a bridge
+	  from a USB device to a Unipro network.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-es2.ko
+
+config GREYBUS_AUDIO
+	tristate "Greybus Audio Class driver"
+	depends on SOUND
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Audio Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-audio.ko
+
+config GREYBUS_BOOTROM
+	tristate "Greybus Bootrom Class driver"
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Bootrom Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-bootrom.ko
+
+config GREYBUS_CAMERA
+	tristate "Greybus Camera Class driver"
+	depends on MEDIA && LEDS_CLASS_FLASH && BROKEN
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Camera Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-camera.ko
+
+config GREYBUS_FIRMWARE
+	tristate "Greybus Firmware Download Class driver"
+	depends on SPI
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Firmware Download Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-firmware.ko
+
+config GREYBUS_HID
+	tristate "Greybus HID Class driver"
+	depends on HID && INPUT
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus HID Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-hid.ko
+
+config GREYBUS_LIGHT
+	tristate "Greybus LED Class driver"
+	depends on LEDS_CLASS
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus LED Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-light.ko
+
+config GREYBUS_LOG
+	tristate "Greybus Debug Log Class driver"
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Debug Log Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-log.ko
+
+config GREYBUS_LOOPBACK
+	tristate "Greybus Loopback Class driver"
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Debug Log Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-log.ko
+
+config GREYBUS_POWER
+	tristate "Greybus Powersupply Class driver"
+	depends on POWER_SUPPLY
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Powersupply Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-power-supply.ko
+
+config GREYBUS_RAW
+	tristate "Greybus Raw Class driver"
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Raw Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-raw.ko
+
+config GREYBUS_VIBRATOR
+	tristate "Greybus Vibrator Motor Class driver"
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus Vibrator Motor Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-vibrator.ko
+
+menuconfig GREYBUS_BRIDGED_PHY
+	tristate "Greybus Bridged PHY Class drivers"
+	---help---
+	  Select this option to pick from a variety of Greybus Bridged
+	  PHY class drivers.  These drivers emulate a number of
+	  different "traditional" busses by tunneling them over Greybus.
+	  Examples of this include serial, SPI, USB, and others.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-phy.ko
+
+if GREYBUS_BRIDGED_PHY
+
+config GREYBUS_GPIO
+	tristate "Greybus GPIO Bridged PHY driver"
+	depends on GPIOLIB
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus GPIO Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-gpio.ko
+
+config GREYBUS_I2C
+	tristate "Greybus I2C Bridged PHY driver"
+	depends on I2C
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus I2C Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-i2c.ko
+
+config GREYBUS_PWM
+	tristate "Greybus PWM Bridged PHY driver"
+	depends on PWM
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus PWM Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-pwm.ko
+
+config GREYBUS_SDIO
+	tristate "Greybus SDIO Bridged PHY driver"
+	depends on MMC
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus SDIO Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-sdio.ko
+
+config GREYBUS_SPI
+	tristate "Greybus SPI Bridged PHY driver"
+	depends on SPI
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus SPI Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-spi.ko
+
+config GREYBUS_UART
+	tristate "Greybus UART Bridged PHY driver"
+	depends on TTY
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus UART Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-uart.ko
+
+config GREYBUS_USB
+	tristate "Greybus USB Host Bridged PHY driver"
+	depends on USB
+	---help---
+	  Select this option if you have a device that follows the
+	  Greybus USB Host Bridged PHY Class specification.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called gb-usb.ko
+
+endif	# GREYBUS_BRIDGED_PHY
+endif	# GREYBUS
diff --git a/drivers/staging/greybus/Makefile b/drivers/staging/greybus/Makefile
new file mode 100644
index 000000000000..f337b7b70782
--- /dev/null
+++ b/drivers/staging/greybus/Makefile
@@ -0,0 +1,96 @@
+# Greybus core
+greybus-y :=	core.o		\
+		debugfs.o	\
+		hd.o		\
+		manifest.o	\
+		module.o	\
+		interface.o	\
+		bundle.o	\
+		connection.o	\
+		control.o	\
+		svc.o		\
+		svc_watchdog.o	\
+		operation.o	\
+		timesync.o	\
+		timesync_platform.o
+
+obj-$(CONFIG_GREYBUS)		+= greybus.o
+
+# needed for trace events
+ccflags-y += -I$(src)
+
+
+# Greybus Host controller drivers
+gb-es2-y := es2.o
+
+obj-$(CONFIG_GREYBUS_ES2)	+= gb-es2.o
+
+# Greybus class drivers
+gb-bootrom-y		:= bootrom.o
+gb-camera-y		:= camera.o
+gb-firmware-y		:= fw-core.o fw-download.o fw-management.o authentication.o
+gb-spilib-y		:= spilib.o
+gb-hid-y		:= hid.o
+gb-light-y		:= light.o
+gb-log-y		:= log.o
+gb-loopback-y		:= loopback.o
+gb-power-supply-y	:= power_supply.o
+gb-raw-y		:= raw.o
+gb-vibrator-y		:= vibrator.o
+
+obj-$(CONFIG_GREYBUS_BOOTROM)	+= gb-bootrom.o
+obj-$(CONFIG_GREYBUS_CAMERA)	+= gb-camera.o
+obj-$(CONFIG_GREYBUS_FIRMWARE)	+= gb-firmware.o gb-spilib.o
+obj-$(CONFIG_GREYBUS_HID)	+= gb-hid.o
+obj-$(CONFIG_GREYBUS_LIGHT)	+= gb-light.o
+obj-$(CONFIG_GREYBUS_LOG)	+= gb-log.o
+obj-$(CONFIG_GREYBUS_LOOPBACK)	+= gb-loopback.o
+obj-$(CONFIG_GREYBUS_POWER)	+= gb-power-supply.o
+obj-$(CONFIG_GREYBUS_RAW)	+= gb-raw.o
+obj-$(CONFIG_GREYBUS_VIBRATOR)	+= gb-vibrator.o
+
+# Greybus Audio is a bunch of modules
+gb-audio-module-y	:= audio_module.o audio_topology.o
+gb-audio-codec-y	:= audio_codec.o
+gb-audio-gb-y		:= audio_gb.o
+gb-audio-apbridgea-y	:= audio_apbridgea.o
+gb-audio-manager-y	:= audio_manager.o audio_manager_module.o
+
+# Greybus Audio sysfs helpers can be useful when debugging
+#GB_AUDIO_MANAGER_SYSFS ?= true
+#ifeq ($(GB_AUDIO_MANAGER_SYSFS),true)
+#gb-audio-manager-y += audio_manager_sysfs.o
+#ccflags-y += -DGB_AUDIO_MANAGER_SYSFS
+#endif
+
+obj-$(CONFIG_GREYBUS_AUDIO_MSM8994)	+= gb-audio-codec.o
+obj-$(CONFIG_GREYBUS_AUDIO_MSM8994)	+= gb-audio-module.o
+obj-$(CONFIG_GREYBUS_AUDIO)		+= gb-audio-gb.o
+obj-$(CONFIG_GREYBUS_AUDIO)		+= gb-audio-apbridgea.o
+obj-$(CONFIG_GREYBUS_AUDIO)		+= gb-audio-manager.o
+
+
+# Greybus Bridged PHY drivers
+gb-gbphy-y := gbphy.o
+gb-gpio-y := gpio.o
+gb-i2c-y := i2c.o
+gb-pwm-y := pwm.o
+gb-sdio-y := sdio.o
+gb-spi-y := spi.o
+gb-uart-y := uart.o
+gb-usb-y := usb.o
+
+obj-$(CONFIG_GREYBUS_BRIDGED_PHY)	+= gb-gbphy.o
+obj-$(CONFIG_GREYBUS_GPIO)		+= gb-gpio.o
+obj-$(CONFIG_GREYBUS_I2C)		+= gb-i2c.o
+obj-$(CONFIG_GREYBUS_PWM)		+= gb-pwm.o
+obj-$(CONFIG_GREYBUS_SDIO)		+= gb-sdio.o
+obj-$(CONFIG_GREYBUS_SPI)		+= gb-spi.o gb-spilib.o
+obj-$(CONFIG_GREYBUS_UART)		+= gb-uart.o
+obj-$(CONFIG_GREYBUS_USB)		+= gb-usb.o
+
+
+# Greybus Platform driver
+gb-arche-y	:= arche-platform.o arche-apb-ctrl.o
+
+obj-$(CONFIG_USB_HSIC_USB3613)	+= gb-arche.o
diff --git a/drivers/staging/greybus/arche-apb-ctrl.c b/drivers/staging/greybus/arche-apb-ctrl.c
new file mode 100644
index 000000000000..59d9d422cf04
--- /dev/null
+++ b/drivers/staging/greybus/arche-apb-ctrl.c
@@ -0,0 +1,522 @@
+/*
+ * Arche Platform driver to control APB.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spinlock.h>
+#include "arche_platform.h"
+
+
+struct arche_apb_ctrl_drvdata {
+	/* Control GPIO signals to and from AP <=> AP Bridges */
+	int resetn_gpio;
+	int boot_ret_gpio;
+	int pwroff_gpio;
+	int wake_in_gpio;
+	int wake_out_gpio;
+	int pwrdn_gpio;
+
+	enum arche_platform_state state;
+	bool init_disabled;
+
+	struct regulator *vcore;
+	struct regulator *vio;
+
+	int clk_en_gpio;
+	struct clk *clk;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pin_default;
+
+	/* V2: SPI Bus control  */
+	int spi_en_gpio;
+	bool spi_en_polarity_high;
+};
+
+/*
+ * Note that these low level api's are active high
+ */
+static inline void deassert_reset(unsigned int gpio)
+{
+	gpio_set_value(gpio, 1);
+}
+
+static inline void assert_reset(unsigned int gpio)
+{
+	gpio_set_value(gpio, 0);
+}
+
+/*
+ * Note: Please do not modify the below sequence, as it is as per the spec
+ */
+static int coldboot_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret;
+
+	if (apb->init_disabled ||
+			apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
+		return 0;
+
+	/* Hold APB in reset state */
+	assert_reset(apb->resetn_gpio);
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/* Enable power to APB */
+	if (!IS_ERR(apb->vcore)) {
+		ret = regulator_enable(apb->vcore);
+		if (ret) {
+			dev_err(dev, "failed to enable core regulator\n");
+			return ret;
+		}
+	}
+
+	if (!IS_ERR(apb->vio)) {
+		ret = regulator_enable(apb->vio);
+		if (ret) {
+			dev_err(dev, "failed to enable IO regulator\n");
+			return ret;
+		}
+	}
+
+	apb_bootret_deassert(dev);
+
+	/* On DB3 clock was not mandatory */
+	if (gpio_is_valid(apb->clk_en_gpio))
+		gpio_set_value(apb->clk_en_gpio, 1);
+
+	usleep_range(100, 200);
+
+	/* deassert reset to APB : Active-low signal */
+	deassert_reset(apb->resetn_gpio);
+
+	apb->state = ARCHE_PLATFORM_STATE_ACTIVE;
+
+	return 0;
+}
+
+static int fw_flashing_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret;
+
+	if (apb->init_disabled ||
+			apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+		return 0;
+
+	ret = regulator_enable(apb->vcore);
+	if (ret) {
+		dev_err(dev, "failed to enable core regulator\n");
+		return ret;
+	}
+
+	ret = regulator_enable(apb->vio);
+	if (ret) {
+		dev_err(dev, "failed to enable IO regulator\n");
+		return ret;
+	}
+
+	if (gpio_is_valid(apb->spi_en_gpio)) {
+		unsigned long flags;
+
+		if (apb->spi_en_polarity_high)
+			flags = GPIOF_OUT_INIT_HIGH;
+		else
+			flags = GPIOF_OUT_INIT_LOW;
+
+		ret = devm_gpio_request_one(dev, apb->spi_en_gpio,
+				flags, "apb_spi_en");
+		if (ret) {
+			dev_err(dev, "Failed requesting SPI bus en gpio %d\n",
+				apb->spi_en_gpio);
+			return ret;
+		}
+	}
+
+	/* for flashing device should be in reset state */
+	assert_reset(apb->resetn_gpio);
+	apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
+
+	return 0;
+}
+
+static int standby_boot_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+
+	if (apb->init_disabled)
+		return 0;
+
+	/* Even if it is in OFF state, then we do not want to change the state */
+	if (apb->state == ARCHE_PLATFORM_STATE_STANDBY ||
+			apb->state == ARCHE_PLATFORM_STATE_OFF)
+		return 0;
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/*
+	 * As per WDM spec, do nothing
+	 *
+	 * Pasted from WDM spec,
+	 *  - A falling edge on POWEROFF_L is detected (a)
+	 *  - WDM enters standby mode, but no output signals are changed
+	 * */
+
+	/* TODO: POWEROFF_L is input to WDM module  */
+	apb->state = ARCHE_PLATFORM_STATE_STANDBY;
+	return 0;
+}
+
+static void poweroff_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+
+	if (apb->init_disabled || apb->state == ARCHE_PLATFORM_STATE_OFF)
+		return;
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/* disable the clock */
+	if (gpio_is_valid(apb->clk_en_gpio))
+		gpio_set_value(apb->clk_en_gpio, 0);
+
+	if (!IS_ERR(apb->vcore) && regulator_is_enabled(apb->vcore) > 0)
+		regulator_disable(apb->vcore);
+
+	if (!IS_ERR(apb->vio) && regulator_is_enabled(apb->vio) > 0)
+		regulator_disable(apb->vio);
+
+	/* As part of exit, put APB back in reset state */
+	assert_reset(apb->resetn_gpio);
+	apb->state = ARCHE_PLATFORM_STATE_OFF;
+
+	/* TODO: May have to send an event to SVC about this exit */
+}
+
+void apb_bootret_assert(struct device *dev)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	gpio_set_value(apb->boot_ret_gpio, 1);
+}
+
+void apb_bootret_deassert(struct device *dev)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	gpio_set_value(apb->boot_ret_gpio, 0);
+}
+
+int apb_ctrl_coldboot(struct device *dev)
+{
+	return coldboot_seq(to_platform_device(dev));
+}
+
+int apb_ctrl_fw_flashing(struct device *dev)
+{
+	return fw_flashing_seq(to_platform_device(dev));
+}
+
+int apb_ctrl_standby_boot(struct device *dev)
+{
+	return standby_boot_seq(to_platform_device(dev));
+}
+
+void apb_ctrl_poweroff(struct device *dev)
+{
+	poweroff_seq(to_platform_device(dev));
+}
+
+static ssize_t state_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret = 0;
+	bool is_disabled;
+
+	if (sysfs_streq(buf, "off")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_OFF)
+			return count;
+
+		poweroff_seq(pdev);
+	} else if (sysfs_streq(buf, "active")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
+			return count;
+
+		poweroff_seq(pdev);
+		is_disabled = apb->init_disabled;
+		apb->init_disabled = false;
+		ret = coldboot_seq(pdev);
+		if (ret)
+			apb->init_disabled = is_disabled;
+	} else if (sysfs_streq(buf, "standby")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_STANDBY)
+			return count;
+
+		ret = standby_boot_seq(pdev);
+	} else if (sysfs_streq(buf, "fw_flashing")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+			return count;
+
+		/* First we want to make sure we power off everything
+		 * and then enter FW flashing state */
+		poweroff_seq(pdev);
+		ret = fw_flashing_seq(pdev);
+	} else {
+		dev_err(dev, "unknown state\n");
+		ret = -EINVAL;
+	}
+
+	return ret ? ret : count;
+}
+
+static ssize_t state_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	switch (apb->state) {
+	case ARCHE_PLATFORM_STATE_OFF:
+		return sprintf(buf, "off%s\n",
+				apb->init_disabled ? ",disabled" : "");
+	case ARCHE_PLATFORM_STATE_ACTIVE:
+		return sprintf(buf, "active\n");
+	case ARCHE_PLATFORM_STATE_STANDBY:
+		return sprintf(buf, "standby\n");
+	case ARCHE_PLATFORM_STATE_FW_FLASHING:
+		return sprintf(buf, "fw_flashing\n");
+	default:
+		return sprintf(buf, "unknown state\n");
+	}
+}
+
+static DEVICE_ATTR_RW(state);
+
+static int apb_ctrl_get_devtree_data(struct platform_device *pdev,
+		struct arche_apb_ctrl_drvdata *apb)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	apb->resetn_gpio = of_get_named_gpio(np, "reset-gpios", 0);
+	if (apb->resetn_gpio < 0) {
+		dev_err(dev, "failed to get reset gpio\n");
+		return apb->resetn_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->resetn_gpio,
+			GPIOF_OUT_INIT_LOW, "apb-reset");
+	if (ret) {
+		dev_err(dev, "Failed requesting reset gpio %d\n",
+				apb->resetn_gpio);
+		return ret;
+	}
+
+	apb->boot_ret_gpio = of_get_named_gpio(np, "boot-ret-gpios", 0);
+	if (apb->boot_ret_gpio < 0) {
+		dev_err(dev, "failed to get boot retention gpio\n");
+		return apb->boot_ret_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->boot_ret_gpio,
+			GPIOF_OUT_INIT_LOW, "boot retention");
+	if (ret) {
+		dev_err(dev, "Failed requesting bootret gpio %d\n",
+				apb->boot_ret_gpio);
+		return ret;
+	}
+
+	/* It's not mandatory to support power management interface */
+	apb->pwroff_gpio = of_get_named_gpio(np, "pwr-off-gpios", 0);
+	if (apb->pwroff_gpio < 0) {
+		dev_err(dev, "failed to get power off gpio\n");
+		return apb->pwroff_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->pwroff_gpio,
+			GPIOF_IN, "pwroff_n");
+	if (ret) {
+		dev_err(dev, "Failed requesting pwroff_n gpio %d\n",
+				apb->pwroff_gpio);
+		return ret;
+	}
+
+	/* Do not make clock mandatory as of now (for DB3) */
+	apb->clk_en_gpio = of_get_named_gpio(np, "clock-en-gpio", 0);
+	if (apb->clk_en_gpio < 0) {
+		dev_warn(dev, "failed to get clock en gpio\n");
+	} else if (gpio_is_valid(apb->clk_en_gpio)) {
+		ret = devm_gpio_request_one(dev, apb->clk_en_gpio,
+				GPIOF_OUT_INIT_LOW, "apb_clk_en");
+		if (ret) {
+			dev_warn(dev, "Failed requesting APB clock en gpio %d\n",
+					apb->clk_en_gpio);
+			return ret;
+		}
+	}
+
+	apb->pwrdn_gpio = of_get_named_gpio(np, "pwr-down-gpios", 0);
+	if (apb->pwrdn_gpio < 0)
+		dev_warn(dev, "failed to get power down gpio\n");
+
+	/* Regulators are optional, as we may have fixed supply coming in */
+	apb->vcore = devm_regulator_get(dev, "vcore");
+	if (IS_ERR(apb->vcore))
+		dev_warn(dev, "no core regulator found\n");
+
+	apb->vio = devm_regulator_get(dev, "vio");
+	if (IS_ERR(apb->vio))
+		dev_warn(dev, "no IO regulator found\n");
+
+	apb->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(apb->pinctrl)) {
+		dev_err(&pdev->dev, "could not get pinctrl handle\n");
+		return PTR_ERR(apb->pinctrl);
+	}
+	apb->pin_default = pinctrl_lookup_state(apb->pinctrl, "default");
+	if (IS_ERR(apb->pin_default)) {
+		dev_err(&pdev->dev, "could not get default pin state\n");
+		return PTR_ERR(apb->pin_default);
+	}
+
+	/* Only applicable for platform >= V2 */
+	apb->spi_en_gpio = of_get_named_gpio(np, "spi-en-gpio", 0);
+	if (apb->spi_en_gpio >= 0) {
+		if (of_property_read_bool(pdev->dev.of_node,
+					"spi-en-active-high"))
+			apb->spi_en_polarity_high = true;
+	}
+
+	return 0;
+}
+
+static int arche_apb_ctrl_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct arche_apb_ctrl_drvdata *apb;
+	struct device *dev = &pdev->dev;
+
+	apb = devm_kzalloc(&pdev->dev, sizeof(*apb), GFP_KERNEL);
+	if (!apb)
+		return -ENOMEM;
+
+	ret = apb_ctrl_get_devtree_data(pdev, apb);
+	if (ret) {
+		dev_err(dev, "failed to get apb devicetree data %d\n", ret);
+		return ret;
+	}
+
+	/* Initially set APB to OFF state */
+	apb->state = ARCHE_PLATFORM_STATE_OFF;
+	/* Check whether device needs to be enabled on boot */
+	if (of_property_read_bool(pdev->dev.of_node, "arche,init-disable"))
+		apb->init_disabled = true;
+
+	platform_set_drvdata(pdev, apb);
+
+	/* Create sysfs interface to allow user to change state dynamically */
+	ret = device_create_file(dev, &dev_attr_state);
+	if (ret) {
+		dev_err(dev, "failed to create state file in sysfs\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "Device registered successfully\n");
+	return 0;
+}
+
+static int arche_apb_ctrl_remove(struct platform_device *pdev)
+{
+	device_remove_file(&pdev->dev, &dev_attr_state);
+	poweroff_seq(pdev);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static int arche_apb_ctrl_suspend(struct device *dev)
+{
+	/*
+	 * If timing profile permits, we may shutdown bridge
+	 * completely
+	 *
+	 * TODO: sequence ??
+	 *
+	 * Also, need to make sure we meet precondition for unipro suspend
+	 * Precondition: Definition ???
+	 */
+	return 0;
+}
+
+static int arche_apb_ctrl_resume(struct device *dev)
+{
+	/*
+	 * Atleast for ES2 we have to meet the delay requirement between
+	 * unipro switch and AP bridge init, depending on whether bridge is in
+	 * OFF state or standby state.
+	 *
+	 * Based on whether bridge is in standby or OFF state we may have to
+	 * assert multiple signals. Please refer to WDM spec, for more info.
+	 *
+	 */
+	return 0;
+}
+
+static void arche_apb_ctrl_shutdown(struct platform_device *pdev)
+{
+	apb_ctrl_poweroff(&pdev->dev);
+}
+
+static SIMPLE_DEV_PM_OPS(arche_apb_ctrl_pm_ops, arche_apb_ctrl_suspend,
+			 arche_apb_ctrl_resume);
+
+static struct of_device_id arche_apb_ctrl_of_match[] = {
+	{ .compatible = "usbffff,2", },
+	{ },
+};
+
+static struct platform_driver arche_apb_ctrl_device_driver = {
+	.probe		= arche_apb_ctrl_probe,
+	.remove		= arche_apb_ctrl_remove,
+	.shutdown	= arche_apb_ctrl_shutdown,
+	.driver		= {
+		.name	= "arche-apb-ctrl",
+		.pm	= &arche_apb_ctrl_pm_ops,
+		.of_match_table = arche_apb_ctrl_of_match,
+	}
+};
+
+int __init arche_apb_init(void)
+{
+	return platform_driver_register(&arche_apb_ctrl_device_driver);
+}
+
+void __exit arche_apb_exit(void)
+{
+	platform_driver_unregister(&arche_apb_ctrl_device_driver);
+}
diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
new file mode 100644
index 000000000000..9d9048e6aed3
--- /dev/null
+++ b/drivers/staging/greybus/arche-platform.c
@@ -0,0 +1,828 @@
+/*
+ * Arche Platform driver to enable Unipro link.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/suspend.h>
+#include <linux/time.h>
+#include "arche_platform.h"
+#include "greybus.h"
+
+#include <linux/usb/usb3613.h>
+
+#define WD_COLDBOOT_PULSE_WIDTH_MS	30
+
+enum svc_wakedetect_state {
+	WD_STATE_IDLE,			/* Default state = pulled high/low */
+	WD_STATE_BOOT_INIT,		/* WD = falling edge (low) */
+	WD_STATE_COLDBOOT_TRIG,		/* WD = rising edge (high), > 30msec */
+	WD_STATE_STANDBYBOOT_TRIG,	/* As of now not used ?? */
+	WD_STATE_COLDBOOT_START,	/* Cold boot process started */
+	WD_STATE_STANDBYBOOT_START,	/* Not used */
+	WD_STATE_TIMESYNC,
+};
+
+struct arche_platform_drvdata {
+	/* Control GPIO signals to and from AP <=> SVC */
+	int svc_reset_gpio;
+	bool is_reset_act_hi;
+	int svc_sysboot_gpio;
+	int wake_detect_gpio; /* bi-dir,maps to WAKE_MOD & WAKE_FRAME signals */
+
+	enum arche_platform_state state;
+
+	int svc_refclk_req;
+	struct clk *svc_ref_clk;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pin_default;
+
+	int num_apbs;
+
+	enum svc_wakedetect_state wake_detect_state;
+	int wake_detect_irq;
+	spinlock_t wake_lock;			/* Protect wake_detect_state */
+	struct mutex platform_state_mutex;	/* Protect state */
+	wait_queue_head_t wq;			/* WQ for arche_pdata->state */
+	unsigned long wake_detect_start;
+	struct notifier_block pm_notifier;
+
+	struct device *dev;
+	struct gb_timesync_svc *timesync_svc_pdata;
+};
+
+static int arche_apb_bootret_assert(struct device *dev, void *data)
+{
+	apb_bootret_assert(dev);
+	return 0;
+}
+
+static int arche_apb_bootret_deassert(struct device *dev, void *data)
+{
+	apb_bootret_deassert(dev);
+	return 0;
+}
+
+/* Requires calling context to hold arche_pdata->platform_state_mutex */
+static void arche_platform_set_state(struct arche_platform_drvdata *arche_pdata,
+				     enum arche_platform_state state)
+{
+	arche_pdata->state = state;
+}
+
+/*
+ * arche_platform_change_state: Change the operational state
+ *
+ * This exported function allows external drivers to change the state
+ * of the arche-platform driver.
+ * Note that this function only supports transitions between two states
+ * with limited functionality.
+ *
+ *  - ARCHE_PLATFORM_STATE_TIME_SYNC:
+ *    Once set, allows timesync operations between SVC <=> AP and makes
+ *    sure that arche-platform driver ignores any subsequent events/pulses
+ *    from SVC over wake/detect.
+ *
+ *  - ARCHE_PLATFORM_STATE_ACTIVE:
+ *    Puts back driver to active state, where any pulse from SVC on wake/detect
+ *    line would trigger either cold/standby boot.
+ *    Note: Transition request from this function does not trigger cold/standby
+ *          boot. It just puts back driver book keeping variable back to ACTIVE
+ *          state and restores the interrupt.
+ *
+ * Returns -ENODEV if device not found, -EAGAIN if the driver cannot currently
+ * satisfy the requested state-transition or -EINVAL for all other
+ * state-transition requests.
+ */
+int arche_platform_change_state(enum arche_platform_state state,
+				struct gb_timesync_svc *timesync_svc_pdata)
+{
+	struct arche_platform_drvdata *arche_pdata;
+	struct platform_device *pdev;
+	struct device_node *np;
+	int ret = -EAGAIN;
+	unsigned long flags;
+
+	np = of_find_compatible_node(NULL, NULL, "google,arche-platform");
+	if (!np) {
+		pr_err("google,arche-platform device node not found\n");
+		return -ENODEV;
+	}
+
+	pdev = of_find_device_by_node(np);
+	if (!pdev) {
+		pr_err("arche-platform device not found\n");
+		return -ENODEV;
+	}
+
+	arche_pdata = platform_get_drvdata(pdev);
+
+	mutex_lock(&arche_pdata->platform_state_mutex);
+	spin_lock_irqsave(&arche_pdata->wake_lock, flags);
+
+	if (arche_pdata->state == state) {
+		ret = 0;
+		goto exit;
+	}
+
+	switch (state) {
+	case ARCHE_PLATFORM_STATE_TIME_SYNC:
+		if (arche_pdata->state != ARCHE_PLATFORM_STATE_ACTIVE) {
+			ret = -EINVAL;
+			goto exit;
+		}
+		if (arche_pdata->wake_detect_state != WD_STATE_IDLE) {
+			dev_err(arche_pdata->dev,
+				"driver busy with wake/detect line ops\n");
+			goto  exit;
+		}
+		device_for_each_child(arche_pdata->dev, NULL,
+				      arche_apb_bootret_assert);
+		arche_pdata->wake_detect_state = WD_STATE_TIMESYNC;
+		break;
+	case ARCHE_PLATFORM_STATE_ACTIVE:
+		if (arche_pdata->state != ARCHE_PLATFORM_STATE_TIME_SYNC) {
+			ret = -EINVAL;
+			goto exit;
+		}
+		device_for_each_child(arche_pdata->dev, NULL,
+				      arche_apb_bootret_deassert);
+		arche_pdata->wake_detect_state = WD_STATE_IDLE;
+		break;
+	case ARCHE_PLATFORM_STATE_OFF:
+	case ARCHE_PLATFORM_STATE_STANDBY:
+	case ARCHE_PLATFORM_STATE_FW_FLASHING:
+		dev_err(arche_pdata->dev, "busy, request to retry later\n");
+		goto exit;
+	default:
+		ret = -EINVAL;
+		dev_err(arche_pdata->dev,
+			"invalid state transition request\n");
+		goto exit;
+	}
+	arche_pdata->timesync_svc_pdata = timesync_svc_pdata;
+	arche_platform_set_state(arche_pdata, state);
+	if (state == ARCHE_PLATFORM_STATE_ACTIVE)
+		wake_up(&arche_pdata->wq);
+
+	ret = 0;
+exit:
+	spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+	mutex_unlock(&arche_pdata->platform_state_mutex);
+	of_node_put(np);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(arche_platform_change_state);
+
+/* Requires arche_pdata->wake_lock is held by calling context */
+static void arche_platform_set_wake_detect_state(
+				struct arche_platform_drvdata *arche_pdata,
+				enum svc_wakedetect_state state)
+{
+	arche_pdata->wake_detect_state = state;
+}
+
+static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
+{
+	gpio_set_value(gpio, onoff);
+}
+
+static int apb_cold_boot(struct device *dev, void *data)
+{
+	int ret;
+
+	ret = apb_ctrl_coldboot(dev);
+	if (ret)
+		dev_warn(dev, "failed to coldboot\n");
+
+	/*Child nodes are independent, so do not exit coldboot operation */
+	return 0;
+}
+
+static int apb_poweroff(struct device *dev, void *data)
+{
+	apb_ctrl_poweroff(dev);
+
+	/* Enable HUB3613 into HUB mode. */
+	if (usb3613_hub_mode_ctrl(false))
+		dev_warn(dev, "failed to control hub device\n");
+
+	return 0;
+}
+
+static void arche_platform_wd_irq_en(struct arche_platform_drvdata *arche_pdata)
+{
+	/* Enable interrupt here, to read event back from SVC */
+	gpio_direction_input(arche_pdata->wake_detect_gpio);
+	enable_irq(arche_pdata->wake_detect_irq);
+}
+
+static irqreturn_t arche_platform_wd_irq_thread(int irq, void *devid)
+{
+	struct arche_platform_drvdata *arche_pdata = devid;
+	unsigned long flags;
+
+	spin_lock_irqsave(&arche_pdata->wake_lock, flags);
+	if (arche_pdata->wake_detect_state != WD_STATE_COLDBOOT_TRIG) {
+		/* Something is wrong */
+		spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+		return IRQ_HANDLED;
+	}
+
+	arche_platform_set_wake_detect_state(arche_pdata,
+					     WD_STATE_COLDBOOT_START);
+	spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+
+	/* It should complete power cycle, so first make sure it is poweroff */
+	device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+
+	/* Bring APB out of reset: cold boot sequence */
+	device_for_each_child(arche_pdata->dev, NULL, apb_cold_boot);
+
+	/* Enable HUB3613 into HUB mode. */
+	if (usb3613_hub_mode_ctrl(true))
+		dev_warn(arche_pdata->dev, "failed to control hub device\n");
+
+	spin_lock_irqsave(&arche_pdata->wake_lock, flags);
+	arche_platform_set_wake_detect_state(arche_pdata, WD_STATE_IDLE);
+	spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t arche_platform_wd_irq(int irq, void *devid)
+{
+	struct arche_platform_drvdata *arche_pdata = devid;
+	unsigned long flags;
+
+	spin_lock_irqsave(&arche_pdata->wake_lock, flags);
+
+	if (arche_pdata->wake_detect_state == WD_STATE_TIMESYNC) {
+		gb_timesync_irq(arche_pdata->timesync_svc_pdata);
+		goto exit;
+	}
+
+	if (gpio_get_value(arche_pdata->wake_detect_gpio)) {
+		/* wake/detect rising */
+
+		/*
+		 * If wake/detect line goes high after low, within less than
+		 * 30msec, then standby boot sequence is initiated, which is not
+		 * supported/implemented as of now. So ignore it.
+		 */
+		if (arche_pdata->wake_detect_state == WD_STATE_BOOT_INIT) {
+			if (time_before(jiffies,
+					arche_pdata->wake_detect_start +
+					msecs_to_jiffies(WD_COLDBOOT_PULSE_WIDTH_MS))) {
+				arche_platform_set_wake_detect_state(arche_pdata,
+								     WD_STATE_IDLE);
+			} else {
+				/* Check we are not in middle of irq thread already */
+				if (arche_pdata->wake_detect_state !=
+						WD_STATE_COLDBOOT_START) {
+					arche_platform_set_wake_detect_state(arche_pdata,
+									     WD_STATE_COLDBOOT_TRIG);
+					spin_unlock_irqrestore(
+						&arche_pdata->wake_lock,
+						flags);
+					return IRQ_WAKE_THREAD;
+				}
+			}
+		}
+	} else {
+		/* wake/detect falling */
+		if (arche_pdata->wake_detect_state == WD_STATE_IDLE) {
+			arche_pdata->wake_detect_start = jiffies;
+			/*
+			 * In the begining, when wake/detect goes low (first time), we assume
+			 * it is meant for coldboot and set the flag. If wake/detect line stays low
+			 * beyond 30msec, then it is coldboot else fallback to standby boot.
+			 */
+			arche_platform_set_wake_detect_state(arche_pdata,
+							     WD_STATE_BOOT_INIT);
+		}
+	}
+
+exit:
+	spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Requires arche_pdata->platform_state_mutex to be held
+ */
+static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdata)
+{
+	int ret;
+
+	if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
+		return 0;
+
+	dev_info(arche_pdata->dev, "Booting from cold boot state\n");
+
+	svc_reset_onoff(arche_pdata->svc_reset_gpio,
+			arche_pdata->is_reset_act_hi);
+
+	gpio_set_value(arche_pdata->svc_sysboot_gpio, 0);
+	usleep_range(100, 200);
+
+	ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
+	if (ret) {
+		dev_err(arche_pdata->dev, "failed to enable svc_ref_clk: %d\n",
+				ret);
+		return ret;
+	}
+
+	/* bring SVC out of reset */
+	svc_reset_onoff(arche_pdata->svc_reset_gpio,
+			!arche_pdata->is_reset_act_hi);
+
+	arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_ACTIVE);
+
+	return 0;
+}
+
+/*
+ * Requires arche_pdata->platform_state_mutex to be held
+ */
+static int arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_pdata)
+{
+	int ret;
+
+	if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+		return 0;
+
+	dev_info(arche_pdata->dev, "Switching to FW flashing state\n");
+
+	svc_reset_onoff(arche_pdata->svc_reset_gpio,
+			arche_pdata->is_reset_act_hi);
+
+	gpio_set_value(arche_pdata->svc_sysboot_gpio, 1);
+
+	usleep_range(100, 200);
+
+	ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
+	if (ret) {
+		dev_err(arche_pdata->dev, "failed to enable svc_ref_clk: %d\n",
+				ret);
+		return ret;
+	}
+
+	svc_reset_onoff(arche_pdata->svc_reset_gpio,
+			!arche_pdata->is_reset_act_hi);
+
+	arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_FW_FLASHING);
+
+	return 0;
+}
+
+/*
+ * Requires arche_pdata->platform_state_mutex to be held
+ */
+static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pdata)
+{
+	unsigned long flags;
+
+	if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
+		return;
+
+	/* If in fw_flashing mode, then no need to repeate things again */
+	if (arche_pdata->state != ARCHE_PLATFORM_STATE_FW_FLASHING) {
+		disable_irq(arche_pdata->wake_detect_irq);
+
+		spin_lock_irqsave(&arche_pdata->wake_lock, flags);
+		arche_platform_set_wake_detect_state(arche_pdata,
+						     WD_STATE_IDLE);
+		spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
+	}
+
+	clk_disable_unprepare(arche_pdata->svc_ref_clk);
+
+	/* As part of exit, put APB back in reset state */
+	svc_reset_onoff(arche_pdata->svc_reset_gpio,
+			arche_pdata->is_reset_act_hi);
+
+	arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_OFF);
+}
+
+static ssize_t state_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
+	int ret = 0;
+
+retry:
+	mutex_lock(&arche_pdata->platform_state_mutex);
+	if (arche_pdata->state == ARCHE_PLATFORM_STATE_TIME_SYNC) {
+		mutex_unlock(&arche_pdata->platform_state_mutex);
+		ret = wait_event_interruptible(
+			arche_pdata->wq,
+			arche_pdata->state != ARCHE_PLATFORM_STATE_TIME_SYNC);
+		if (ret)
+			return ret;
+		goto retry;
+	}
+
+	if (sysfs_streq(buf, "off")) {
+		if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
+			goto exit;
+
+		/*  If SVC goes down, bring down APB's as well */
+		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+
+		arche_platform_poweroff_seq(arche_pdata);
+
+	} else if (sysfs_streq(buf, "active")) {
+		if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
+			goto exit;
+
+		/* First we want to make sure we power off everything
+		 * and then activate back again */
+		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+		arche_platform_poweroff_seq(arche_pdata);
+
+		arche_platform_wd_irq_en(arche_pdata);
+		ret = arche_platform_coldboot_seq(arche_pdata);
+		if (ret)
+			goto exit;
+
+	} else if (sysfs_streq(buf, "standby")) {
+		if (arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY)
+			goto exit;
+
+		dev_warn(arche_pdata->dev, "standby state not supported\n");
+	} else if (sysfs_streq(buf, "fw_flashing")) {
+		if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+			goto exit;
+
+		/*
+		 * Here we only control SVC.
+		 *
+		 * In case of FW_FLASHING mode we do not want to control
+		 * APBs, as in case of V2, SPI bus is shared between both
+		 * the APBs. So let user chose which APB he wants to flash.
+		 */
+		arche_platform_poweroff_seq(arche_pdata);
+
+		ret = arche_platform_fw_flashing_seq(arche_pdata);
+		if (ret)
+			goto exit;
+	} else {
+		dev_err(arche_pdata->dev, "unknown state\n");
+		ret = -EINVAL;
+	}
+
+exit:
+	mutex_unlock(&arche_pdata->platform_state_mutex);
+	return ret ? ret : count;
+}
+
+static ssize_t state_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct arche_platform_drvdata *arche_pdata = dev_get_drvdata(dev);
+
+	switch (arche_pdata->state) {
+	case ARCHE_PLATFORM_STATE_OFF:
+		return sprintf(buf, "off\n");
+	case ARCHE_PLATFORM_STATE_ACTIVE:
+		return sprintf(buf, "active\n");
+	case ARCHE_PLATFORM_STATE_STANDBY:
+		return sprintf(buf, "standby\n");
+	case ARCHE_PLATFORM_STATE_FW_FLASHING:
+		return sprintf(buf, "fw_flashing\n");
+	case ARCHE_PLATFORM_STATE_TIME_SYNC:
+		return sprintf(buf, "time_sync\n");
+	default:
+		return sprintf(buf, "unknown state\n");
+	}
+}
+
+static DEVICE_ATTR_RW(state);
+
+static int arche_platform_pm_notifier(struct notifier_block *notifier,
+				      unsigned long pm_event, void *unused)
+{
+	struct arche_platform_drvdata *arche_pdata =
+		container_of(notifier, struct arche_platform_drvdata,
+			     pm_notifier);
+	int ret = NOTIFY_DONE;
+
+	mutex_lock(&arche_pdata->platform_state_mutex);
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		if (arche_pdata->state != ARCHE_PLATFORM_STATE_ACTIVE) {
+			ret = NOTIFY_STOP;
+			break;
+		}
+		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+		arche_platform_poweroff_seq(arche_pdata);
+		break;
+	case PM_POST_SUSPEND:
+		if (arche_pdata->state != ARCHE_PLATFORM_STATE_OFF)
+			break;
+
+		arche_platform_wd_irq_en(arche_pdata);
+		arche_platform_coldboot_seq(arche_pdata);
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&arche_pdata->platform_state_mutex);
+
+	return ret;
+}
+
+static int arche_platform_probe(struct platform_device *pdev)
+{
+	struct arche_platform_drvdata *arche_pdata;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	arche_pdata = devm_kzalloc(&pdev->dev, sizeof(*arche_pdata), GFP_KERNEL);
+	if (!arche_pdata)
+		return -ENOMEM;
+
+	/* setup svc reset gpio */
+	arche_pdata->is_reset_act_hi = of_property_read_bool(np,
+					"svc,reset-active-high");
+	arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
+	if (arche_pdata->svc_reset_gpio < 0) {
+		dev_err(dev, "failed to get reset-gpio\n");
+		return arche_pdata->svc_reset_gpio;
+	}
+	ret = devm_gpio_request(dev, arche_pdata->svc_reset_gpio, "svc-reset");
+	if (ret) {
+		dev_err(dev, "failed to request svc-reset gpio:%d\n", ret);
+		return ret;
+	}
+	ret = gpio_direction_output(arche_pdata->svc_reset_gpio,
+					arche_pdata->is_reset_act_hi);
+	if (ret) {
+		dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
+		return ret;
+	}
+	arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_OFF);
+
+	arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
+					"svc,sysboot-gpio", 0);
+	if (arche_pdata->svc_sysboot_gpio < 0) {
+		dev_err(dev, "failed to get sysboot gpio\n");
+		return arche_pdata->svc_sysboot_gpio;
+	}
+	ret = devm_gpio_request(dev, arche_pdata->svc_sysboot_gpio, "sysboot0");
+	if (ret) {
+		dev_err(dev, "failed to request sysboot0 gpio:%d\n", ret);
+		return ret;
+	}
+	ret = gpio_direction_output(arche_pdata->svc_sysboot_gpio, 0);
+	if (ret) {
+		dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
+		return ret;
+	}
+
+	/* setup the clock request gpio first */
+	arche_pdata->svc_refclk_req = of_get_named_gpio(np,
+					"svc,refclk-req-gpio", 0);
+	if (arche_pdata->svc_refclk_req < 0) {
+		dev_err(dev, "failed to get svc clock-req gpio\n");
+		return arche_pdata->svc_refclk_req;
+	}
+	ret = devm_gpio_request(dev, arche_pdata->svc_refclk_req, "svc-clk-req");
+	if (ret) {
+		dev_err(dev, "failed to request svc-clk-req gpio: %d\n", ret);
+		return ret;
+	}
+	ret = gpio_direction_input(arche_pdata->svc_refclk_req);
+	if (ret) {
+		dev_err(dev, "failed to set svc-clk-req gpio dir :%d\n", ret);
+		return ret;
+	}
+
+	/* setup refclk2 to follow the pin */
+	arche_pdata->svc_ref_clk = devm_clk_get(dev, "svc_ref_clk");
+	if (IS_ERR(arche_pdata->svc_ref_clk)) {
+		ret = PTR_ERR(arche_pdata->svc_ref_clk);
+		dev_err(dev, "failed to get svc_ref_clk: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, arche_pdata);
+
+	arche_pdata->num_apbs = of_get_child_count(np);
+	dev_dbg(dev, "Number of APB's available - %d\n", arche_pdata->num_apbs);
+
+	arche_pdata->wake_detect_gpio = of_get_named_gpio(np, "svc,wake-detect-gpio", 0);
+	if (arche_pdata->wake_detect_gpio < 0) {
+		dev_err(dev, "failed to get wake detect gpio\n");
+		ret = arche_pdata->wake_detect_gpio;
+		return ret;
+	}
+
+	ret = devm_gpio_request(dev, arche_pdata->wake_detect_gpio, "wake detect");
+	if (ret) {
+		dev_err(dev, "Failed requesting wake_detect gpio %d\n",
+				arche_pdata->wake_detect_gpio);
+		return ret;
+	}
+
+	arche_platform_set_wake_detect_state(arche_pdata, WD_STATE_IDLE);
+
+	arche_pdata->dev = &pdev->dev;
+
+	spin_lock_init(&arche_pdata->wake_lock);
+	mutex_init(&arche_pdata->platform_state_mutex);
+	init_waitqueue_head(&arche_pdata->wq);
+	arche_pdata->wake_detect_irq =
+		gpio_to_irq(arche_pdata->wake_detect_gpio);
+
+	ret = devm_request_threaded_irq(dev, arche_pdata->wake_detect_irq,
+			arche_platform_wd_irq,
+			arche_platform_wd_irq_thread,
+			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+			dev_name(dev), arche_pdata);
+	if (ret) {
+		dev_err(dev, "failed to request wake detect IRQ %d\n", ret);
+		return ret;
+	}
+	disable_irq(arche_pdata->wake_detect_irq);
+
+	ret = device_create_file(dev, &dev_attr_state);
+	if (ret) {
+		dev_err(dev, "failed to create state file in sysfs\n");
+		return ret;
+	}
+
+	ret = of_platform_populate(np, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "failed to populate child nodes %d\n", ret);
+		goto err_device_remove;
+	}
+
+	arche_pdata->pm_notifier.notifier_call = arche_platform_pm_notifier;
+	ret = register_pm_notifier(&arche_pdata->pm_notifier);
+
+	if (ret) {
+		dev_err(dev, "failed to register pm notifier %d\n", ret);
+		goto err_device_remove;
+	}
+
+	/* Register callback pointer */
+	arche_platform_change_state_cb = arche_platform_change_state;
+
+	/* Explicitly power off if requested */
+	if (!of_property_read_bool(pdev->dev.of_node, "arche,init-off")) {
+		mutex_lock(&arche_pdata->platform_state_mutex);
+		ret = arche_platform_coldboot_seq(arche_pdata);
+		if (ret) {
+			dev_err(dev, "Failed to cold boot svc %d\n", ret);
+			goto err_coldboot;
+		}
+		arche_platform_wd_irq_en(arche_pdata);
+		mutex_unlock(&arche_pdata->platform_state_mutex);
+	}
+
+	dev_info(dev, "Device registered successfully\n");
+	return 0;
+
+err_coldboot:
+	mutex_unlock(&arche_pdata->platform_state_mutex);
+err_device_remove:
+	device_remove_file(&pdev->dev, &dev_attr_state);
+	return ret;
+}
+
+static int arche_remove_child(struct device *dev, void *unused)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	platform_device_unregister(pdev);
+
+	return 0;
+}
+
+static int arche_platform_remove(struct platform_device *pdev)
+{
+	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
+
+	unregister_pm_notifier(&arche_pdata->pm_notifier);
+	device_remove_file(&pdev->dev, &dev_attr_state);
+	device_for_each_child(&pdev->dev, NULL, arche_remove_child);
+	arche_platform_poweroff_seq(arche_pdata);
+	platform_set_drvdata(pdev, NULL);
+
+	if (usb3613_hub_mode_ctrl(false))
+		dev_warn(arche_pdata->dev, "failed to control hub device\n");
+		/* TODO: Should we do anything more here ?? */
+	return 0;
+}
+
+static int arche_platform_suspend(struct device *dev)
+{
+	/*
+	 * If timing profile premits, we may shutdown bridge
+	 * completely
+	 *
+	 * TODO: sequence ??
+	 *
+	 * Also, need to make sure we meet precondition for unipro suspend
+	 * Precondition: Definition ???
+	 */
+	return 0;
+}
+
+static int arche_platform_resume(struct device *dev)
+{
+	/*
+	 * Atleast for ES2 we have to meet the delay requirement between
+	 * unipro switch and AP bridge init, depending on whether bridge is in
+	 * OFF state or standby state.
+	 *
+	 * Based on whether bridge is in standby or OFF state we may have to
+	 * assert multiple signals. Please refer to WDM spec, for more info.
+	 *
+	 */
+	return 0;
+}
+
+static void arche_platform_shutdown(struct platform_device *pdev)
+{
+	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
+
+	arche_platform_poweroff_seq(arche_pdata);
+
+	usb3613_hub_mode_ctrl(false);
+}
+
+static SIMPLE_DEV_PM_OPS(arche_platform_pm_ops,
+			arche_platform_suspend,
+			arche_platform_resume);
+
+static struct of_device_id arche_platform_of_match[] = {
+	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
+	{ },
+};
+
+static struct of_device_id arche_combined_id[] = {
+	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
+	{ .compatible = "usbffff,2", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, arche_combined_id);
+
+static struct platform_driver arche_platform_device_driver = {
+	.probe		= arche_platform_probe,
+	.remove		= arche_platform_remove,
+	.shutdown	= arche_platform_shutdown,
+	.driver		= {
+		.name	= "arche-platform-ctrl",
+		.pm	= &arche_platform_pm_ops,
+		.of_match_table = arche_platform_of_match,
+	}
+};
+
+static int __init arche_init(void)
+{
+	int retval;
+
+	retval = platform_driver_register(&arche_platform_device_driver);
+	if (retval)
+		return retval;
+
+	retval = arche_apb_init();
+	if (retval)
+		platform_driver_unregister(&arche_platform_device_driver);
+
+	return retval;
+}
+module_init(arche_init);
+
+static void __exit arche_exit(void)
+{
+	arche_apb_exit();
+	platform_driver_unregister(&arche_platform_device_driver);
+}
+module_exit(arche_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Vaibhav Hiremath <vaibhav.hiremath@linaro.org>");
+MODULE_DESCRIPTION("Arche Platform Driver");
diff --git a/drivers/staging/greybus/arche_platform.h b/drivers/staging/greybus/arche_platform.h
new file mode 100644
index 000000000000..bd12345b82a2
--- /dev/null
+++ b/drivers/staging/greybus/arche_platform.h
@@ -0,0 +1,39 @@
+/*
+ * Arche Platform driver to enable Unipro link.
+ *
+ * Copyright 2015-2016 Google Inc.
+ * Copyright 2015-2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __ARCHE_PLATFORM_H
+#define __ARCHE_PLATFORM_H
+
+#include "timesync.h"
+
+enum arche_platform_state {
+	ARCHE_PLATFORM_STATE_OFF,
+	ARCHE_PLATFORM_STATE_ACTIVE,
+	ARCHE_PLATFORM_STATE_STANDBY,
+	ARCHE_PLATFORM_STATE_FW_FLASHING,
+	ARCHE_PLATFORM_STATE_TIME_SYNC,
+};
+
+int arche_platform_change_state(enum arche_platform_state state,
+				struct gb_timesync_svc *pdata);
+
+extern int (*arche_platform_change_state_cb)(enum arche_platform_state state,
+					     struct gb_timesync_svc *pdata);
+int __init arche_apb_init(void);
+void __exit arche_apb_exit(void);
+
+/* Operational states for the APB device */
+int apb_ctrl_coldboot(struct device *dev);
+int apb_ctrl_fw_flashing(struct device *dev);
+int apb_ctrl_standby_boot(struct device *dev);
+void apb_ctrl_poweroff(struct device *dev);
+void apb_bootret_assert(struct device *dev);
+void apb_bootret_deassert(struct device *dev);
+
+#endif	/* __ARCHE_PLATFORM_H */
diff --git a/drivers/staging/greybus/arpc.h b/drivers/staging/greybus/arpc.h
new file mode 100644
index 000000000000..7fbddfc40d83
--- /dev/null
+++ b/drivers/staging/greybus/arpc.h
@@ -0,0 +1,109 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __ARPC_H
+#define __ARPC_H
+
+/* APBridgeA RPC (ARPC) */
+
+enum arpc_result {
+	ARPC_SUCCESS		= 0x00,
+	ARPC_NO_MEMORY		= 0x01,
+	ARPC_INVALID		= 0x02,
+	ARPC_TIMEOUT		= 0x03,
+	ARPC_UNKNOWN_ERROR	= 0xff,
+};
+
+struct arpc_request_message {
+	__le16	id;		/* RPC unique id */
+	__le16	size;		/* Size in bytes of header + payload */
+	__u8	type;		/* RPC type */
+	__u8	data[0];	/* ARPC data */
+} __packed;
+
+struct arpc_response_message {
+	__le16	id;		/* RPC unique id */
+	__u8	result;		/* Result of RPC */
+} __packed;
+
+
+/* ARPC requests */
+#define ARPC_TYPE_CPORT_CONNECTED		0x01
+#define ARPC_TYPE_CPORT_QUIESCE			0x02
+#define ARPC_TYPE_CPORT_CLEAR			0x03
+#define ARPC_TYPE_CPORT_FLUSH			0x04
+#define ARPC_TYPE_CPORT_SHUTDOWN		0x05
+
+struct arpc_cport_connected_req {
+	__le16 cport_id;
+} __packed;
+
+struct arpc_cport_quiesce_req {
+	__le16 cport_id;
+	__le16 peer_space;
+	__le16 timeout;
+} __packed;
+
+struct arpc_cport_clear_req {
+	__le16 cport_id;
+} __packed;
+
+struct arpc_cport_flush_req {
+	__le16 cport_id;
+} __packed;
+
+struct arpc_cport_shutdown_req {
+	__le16 cport_id;
+	__le16 timeout;
+	__u8 phase;
+} __packed;
+
+#endif	/* __ARPC_H */
diff --git a/drivers/staging/greybus/audio_apbridgea.c b/drivers/staging/greybus/audio_apbridgea.c
new file mode 100644
index 000000000000..1b4252d5d255
--- /dev/null
+++ b/drivers/staging/greybus/audio_apbridgea.c
@@ -0,0 +1,207 @@
+/*
+ * Greybus Audio Device Class Protocol helpers
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+#include "audio_apbridgea.h"
+#include "audio_codec.h"
+
+int gb_audio_apbridgea_set_config(struct gb_connection *connection,
+				  __u16 i2s_port, __u32 format, __u32 rate,
+				  __u32 mclk_freq)
+{
+	struct audio_apbridgea_set_config_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_CONFIG;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.format = cpu_to_le32(format);
+	req.rate = cpu_to_le32(rate);
+	req.mclk_freq = cpu_to_le32(mclk_freq);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_config);
+
+int gb_audio_apbridgea_register_cport(struct gb_connection *connection,
+				      __u16 i2s_port, __u16 cportid,
+				      __u8 direction)
+{
+	struct audio_apbridgea_register_cport_request req;
+	int ret;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_REGISTER_CPORT;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.cport = cpu_to_le16(cportid);
+	req.direction = direction;
+
+	ret = gb_pm_runtime_get_sync(connection->bundle);
+	if (ret)
+		return ret;
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_register_cport);
+
+int gb_audio_apbridgea_unregister_cport(struct gb_connection *connection,
+					__u16 i2s_port, __u16 cportid,
+					__u8 direction)
+{
+	struct audio_apbridgea_unregister_cport_request req;
+	int ret;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_UNREGISTER_CPORT;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.cport = cpu_to_le16(cportid);
+	req.direction = direction;
+
+	ret = gb_hd_output(connection->hd, &req, sizeof(req),
+			   GB_APB_REQUEST_AUDIO_CONTROL, true);
+
+	gb_pm_runtime_put_autosuspend(connection->bundle);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_unregister_cport);
+
+int gb_audio_apbridgea_set_tx_data_size(struct gb_connection *connection,
+					__u16 i2s_port, __u16 size)
+{
+	struct audio_apbridgea_set_tx_data_size_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_TX_DATA_SIZE;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.size = cpu_to_le16(size);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_tx_data_size);
+
+int gb_audio_apbridgea_prepare_tx(struct gb_connection *connection,
+				  __u16 i2s_port)
+{
+	struct audio_apbridgea_prepare_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_PREPARE_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_prepare_tx);
+
+int gb_audio_apbridgea_start_tx(struct gb_connection *connection,
+				__u16 i2s_port, __u64 timestamp)
+{
+	struct audio_apbridgea_start_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_START_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.timestamp = cpu_to_le64(timestamp);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_start_tx);
+
+int gb_audio_apbridgea_stop_tx(struct gb_connection *connection, __u16 i2s_port)
+{
+	struct audio_apbridgea_stop_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_STOP_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_stop_tx);
+
+int gb_audio_apbridgea_shutdown_tx(struct gb_connection *connection,
+				   __u16 i2s_port)
+{
+	struct audio_apbridgea_shutdown_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SHUTDOWN_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_shutdown_tx);
+
+int gb_audio_apbridgea_set_rx_data_size(struct gb_connection *connection,
+					__u16 i2s_port, __u16 size)
+{
+	struct audio_apbridgea_set_rx_data_size_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_RX_DATA_SIZE;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.size = cpu_to_le16(size);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_rx_data_size);
+
+int gb_audio_apbridgea_prepare_rx(struct gb_connection *connection,
+				  __u16 i2s_port)
+{
+	struct audio_apbridgea_prepare_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_PREPARE_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_prepare_rx);
+
+int gb_audio_apbridgea_start_rx(struct gb_connection *connection,
+				__u16 i2s_port)
+{
+	struct audio_apbridgea_start_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_START_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_start_rx);
+
+int gb_audio_apbridgea_stop_rx(struct gb_connection *connection, __u16 i2s_port)
+{
+	struct audio_apbridgea_stop_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_STOP_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_stop_rx);
+
+int gb_audio_apbridgea_shutdown_rx(struct gb_connection *connection,
+				   __u16 i2s_port)
+{
+	struct audio_apbridgea_shutdown_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SHUTDOWN_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_shutdown_rx);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("greybus:audio-apbridgea");
+MODULE_DESCRIPTION("Greybus Special APBridgeA Audio Protocol library");
+MODULE_AUTHOR("Mark Greer <mgreer@animalcreek.com>");
diff --git a/drivers/staging/greybus/audio_apbridgea.h b/drivers/staging/greybus/audio_apbridgea.h
new file mode 100644
index 000000000000..b94cb05c89e4
--- /dev/null
+++ b/drivers/staging/greybus/audio_apbridgea.h
@@ -0,0 +1,156 @@
+/**
+ * Copyright (c) 2015-2016 Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/*
+ * This is a special protocol for configuring communication over the
+ * I2S bus between the DSP on the MSM8994 and APBridgeA.  Therefore,
+ * we can predefine several low-level attributes of the communication
+ * because we know that they are supported.  In particular, the following
+ * assumptions are made:
+ *	- there are two channels (i.e., stereo)
+ *	- the low-level protocol is I2S as defined by Philips/NXP
+ *	- the DSP on the MSM8994 is the clock master for MCLK, BCLK, and WCLK
+ *	- WCLK changes on the falling edge of BCLK
+ *	- WCLK low for left channel; high for right channel
+ *	- TX data is sent on the falling edge of BCLK
+ *	- RX data is received/latched on the rising edge of BCLK
+ */
+
+#ifndef __AUDIO_APBRIDGEA_H
+#define __AUDIO_APBRIDGEA_H
+
+#define AUDIO_APBRIDGEA_TYPE_SET_CONFIG			0x01
+#define AUDIO_APBRIDGEA_TYPE_REGISTER_CPORT		0x02
+#define AUDIO_APBRIDGEA_TYPE_UNREGISTER_CPORT		0x03
+#define AUDIO_APBRIDGEA_TYPE_SET_TX_DATA_SIZE		0x04
+							/* 0x05 unused */
+#define AUDIO_APBRIDGEA_TYPE_PREPARE_TX			0x06
+#define AUDIO_APBRIDGEA_TYPE_START_TX			0x07
+#define AUDIO_APBRIDGEA_TYPE_STOP_TX			0x08
+#define AUDIO_APBRIDGEA_TYPE_SHUTDOWN_TX		0x09
+#define AUDIO_APBRIDGEA_TYPE_SET_RX_DATA_SIZE		0x0a
+							/* 0x0b unused */
+#define AUDIO_APBRIDGEA_TYPE_PREPARE_RX			0x0c
+#define AUDIO_APBRIDGEA_TYPE_START_RX			0x0d
+#define AUDIO_APBRIDGEA_TYPE_STOP_RX			0x0e
+#define AUDIO_APBRIDGEA_TYPE_SHUTDOWN_RX		0x0f
+
+#define AUDIO_APBRIDGEA_PCM_FMT_8			BIT(0)
+#define AUDIO_APBRIDGEA_PCM_FMT_16			BIT(1)
+#define AUDIO_APBRIDGEA_PCM_FMT_24			BIT(2)
+#define AUDIO_APBRIDGEA_PCM_FMT_32			BIT(3)
+#define AUDIO_APBRIDGEA_PCM_FMT_64			BIT(4)
+
+#define AUDIO_APBRIDGEA_PCM_RATE_5512			BIT(0)
+#define AUDIO_APBRIDGEA_PCM_RATE_8000			BIT(1)
+#define AUDIO_APBRIDGEA_PCM_RATE_11025			BIT(2)
+#define AUDIO_APBRIDGEA_PCM_RATE_16000			BIT(3)
+#define AUDIO_APBRIDGEA_PCM_RATE_22050			BIT(4)
+#define AUDIO_APBRIDGEA_PCM_RATE_32000			BIT(5)
+#define AUDIO_APBRIDGEA_PCM_RATE_44100			BIT(6)
+#define AUDIO_APBRIDGEA_PCM_RATE_48000			BIT(7)
+#define AUDIO_APBRIDGEA_PCM_RATE_64000			BIT(8)
+#define AUDIO_APBRIDGEA_PCM_RATE_88200			BIT(9)
+#define AUDIO_APBRIDGEA_PCM_RATE_96000			BIT(10)
+#define AUDIO_APBRIDGEA_PCM_RATE_176400			BIT(11)
+#define AUDIO_APBRIDGEA_PCM_RATE_192000			BIT(12)
+
+#define AUDIO_APBRIDGEA_DIRECTION_TX			BIT(0)
+#define AUDIO_APBRIDGEA_DIRECTION_RX			BIT(1)
+
+/* The I2S port is passed in the 'index' parameter of the USB request */
+/* The CPort is passed in the 'value' parameter of the USB request */
+
+struct audio_apbridgea_hdr {
+	__u8	type;
+	__le16	i2s_port;
+	__u8	data[0];
+} __packed;
+
+struct audio_apbridgea_set_config_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le32				format;	/* AUDIO_APBRIDGEA_PCM_FMT_* */
+	__le32				rate;	/* AUDIO_APBRIDGEA_PCM_RATE_* */
+	__le32				mclk_freq; /* XXX Remove? */
+} __packed;
+
+struct audio_apbridgea_register_cport_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				cport;
+	__u8				direction;
+} __packed;
+
+struct audio_apbridgea_unregister_cport_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				cport;
+	__u8				direction;
+} __packed;
+
+struct audio_apbridgea_set_tx_data_size_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				size;
+} __packed;
+
+struct audio_apbridgea_prepare_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_start_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le64				timestamp;
+} __packed;
+
+struct audio_apbridgea_stop_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_shutdown_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_set_rx_data_size_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				size;
+} __packed;
+
+struct audio_apbridgea_prepare_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_start_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_stop_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_shutdown_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+#endif /*__AUDIO_APBRIDGEA_H */
diff --git a/drivers/staging/greybus/audio_codec.c b/drivers/staging/greybus/audio_codec.c
new file mode 100644
index 000000000000..2f70295e0094
--- /dev/null
+++ b/drivers/staging/greybus/audio_codec.c
@@ -0,0 +1,1132 @@
+/*
+ * APBridge ALSA SoC dummy codec driver
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <sound/soc.h>
+#include <sound/pcm_params.h>
+#include <uapi/linux/input.h>
+
+#include "audio_codec.h"
+#include "audio_apbridgea.h"
+#include "audio_manager.h"
+
+static struct gbaudio_codec_info *gbcodec;
+
+static struct gbaudio_data_connection *
+find_data(struct gbaudio_module_info *module, int id)
+{
+	struct gbaudio_data_connection *data;
+
+	list_for_each_entry(data, &module->data_list, list) {
+		if (id == data->id)
+			return data;
+	}
+	return NULL;
+}
+
+static struct gbaudio_stream_params *
+find_dai_stream_params(struct gbaudio_codec_info *codec, int id, int stream)
+{
+	struct gbaudio_codec_dai *dai;
+
+	list_for_each_entry(dai, &codec->dai_list, list) {
+		if (dai->id == id)
+			return &dai->params[stream];
+	}
+	return NULL;
+}
+
+static int gbaudio_module_enable_tx(struct gbaudio_codec_info *codec,
+				    struct gbaudio_module_info *module, int id)
+{
+	int module_state, ret = 0;
+	uint16_t data_cport, i2s_port, cportid;
+	uint8_t sig_bits, channels;
+	uint32_t format, rate;
+	struct gbaudio_data_connection *data;
+	struct gbaudio_stream_params *params;
+
+	/* find the dai */
+	data = find_data(module, id);
+	if (!data) {
+		dev_err(module->dev, "%d:DATA connection missing\n", id);
+		return -ENODEV;
+	}
+	module_state = data->state[SNDRV_PCM_STREAM_PLAYBACK];
+
+	params = find_dai_stream_params(codec, id, SNDRV_PCM_STREAM_PLAYBACK);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		return -EINVAL;
+	}
+
+	/* register cport */
+	if (module_state < GBAUDIO_CODEC_STARTUP) {
+		i2s_port = 0;	/* fixed for now */
+		cportid = data->connection->hd_cport_id;
+		ret = gb_audio_apbridgea_register_cport(data->connection,
+						i2s_port, cportid,
+						AUDIO_APBRIDGEA_DIRECTION_TX);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "reg_cport failed:%d\n", ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_PLAYBACK] =
+			GBAUDIO_CODEC_STARTUP;
+		dev_dbg(module->dev, "Dynamic Register %d DAI\n", cportid);
+	}
+
+	/* hw_params */
+	if (module_state < GBAUDIO_CODEC_HWPARAMS) {
+		format = params->format;
+		channels = params->channels;
+		rate = params->rate;
+		sig_bits = params->sig_bits;
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_set_pcm(module->mgmt_connection, data_cport,
+					  format, rate, channels, sig_bits);
+		if (ret) {
+			dev_err_ratelimited(module->dev, "set_pcm failed:%d\n",
+					    ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_PLAYBACK] =
+			GBAUDIO_CODEC_HWPARAMS;
+		dev_dbg(module->dev, "Dynamic hw_params %d DAI\n", data_cport);
+	}
+
+	/* prepare */
+	if (module_state < GBAUDIO_CODEC_PREPARE) {
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_set_tx_data_size(module->mgmt_connection,
+						   data_cport, 192);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "set_tx_data_size failed:%d\n",
+					    ret);
+			return ret;
+		}
+		ret = gb_audio_gb_activate_tx(module->mgmt_connection,
+					      data_cport);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "activate_tx failed:%d\n", ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_PLAYBACK] =
+			GBAUDIO_CODEC_PREPARE;
+		dev_dbg(module->dev, "Dynamic prepare %d DAI\n", data_cport);
+	}
+
+	return 0;
+}
+
+static int gbaudio_module_disable_tx(struct gbaudio_module_info *module, int id)
+{
+	int ret;
+	uint16_t data_cport, cportid, i2s_port;
+	int module_state;
+	struct gbaudio_data_connection *data;
+
+	/* find the dai */
+	data = find_data(module, id);
+	if (!data) {
+		dev_err(module->dev, "%d:DATA connection missing\n", id);
+		return -ENODEV;
+	}
+	module_state = data->state[SNDRV_PCM_STREAM_PLAYBACK];
+
+	if (module_state > GBAUDIO_CODEC_HWPARAMS) {
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_deactivate_tx(module->mgmt_connection,
+						data_cport);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "deactivate_tx failed:%d\n", ret);
+			return ret;
+		}
+		dev_dbg(module->dev, "Dynamic deactivate %d DAI\n", data_cport);
+		data->state[SNDRV_PCM_STREAM_PLAYBACK] =
+			GBAUDIO_CODEC_HWPARAMS;
+	}
+
+	if (module_state > GBAUDIO_CODEC_SHUTDOWN) {
+		i2s_port = 0;	/* fixed for now */
+		cportid = data->connection->hd_cport_id;
+		ret = gb_audio_apbridgea_unregister_cport(data->connection,
+						i2s_port, cportid,
+						AUDIO_APBRIDGEA_DIRECTION_TX);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "unregister_cport failed:%d\n",
+					    ret);
+			return ret;
+		}
+		dev_dbg(module->dev, "Dynamic Unregister %d DAI\n", cportid);
+		data->state[SNDRV_PCM_STREAM_PLAYBACK] =
+			GBAUDIO_CODEC_SHUTDOWN;
+	}
+
+	return 0;
+}
+
+static int gbaudio_module_enable_rx(struct gbaudio_codec_info *codec,
+				    struct gbaudio_module_info *module, int id)
+{
+	int module_state, ret = 0;
+	uint16_t data_cport, i2s_port, cportid;
+	uint8_t sig_bits, channels;
+	uint32_t format, rate;
+	struct gbaudio_data_connection *data;
+	struct gbaudio_stream_params *params;
+
+	/* find the dai */
+	data = find_data(module, id);
+	if (!data) {
+		dev_err(module->dev, "%d:DATA connection missing\n", id);
+		return -ENODEV;
+	}
+	module_state = data->state[SNDRV_PCM_STREAM_CAPTURE];
+
+	params = find_dai_stream_params(codec, id, SNDRV_PCM_STREAM_CAPTURE);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		return -EINVAL;
+	}
+
+	/* register cport */
+	if (module_state < GBAUDIO_CODEC_STARTUP) {
+		i2s_port = 0;	/* fixed for now */
+		cportid = data->connection->hd_cport_id;
+		ret = gb_audio_apbridgea_register_cport(data->connection,
+						i2s_port, cportid,
+						AUDIO_APBRIDGEA_DIRECTION_RX);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "reg_cport failed:%d\n", ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_CAPTURE] =
+			GBAUDIO_CODEC_STARTUP;
+		dev_dbg(module->dev, "Dynamic Register %d DAI\n", cportid);
+	}
+
+	/* hw_params */
+	if (module_state < GBAUDIO_CODEC_HWPARAMS) {
+		format = params->format;
+		channels = params->channels;
+		rate = params->rate;
+		sig_bits = params->sig_bits;
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_set_pcm(module->mgmt_connection, data_cport,
+					  format, rate, channels, sig_bits);
+		if (ret) {
+			dev_err_ratelimited(module->dev, "set_pcm failed:%d\n",
+					    ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_CAPTURE] =
+			GBAUDIO_CODEC_HWPARAMS;
+		dev_dbg(module->dev, "Dynamic hw_params %d DAI\n", data_cport);
+	}
+
+	/* prepare */
+	if (module_state < GBAUDIO_CODEC_PREPARE) {
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_set_rx_data_size(module->mgmt_connection,
+						   data_cport, 192);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "set_rx_data_size failed:%d\n",
+					    ret);
+			return ret;
+		}
+		ret = gb_audio_gb_activate_rx(module->mgmt_connection,
+					      data_cport);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "activate_rx failed:%d\n", ret);
+			return ret;
+		}
+		data->state[SNDRV_PCM_STREAM_CAPTURE] =
+			GBAUDIO_CODEC_PREPARE;
+		dev_dbg(module->dev, "Dynamic prepare %d DAI\n", data_cport);
+	}
+
+	return 0;
+}
+
+static int gbaudio_module_disable_rx(struct gbaudio_module_info *module, int id)
+{
+	int ret;
+	uint16_t data_cport, cportid, i2s_port;
+	int module_state;
+	struct gbaudio_data_connection *data;
+
+	/* find the dai */
+	data = find_data(module, id);
+	if (!data) {
+		dev_err(module->dev, "%d:DATA connection missing\n", id);
+		return -ENODEV;
+	}
+	module_state = data->state[SNDRV_PCM_STREAM_CAPTURE];
+
+	if (module_state > GBAUDIO_CODEC_HWPARAMS) {
+		data_cport = data->connection->intf_cport_id;
+		ret = gb_audio_gb_deactivate_rx(module->mgmt_connection,
+						data_cport);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "deactivate_rx failed:%d\n", ret);
+			return ret;
+		}
+		dev_dbg(module->dev, "Dynamic deactivate %d DAI\n", data_cport);
+		data->state[SNDRV_PCM_STREAM_CAPTURE] =
+			GBAUDIO_CODEC_HWPARAMS;
+	}
+
+	if (module_state > GBAUDIO_CODEC_SHUTDOWN) {
+		i2s_port = 0;	/* fixed for now */
+		cportid = data->connection->hd_cport_id;
+		ret = gb_audio_apbridgea_unregister_cport(data->connection,
+						i2s_port, cportid,
+						AUDIO_APBRIDGEA_DIRECTION_RX);
+		if (ret) {
+			dev_err_ratelimited(module->dev,
+					    "unregister_cport failed:%d\n",
+					    ret);
+			return ret;
+		}
+		dev_dbg(module->dev, "Dynamic Unregister %d DAI\n", cportid);
+		data->state[SNDRV_PCM_STREAM_CAPTURE] =
+			GBAUDIO_CODEC_SHUTDOWN;
+	}
+
+	return 0;
+}
+
+int gbaudio_module_update(struct gbaudio_codec_info *codec,
+			  struct snd_soc_dapm_widget *w,
+			  struct gbaudio_module_info *module, int enable)
+{
+	int dai_id, ret;
+	char intf_name[NAME_SIZE], dir[NAME_SIZE];
+
+	dev_dbg(module->dev, "%s:Module update %s sequence\n", w->name,
+		enable ? "Enable":"Disable");
+
+	if ((w->id != snd_soc_dapm_aif_in) && (w->id != snd_soc_dapm_aif_out)){
+		dev_dbg(codec->dev, "No action required for %s\n", w->name);
+		return 0;
+	}
+
+	/* parse dai_id from AIF widget's stream_name */
+	ret = sscanf(w->sname, "%s %d %s", intf_name, &dai_id, dir);
+	if (ret < 3) {
+		dev_err(codec->dev, "Error while parsing dai_id for %s\n",
+			w->name);
+		return -EINVAL;
+	}
+
+	mutex_lock(&codec->lock);
+	if (w->id == snd_soc_dapm_aif_in) {
+		if (enable)
+			ret = gbaudio_module_enable_tx(codec, module, dai_id);
+		else
+			ret = gbaudio_module_disable_tx(module, dai_id);
+	} else if (w->id == snd_soc_dapm_aif_out) {
+		if (enable)
+			ret = gbaudio_module_enable_rx(codec, module, dai_id);
+		else
+			ret = gbaudio_module_disable_rx(module, dai_id);
+	}
+
+	mutex_unlock(&codec->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(gbaudio_module_update);
+
+/*
+ * codec DAI ops
+ */
+static int gbcodec_startup(struct snd_pcm_substream *substream,
+			   struct snd_soc_dai *dai)
+{
+	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
+	struct gbaudio_stream_params *params;
+
+	mutex_lock(&codec->lock);
+
+	if (list_empty(&codec->module_list)) {
+		dev_err(codec->dev, "No codec module available\n");
+		mutex_unlock(&codec->lock);
+		return -ENODEV;
+	}
+
+	params = find_dai_stream_params(codec, dai->id, substream->stream);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+	params->state = GBAUDIO_CODEC_STARTUP;
+	mutex_unlock(&codec->lock);
+	/* to prevent suspend in case of active audio */
+	pm_stay_awake(dai->dev);
+
+	return 0;
+}
+
+static void gbcodec_shutdown(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
+	struct gbaudio_stream_params *params;
+
+	mutex_lock(&codec->lock);
+
+	if (list_empty(&codec->module_list))
+		dev_info(codec->dev, "No codec module available during shutdown\n");
+
+	params = find_dai_stream_params(codec, dai->id, substream->stream);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		mutex_unlock(&codec->lock);
+		return;
+	}
+	params->state = GBAUDIO_CODEC_SHUTDOWN;
+	mutex_unlock(&codec->lock);
+	pm_relax(dai->dev);
+	return;
+}
+
+static int gbcodec_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *hwparams,
+			     struct snd_soc_dai *dai)
+{
+	int ret;
+	uint8_t sig_bits, channels;
+	uint32_t format, rate;
+	struct gbaudio_module_info *module;
+	struct gbaudio_data_connection *data;
+	struct gb_bundle *bundle;
+	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
+	struct gbaudio_stream_params *params;
+
+	mutex_lock(&codec->lock);
+
+	if (list_empty(&codec->module_list)) {
+		dev_err(codec->dev, "No codec module available\n");
+		mutex_unlock(&codec->lock);
+		return -ENODEV;
+	}
+
+	/*
+	 * assuming, currently only 48000 Hz, 16BIT_LE, stereo
+	 * is supported, validate params before configuring codec
+	 */
+	if (params_channels(hwparams) != 2) {
+		dev_err(dai->dev, "Invalid channel count:%d\n",
+			params_channels(hwparams));
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+	channels = params_channels(hwparams);
+
+	if (params_rate(hwparams) != 48000) {
+		dev_err(dai->dev, "Invalid sampling rate:%d\n",
+			params_rate(hwparams));
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+	rate = GB_AUDIO_PCM_RATE_48000;
+
+	if (params_format(hwparams) != SNDRV_PCM_FORMAT_S16_LE) {
+		dev_err(dai->dev, "Invalid format:%d\n",
+			params_format(hwparams));
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+	format = GB_AUDIO_PCM_FMT_S16_LE;
+
+	/* find the data connection */
+	list_for_each_entry(module, &codec->module_list, list) {
+		data = find_data(module, dai->id);
+		if (data)
+			break;
+	}
+
+	if (!data) {
+		dev_err(dai->dev, "DATA connection missing\n");
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+
+	params = find_dai_stream_params(codec, dai->id, substream->stream);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+
+	bundle = to_gb_bundle(module->dev);
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret) {
+		mutex_unlock(&codec->lock);
+		return ret;
+	}
+
+	ret = gb_audio_apbridgea_set_config(data->connection, 0,
+					    AUDIO_APBRIDGEA_PCM_FMT_16,
+					    AUDIO_APBRIDGEA_PCM_RATE_48000,
+					    6144000);
+	if (ret) {
+		dev_err_ratelimited(dai->dev, "%d: Error during set_config\n",
+				    ret);
+		mutex_unlock(&codec->lock);
+		return ret;
+	}
+
+	gb_pm_runtime_put_noidle(bundle);
+
+	params->state = GBAUDIO_CODEC_HWPARAMS;
+	params->format = format;
+	params->rate = rate;
+	params->channels = channels;
+	params->sig_bits = sig_bits;
+
+	mutex_unlock(&codec->lock);
+	return 0;
+}
+
+static int gbcodec_prepare(struct snd_pcm_substream *substream,
+			   struct snd_soc_dai *dai)
+{
+	int ret;
+	struct gbaudio_module_info *module;
+	struct gbaudio_data_connection *data;
+	struct gb_bundle *bundle;
+	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
+	struct gbaudio_stream_params *params;
+
+	mutex_lock(&codec->lock);
+
+	if (list_empty(&codec->module_list)) {
+		dev_err(codec->dev, "No codec module available\n");
+		mutex_unlock(&codec->lock);
+		return -ENODEV;
+	}
+
+	list_for_each_entry(module, &codec->module_list, list) {
+		/* find the dai */
+		data = find_data(module, dai->id);
+		if (data)
+			break;
+	}
+	if (!data) {
+		dev_err(dai->dev, "DATA connection missing\n");
+		mutex_unlock(&codec->lock);
+		return -ENODEV;
+	}
+
+	params = find_dai_stream_params(codec, dai->id, substream->stream);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+
+	bundle = to_gb_bundle(module->dev);
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret) {
+		mutex_unlock(&codec->lock);
+		return ret;
+	}
+
+	switch (substream->stream) {
+	case SNDRV_PCM_STREAM_PLAYBACK:
+		ret = gb_audio_apbridgea_set_tx_data_size(data->connection, 0,
+							  192);
+		break;
+	case SNDRV_PCM_STREAM_CAPTURE:
+		ret = gb_audio_apbridgea_set_rx_data_size(data->connection, 0,
+							  192);
+		break;
+	}
+	if (ret) {
+		mutex_unlock(&codec->lock);
+		dev_err_ratelimited(dai->dev, "set_data_size failed:%d\n",
+				     ret);
+		return ret;
+	}
+
+	gb_pm_runtime_put_noidle(bundle);
+
+	params->state = GBAUDIO_CODEC_PREPARE;
+	mutex_unlock(&codec->lock);
+	return 0;
+}
+
+static int gbcodec_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
+{
+	int ret;
+	struct gbaudio_data_connection *data;
+	struct gbaudio_module_info *module;
+	struct gb_bundle *bundle;
+	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
+	struct gbaudio_stream_params *params;
+
+
+	dev_dbg(dai->dev, "Mute:%d, Direction:%s\n", mute,
+		stream ? "CAPTURE":"PLAYBACK");
+
+	mutex_lock(&codec->lock);
+
+	params = find_dai_stream_params(codec, dai->id, stream);
+	if (!params) {
+		dev_err(codec->dev, "Failed to fetch dai_stream pointer\n");
+		mutex_unlock(&codec->lock);
+		return -EINVAL;
+	}
+
+	if (list_empty(&codec->module_list)) {
+		dev_err(codec->dev, "No codec module available\n");
+		if (mute) {
+			params->state = GBAUDIO_CODEC_STOP;
+			ret = 0;
+		} else {
+			ret = -ENODEV;
+		}
+		mutex_unlock(&codec->lock);
+		return ret;
+	}
+
+	list_for_each_entry(module, &codec->module_list, list) {
+		/* find the dai */
+		data = find_data(module, dai->id);
+		if (data)
+			break;
+	}
+	if (!data) {
+		dev_err(dai->dev, "%s:%s DATA connection missing\n",
+			dai->name, module->name);
+		mutex_unlock(&codec->lock);
+		return -ENODEV;
+	}
+
+	bundle = to_gb_bundle(module->dev);
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret) {
+		mutex_unlock(&codec->lock);
+		return ret;
+	}
+
+	if (!mute && !stream) {/* start playback */
+		ret = gb_audio_apbridgea_prepare_tx(data->connection,
+						    0);
+		if (!ret)
+			ret = gb_audio_apbridgea_start_tx(data->connection,
+							  0, 0);
+		params->state = GBAUDIO_CODEC_START;
+	} else if (!mute && stream) {/* start capture */
+		ret = gb_audio_apbridgea_prepare_rx(data->connection,
+						    0);
+		if (!ret)
+			ret = gb_audio_apbridgea_start_rx(data->connection,
+							  0);
+		params->state = GBAUDIO_CODEC_START;
+	} else if (mute && !stream) {/* stop playback */
+		ret = gb_audio_apbridgea_stop_tx(data->connection, 0);
+		if (!ret)
+			ret = gb_audio_apbridgea_shutdown_tx(data->connection,
+							     0);
+		params->state = GBAUDIO_CODEC_STOP;
+	} else if (mute && stream) {/* stop capture */
+		ret = gb_audio_apbridgea_stop_rx(data->connection, 0);
+		if (!ret)
+			ret = gb_audio_apbridgea_shutdown_rx(data->connection,
+							     0);
+		params->state = GBAUDIO_CODEC_STOP;
+	} else
+		ret = -EINVAL;
+	if (ret)
+		dev_err_ratelimited(dai->dev,
+				    "%s:Error during %s %s stream:%d\n",
+				    module->name, mute ? "Mute" : "Unmute",
+				    stream ? "Capture" : "Playback", ret);
+
+	gb_pm_runtime_put_noidle(bundle);
+	mutex_unlock(&codec->lock);
+	return ret;
+}
+
+static struct snd_soc_dai_ops gbcodec_dai_ops = {
+	.startup = gbcodec_startup,
+	.shutdown = gbcodec_shutdown,
+	.hw_params = gbcodec_hw_params,
+	.prepare = gbcodec_prepare,
+	.mute_stream = gbcodec_mute_stream,
+};
+
+static struct snd_soc_dai_driver gbaudio_dai[] = {
+	{
+		.name = "apb-i2s0",
+		.id = 0,
+		.playback = {
+			.stream_name = "I2S 0 Playback",
+			.rates = SNDRV_PCM_RATE_48000,
+			.formats = SNDRV_PCM_FORMAT_S16_LE,
+			.rate_max = 48000,
+			.rate_min = 48000,
+			.channels_min = 1,
+			.channels_max = 2,
+		},
+		.capture = {
+			.stream_name = "I2S 0 Capture",
+			.rates = SNDRV_PCM_RATE_48000,
+			.formats = SNDRV_PCM_FORMAT_S16_LE,
+			.rate_max = 48000,
+			.rate_min = 48000,
+			.channels_min = 1,
+			.channels_max = 2,
+		},
+		.ops = &gbcodec_dai_ops,
+	},
+};
+
+static int gbaudio_init_jack(struct gbaudio_module_info *module,
+			     struct snd_soc_codec *codec)
+{
+	int ret;
+
+	if (!module->jack_mask)
+		return 0;
+
+	snprintf(module->jack_name, NAME_SIZE, "GB %d Headset Jack",
+		 module->dev_id);
+	ret = snd_soc_jack_new(codec, module->jack_name, module->jack_mask,
+			       &module->headset_jack);
+	if (ret) {
+		dev_err(module->dev, "Failed to create new jack\n");
+		return ret;
+	}
+
+	if (!module->button_mask)
+		return 0;
+
+	snprintf(module->button_name, NAME_SIZE, "GB %d Button Jack",
+		 module->dev_id);
+	ret = snd_soc_jack_new(codec, module->button_name, module->button_mask,
+			       &module->button_jack);
+	if (ret) {
+		dev_err(module->dev, "Failed to create button jack\n");
+		return ret;
+	}
+
+	/*
+	 * Currently, max 4 buttons are supported with following key mapping
+	 * BTN_0 = KEY_MEDIA
+	 * BTN_1 = KEY_VOICECOMMAND
+	 * BTN_2 = KEY_VOLUMEUP
+	 * BTN_3 = KEY_VOLUMEDOWN
+	 */
+
+	if (module->button_mask & SND_JACK_BTN_0) {
+		ret = snd_jack_set_key(module->button_jack.jack, SND_JACK_BTN_0,
+				       KEY_MEDIA);
+		if (ret) {
+			dev_err(module->dev, "Failed to set BTN_0\n");
+			return ret;
+		}
+	}
+
+	if (module->button_mask & SND_JACK_BTN_1) {
+		ret = snd_jack_set_key(module->button_jack.jack, SND_JACK_BTN_1,
+				       KEY_VOICECOMMAND);
+		if (ret) {
+			dev_err(module->dev, "Failed to set BTN_1\n");
+			return ret;
+		}
+	}
+
+	if (module->button_mask & SND_JACK_BTN_2) {
+		ret = snd_jack_set_key(module->button_jack.jack, SND_JACK_BTN_2,
+				       KEY_VOLUMEUP);
+		if (ret) {
+			dev_err(module->dev, "Failed to set BTN_2\n");
+			return ret;
+		}
+	}
+
+	if (module->button_mask & SND_JACK_BTN_3) {
+		ret = snd_jack_set_key(module->button_jack.jack, SND_JACK_BTN_3,
+				       KEY_VOLUMEDOWN);
+		if (ret) {
+			dev_err(module->dev, "Failed to set BTN_0\n");
+			return ret;
+		}
+	}
+
+	/* FIXME
+	 * verify if this is really required
+	set_bit(INPUT_PROP_NO_DUMMY_RELEASE,
+		module->button_jack.jack->input_dev->propbit);
+	*/
+
+	return 0;
+}
+
+int gbaudio_register_module(struct gbaudio_module_info *module)
+{
+	int ret;
+	struct snd_soc_codec *codec;
+	struct snd_card *card;
+	struct snd_soc_jack *jack = NULL;
+
+	if (!gbcodec) {
+		dev_err(module->dev, "GB Codec not yet probed\n");
+		return -EAGAIN;
+	}
+
+	codec = gbcodec->codec;
+	card = codec->card->snd_card;
+
+	down_write(&card->controls_rwsem);
+
+	if (module->num_dais) {
+		dev_err(gbcodec->dev,
+			"%d:DAIs not supported via gbcodec driver\n",
+			module->num_dais);
+		up_write(&card->controls_rwsem);
+		return -EINVAL;
+	}
+
+	ret = gbaudio_init_jack(module, codec);
+	if (ret) {
+		up_write(&card->controls_rwsem);
+		return ret;
+	}
+
+	if (module->dapm_widgets)
+		snd_soc_dapm_new_controls(&codec->dapm, module->dapm_widgets,
+					  module->num_dapm_widgets);
+	if (module->controls)
+		snd_soc_add_codec_controls(codec, module->controls,
+				     module->num_controls);
+	if (module->dapm_routes)
+		snd_soc_dapm_add_routes(&codec->dapm, module->dapm_routes,
+					module->num_dapm_routes);
+
+	/* card already instantiated, create widgets here only */
+	if (codec->card->instantiated) {
+		snd_soc_dapm_link_component_dai_widgets(codec->card,
+							&codec->dapm);
+#ifdef CONFIG_SND_JACK
+		/* register jack devices for this module from codec->jack_list */
+		list_for_each_entry(jack, &codec->jack_list, list) {
+			if ((jack == &module->headset_jack)
+			    || (jack == &module->button_jack))
+				snd_device_register(codec->card->snd_card,
+						    jack->jack);
+		}
+#endif
+	}
+
+	mutex_lock(&gbcodec->lock);
+	list_add(&module->list, &gbcodec->module_list);
+	mutex_unlock(&gbcodec->lock);
+
+	if (codec->card->instantiated)
+		ret = snd_soc_dapm_new_widgets(&codec->dapm);
+	dev_dbg(codec->dev, "Registered %s module\n", module->name);
+
+	up_write(&card->controls_rwsem);
+	return ret;
+}
+EXPORT_SYMBOL(gbaudio_register_module);
+
+static void gbaudio_codec_clean_data_tx(struct gbaudio_data_connection *data)
+{
+	uint16_t i2s_port, cportid;
+	int ret;
+
+	if (list_is_singular(&gbcodec->module_list)) {
+		ret = gb_audio_apbridgea_stop_tx(data->connection, 0);
+		if (ret)
+			return;
+		ret = gb_audio_apbridgea_shutdown_tx(data->connection,
+						     0);
+		if (ret)
+			return;
+	}
+	i2s_port = 0;	/* fixed for now */
+	cportid = data->connection->hd_cport_id;
+	ret = gb_audio_apbridgea_unregister_cport(data->connection,
+						  i2s_port, cportid,
+						  AUDIO_APBRIDGEA_DIRECTION_TX);
+	data->state[0] = GBAUDIO_CODEC_SHUTDOWN;
+}
+
+static void gbaudio_codec_clean_data_rx(struct gbaudio_data_connection *data)
+{
+	uint16_t i2s_port, cportid;
+	int ret;
+
+	if (list_is_singular(&gbcodec->module_list)) {
+		ret = gb_audio_apbridgea_stop_rx(data->connection, 0);
+		if (ret)
+			return;
+		ret = gb_audio_apbridgea_shutdown_rx(data->connection,
+						     0);
+		if (ret)
+			return;
+	}
+	i2s_port = 0;	/* fixed for now */
+	cportid = data->connection->hd_cport_id;
+	ret = gb_audio_apbridgea_unregister_cport(data->connection,
+						  i2s_port, cportid,
+						  AUDIO_APBRIDGEA_DIRECTION_RX);
+	data->state[1] = GBAUDIO_CODEC_SHUTDOWN;
+}
+
+
+static void gbaudio_codec_cleanup(struct gbaudio_module_info *module)
+{
+	struct gbaudio_data_connection *data;
+	int pb_state, cap_state;
+
+	dev_dbg(gbcodec->dev, "%s: removed, cleanup APBridge\n", module->name);
+	list_for_each_entry(data, &module->data_list, list) {
+		pb_state = data->state[0];
+		cap_state = data->state[1];
+
+		if (pb_state > GBAUDIO_CODEC_SHUTDOWN)
+			gbaudio_codec_clean_data_tx(data);
+
+		if (cap_state > GBAUDIO_CODEC_SHUTDOWN)
+			gbaudio_codec_clean_data_rx(data);
+
+	}
+}
+
+void gbaudio_unregister_module(struct gbaudio_module_info *module)
+{
+	struct snd_soc_codec *codec = gbcodec->codec;
+	struct snd_card *card = codec->card->snd_card;
+	struct snd_soc_jack *jack, *next_j;
+	int mask;
+
+	dev_dbg(codec->dev, "Unregister %s module\n", module->name);
+
+	down_write(&card->controls_rwsem);
+	mutex_lock(&gbcodec->lock);
+	gbaudio_codec_cleanup(module);
+	list_del(&module->list);
+	dev_dbg(codec->dev, "Process Unregister %s module\n", module->name);
+	mutex_unlock(&gbcodec->lock);
+
+#ifdef CONFIG_SND_JACK
+	/* free jack devices for this module from codec->jack_list */
+	list_for_each_entry_safe(jack, next_j, &codec->jack_list, list) {
+		if (jack == &module->headset_jack)
+			mask = GBCODEC_JACK_MASK;
+		else if (jack == &module->button_jack)
+			mask = GBCODEC_JACK_BUTTON_MASK;
+		else
+			mask = 0;
+		if (mask) {
+			dev_dbg(module->dev, "Report %s removal\n",
+				jack->jack->id);
+			snd_soc_jack_report(jack, 0, mask);
+			snd_device_free(codec->card->snd_card, jack->jack);
+			list_del(&jack->list);
+		}
+	}
+#endif
+
+	if (module->dapm_routes) {
+		dev_dbg(codec->dev, "Removing %d routes\n",
+			module->num_dapm_routes);
+		snd_soc_dapm_del_routes(&codec->dapm, module->dapm_routes,
+					module->num_dapm_routes);
+	}
+	if (module->controls) {
+		dev_dbg(codec->dev, "Removing %d controls\n",
+			module->num_controls);
+		snd_soc_remove_codec_controls(codec, module->controls,
+					  module->num_controls);
+	}
+	if (module->dapm_widgets) {
+		dev_dbg(codec->dev, "Removing %d widgets\n",
+			module->num_dapm_widgets);
+		snd_soc_dapm_free_controls(&codec->dapm, module->dapm_widgets,
+					   module->num_dapm_widgets);
+	}
+
+	dev_dbg(codec->dev, "Unregistered %s module\n", module->name);
+
+	up_write(&card->controls_rwsem);
+}
+EXPORT_SYMBOL(gbaudio_unregister_module);
+
+/*
+ * codec driver ops
+ */
+static int gbcodec_probe(struct snd_soc_codec *codec)
+{
+	int i;
+	struct gbaudio_codec_info *info;
+	struct gbaudio_codec_dai *dai;
+
+	info = devm_kzalloc(codec->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->dev = codec->dev;
+	INIT_LIST_HEAD(&info->module_list);
+	mutex_init(&info->lock);
+	INIT_LIST_HEAD(&info->dai_list);
+
+	/* init dai_list used to maintain runtime stream info */
+	for (i = 0; i < ARRAY_SIZE(gbaudio_dai); i++) {
+		dai = devm_kzalloc(codec->dev, sizeof(*dai), GFP_KERNEL);
+		if (!dai)
+			return -ENOMEM;
+		dai->id = gbaudio_dai[i].id;
+		list_add(&dai->list, &info->dai_list);
+	}
+
+	info->codec = codec;
+	snd_soc_codec_set_drvdata(codec, info);
+	gbcodec = info;
+
+        device_init_wakeup(codec->dev, 1);
+	return 0;
+}
+
+static int gbcodec_remove(struct snd_soc_codec *codec)
+{
+	/* Empty function for now */
+	return 0;
+}
+
+static u8 gbcodec_reg[GBCODEC_REG_COUNT] = {
+	[GBCODEC_CTL_REG] = GBCODEC_CTL_REG_DEFAULT,
+	[GBCODEC_MUTE_REG] = GBCODEC_MUTE_REG_DEFAULT,
+	[GBCODEC_PB_LVOL_REG] = GBCODEC_PB_VOL_REG_DEFAULT,
+	[GBCODEC_PB_RVOL_REG] = GBCODEC_PB_VOL_REG_DEFAULT,
+	[GBCODEC_CAP_LVOL_REG] = GBCODEC_CAP_VOL_REG_DEFAULT,
+	[GBCODEC_CAP_RVOL_REG] = GBCODEC_CAP_VOL_REG_DEFAULT,
+	[GBCODEC_APB1_MUX_REG] = GBCODEC_APB1_MUX_REG_DEFAULT,
+	[GBCODEC_APB2_MUX_REG] = GBCODEC_APB2_MUX_REG_DEFAULT,
+};
+
+static int gbcodec_write(struct snd_soc_codec *codec, unsigned int reg,
+			 unsigned int value)
+{
+	int ret = 0;
+
+	if (reg == SND_SOC_NOPM)
+		return 0;
+
+	BUG_ON(reg >= GBCODEC_REG_COUNT);
+
+	gbcodec_reg[reg] = value;
+	dev_dbg(codec->dev, "reg[%d] = 0x%x\n", reg, value);
+
+	return ret;
+}
+
+static unsigned int gbcodec_read(struct snd_soc_codec *codec,
+				 unsigned int reg)
+{
+	unsigned int val = 0;
+
+	if (reg == SND_SOC_NOPM)
+		return 0;
+
+	BUG_ON(reg >= GBCODEC_REG_COUNT);
+
+	val = gbcodec_reg[reg];
+	dev_dbg(codec->dev, "reg[%d] = 0x%x\n", reg, val);
+
+	return val;
+}
+
+static struct snd_soc_codec_driver soc_codec_dev_gbaudio = {
+	.probe	= gbcodec_probe,
+	.remove	= gbcodec_remove,
+
+	.read = gbcodec_read,
+	.write = gbcodec_write,
+
+	.reg_cache_size = GBCODEC_REG_COUNT,
+	.reg_cache_default = gbcodec_reg_defaults,
+	.reg_word_size = 1,
+
+	.idle_bias_off = true,
+	.ignore_pmdown_time = 1,
+};
+
+#ifdef CONFIG_PM
+static int gbaudio_codec_suspend(struct device *dev)
+{
+	dev_dbg(dev, "%s: suspend\n", __func__);
+	return 0;
+}
+
+static int gbaudio_codec_resume(struct device *dev)
+{
+	dev_dbg(dev, "%s: resume\n", __func__);
+	return 0;
+}
+
+static const struct dev_pm_ops gbaudio_codec_pm_ops = {
+	.suspend	= gbaudio_codec_suspend,
+	.resume		= gbaudio_codec_resume,
+};
+#endif
+
+static int gbaudio_codec_probe(struct platform_device *pdev)
+{
+	return snd_soc_register_codec(&pdev->dev, &soc_codec_dev_gbaudio,
+			gbaudio_dai, ARRAY_SIZE(gbaudio_dai));
+}
+
+static int gbaudio_codec_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_codec(&pdev->dev);
+	return 0;
+}
+
+static const struct of_device_id greybus_asoc_machine_of_match[]  = {
+	{ .compatible = "toshiba,apb-dummy-codec", },
+	{},
+};
+
+static struct platform_driver gbaudio_codec_driver = {
+	.driver = {
+		.name = "apb-dummy-codec",
+		.owner = THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm = &gbaudio_codec_pm_ops,
+#endif
+		.of_match_table = greybus_asoc_machine_of_match,
+	},
+	.probe = gbaudio_codec_probe,
+	.remove = gbaudio_codec_remove,
+};
+module_platform_driver(gbaudio_codec_driver);
+
+MODULE_DESCRIPTION("APBridge ALSA SoC dummy codec driver");
+MODULE_AUTHOR("Vaibhav Agarwal <vaibhav.agarwal@linaro.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:apb-dummy-codec");
diff --git a/drivers/staging/greybus/audio_codec.h b/drivers/staging/greybus/audio_codec.h
new file mode 100644
index 000000000000..0a864592560f
--- /dev/null
+++ b/drivers/staging/greybus/audio_codec.h
@@ -0,0 +1,283 @@
+/*
+ * Greybus audio driver
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __LINUX_GBAUDIO_CODEC_H
+#define __LINUX_GBAUDIO_CODEC_H
+
+#include <sound/soc.h>
+#include <sound/jack.h>
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+
+#define NAME_SIZE	32
+#define MAX_DAIS	2	/* APB1, APB2 */
+
+enum {
+	APB1_PCM = 0,
+	APB2_PCM,
+	NUM_CODEC_DAIS,
+};
+
+enum gbcodec_reg_index {
+	GBCODEC_CTL_REG,
+	GBCODEC_MUTE_REG,
+	GBCODEC_PB_LVOL_REG,
+	GBCODEC_PB_RVOL_REG,
+	GBCODEC_CAP_LVOL_REG,
+	GBCODEC_CAP_RVOL_REG,
+	GBCODEC_APB1_MUX_REG,
+	GBCODEC_APB2_MUX_REG,
+	GBCODEC_REG_COUNT
+};
+
+/* device_type should be same as defined in audio.h (Android media layer) */
+enum {
+	GBAUDIO_DEVICE_NONE                     = 0x0,
+	/* reserved bits */
+	GBAUDIO_DEVICE_BIT_IN                   = 0x80000000,
+	GBAUDIO_DEVICE_BIT_DEFAULT              = 0x40000000,
+	/* output devices */
+	GBAUDIO_DEVICE_OUT_SPEAKER              = 0x2,
+	GBAUDIO_DEVICE_OUT_WIRED_HEADSET        = 0x4,
+	GBAUDIO_DEVICE_OUT_WIRED_HEADPHONE      = 0x8,
+	/* input devices */
+	GBAUDIO_DEVICE_IN_BUILTIN_MIC           = GBAUDIO_DEVICE_BIT_IN | 0x4,
+	GBAUDIO_DEVICE_IN_WIRED_HEADSET         = GBAUDIO_DEVICE_BIT_IN | 0x10,
+};
+
+/* bit 0-SPK, 1-HP, 2-DAC,
+ * 4-MIC, 5-HSMIC, 6-MIC2
+ */
+#define GBCODEC_CTL_REG_DEFAULT		0x00
+
+/* bit 0,1 - APB1-PB-L/R
+ * bit 2,3 - APB2-PB-L/R
+ * bit 4,5 - APB1-Cap-L/R
+ * bit 6,7 - APB2-Cap-L/R
+ */
+#define	GBCODEC_MUTE_REG_DEFAULT	0x00
+
+/* 0-127 steps */
+#define	GBCODEC_PB_VOL_REG_DEFAULT	0x00
+#define	GBCODEC_CAP_VOL_REG_DEFAULT	0x00
+
+/* bit 0,1,2 - PB stereo, left, right
+ * bit 8,9,10 - Cap stereo, left, right
+ */
+#define GBCODEC_APB1_MUX_REG_DEFAULT	0x00
+#define GBCODEC_APB2_MUX_REG_DEFAULT	0x00
+
+#define GBCODEC_JACK_MASK		0x0000FFFF
+#define GBCODEC_JACK_BUTTON_MASK	0xFFFF0000
+
+static const u8 gbcodec_reg_defaults[GBCODEC_REG_COUNT] = {
+	GBCODEC_CTL_REG_DEFAULT,
+	GBCODEC_MUTE_REG_DEFAULT,
+	GBCODEC_PB_VOL_REG_DEFAULT,
+	GBCODEC_PB_VOL_REG_DEFAULT,
+	GBCODEC_CAP_VOL_REG_DEFAULT,
+	GBCODEC_CAP_VOL_REG_DEFAULT,
+	GBCODEC_APB1_MUX_REG_DEFAULT,
+	GBCODEC_APB2_MUX_REG_DEFAULT,
+};
+
+enum gbaudio_codec_state {
+	GBAUDIO_CODEC_SHUTDOWN = 0,
+	GBAUDIO_CODEC_STARTUP,
+	GBAUDIO_CODEC_HWPARAMS,
+	GBAUDIO_CODEC_PREPARE,
+	GBAUDIO_CODEC_START,
+	GBAUDIO_CODEC_STOP,
+};
+
+struct gbaudio_stream_params {
+	int state;
+	uint8_t sig_bits, channels;
+	uint32_t format, rate;
+};
+
+struct gbaudio_codec_dai {
+	int id;
+	/* runtime params for playback/capture streams */
+	struct gbaudio_stream_params params[2];
+	struct list_head list;
+};
+
+struct gbaudio_codec_info {
+	struct device *dev;
+	struct snd_soc_codec *codec;
+	struct list_head module_list;
+	/* to maintain runtime stream params for each DAI */
+	struct list_head dai_list;
+	struct mutex lock;
+	u8 reg[GBCODEC_REG_COUNT];
+};
+
+struct gbaudio_widget {
+	__u8 id;
+	const char *name;
+	struct list_head list;
+};
+
+struct gbaudio_control {
+	__u8 id;
+	char *name;
+	char *wname;
+	const char * const *texts;
+	int items;
+	struct list_head list;
+};
+
+struct gbaudio_data_connection {
+	int id;
+	__le16 data_cport;
+	struct gb_connection *connection;
+	struct list_head list;
+	/* maintain runtime state for playback/capture stream */
+	int state[2];
+};
+
+/* stream direction */
+#define GB_PLAYBACK	BIT(0)
+#define GB_CAPTURE	BIT(1)
+
+enum gbaudio_module_state {
+	GBAUDIO_MODULE_OFF = 0,
+	GBAUDIO_MODULE_ON,
+};
+
+struct gbaudio_module_info {
+	/* module info */
+	struct device *dev;
+	int dev_id;	/* check if it should be bundle_id/hd_cport_id */
+	int vid;
+	int pid;
+	int slot;
+	int type;
+	int set_uevent;
+	char vstr[NAME_SIZE];
+	char pstr[NAME_SIZE];
+	struct list_head list;
+	/* need to share this info to above user space */
+	int manager_id;
+	char name[NAME_SIZE];
+	unsigned int ip_devices;
+	unsigned int op_devices;
+
+	/* jack related */
+	char jack_name[NAME_SIZE];
+	char button_name[NAME_SIZE];
+	int jack_type;
+	int jack_mask;
+	int button_mask;
+	int button_status;
+	struct snd_soc_jack headset_jack;
+	struct snd_soc_jack button_jack;
+
+	/* connection info */
+	struct gb_connection *mgmt_connection;
+	size_t num_data_connections;
+	struct list_head data_list;
+
+	/* topology related */
+	int num_dais;
+	int num_controls;
+	int num_dapm_widgets;
+	int num_dapm_routes;
+	unsigned long dai_offset;
+	unsigned long widget_offset;
+	unsigned long control_offset;
+	unsigned long route_offset;
+	struct snd_kcontrol_new *controls;
+	struct snd_soc_dapm_widget *dapm_widgets;
+	struct snd_soc_dapm_route *dapm_routes;
+	struct snd_soc_dai_driver *dais;
+
+	struct list_head widget_list;
+	struct list_head ctl_list;
+	struct list_head widget_ctl_list;
+
+	struct gb_audio_topology *topology;
+};
+
+int gbaudio_tplg_parse_data(struct gbaudio_module_info *module,
+			       struct gb_audio_topology *tplg_data);
+void gbaudio_tplg_release(struct gbaudio_module_info *module);
+
+int gbaudio_module_update(struct gbaudio_codec_info *codec,
+			  struct snd_soc_dapm_widget *w,
+			  struct gbaudio_module_info *module,
+			  int enable);
+int gbaudio_register_module(struct gbaudio_module_info *module);
+void gbaudio_unregister_module(struct gbaudio_module_info *module);
+
+/* protocol related */
+extern int gb_audio_gb_get_topology(struct gb_connection *connection,
+				    struct gb_audio_topology **topology);
+extern int gb_audio_gb_get_control(struct gb_connection *connection,
+				   uint8_t control_id, uint8_t index,
+				   struct gb_audio_ctl_elem_value *value);
+extern int gb_audio_gb_set_control(struct gb_connection *connection,
+				   uint8_t control_id, uint8_t index,
+				   struct gb_audio_ctl_elem_value *value);
+extern int gb_audio_gb_enable_widget(struct gb_connection *connection,
+				     uint8_t widget_id);
+extern int gb_audio_gb_disable_widget(struct gb_connection *connection,
+				      uint8_t widget_id);
+extern int gb_audio_gb_get_pcm(struct gb_connection *connection,
+			       uint16_t data_cport, uint32_t *format,
+			       uint32_t *rate, uint8_t *channels,
+			       uint8_t *sig_bits);
+extern int gb_audio_gb_set_pcm(struct gb_connection *connection,
+			       uint16_t data_cport, uint32_t format,
+			       uint32_t rate, uint8_t channels,
+			       uint8_t sig_bits);
+extern int gb_audio_gb_set_tx_data_size(struct gb_connection *connection,
+					uint16_t data_cport, uint16_t size);
+extern int gb_audio_gb_activate_tx(struct gb_connection *connection,
+				   uint16_t data_cport);
+extern int gb_audio_gb_deactivate_tx(struct gb_connection *connection,
+				     uint16_t data_cport);
+extern int gb_audio_gb_set_rx_data_size(struct gb_connection *connection,
+					uint16_t data_cport, uint16_t size);
+extern int gb_audio_gb_activate_rx(struct gb_connection *connection,
+				   uint16_t data_cport);
+extern int gb_audio_gb_deactivate_rx(struct gb_connection *connection,
+				     uint16_t data_cport);
+extern int gb_audio_apbridgea_set_config(struct gb_connection *connection,
+					 __u16 i2s_port, __u32 format,
+					 __u32 rate, __u32 mclk_freq);
+extern int gb_audio_apbridgea_register_cport(struct gb_connection *connection,
+					     __u16 i2s_port, __u16 cportid,
+					     __u8 direction);
+extern int gb_audio_apbridgea_unregister_cport(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 cportid,
+					       __u8 direction);
+extern int gb_audio_apbridgea_set_tx_data_size(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 size);
+extern int gb_audio_apbridgea_prepare_tx(struct gb_connection *connection,
+					 __u16 i2s_port);
+extern int gb_audio_apbridgea_start_tx(struct gb_connection *connection,
+				       __u16 i2s_port, __u64 timestamp);
+extern int gb_audio_apbridgea_stop_tx(struct gb_connection *connection,
+				      __u16 i2s_port);
+extern int gb_audio_apbridgea_shutdown_tx(struct gb_connection *connection,
+					  __u16 i2s_port);
+extern int gb_audio_apbridgea_set_rx_data_size(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 size);
+extern int gb_audio_apbridgea_prepare_rx(struct gb_connection *connection,
+					 __u16 i2s_port);
+extern int gb_audio_apbridgea_start_rx(struct gb_connection *connection,
+				       __u16 i2s_port);
+extern int gb_audio_apbridgea_stop_rx(struct gb_connection *connection,
+				      __u16 i2s_port);
+extern int gb_audio_apbridgea_shutdown_rx(struct gb_connection *connection,
+					  __u16 i2s_port);
+
+#endif /* __LINUX_GBAUDIO_CODEC_H */
diff --git a/drivers/staging/greybus/audio_gb.c b/drivers/staging/greybus/audio_gb.c
new file mode 100644
index 000000000000..a2f1c92e7445
--- /dev/null
+++ b/drivers/staging/greybus/audio_gb.c
@@ -0,0 +1,228 @@
+/*
+ * Greybus Audio Device Class Protocol helpers
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+#include "operation.h"
+#include "audio_codec.h"
+
+/* TODO: Split into separate calls */
+int gb_audio_gb_get_topology(struct gb_connection *connection,
+			     struct gb_audio_topology **topology)
+{
+	struct gb_audio_get_topology_size_response size_resp;
+	struct gb_audio_topology *topo;
+	uint16_t size;
+	int ret;
+
+	ret = gb_operation_sync(connection, GB_AUDIO_TYPE_GET_TOPOLOGY_SIZE,
+				NULL, 0, &size_resp, sizeof(size_resp));
+	if (ret)
+		return ret;
+
+	size = le16_to_cpu(size_resp.size);
+	if (size < sizeof(*topo))
+		return -ENODATA;
+
+	topo = kzalloc(size, GFP_KERNEL);
+	if (!topo)
+		return -ENOMEM;
+
+	ret = gb_operation_sync(connection, GB_AUDIO_TYPE_GET_TOPOLOGY, NULL, 0,
+				topo, size);
+	if (ret) {
+		kfree(topo);
+		return ret;
+	}
+
+	*topology = topo;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_get_topology);
+
+int gb_audio_gb_get_control(struct gb_connection *connection,
+			    uint8_t control_id, uint8_t index,
+			    struct gb_audio_ctl_elem_value *value)
+{
+	struct gb_audio_get_control_request req;
+	struct gb_audio_get_control_response resp;
+	int ret;
+
+	req.control_id = control_id;
+	req.index = index;
+
+	ret = gb_operation_sync(connection, GB_AUDIO_TYPE_GET_CONTROL,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret)
+		return ret;
+
+	memcpy(value, &resp.value, sizeof(*value));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_get_control);
+
+int gb_audio_gb_set_control(struct gb_connection *connection,
+			    uint8_t control_id, uint8_t index,
+			    struct gb_audio_ctl_elem_value *value)
+{
+	struct gb_audio_set_control_request req;
+
+	req.control_id = control_id;
+	req.index = index;
+	memcpy(&req.value, value, sizeof(req.value));
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_SET_CONTROL,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_set_control);
+
+int gb_audio_gb_enable_widget(struct gb_connection *connection,
+			      uint8_t widget_id)
+{
+	struct gb_audio_enable_widget_request req;
+
+	req.widget_id = widget_id;
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_ENABLE_WIDGET,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_enable_widget);
+
+int gb_audio_gb_disable_widget(struct gb_connection *connection,
+			       uint8_t widget_id)
+{
+	struct gb_audio_disable_widget_request req;
+
+	req.widget_id = widget_id;
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_DISABLE_WIDGET,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_disable_widget);
+
+int gb_audio_gb_get_pcm(struct gb_connection *connection, uint16_t data_cport,
+			uint32_t *format, uint32_t *rate, uint8_t *channels,
+			uint8_t *sig_bits)
+{
+	struct gb_audio_get_pcm_request req;
+	struct gb_audio_get_pcm_response resp;
+	int ret;
+
+	req.data_cport = cpu_to_le16(data_cport);
+
+	ret = gb_operation_sync(connection, GB_AUDIO_TYPE_GET_PCM,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret)
+		return ret;
+
+	*format = le32_to_cpu(resp.format);
+	*rate = le32_to_cpu(resp.rate);
+	*channels = resp.channels;
+	*sig_bits = resp.sig_bits;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_get_pcm);
+
+int gb_audio_gb_set_pcm(struct gb_connection *connection, uint16_t data_cport,
+			uint32_t format, uint32_t rate, uint8_t channels,
+			uint8_t sig_bits)
+{
+	struct gb_audio_set_pcm_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+	req.format = cpu_to_le32(format);
+	req.rate = cpu_to_le32(rate);
+	req.channels = channels;
+	req.sig_bits = sig_bits;
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_SET_PCM,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_set_pcm);
+
+int gb_audio_gb_set_tx_data_size(struct gb_connection *connection,
+				 uint16_t data_cport, uint16_t size)
+{
+	struct gb_audio_set_tx_data_size_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+	req.size = cpu_to_le16(size);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_SET_TX_DATA_SIZE,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_set_tx_data_size);
+
+int gb_audio_gb_activate_tx(struct gb_connection *connection,
+			    uint16_t data_cport)
+{
+	struct gb_audio_activate_tx_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_ACTIVATE_TX,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_activate_tx);
+
+int gb_audio_gb_deactivate_tx(struct gb_connection *connection,
+			      uint16_t data_cport)
+{
+	struct gb_audio_deactivate_tx_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_DEACTIVATE_TX,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_deactivate_tx);
+
+int gb_audio_gb_set_rx_data_size(struct gb_connection *connection,
+				 uint16_t data_cport, uint16_t size)
+{
+	struct gb_audio_set_rx_data_size_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+	req.size = cpu_to_le16(size);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_SET_RX_DATA_SIZE,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_set_rx_data_size);
+
+int gb_audio_gb_activate_rx(struct gb_connection *connection,
+			    uint16_t data_cport)
+{
+	struct gb_audio_activate_rx_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_ACTIVATE_RX,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_activate_rx);
+
+int gb_audio_gb_deactivate_rx(struct gb_connection *connection,
+			      uint16_t data_cport)
+{
+	struct gb_audio_deactivate_rx_request req;
+
+	req.data_cport = cpu_to_le16(data_cport);
+
+	return gb_operation_sync(connection, GB_AUDIO_TYPE_DEACTIVATE_RX,
+				 &req, sizeof(req), NULL, 0);
+}
+EXPORT_SYMBOL_GPL(gb_audio_gb_deactivate_rx);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("greybus:audio-gb");
+MODULE_DESCRIPTION("Greybus Audio Device Class Protocol library");
+MODULE_AUTHOR("Mark Greer <mgreer@animalcreek.com>");
diff --git a/drivers/staging/greybus/audio_manager.c b/drivers/staging/greybus/audio_manager.c
new file mode 100644
index 000000000000..aa6508b44fab
--- /dev/null
+++ b/drivers/staging/greybus/audio_manager.c
@@ -0,0 +1,184 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rwlock.h>
+#include <linux/idr.h>
+
+#include "audio_manager.h"
+#include "audio_manager_private.h"
+
+static struct kset *manager_kset;
+
+static LIST_HEAD(modules_list);
+static DECLARE_RWSEM(modules_rwsem);
+static DEFINE_IDA(module_id);
+
+/* helpers */
+static struct gb_audio_manager_module *gb_audio_manager_get_locked(int id)
+{
+	struct gb_audio_manager_module *module;
+
+	if (id < 0)
+		return NULL;
+
+	list_for_each_entry(module, &modules_list, list) {
+		if (module->id == id)
+			return module;
+	}
+
+	return NULL;
+}
+
+/* public API */
+int gb_audio_manager_add(struct gb_audio_manager_module_descriptor *desc)
+{
+	struct gb_audio_manager_module *module;
+	int id;
+	int err;
+
+	id = ida_simple_get(&module_id, 0, 0, GFP_KERNEL);
+	err = gb_audio_manager_module_create(&module, manager_kset,
+					     id, desc);
+	if (err) {
+		ida_simple_remove(&module_id, id);
+		return err;
+	}
+
+	/* Add it to the list */
+	down_write(&modules_rwsem);
+	list_add_tail(&module->list, &modules_list);
+	up_write(&modules_rwsem);
+
+	return module->id;
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_add);
+
+int gb_audio_manager_remove(int id)
+{
+	struct gb_audio_manager_module *module;
+
+	down_write(&modules_rwsem);
+
+	module = gb_audio_manager_get_locked(id);
+	if (!module) {
+		up_write(&modules_rwsem);
+		return -EINVAL;
+	}
+	list_del(&module->list);
+	kobject_put(&module->kobj);
+	up_write(&modules_rwsem);
+	ida_simple_remove(&module_id, id);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_remove);
+
+void gb_audio_manager_remove_all(void)
+{
+	struct gb_audio_manager_module *module, *next;
+	int is_empty = 1;
+
+	down_write(&modules_rwsem);
+
+	list_for_each_entry_safe(module, next, &modules_list, list) {
+		list_del(&module->list);
+		kobject_put(&module->kobj);
+		ida_simple_remove(&module_id, module->id);
+	}
+
+	is_empty = list_empty(&modules_list);
+
+	up_write(&modules_rwsem);
+
+	if (!is_empty)
+		pr_warn("Not all nodes were deleted\n");
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_remove_all);
+
+struct gb_audio_manager_module *gb_audio_manager_get_module(int id)
+{
+	struct gb_audio_manager_module *module;
+
+	down_read(&modules_rwsem);
+	module = gb_audio_manager_get_locked(id);
+	kobject_get(&module->kobj);
+	up_read(&modules_rwsem);
+	return module;
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_get_module);
+
+void gb_audio_manager_put_module(struct gb_audio_manager_module *module)
+{
+	kobject_put(&module->kobj);
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_put_module);
+
+int gb_audio_manager_dump_module(int id)
+{
+	struct gb_audio_manager_module *module;
+
+	down_read(&modules_rwsem);
+	module = gb_audio_manager_get_locked(id);
+	up_read(&modules_rwsem);
+
+	if (!module)
+		return -EINVAL;
+
+	gb_audio_manager_module_dump(module);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_dump_module);
+
+void gb_audio_manager_dump_all(void)
+{
+	struct gb_audio_manager_module *module;
+	int count = 0;
+
+	down_read(&modules_rwsem);
+	list_for_each_entry(module, &modules_list, list) {
+		gb_audio_manager_module_dump(module);
+		count++;
+	}
+	up_read(&modules_rwsem);
+
+	pr_info("Number of connected modules: %d\n", count);
+}
+EXPORT_SYMBOL_GPL(gb_audio_manager_dump_all);
+
+/*
+ * module init/deinit
+ */
+static int __init manager_init(void)
+{
+	manager_kset = kset_create_and_add(GB_AUDIO_MANAGER_NAME, NULL,
+					   kernel_kobj);
+	if (!manager_kset)
+		return -ENOMEM;
+
+#ifdef GB_AUDIO_MANAGER_SYSFS
+	gb_audio_manager_sysfs_init(&manager_kset->kobj);
+#endif
+
+	return 0;
+}
+
+static void __exit manager_exit(void)
+{
+	gb_audio_manager_remove_all();
+	kset_unregister(manager_kset);
+	ida_destroy(&module_id);
+}
+
+module_init(manager_init);
+module_exit(manager_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Svetlin Ankov <ankov_svetlin@projectara.com>");
diff --git a/drivers/staging/greybus/audio_manager.h b/drivers/staging/greybus/audio_manager.h
new file mode 100644
index 000000000000..c4ca09754a6a
--- /dev/null
+++ b/drivers/staging/greybus/audio_manager.h
@@ -0,0 +1,83 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef _GB_AUDIO_MANAGER_H_
+#define _GB_AUDIO_MANAGER_H_
+
+#include <linux/kobject.h>
+#include <linux/list.h>
+
+#define GB_AUDIO_MANAGER_NAME "gb_audio_manager"
+#define GB_AUDIO_MANAGER_MODULE_NAME_LEN 64
+#define GB_AUDIO_MANAGER_MODULE_NAME_LEN_SSCANF "63"
+
+struct gb_audio_manager_module_descriptor {
+	char name[GB_AUDIO_MANAGER_MODULE_NAME_LEN];
+	int slot;
+	int vid;
+	int pid;
+	int cport;
+	unsigned int ip_devices;
+	unsigned int op_devices;
+};
+
+struct gb_audio_manager_module {
+	struct kobject kobj;
+	struct list_head list;
+	int id;
+	struct gb_audio_manager_module_descriptor desc;
+};
+
+/*
+ * Creates a new gb_audio_manager_module_descriptor, using the specified
+ * descriptor.
+ *
+ * Returns a negative result on error, or the id of the newly created module.
+ *
+ */
+int gb_audio_manager_add(struct gb_audio_manager_module_descriptor *desc);
+
+/*
+ * Removes a connected gb_audio_manager_module_descriptor for the specified ID.
+ *
+ * Returns zero on success, or a negative value on error.
+ */
+int gb_audio_manager_remove(int id);
+
+/*
+ * Removes all connected gb_audio_modules
+ *
+ * Returns zero on success, or a negative value on error.
+ */
+void gb_audio_manager_remove_all(void);
+
+/*
+ * Retrieves a gb_audio_manager_module_descriptor for the specified id.
+ * Returns the gb_audio_manager_module_descriptor structure,
+ * or NULL if there is no module with the specified ID.
+ */
+struct gb_audio_manager_module *gb_audio_manager_get_module(int id);
+
+/*
+ * Decreases the refcount of the module, obtained by the get function.
+ * Modules are removed via gb_audio_manager_remove
+ */
+void gb_audio_manager_put_module(struct gb_audio_manager_module *module);
+
+/*
+ * Dumps the module for the specified id
+ * Return 0 on success
+ */
+int gb_audio_manager_dump_module(int id);
+
+/*
+ * Dumps all connected modules
+ */
+void gb_audio_manager_dump_all(void);
+
+#endif /* _GB_AUDIO_MANAGER_H_ */
diff --git a/drivers/staging/greybus/audio_manager_module.c b/drivers/staging/greybus/audio_manager_module.c
new file mode 100644
index 000000000000..a10e96ad79c1
--- /dev/null
+++ b/drivers/staging/greybus/audio_manager_module.c
@@ -0,0 +1,258 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/slab.h>
+
+#include "audio_manager.h"
+#include "audio_manager_private.h"
+
+#define to_gb_audio_module_attr(x)	\
+		container_of(x, struct gb_audio_manager_module_attribute, attr)
+#define to_gb_audio_module(x)		\
+		container_of(x, struct gb_audio_manager_module, kobj)
+
+struct gb_audio_manager_module_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct gb_audio_manager_module *module,
+			struct gb_audio_manager_module_attribute *attr,
+			char *buf);
+	ssize_t (*store)(struct gb_audio_manager_module *module,
+			 struct gb_audio_manager_module_attribute *attr,
+			 const char *buf, size_t count);
+};
+
+static ssize_t gb_audio_module_attr_show(
+	struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct gb_audio_manager_module_attribute *attribute;
+	struct gb_audio_manager_module *module;
+
+	attribute = to_gb_audio_module_attr(attr);
+	module = to_gb_audio_module(kobj);
+
+	if (!attribute->show)
+		return -EIO;
+
+	return attribute->show(module, attribute, buf);
+}
+
+static ssize_t gb_audio_module_attr_store(struct kobject *kobj,
+					  struct attribute *attr,
+					  const char *buf, size_t len)
+{
+	struct gb_audio_manager_module_attribute *attribute;
+	struct gb_audio_manager_module *module;
+
+	attribute = to_gb_audio_module_attr(attr);
+	module = to_gb_audio_module(kobj);
+
+	if (!attribute->store)
+		return -EIO;
+
+	return attribute->store(module, attribute, buf, len);
+}
+
+static const struct sysfs_ops gb_audio_module_sysfs_ops = {
+	.show = gb_audio_module_attr_show,
+	.store = gb_audio_module_attr_store,
+};
+
+static void gb_audio_module_release(struct kobject *kobj)
+{
+	struct gb_audio_manager_module *module = to_gb_audio_module(kobj);
+
+	pr_info("Destroying audio module #%d\n", module->id);
+	/* TODO -> delete from list */
+	kfree(module);
+}
+
+static ssize_t gb_audio_module_name_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s", module->desc.name);
+}
+
+static struct gb_audio_manager_module_attribute gb_audio_module_name_attribute =
+	__ATTR(name, 0664, gb_audio_module_name_show, NULL);
+
+static ssize_t gb_audio_module_slot_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d", module->desc.slot);
+}
+
+static struct gb_audio_manager_module_attribute gb_audio_module_slot_attribute =
+	__ATTR(slot, 0664, gb_audio_module_slot_show, NULL);
+
+static ssize_t gb_audio_module_vid_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d", module->desc.vid);
+}
+
+static struct gb_audio_manager_module_attribute gb_audio_module_vid_attribute =
+	__ATTR(vid, 0664, gb_audio_module_vid_show, NULL);
+
+static ssize_t gb_audio_module_pid_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d", module->desc.pid);
+}
+
+static struct gb_audio_manager_module_attribute gb_audio_module_pid_attribute =
+	__ATTR(pid, 0664, gb_audio_module_pid_show, NULL);
+
+static ssize_t gb_audio_module_cport_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d", module->desc.cport);
+}
+
+static struct gb_audio_manager_module_attribute
+					gb_audio_module_cport_attribute =
+	__ATTR(cport, 0664, gb_audio_module_cport_show, NULL);
+
+static ssize_t gb_audio_module_ip_devices_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "0x%X", module->desc.ip_devices);
+}
+
+static struct gb_audio_manager_module_attribute
+					gb_audio_module_ip_devices_attribute =
+	__ATTR(ip_devices, 0664, gb_audio_module_ip_devices_show, NULL);
+
+static ssize_t gb_audio_module_op_devices_show(
+	struct gb_audio_manager_module *module,
+	struct gb_audio_manager_module_attribute *attr, char *buf)
+{
+	return sprintf(buf, "0x%X", module->desc.op_devices);
+}
+
+static struct gb_audio_manager_module_attribute
+					gb_audio_module_op_devices_attribute =
+	__ATTR(op_devices, 0664, gb_audio_module_op_devices_show, NULL);
+
+static struct attribute *gb_audio_module_default_attrs[] = {
+	&gb_audio_module_name_attribute.attr,
+	&gb_audio_module_slot_attribute.attr,
+	&gb_audio_module_vid_attribute.attr,
+	&gb_audio_module_pid_attribute.attr,
+	&gb_audio_module_cport_attribute.attr,
+	&gb_audio_module_ip_devices_attribute.attr,
+	&gb_audio_module_op_devices_attribute.attr,
+	NULL,   /* need to NULL terminate the list of attributes */
+};
+
+static struct kobj_type gb_audio_module_type = {
+	.sysfs_ops = &gb_audio_module_sysfs_ops,
+	.release = gb_audio_module_release,
+	.default_attrs = gb_audio_module_default_attrs,
+};
+
+static void send_add_uevent(struct gb_audio_manager_module *module)
+{
+	char name_string[128];
+	char slot_string[64];
+	char vid_string[64];
+	char pid_string[64];
+	char cport_string[64];
+	char ip_devices_string[64];
+	char op_devices_string[64];
+
+	char *envp[] = {
+		name_string,
+		slot_string,
+		vid_string,
+		pid_string,
+		cport_string,
+		ip_devices_string,
+		op_devices_string,
+		NULL
+	};
+
+	snprintf(name_string, 128, "NAME=%s", module->desc.name);
+	snprintf(slot_string, 64, "SLOT=%d", module->desc.slot);
+	snprintf(vid_string, 64, "VID=%d", module->desc.vid);
+	snprintf(pid_string, 64, "PID=%d", module->desc.pid);
+	snprintf(cport_string, 64, "CPORT=%d", module->desc.cport);
+	snprintf(ip_devices_string, 64, "I/P DEVICES=0x%X",
+		 module->desc.ip_devices);
+	snprintf(op_devices_string, 64, "O/P DEVICES=0x%X",
+		 module->desc.op_devices);
+
+	kobject_uevent_env(&module->kobj, KOBJ_ADD, envp);
+}
+
+int gb_audio_manager_module_create(
+	struct gb_audio_manager_module **module,
+	struct kset *manager_kset,
+	int id, struct gb_audio_manager_module_descriptor *desc)
+{
+	int err;
+	struct gb_audio_manager_module *m;
+
+	m = kzalloc(sizeof(*m), GFP_ATOMIC);
+	if (!m)
+		return -ENOMEM;
+
+	/* Initialize the node */
+	INIT_LIST_HEAD(&m->list);
+
+	/* Set the module id */
+	m->id = id;
+
+	/* Copy the provided descriptor */
+	memcpy(&m->desc, desc, sizeof(*desc));
+
+	/* set the kset */
+	m->kobj.kset = manager_kset;
+
+	/*
+	 * Initialize and add the kobject to the kernel.  All the default files
+	 * will be created here.  As we have already specified a kset for this
+	 * kobject, we don't have to set a parent for the kobject, the kobject
+	 * will be placed beneath that kset automatically.
+	 */
+	err = kobject_init_and_add(&m->kobj, &gb_audio_module_type, NULL, "%d",
+				   id);
+	if (err) {
+		pr_err("failed initializing kobject for audio module #%d\n",
+		       id);
+		kobject_put(&m->kobj);
+		return err;
+	}
+
+	/*
+	 * Notify the object was created
+	 */
+	send_add_uevent(m);
+
+	*module = m;
+	pr_info("Created audio module #%d\n", id);
+	return 0;
+}
+
+void gb_audio_manager_module_dump(struct gb_audio_manager_module *module)
+{
+	pr_info("audio module #%d name=%s slot=%d vid=%d pid=%d cport=%d i/p devices=0x%X o/p devices=0x%X\n",
+		module->id,
+		module->desc.name,
+		module->desc.slot,
+		module->desc.vid,
+		module->desc.pid,
+		module->desc.cport,
+		module->desc.ip_devices,
+		module->desc.op_devices);
+}
diff --git a/drivers/staging/greybus/audio_manager_private.h b/drivers/staging/greybus/audio_manager_private.h
new file mode 100644
index 000000000000..079ce953c256
--- /dev/null
+++ b/drivers/staging/greybus/audio_manager_private.h
@@ -0,0 +1,28 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef _GB_AUDIO_MANAGER_PRIVATE_H_
+#define _GB_AUDIO_MANAGER_PRIVATE_H_
+
+#include <linux/kobject.h>
+
+#include "audio_manager.h"
+
+int gb_audio_manager_module_create(
+	struct gb_audio_manager_module **module,
+	struct kset *manager_kset,
+	int id, struct gb_audio_manager_module_descriptor *desc);
+
+/* module destroyed via kobject_put */
+
+void gb_audio_manager_module_dump(struct gb_audio_manager_module *module);
+
+/* sysfs control */
+void gb_audio_manager_sysfs_init(struct kobject *kobj);
+
+#endif /* _GB_AUDIO_MANAGER_PRIVATE_H_ */
diff --git a/drivers/staging/greybus/audio_manager_sysfs.c b/drivers/staging/greybus/audio_manager_sysfs.c
new file mode 100644
index 000000000000..d8bf8591ff9e
--- /dev/null
+++ b/drivers/staging/greybus/audio_manager_sysfs.c
@@ -0,0 +1,102 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+#include "audio_manager.h"
+#include "audio_manager_private.h"
+
+static ssize_t manager_sysfs_add_store(
+	struct kobject *kobj, struct kobj_attribute *attr,
+	const char *buf, size_t count)
+{
+	struct gb_audio_manager_module_descriptor desc = { {0} };
+
+	int num = sscanf(buf,
+			"name=%" GB_AUDIO_MANAGER_MODULE_NAME_LEN_SSCANF "s "
+			"slot=%d vid=%d pid=%d cport=%d i/p devices=0x%X"
+			"o/p devices=0x%X",
+			desc.name, &desc.slot, &desc.vid, &desc.pid,
+			&desc.cport, &desc.ip_devices, &desc.op_devices);
+
+	if (num != 7)
+		return -EINVAL;
+
+	num = gb_audio_manager_add(&desc);
+	if (num < 0)
+		return -EINVAL;
+
+	return count;
+}
+
+static struct kobj_attribute manager_add_attribute =
+	__ATTR(add, 0664, NULL, manager_sysfs_add_store);
+
+static ssize_t manager_sysfs_remove_store(
+	struct kobject *kobj, struct kobj_attribute *attr,
+	const char *buf, size_t count)
+{
+	int id;
+
+	int num = sscanf(buf, "%d", &id);
+
+	if (num != 1)
+		return -EINVAL;
+
+	num = gb_audio_manager_remove(id);
+	if (num)
+		return num;
+
+	return count;
+}
+
+static struct kobj_attribute manager_remove_attribute =
+	__ATTR(remove, 0664, NULL, manager_sysfs_remove_store);
+
+static ssize_t manager_sysfs_dump_store(
+	struct kobject *kobj, struct kobj_attribute *attr,
+	const char *buf, size_t count)
+{
+	int id;
+
+	int num = sscanf(buf, "%d", &id);
+
+	if (num == 1) {
+		num = gb_audio_manager_dump_module(id);
+		if (num)
+			return num;
+	} else if (!strncmp("all", buf, 3))
+		gb_audio_manager_dump_all();
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static struct kobj_attribute manager_dump_attribute =
+	__ATTR(dump, 0664, NULL, manager_sysfs_dump_store);
+
+static void manager_sysfs_init_attribute(
+		struct kobject *kobj, struct kobj_attribute *kattr)
+{
+	int err;
+
+	err = sysfs_create_file(kobj, &kattr->attr);
+	if (err) {
+		pr_warn("creating the sysfs entry for %s failed: %d\n",
+			kattr->attr.name, err);
+	}
+}
+
+void gb_audio_manager_sysfs_init(struct kobject *kobj)
+{
+	manager_sysfs_init_attribute(kobj, &manager_add_attribute);
+	manager_sysfs_init_attribute(kobj, &manager_remove_attribute);
+	manager_sysfs_init_attribute(kobj, &manager_dump_attribute);
+}
diff --git a/drivers/staging/greybus/audio_module.c b/drivers/staging/greybus/audio_module.c
new file mode 100644
index 000000000000..ae1c0fa85752
--- /dev/null
+++ b/drivers/staging/greybus/audio_module.c
@@ -0,0 +1,482 @@
+/*
+ * Greybus audio driver
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <sound/soc.h>
+#include <sound/pcm_params.h>
+
+#include "audio_codec.h"
+#include "audio_apbridgea.h"
+#include "audio_manager.h"
+
+/*
+ * gb_snd management functions
+ */
+
+static int gbaudio_request_jack(struct gbaudio_module_info *module,
+				  struct gb_audio_jack_event_request *req)
+{
+	int report;
+	struct snd_jack *jack = module->headset_jack.jack;
+	struct snd_jack *btn_jack = module->button_jack.jack;
+
+	if (!jack) {
+		dev_err_ratelimited(module->dev,
+			"Invalid jack event received:type: %u, event: %u\n",
+			req->jack_attribute, req->event);
+		return -EINVAL;
+	}
+
+	dev_warn_ratelimited(module->dev,
+			     "Jack Event received: type: %u, event: %u\n",
+			     req->jack_attribute, req->event);
+
+	if (req->event == GB_AUDIO_JACK_EVENT_REMOVAL) {
+		module->jack_type = 0;
+		if (btn_jack && module->button_status) {
+			snd_soc_jack_report(&module->button_jack, 0,
+					    module->button_mask);
+			module->button_status = 0;
+		}
+		snd_soc_jack_report(&module->headset_jack, 0,
+				    module->jack_mask);
+		return 0;
+	}
+
+	report = req->jack_attribute & module->jack_mask;
+	if (!report) {
+		dev_err_ratelimited(module->dev,
+			"Invalid jack event received:type: %u, event: %u\n",
+			req->jack_attribute, req->event);
+		return -EINVAL;
+	}
+
+	if (module->jack_type)
+		dev_warn_ratelimited(module->dev,
+				     "Modifying jack from %d to %d\n",
+				     module->jack_type, report);
+
+	module->jack_type = report;
+	snd_soc_jack_report(&module->headset_jack, report, module->jack_mask);
+
+	return 0;
+}
+
+static int gbaudio_request_button(struct gbaudio_module_info *module,
+				  struct gb_audio_button_event_request *req)
+{
+	int soc_button_id, report;
+	struct snd_jack *btn_jack = module->button_jack.jack;
+
+	if (!btn_jack) {
+		dev_err_ratelimited(module->dev,
+			"Invalid button event received:type: %u, event: %u\n",
+			req->button_id, req->event);
+		return -EINVAL;
+	}
+
+	dev_warn_ratelimited(module->dev,
+			     "Button Event received: id: %u, event: %u\n",
+			     req->button_id, req->event);
+
+	/* currently supports 4 buttons only */
+	if (!module->jack_type) {
+		dev_err_ratelimited(module->dev,
+				    "Jack not present. Bogus event!!\n");
+		return -EINVAL;
+	}
+
+	report = module->button_status & module->button_mask;
+	soc_button_id = 0;
+
+	switch (req->button_id) {
+	case 1:
+		soc_button_id = SND_JACK_BTN_0 & module->button_mask;
+		break;
+
+	case 2:
+		soc_button_id = SND_JACK_BTN_1 & module->button_mask;
+		break;
+
+	case 3:
+		soc_button_id = SND_JACK_BTN_2 & module->button_mask;
+		break;
+
+	case 4:
+		soc_button_id = SND_JACK_BTN_3 & module->button_mask;
+		break;
+	}
+
+	if (!soc_button_id) {
+		dev_err_ratelimited(module->dev,
+				    "Invalid button request received\n");
+		return -EINVAL;
+	}
+
+	if (req->event == GB_AUDIO_BUTTON_EVENT_PRESS)
+		report = report | soc_button_id;
+	else
+		report = report & ~soc_button_id;
+
+	module->button_status = report;
+
+	snd_soc_jack_report(&module->button_jack, report, module->button_mask);
+
+	return 0;
+}
+
+static int gbaudio_request_stream(struct gbaudio_module_info *module,
+				  struct gb_audio_streaming_event_request *req)
+{
+	dev_warn(module->dev, "Audio Event received: cport: %u, event: %u\n",
+		 req->data_cport, req->event);
+
+	return 0;
+}
+
+static int gbaudio_codec_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gbaudio_module_info *module =
+		greybus_get_drvdata(connection->bundle);
+	struct gb_operation_msg_hdr *header = op->request->header;
+	struct gb_audio_streaming_event_request *stream_req;
+	struct gb_audio_jack_event_request *jack_req;
+	struct gb_audio_button_event_request *button_req;
+	int ret;
+
+	switch (header->type) {
+	case GB_AUDIO_TYPE_STREAMING_EVENT:
+		stream_req = op->request->payload;
+		ret = gbaudio_request_stream(module, stream_req);
+		break;
+
+	case GB_AUDIO_TYPE_JACK_EVENT:
+		jack_req = op->request->payload;
+		ret = gbaudio_request_jack(module, jack_req);
+		break;
+
+	case GB_AUDIO_TYPE_BUTTON_EVENT:
+		button_req = op->request->payload;
+		ret = gbaudio_request_button(module, button_req);
+		break;
+
+	default:
+		dev_err_ratelimited(&connection->bundle->dev,
+				    "Invalid Audio Event received\n");
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int gb_audio_add_mgmt_connection(struct gbaudio_module_info *gbmodule,
+				struct greybus_descriptor_cport *cport_desc,
+				struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+
+	/* Management Cport */
+	if (gbmodule->mgmt_connection) {
+		dev_err(&bundle->dev,
+			"Can't have multiple Management connections\n");
+		return -ENODEV;
+	}
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+					  gbaudio_codec_request_handler);
+	if (IS_ERR(connection))
+		return PTR_ERR(connection);
+
+	greybus_set_drvdata(bundle, gbmodule);
+	gbmodule->mgmt_connection = connection;
+
+	return 0;
+}
+
+static int gb_audio_add_data_connection(struct gbaudio_module_info *gbmodule,
+				struct greybus_descriptor_cport *cport_desc,
+				struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+	struct gbaudio_data_connection *dai;
+
+	dai = devm_kzalloc(gbmodule->dev, sizeof(*dai), GFP_KERNEL);
+	if (!dai) {
+		dev_err(gbmodule->dev, "DAI Malloc failure\n");
+		return -ENOMEM;
+	}
+
+	connection = gb_connection_create_offloaded(bundle,
+					le16_to_cpu(cport_desc->id),
+					GB_CONNECTION_FLAG_CSD);
+	if (IS_ERR(connection)) {
+		devm_kfree(gbmodule->dev, dai);
+		return PTR_ERR(connection);
+	}
+
+	greybus_set_drvdata(bundle, gbmodule);
+	dai->id = 0;
+	dai->data_cport = connection->intf_cport_id;
+	dai->connection = connection;
+	list_add(&dai->list, &gbmodule->data_list);
+
+	return 0;
+}
+
+/*
+ * This is the basic hook get things initialized and registered w/ gb
+ */
+
+static int gb_audio_probe(struct gb_bundle *bundle,
+			  const struct greybus_bundle_id *id)
+{
+	struct device *dev = &bundle->dev;
+	struct gbaudio_module_info *gbmodule;
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_audio_manager_module_descriptor desc;
+	struct gbaudio_data_connection *dai, *_dai;
+	int ret, i;
+	struct gb_audio_topology *topology;
+
+	/* There should be at least one Management and one Data cport */
+	if (bundle->num_cports < 2)
+		return -ENODEV;
+
+	/*
+	 * There can be only one Management connection and any number of data
+	 * connections.
+	 */
+	gbmodule = devm_kzalloc(dev, sizeof(*gbmodule), GFP_KERNEL);
+	if (!gbmodule)
+		return -ENOMEM;
+
+	gbmodule->num_data_connections = bundle->num_cports - 1;
+	INIT_LIST_HEAD(&gbmodule->data_list);
+	INIT_LIST_HEAD(&gbmodule->widget_list);
+	INIT_LIST_HEAD(&gbmodule->ctl_list);
+	INIT_LIST_HEAD(&gbmodule->widget_ctl_list);
+	gbmodule->dev = dev;
+	snprintf(gbmodule->name, NAME_SIZE, "%s.%s", dev->driver->name,
+		 dev_name(dev));
+	greybus_set_drvdata(bundle, gbmodule);
+
+	/* Create all connections */
+	for (i = 0; i < bundle->num_cports; i++) {
+		cport_desc = &bundle->cport_desc[i];
+
+		switch (cport_desc->protocol_id) {
+		case GREYBUS_PROTOCOL_AUDIO_MGMT:
+			ret = gb_audio_add_mgmt_connection(gbmodule, cport_desc,
+							   bundle);
+			if (ret)
+				goto destroy_connections;
+			break;
+		case GREYBUS_PROTOCOL_AUDIO_DATA:
+			ret = gb_audio_add_data_connection(gbmodule, cport_desc,
+							   bundle);
+			if (ret)
+				goto destroy_connections;
+			break;
+		default:
+			dev_err(dev, "Unsupported protocol: 0x%02x\n",
+				cport_desc->protocol_id);
+			ret = -ENODEV;
+			goto destroy_connections;
+		}
+	}
+
+	/* There must be a management cport */
+	if (!gbmodule->mgmt_connection) {
+		ret = -EINVAL;
+		dev_err(dev, "Missing management connection\n");
+		goto destroy_connections;
+	}
+
+	/* Initialize management connection */
+	ret = gb_connection_enable(gbmodule->mgmt_connection);
+	if (ret) {
+		dev_err(dev, "%d: Error while enabling mgmt connection\n", ret);
+		goto destroy_connections;
+	}
+	gbmodule->dev_id = gbmodule->mgmt_connection->intf->interface_id;
+
+	/*
+	 * FIXME: malloc for topology happens via audio_gb driver
+	 * should be done within codec driver itself
+	 */
+	ret = gb_audio_gb_get_topology(gbmodule->mgmt_connection, &topology);
+	if (ret) {
+		dev_err(dev, "%d:Error while fetching topology\n", ret);
+		goto disable_connection;
+	}
+
+	/* process topology data */
+	ret = gbaudio_tplg_parse_data(gbmodule, topology);
+	if (ret) {
+		dev_err(dev, "%d:Error while parsing topology data\n",
+			  ret);
+		goto free_topology;
+	}
+	gbmodule->topology = topology;
+
+	/* Initialize data connections */
+	list_for_each_entry(dai, &gbmodule->data_list, list) {
+		ret = gb_connection_enable(dai->connection);
+		if (ret) {
+			dev_err(dev,
+				"%d:Error while enabling %d:data connection\n",
+				ret, dai->data_cport);
+			goto disable_data_connection;
+		}
+	}
+
+	/* register module with gbcodec */
+	ret = gbaudio_register_module(gbmodule);
+	if (ret)
+		goto disable_data_connection;
+
+	/* inform above layer for uevent */
+	dev_dbg(dev, "Inform set_event:%d to above layer\n", 1);
+	/* prepare for the audio manager */
+	strlcpy(desc.name, gbmodule->name, GB_AUDIO_MANAGER_MODULE_NAME_LEN);
+	desc.slot = 1; /* todo */
+	desc.vid = 2; /* todo */
+	desc.pid = 3; /* todo */
+	desc.cport = gbmodule->dev_id;
+	desc.op_devices = gbmodule->op_devices;
+	desc.ip_devices = gbmodule->ip_devices;
+	gbmodule->manager_id = gb_audio_manager_add(&desc);
+
+	dev_dbg(dev, "Add GB Audio device:%s\n", gbmodule->name);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+disable_data_connection:
+	list_for_each_entry_safe(dai, _dai, &gbmodule->data_list, list)
+		gb_connection_disable(dai->connection);
+	gbaudio_tplg_release(gbmodule);
+	gbmodule->topology = NULL;
+
+free_topology:
+	kfree(topology);
+
+disable_connection:
+	gb_connection_disable(gbmodule->mgmt_connection);
+
+destroy_connections:
+	list_for_each_entry_safe(dai, _dai, &gbmodule->data_list, list) {
+		gb_connection_destroy(dai->connection);
+		list_del(&dai->list);
+		devm_kfree(dev, dai);
+	}
+
+	if (gbmodule->mgmt_connection)
+		gb_connection_destroy(gbmodule->mgmt_connection);
+
+	devm_kfree(dev, gbmodule);
+
+	return ret;
+}
+
+static void gb_audio_disconnect(struct gb_bundle *bundle)
+{
+	struct gbaudio_module_info *gbmodule = greybus_get_drvdata(bundle);
+	struct gbaudio_data_connection *dai, *_dai;
+
+	gb_pm_runtime_get_sync(bundle);
+
+	/* cleanup module related resources first */
+	gbaudio_unregister_module(gbmodule);
+
+	/* inform uevent to above layers */
+	gb_audio_manager_remove(gbmodule->manager_id);
+
+	gbaudio_tplg_release(gbmodule);
+	kfree(gbmodule->topology);
+	gbmodule->topology = NULL;
+	gb_connection_disable(gbmodule->mgmt_connection);
+	list_for_each_entry_safe(dai, _dai, &gbmodule->data_list, list) {
+		gb_connection_disable(dai->connection);
+		gb_connection_destroy(dai->connection);
+		list_del(&dai->list);
+		devm_kfree(gbmodule->dev, dai);
+	}
+	gb_connection_destroy(gbmodule->mgmt_connection);
+	gbmodule->mgmt_connection = NULL;
+
+	devm_kfree(&bundle->dev, gbmodule);
+}
+
+static const struct greybus_bundle_id gb_audio_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_AUDIO) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_audio_id_table);
+
+#ifdef CONFIG_PM
+static int gb_audio_suspend(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gbaudio_module_info *gbmodule = greybus_get_drvdata(bundle);
+	struct gbaudio_data_connection *dai;
+
+	list_for_each_entry(dai, &gbmodule->data_list, list)
+		gb_connection_disable(dai->connection);
+
+	gb_connection_disable(gbmodule->mgmt_connection);
+
+	return 0;
+}
+
+static int gb_audio_resume(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gbaudio_module_info *gbmodule = greybus_get_drvdata(bundle);
+	struct gbaudio_data_connection *dai;
+	int ret;
+
+	ret = gb_connection_enable(gbmodule->mgmt_connection);
+	if (ret) {
+		dev_err(dev, "%d:Error while enabling mgmt connection\n", ret);
+		return ret;
+	}
+
+	list_for_each_entry(dai, &gbmodule->data_list, list) {
+		ret = gb_connection_enable(dai->connection);
+		if (ret) {
+			dev_err(dev,
+				"%d:Error while enabling %d:data connection\n",
+				ret, dai->data_cport);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_audio_pm_ops = {
+	SET_RUNTIME_PM_OPS(gb_audio_suspend, gb_audio_resume, NULL)
+};
+
+static struct greybus_driver gb_audio_driver = {
+	.name		= "gb-audio",
+	.probe		= gb_audio_probe,
+	.disconnect	= gb_audio_disconnect,
+	.id_table	= gb_audio_id_table,
+	.driver.pm	= &gb_audio_pm_ops,
+};
+module_greybus_driver(gb_audio_driver);
+
+MODULE_DESCRIPTION("Greybus Audio module driver");
+MODULE_AUTHOR("Vaibhav Agarwal <vaibhav.agarwal@linaro.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:gbaudio-module");
diff --git a/drivers/staging/greybus/audio_topology.c b/drivers/staging/greybus/audio_topology.c
new file mode 100644
index 000000000000..5eef5367896c
--- /dev/null
+++ b/drivers/staging/greybus/audio_topology.c
@@ -0,0 +1,1442 @@
+/*
+ * Greybus audio driver
+ * Copyright 2015-2016 Google Inc.
+ * Copyright 2015-2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "audio_codec.h"
+#include "greybus_protocols.h"
+
+#define GBAUDIO_INVALID_ID	0xFF
+
+/* mixer control */
+struct gb_mixer_control {
+	int min, max;
+	unsigned int reg, rreg, shift, rshift, invert;
+};
+
+struct gbaudio_ctl_pvt {
+	unsigned int ctl_id;
+	unsigned int data_cport;
+	unsigned int access;
+	unsigned int vcount;
+	struct gb_audio_ctl_elem_info *info;
+};
+
+static struct gbaudio_module_info *find_gb_module(
+					struct gbaudio_codec_info *codec,
+					char const *name)
+{
+	int dev_id, ret;
+	char begin[NAME_SIZE];
+	struct gbaudio_module_info *module;
+
+	if (!name)
+		return NULL;
+
+	ret = sscanf(name, "%s %d", begin, &dev_id);
+	dev_dbg(codec->dev, "%s:Find module#%d\n", __func__, dev_id);
+
+	mutex_lock(&codec->lock);
+	list_for_each_entry(module, &codec->module_list, list) {
+		if (module->dev_id == dev_id) {
+			mutex_unlock(&codec->lock);
+			return module;
+		}
+	}
+	mutex_unlock(&codec->lock);
+	dev_warn(codec->dev, "%s: module#%d missing in codec list\n", name,
+		 dev_id);
+	return NULL;
+}
+
+static const char *gbaudio_map_controlid(struct gbaudio_module_info *module,
+					 __u8 control_id, __u8 index)
+{
+	struct gbaudio_control *control;
+
+	if (control_id == GBAUDIO_INVALID_ID)
+		return NULL;
+
+	list_for_each_entry(control, &module->ctl_list, list) {
+		if (control->id == control_id) {
+			if (index == GBAUDIO_INVALID_ID)
+				return control->name;
+			if (index >= control->items)
+				return NULL;
+			return control->texts[index];
+		}
+	}
+	list_for_each_entry(control, &module->widget_ctl_list, list) {
+		if (control->id == control_id) {
+			if (index == GBAUDIO_INVALID_ID)
+				return control->name;
+			if (index >= control->items)
+				return NULL;
+			return control->texts[index];
+		}
+	}
+	return NULL;
+}
+
+static int gbaudio_map_controlname(struct gbaudio_module_info *module,
+				   const char *name)
+{
+	struct gbaudio_control *control;
+
+	list_for_each_entry(control, &module->ctl_list, list) {
+		if (!strncmp(control->name, name, NAME_SIZE))
+			return control->id;
+	}
+
+	dev_warn(module->dev, "%s: missing in modules controls list\n", name);
+
+	return -EINVAL;
+}
+
+static int gbaudio_map_wcontrolname(struct gbaudio_module_info *module,
+				    const char *name)
+{
+	struct gbaudio_control *control;
+
+	list_for_each_entry(control, &module->widget_ctl_list, list) {
+		if (!strncmp(control->wname, name, NAME_SIZE))
+			return control->id;
+	}
+	dev_warn(module->dev, "%s: missing in modules controls list\n", name);
+
+	return -EINVAL;
+}
+
+static int gbaudio_map_widgetname(struct gbaudio_module_info *module,
+				  const char *name)
+{
+	struct gbaudio_widget *widget;
+	list_for_each_entry(widget, &module->widget_list, list) {
+		if (!strncmp(widget->name, name, NAME_SIZE))
+			return widget->id;
+	}
+	dev_warn(module->dev, "%s: missing in modules widgets list\n", name);
+
+	return -EINVAL;
+}
+
+static const char *gbaudio_map_widgetid(struct gbaudio_module_info *module,
+					__u8 widget_id)
+{
+	struct gbaudio_widget *widget;
+
+	list_for_each_entry(widget, &module->widget_list, list) {
+		if (widget->id == widget_id)
+			return widget->name;
+	}
+	return NULL;
+}
+
+static const char **gb_generate_enum_strings(struct gbaudio_module_info *gb,
+					     struct gb_audio_enumerated *gbenum)
+{
+	const char **strings;
+	int i;
+	__u8 *data;
+
+	strings = devm_kzalloc(gb->dev, sizeof(char *) * gbenum->items,
+			       GFP_KERNEL);
+	data = gbenum->names;
+
+	for (i = 0; i < gbenum->items; i++) {
+		strings[i] = (const char *)data;
+		while (*data != '\0')
+			data++;
+		data++;
+	}
+
+	return strings;
+}
+
+static int gbcodec_mixer_ctl_info(struct snd_kcontrol *kcontrol,
+		     struct snd_ctl_elem_info *uinfo)
+{
+	unsigned int max;
+	const char *name;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_info *info;
+	struct gbaudio_module_info *module;
+	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct gbaudio_codec_info *gbcodec = snd_soc_codec_get_drvdata(codec);
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+
+	if (!info) {
+		dev_err(module->dev, "NULL info for %s\n", uinfo->id.name);
+		return -EINVAL;
+	}
+
+	/* update uinfo */
+	uinfo->access = data->access;
+	uinfo->count = data->vcount;
+	uinfo->type = (snd_ctl_elem_type_t)info->type;
+
+	switch (info->type) {
+	case GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN:
+	case GB_AUDIO_CTL_ELEM_TYPE_INTEGER:
+		uinfo->value.integer.min = info->value.integer.min;
+		uinfo->value.integer.max = info->value.integer.max;
+		break;
+	case GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED:
+		max = info->value.enumerated.items;
+		uinfo->value.enumerated.items = max;
+		if (uinfo->value.enumerated.item > max - 1)
+			uinfo->value.enumerated.item = max - 1;
+		module = find_gb_module(gbcodec, kcontrol->id.name);
+		if (!module)
+			return -EINVAL;
+		name = gbaudio_map_controlid(module, data->ctl_id,
+					     uinfo->value.enumerated.item);
+		strlcpy(uinfo->value.enumerated.name, name, NAME_SIZE);
+		break;
+	default:
+		dev_err(codec->dev, "Invalid type: %d for %s:kcontrol\n",
+			info->type, kcontrol->id.name);
+		break;
+	}
+	return 0;
+}
+
+static int gbcodec_mixer_ctl_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	int ret;
+	struct gb_audio_ctl_elem_info *info;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, data->ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+		return ret;
+	}
+
+	/* update ucontrol */
+	switch (info->type) {
+	case GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN:
+	case GB_AUDIO_CTL_ELEM_TYPE_INTEGER:
+		ucontrol->value.integer.value[0] =
+			gbvalue.value.integer_value[0];
+		if (data->vcount == 2)
+			ucontrol->value.integer.value[1] =
+				gbvalue.value.integer_value[1];
+		break;
+	case GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED:
+		ucontrol->value.enumerated.item[0] =
+			gbvalue.value.enumerated_item[0];
+		if (data->vcount == 2)
+			ucontrol->value.enumerated.item[1] =
+				gbvalue.value.enumerated_item[1];
+		break;
+	default:
+		dev_err(codec->dev, "Invalid type: %d for %s:kcontrol\n",
+			info->type, kcontrol->id.name);
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
+static int gbcodec_mixer_ctl_put(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	int ret = 0;
+	struct gb_audio_ctl_elem_info *info;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+	bundle = to_gb_bundle(module->dev);
+
+	/* update ucontrol */
+	switch (info->type) {
+	case GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN:
+	case GB_AUDIO_CTL_ELEM_TYPE_INTEGER:
+		gbvalue.value.integer_value[0] =
+			ucontrol->value.integer.value[0];
+		if (data->vcount == 2)
+			gbvalue.value.integer_value[1] =
+				ucontrol->value.integer.value[1];
+		break;
+	case GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED:
+		gbvalue.value.enumerated_item[0] =
+			ucontrol->value.enumerated.item[0];
+		if (data->vcount == 2)
+			gbvalue.value.enumerated_item[1] =
+				ucontrol->value.enumerated.item[1];
+		break;
+	default:
+		dev_err(codec->dev, "Invalid type: %d for %s:kcontrol\n",
+			info->type, kcontrol->id.name);
+		ret = -EINVAL;
+		break;
+	}
+
+	if (ret)
+		return ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_set_control(module->mgmt_connection, data->ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+	}
+
+	return ret;
+}
+
+#define SOC_MIXER_GB(xname, kcount, data) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, \
+	.count = kcount, .info = gbcodec_mixer_ctl_info, \
+	.get = gbcodec_mixer_ctl_get, .put = gbcodec_mixer_ctl_put, \
+	.private_value = (unsigned long)data }
+
+/*
+ * although below callback functions seems redundant to above functions.
+ * same are kept to allow provision for different handling in case
+ * of DAPM related sequencing, etc.
+ */
+static int gbcodec_mixer_dapm_ctl_info(struct snd_kcontrol *kcontrol,
+		     struct snd_ctl_elem_info *uinfo)
+{
+	int platform_max, platform_min;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_info *info;
+	struct snd_soc_dapm_widget_list *wlist = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_dapm_widget *widget = wlist->widgets[0];
+	struct snd_soc_codec *codec = widget->codec;
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+
+	/* update uinfo */
+	platform_max = info->value.integer.max;
+	platform_min = info->value.integer.min;
+
+	if (platform_max == 1 &&
+	    !strnstr(kcontrol->id.name, " Volume", NAME_SIZE))
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	else
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+
+	uinfo->count = data->vcount;
+	uinfo->value.integer.min = 0;
+	if (info->value.integer.min < 0 &&
+	    (uinfo->type == SNDRV_CTL_ELEM_TYPE_INTEGER))
+		uinfo->value.integer.max = platform_max - platform_min;
+	else
+		uinfo->value.integer.max = platform_max;
+
+	return 0;
+}
+
+static int gbcodec_mixer_dapm_ctl_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	int ret;
+	struct gb_audio_ctl_elem_info *info;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct snd_soc_dapm_widget_list *wlist = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_dapm_widget *widget = wlist->widgets[0];
+	struct snd_soc_codec *codec = widget->codec;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+	bundle = to_gb_bundle(module->dev);
+
+	if (data->vcount == 2)
+		dev_warn(widget->dapm->dev,
+			 "GB: Control '%s' is stereo, which is not supported\n",
+			 kcontrol->id.name);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, data->ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+		return ret;
+	}
+	/* update ucontrol */
+	ucontrol->value.integer.value[0] = gbvalue.value.integer_value[0];
+
+	return ret;
+}
+
+static int gbcodec_mixer_dapm_ctl_put(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	int ret, wi, max, connect;
+	unsigned int mask, val;
+	struct gb_audio_ctl_elem_info *info;
+	struct gbaudio_ctl_pvt *data;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct snd_soc_dapm_widget_list *wlist = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_dapm_widget *widget = wlist->widgets[0];
+	struct snd_soc_codec *codec = widget->codec;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	dev_dbg(codec->dev, "Entered %s:%s\n", __func__, kcontrol->id.name);
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;
+	info = (struct gb_audio_ctl_elem_info *)data->info;
+	bundle = to_gb_bundle(module->dev);
+
+	if (data->vcount == 2)
+		dev_warn(widget->dapm->dev,
+			 "GB: Control '%s' is stereo, which is not supported\n",
+			 kcontrol->id.name);
+
+	max = info->value.integer.max;
+	mask = (1 << fls(max)) - 1;
+	val = (ucontrol->value.integer.value[0] & mask);
+	connect = !!val;
+
+	/* update ucontrol */
+	if (gbvalue.value.integer_value[0] != val) {
+		for (wi = 0; wi < wlist->num_widgets; wi++) {
+			widget = wlist->widgets[wi];
+
+			widget->value = val;
+			widget->dapm->update = NULL;
+			snd_soc_dapm_mixer_update_power(widget, kcontrol,
+							connect);
+		}
+		gbvalue.value.integer_value[0] =
+			ucontrol->value.integer.value[0];
+
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (ret)
+			return ret;
+
+		ret = gb_audio_gb_set_control(module->mgmt_connection,
+					      data->ctl_id,
+					      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+		gb_pm_runtime_put_autosuspend(bundle);
+
+		if (ret) {
+			dev_err_ratelimited(codec->dev,
+					    "%d:Error in %s for %s\n", ret,
+					    __func__, kcontrol->id.name);
+		}
+	}
+
+	return ret;
+}
+
+#define SOC_DAPM_MIXER_GB(xname, kcount, data) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, \
+	.count = kcount, .info = gbcodec_mixer_dapm_ctl_info, \
+	.get = gbcodec_mixer_dapm_ctl_get, .put = gbcodec_mixer_dapm_ctl_put, \
+	.private_value = (unsigned long)data}
+
+static int gbcodec_event_spk(struct snd_soc_dapm_widget *w,
+					struct snd_kcontrol *k, int event)
+{
+	/* Ensure GB speaker is connected */
+
+	return 0;
+}
+
+static int gbcodec_event_hp(struct snd_soc_dapm_widget *w,
+					struct snd_kcontrol *k, int event)
+{
+	/* Ensure GB module supports jack slot */
+
+	return 0;
+}
+
+static int gbcodec_event_int_mic(struct snd_soc_dapm_widget *w,
+					struct snd_kcontrol *k, int event)
+{
+	/* Ensure GB module supports jack slot */
+
+	return 0;
+}
+
+static int gbaudio_validate_kcontrol_count(struct gb_audio_widget *w)
+{
+	int ret = 0;
+
+	switch (w->type) {
+	case snd_soc_dapm_spk:
+	case snd_soc_dapm_hp:
+	case snd_soc_dapm_mic:
+	case snd_soc_dapm_output:
+	case snd_soc_dapm_input:
+		if (w->ncontrols)
+			ret = -EINVAL;
+		break;
+	case snd_soc_dapm_switch:
+	case snd_soc_dapm_mux:
+		if (w->ncontrols != 1)
+			ret = -EINVAL;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static int gbcodec_enum_ctl_get(struct snd_kcontrol *kcontrol,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	int ret, ctl_id;
+	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	ctl_id = gbaudio_map_controlname(module, kcontrol->id.name);
+	if (ctl_id < 0)
+		return -EINVAL;
+
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+		return ret;
+	}
+
+	ucontrol->value.enumerated.item[0] = gbvalue.value.enumerated_item[0];
+	if (e->shift_l != e->shift_r)
+		ucontrol->value.enumerated.item[1] =
+			gbvalue.value.enumerated_item[1];
+
+	return 0;
+}
+
+static int gbcodec_enum_ctl_put(struct snd_kcontrol *kcontrol,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	int ret, ctl_id;
+	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct gb_bundle *bundle;
+
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	ctl_id = gbaudio_map_controlname(module, kcontrol->id.name);
+	if (ctl_id < 0)
+		return -EINVAL;
+
+	if (ucontrol->value.enumerated.item[0] > e->max - 1)
+		return -EINVAL;
+	gbvalue.value.enumerated_item[0] = ucontrol->value.enumerated.item[0];
+
+	if (e->shift_l != e->shift_r) {
+		if (ucontrol->value.enumerated.item[1] > e->max - 1)
+			return -EINVAL;
+		gbvalue.value.enumerated_item[1] =
+			ucontrol->value.enumerated.item[1];
+	}
+
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_set_control(module->mgmt_connection, ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+	}
+
+	return ret;
+}
+
+static int gbaudio_tplg_create_enum_kctl(struct gbaudio_module_info *gb,
+					 struct snd_kcontrol_new *kctl,
+					 struct gb_audio_control *ctl)
+{
+	struct soc_enum *gbe;
+	struct gb_audio_enumerated *gb_enum;
+	int i;
+
+	gbe = devm_kzalloc(gb->dev, sizeof(*gbe), GFP_KERNEL);
+	if (!gbe)
+		return -ENOMEM;
+
+	gb_enum = &ctl->info.value.enumerated;
+
+	/* since count=1, and reg is dummy */
+	gbe->max = gb_enum->items;
+	gbe->texts = gb_generate_enum_strings(gb, gb_enum);
+
+	/* debug enum info */
+	dev_dbg(gb->dev, "Max:%d, name_length:%d\n", gb_enum->items,
+		 gb_enum->names_length);
+	for (i = 0; i < gb_enum->items; i++)
+		dev_dbg(gb->dev, "src[%d]: %s\n", i, gbe->texts[i]);
+
+	*kctl = (struct snd_kcontrol_new)
+		SOC_ENUM_EXT(ctl->name, *gbe, gbcodec_enum_ctl_get,
+			     gbcodec_enum_ctl_put);
+	return 0;
+}
+
+static int gbaudio_tplg_create_kcontrol(struct gbaudio_module_info *gb,
+					struct snd_kcontrol_new *kctl,
+					struct gb_audio_control *ctl)
+{
+	int ret = 0;
+	struct gbaudio_ctl_pvt *ctldata;
+
+	switch (ctl->iface) {
+	case SNDRV_CTL_ELEM_IFACE_MIXER:
+		switch (ctl->info.type) {
+		case GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED:
+			ret = gbaudio_tplg_create_enum_kctl(gb, kctl, ctl);
+			break;
+		default:
+			ctldata = devm_kzalloc(gb->dev,
+					       sizeof(struct gbaudio_ctl_pvt),
+					       GFP_KERNEL);
+			if (!ctldata)
+				return -ENOMEM;
+			ctldata->ctl_id = ctl->id;
+			ctldata->data_cport = ctl->data_cport;
+			ctldata->access = ctl->access;
+			ctldata->vcount = ctl->count_values;
+			ctldata->info = &ctl->info;
+			*kctl = (struct snd_kcontrol_new)
+				SOC_MIXER_GB(ctl->name, ctl->count, ctldata);
+			ctldata = NULL;
+			break;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(gb->dev, "%s:%d control created\n", ctl->name, ctl->id);
+	return ret;
+}
+
+static int gbcodec_enum_dapm_ctl_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	int ret, ctl_id;
+	struct snd_soc_dapm_widget_list *wlist = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_dapm_widget *widget = wlist->widgets[0];
+	struct gbaudio_module_info *module;
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct snd_soc_codec *codec = widget->codec;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	struct gb_bundle *bundle;
+
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	ctl_id = gbaudio_map_wcontrolname(module, kcontrol->id.name);
+	if (ctl_id < 0)
+		return -EINVAL;
+
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+		return ret;
+	}
+
+	ucontrol->value.enumerated.item[0] = gbvalue.value.enumerated_item[0];
+	if (e->shift_l != e->shift_r)
+		ucontrol->value.enumerated.item[1] =
+			gbvalue.value.enumerated_item[1];
+
+	return 0;
+}
+
+static int gbcodec_enum_dapm_ctl_put(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	int ret, wi, ctl_id;
+	unsigned int val, mux, change;
+	unsigned int mask;
+	struct snd_soc_dapm_widget_list *wlist = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_dapm_widget *widget = wlist->widgets[0];
+	struct gb_audio_ctl_elem_value gbvalue;
+	struct gbaudio_module_info *module;
+	struct snd_soc_codec *codec = widget->codec;
+	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	struct gb_bundle *bundle;
+
+	if (ucontrol->value.enumerated.item[0] > e->max - 1)
+		return -EINVAL;
+
+	module = find_gb_module(gb, kcontrol->id.name);
+	if (!module)
+		return -EINVAL;
+
+	ctl_id = gbaudio_map_wcontrolname(module, kcontrol->id.name);
+	if (ctl_id < 0)
+		return -EINVAL;
+
+	change = 0;
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	if (ret) {
+		dev_err_ratelimited(codec->dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+		return ret;
+	}
+
+	mux = ucontrol->value.enumerated.item[0];
+	val = mux << e->shift_l;
+	mask = e->mask << e->shift_l;
+
+	if (gbvalue.value.enumerated_item[0] !=
+	    ucontrol->value.enumerated.item[0]) {
+		change = 1;
+		gbvalue.value.enumerated_item[0] =
+			ucontrol->value.enumerated.item[0];
+	}
+
+	if (e->shift_l != e->shift_r) {
+		if (ucontrol->value.enumerated.item[1] > e->max - 1)
+			return -EINVAL;
+		val |= ucontrol->value.enumerated.item[1] << e->shift_r;
+		mask |= e->mask << e->shift_r;
+		if (gbvalue.value.enumerated_item[1] !=
+		    ucontrol->value.enumerated.item[1]) {
+			change = 1;
+			gbvalue.value.enumerated_item[1] =
+				ucontrol->value.enumerated.item[1];
+		}
+	}
+
+	if (change) {
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (ret)
+			return ret;
+
+		ret = gb_audio_gb_set_control(module->mgmt_connection, ctl_id,
+					      GB_AUDIO_INVALID_INDEX, &gbvalue);
+
+		gb_pm_runtime_put_autosuspend(bundle);
+
+		if (ret) {
+			dev_err_ratelimited(codec->dev,
+					    "%d:Error in %s for %s\n", ret,
+					    __func__, kcontrol->id.name);
+		}
+		for (wi = 0; wi < wlist->num_widgets; wi++) {
+			widget = wlist->widgets[wi];
+
+			widget->value = val;
+			widget->dapm->update = NULL;
+			snd_soc_dapm_mux_update_power(widget, kcontrol, mux, e);
+		}
+	}
+
+	return change;
+}
+
+static int gbaudio_tplg_create_enum_ctl(struct gbaudio_module_info *gb,
+					struct snd_kcontrol_new *kctl,
+					struct gb_audio_control *ctl)
+{
+	struct soc_enum *gbe;
+	struct gb_audio_enumerated *gb_enum;
+	int i;
+
+	gbe = devm_kzalloc(gb->dev, sizeof(*gbe), GFP_KERNEL);
+	if (!gbe)
+		return -ENOMEM;
+
+	gb_enum = &ctl->info.value.enumerated;
+
+	/* since count=1, and reg is dummy */
+	gbe->max = gb_enum->items;
+	gbe->texts = gb_generate_enum_strings(gb, gb_enum);
+
+	/* debug enum info */
+	dev_dbg(gb->dev, "Max:%d, name_length:%d\n", gb_enum->items,
+		 gb_enum->names_length);
+	for (i = 0; i < gb_enum->items; i++)
+		dev_dbg(gb->dev, "src[%d]: %s\n", i, gbe->texts[i]);
+
+	*kctl = (struct snd_kcontrol_new)
+		SOC_DAPM_ENUM_EXT(ctl->name, *gbe, gbcodec_enum_dapm_ctl_get,
+				  gbcodec_enum_dapm_ctl_put);
+	return 0;
+}
+
+static int gbaudio_tplg_create_mixer_ctl(struct gbaudio_module_info *gb,
+					     struct snd_kcontrol_new *kctl,
+					     struct gb_audio_control *ctl)
+{
+	struct gbaudio_ctl_pvt *ctldata;
+
+	ctldata = devm_kzalloc(gb->dev, sizeof(struct gbaudio_ctl_pvt),
+			       GFP_KERNEL);
+	if (!ctldata)
+		return -ENOMEM;
+	ctldata->ctl_id = ctl->id;
+	ctldata->data_cport = ctl->data_cport;
+	ctldata->access = ctl->access;
+	ctldata->vcount = ctl->count_values;
+	ctldata->info = &ctl->info;
+	*kctl = (struct snd_kcontrol_new)
+		SOC_DAPM_MIXER_GB(ctl->name, ctl->count, ctldata);
+
+	return 0;
+}
+
+static int gbaudio_tplg_create_wcontrol(struct gbaudio_module_info *gb,
+					     struct snd_kcontrol_new *kctl,
+					     struct gb_audio_control *ctl)
+{
+	int ret;
+
+	switch (ctl->iface) {
+	case SNDRV_CTL_ELEM_IFACE_MIXER:
+		switch (ctl->info.type) {
+		case GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED:
+			ret = gbaudio_tplg_create_enum_ctl(gb, kctl, ctl);
+			break;
+		default:
+			ret = gbaudio_tplg_create_mixer_ctl(gb, kctl, ctl);
+			break;
+		}
+		break;
+	default:
+		return -EINVAL;
+
+	}
+
+	dev_dbg(gb->dev, "%s:%d DAPM control created, ret:%d\n", ctl->name,
+		ctl->id, ret);
+	return ret;
+}
+
+static int gbaudio_widget_event(struct snd_soc_dapm_widget *w,
+				struct snd_kcontrol *kcontrol, int event)
+{
+	int wid;
+	int ret;
+	struct snd_soc_codec *codec = w->codec;
+	struct gbaudio_codec_info *gbcodec = snd_soc_codec_get_drvdata(codec);
+	struct gbaudio_module_info *module;
+	struct gb_bundle *bundle;
+
+	dev_dbg(codec->dev, "%s %s %d\n", __func__, w->name, event);
+
+	/* Find relevant module */
+	module = find_gb_module(gbcodec, w->name);
+	if (!module)
+		return -EINVAL;
+
+	/* map name to widget id */
+	wid = gbaudio_map_widgetname(module, w->name);
+	if (wid < 0) {
+		dev_err(codec->dev, "Invalid widget name:%s\n", w->name);
+		return -EINVAL;
+	}
+
+	bundle = to_gb_bundle(module->dev);
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		ret = gb_audio_gb_enable_widget(module->mgmt_connection, wid);
+		if (!ret)
+			ret = gbaudio_module_update(gbcodec, w, module, 1);
+		break;
+	case SND_SOC_DAPM_POST_PMD:
+		ret = gb_audio_gb_disable_widget(module->mgmt_connection, wid);
+		if (!ret)
+			ret = gbaudio_module_update(gbcodec, w, module, 0);
+		break;
+	}
+	if (ret)
+		dev_err_ratelimited(codec->dev,
+				    "%d: widget, event:%d failed:%d\n", wid,
+				    event, ret);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int gbaudio_tplg_create_widget(struct gbaudio_module_info *module,
+				      struct snd_soc_dapm_widget *dw,
+				      struct gb_audio_widget *w, int *w_size)
+{
+	int i, ret, csize;
+	struct snd_kcontrol_new *widget_kctls;
+	struct gb_audio_control *curr;
+	struct gbaudio_control *control, *_control;
+	size_t size;
+	char temp_name[NAME_SIZE];
+
+	ret = gbaudio_validate_kcontrol_count(w);
+	if (ret) {
+		dev_err(module->dev, "Inavlid kcontrol count=%d for %s\n",
+			w->ncontrols, w->name);
+		return ret;
+	}
+
+	/* allocate memory for kcontrol */
+	if (w->ncontrols) {
+		size = sizeof(struct snd_kcontrol_new) * w->ncontrols;
+		widget_kctls = devm_kzalloc(module->dev, size, GFP_KERNEL);
+		if (!widget_kctls)
+			return -ENOMEM;
+	}
+
+	*w_size = sizeof(struct gb_audio_widget);
+
+	/* create relevant kcontrols */
+	curr = w->ctl;
+	for (i = 0; i < w->ncontrols; i++) {
+		ret = gbaudio_tplg_create_wcontrol(module, &widget_kctls[i],
+						   curr);
+		if (ret) {
+			dev_err(module->dev,
+				"%s:%d type widget_ctl not supported\n",
+				curr->name, curr->iface);
+			goto error;
+		}
+		control = devm_kzalloc(module->dev,
+				       sizeof(struct gbaudio_control),
+				       GFP_KERNEL);
+		if (!control) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		control->id = curr->id;
+		control->name = curr->name;
+		control->wname = w->name;
+
+		if (curr->info.type == GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED) {
+			struct gb_audio_enumerated *gbenum =
+				&curr->info.value.enumerated;
+
+			csize = offsetof(struct gb_audio_control, info);
+			csize += offsetof(struct gb_audio_ctl_elem_info, value);
+			csize += offsetof(struct gb_audio_enumerated, names);
+			csize += gbenum->names_length;
+			control->texts = (const char * const *)
+				gb_generate_enum_strings(module, gbenum);
+			control->items = gbenum->items;
+		} else
+			csize = sizeof(struct gb_audio_control);
+		*w_size += csize;
+		curr = (void *)curr + csize;
+		list_add(&control->list, &module->widget_ctl_list);
+		dev_dbg(module->dev, "%s: control of type %d created\n",
+			widget_kctls[i].name, widget_kctls[i].iface);
+	}
+
+	/* Prefix dev_id to widget control_name */
+	strlcpy(temp_name, w->name, NAME_SIZE);
+	snprintf(w->name, NAME_SIZE, "GB %d %s", module->dev_id, temp_name);
+
+	switch (w->type) {
+	case snd_soc_dapm_spk:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_SPK(w->name, gbcodec_event_spk);
+		module->op_devices |= GBAUDIO_DEVICE_OUT_SPEAKER;
+		break;
+	case snd_soc_dapm_hp:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_HP(w->name, gbcodec_event_hp);
+		module->op_devices |= (GBAUDIO_DEVICE_OUT_WIRED_HEADSET
+					| GBAUDIO_DEVICE_OUT_WIRED_HEADPHONE);
+		module->ip_devices |= GBAUDIO_DEVICE_IN_WIRED_HEADSET;
+		break;
+	case snd_soc_dapm_mic:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_MIC(w->name, gbcodec_event_int_mic);
+		module->ip_devices |= GBAUDIO_DEVICE_IN_BUILTIN_MIC;
+		break;
+	case snd_soc_dapm_output:
+		*dw = (struct snd_soc_dapm_widget)SND_SOC_DAPM_OUTPUT(w->name);
+		break;
+	case snd_soc_dapm_input:
+		*dw = (struct snd_soc_dapm_widget)SND_SOC_DAPM_INPUT(w->name);
+		break;
+	case snd_soc_dapm_switch:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_SWITCH_E(w->name, SND_SOC_NOPM, 0, 0,
+					    widget_kctls, gbaudio_widget_event,
+					    SND_SOC_DAPM_PRE_PMU |
+					    SND_SOC_DAPM_POST_PMD);
+		break;
+	case snd_soc_dapm_pga:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_PGA_E(w->name, SND_SOC_NOPM, 0, 0, NULL, 0,
+					   gbaudio_widget_event,
+					   SND_SOC_DAPM_PRE_PMU |
+					   SND_SOC_DAPM_POST_PMD);
+		break;
+	case snd_soc_dapm_mixer:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_MIXER_E(w->name, SND_SOC_NOPM, 0, 0, NULL,
+					   0, gbaudio_widget_event,
+					   SND_SOC_DAPM_PRE_PMU |
+					   SND_SOC_DAPM_POST_PMD);
+		break;
+	case snd_soc_dapm_mux:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_MUX_E(w->name, SND_SOC_NOPM, 0, 0,
+					 widget_kctls, gbaudio_widget_event,
+					 SND_SOC_DAPM_PRE_PMU |
+					 SND_SOC_DAPM_POST_PMD);
+		break;
+	case snd_soc_dapm_aif_in:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_AIF_IN_E(w->name, w->sname, 0,
+					      SND_SOC_NOPM,
+					      0, 0, gbaudio_widget_event,
+					      SND_SOC_DAPM_PRE_PMU |
+					      SND_SOC_DAPM_POST_PMD);
+		break;
+	case snd_soc_dapm_aif_out:
+		*dw = (struct snd_soc_dapm_widget)
+			SND_SOC_DAPM_AIF_OUT_E(w->name, w->sname, 0,
+					       SND_SOC_NOPM,
+					       0, 0, gbaudio_widget_event,
+					       SND_SOC_DAPM_PRE_PMU |
+					       SND_SOC_DAPM_POST_PMD);
+		break;
+	default:
+		ret = -EINVAL;
+		goto error;
+	}
+
+	dev_dbg(module->dev, "%s: widget of type %d created\n", dw->name,
+		dw->id);
+	return 0;
+error:
+	list_for_each_entry_safe(control, _control, &module->widget_ctl_list,
+				 list) {
+		list_del(&control->list);
+		devm_kfree(module->dev, control);
+	}
+	return ret;
+}
+
+static int gbaudio_tplg_process_kcontrols(struct gbaudio_module_info *module,
+				   struct gb_audio_control *controls)
+{
+	int i, csize, ret;
+	struct snd_kcontrol_new *dapm_kctls;
+	struct gb_audio_control *curr;
+	struct gbaudio_control *control, *_control;
+	size_t size;
+	char temp_name[NAME_SIZE];
+
+	size = sizeof(struct snd_kcontrol_new) * module->num_controls;
+	dapm_kctls = devm_kzalloc(module->dev, size, GFP_KERNEL);
+	if (!dapm_kctls)
+		return -ENOMEM;
+
+	curr = controls;
+	for (i = 0; i < module->num_controls; i++) {
+		ret = gbaudio_tplg_create_kcontrol(module, &dapm_kctls[i],
+						   curr);
+		if (ret) {
+			dev_err(module->dev, "%s:%d type not supported\n",
+				curr->name, curr->iface);
+			goto error;
+		}
+		control = devm_kzalloc(module->dev, sizeof(struct
+							   gbaudio_control),
+				      GFP_KERNEL);
+		if (!control) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		control->id = curr->id;
+		/* Prefix dev_id to widget_name */
+		strlcpy(temp_name, curr->name, NAME_SIZE);
+		snprintf(curr->name, NAME_SIZE, "GB %d %s", module->dev_id,
+			 temp_name);
+		control->name = curr->name;
+		if (curr->info.type == GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED) {
+			struct gb_audio_enumerated *gbenum =
+				&curr->info.value.enumerated;
+
+			csize = offsetof(struct gb_audio_control, info);
+			csize += offsetof(struct gb_audio_ctl_elem_info, value);
+			csize += offsetof(struct gb_audio_enumerated, names);
+			csize += gbenum->names_length;
+			control->texts = (const char * const *)
+				gb_generate_enum_strings(module, gbenum);
+			control->items = gbenum->items;
+		} else
+			csize = sizeof(struct gb_audio_control);
+
+		list_add(&control->list, &module->ctl_list);
+		dev_dbg(module->dev, "%d:%s created of type %d\n", curr->id,
+			curr->name, curr->info.type);
+		curr = (void *)curr + csize;
+	}
+	module->controls = dapm_kctls;
+
+	return 0;
+error:
+	list_for_each_entry_safe(control, _control, &module->ctl_list,
+				 list) {
+		list_del(&control->list);
+		devm_kfree(module->dev, control);
+	}
+	devm_kfree(module->dev, dapm_kctls);
+	return ret;
+}
+
+static int gbaudio_tplg_process_widgets(struct gbaudio_module_info *module,
+				   struct gb_audio_widget *widgets)
+{
+	int i, ret, w_size;
+	struct snd_soc_dapm_widget *dapm_widgets;
+	struct gb_audio_widget *curr;
+	struct gbaudio_widget *widget, *_widget;
+	size_t size;
+
+	size = sizeof(struct snd_soc_dapm_widget) * module->num_dapm_widgets;
+	dapm_widgets = devm_kzalloc(module->dev, size, GFP_KERNEL);
+	if (!dapm_widgets)
+		return -ENOMEM;
+
+	curr = widgets;
+	for (i = 0; i < module->num_dapm_widgets; i++) {
+		ret = gbaudio_tplg_create_widget(module, &dapm_widgets[i],
+						 curr, &w_size);
+		if (ret) {
+			dev_err(module->dev, "%s:%d type not supported\n",
+				curr->name, curr->type);
+			goto error;
+		}
+		widget = devm_kzalloc(module->dev, sizeof(struct
+							   gbaudio_widget),
+				      GFP_KERNEL);
+		if (!widget) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		widget->id = curr->id;
+		widget->name = curr->name;
+		list_add(&widget->list, &module->widget_list);
+		curr = (void *)curr + w_size;
+	}
+	module->dapm_widgets = dapm_widgets;
+
+	return 0;
+
+error:
+	list_for_each_entry_safe(widget, _widget, &module->widget_list,
+				 list) {
+		list_del(&widget->list);
+		devm_kfree(module->dev, widget);
+	}
+	devm_kfree(module->dev, dapm_widgets);
+	return ret;
+}
+
+static int gbaudio_tplg_process_routes(struct gbaudio_module_info *module,
+				   struct gb_audio_route *routes)
+{
+	int i, ret;
+	struct snd_soc_dapm_route *dapm_routes;
+	struct gb_audio_route *curr;
+	size_t size;
+
+	size = sizeof(struct snd_soc_dapm_route) * module->num_dapm_routes;
+	dapm_routes = devm_kzalloc(module->dev, size, GFP_KERNEL);
+	if (!dapm_routes)
+		return -ENOMEM;
+
+	module->dapm_routes = dapm_routes;
+	curr = routes;
+
+	for (i = 0; i < module->num_dapm_routes; i++) {
+		dapm_routes->sink =
+			gbaudio_map_widgetid(module, curr->destination_id);
+		if (!dapm_routes->sink) {
+			dev_err(module->dev, "%d:%d:%d:%d - Invalid sink\n",
+				curr->source_id, curr->destination_id,
+				curr->control_id, curr->index);
+			ret = -EINVAL;
+			goto error;
+		}
+		dapm_routes->source =
+			gbaudio_map_widgetid(module, curr->source_id);
+		if (!dapm_routes->source) {
+			dev_err(module->dev, "%d:%d:%d:%d - Invalid source\n",
+				curr->source_id, curr->destination_id,
+				curr->control_id, curr->index);
+			ret = -EINVAL;
+			goto error;
+		}
+		dapm_routes->control =
+			gbaudio_map_controlid(module,
+						      curr->control_id,
+						      curr->index);
+		if ((curr->control_id !=  GBAUDIO_INVALID_ID) &&
+		    !dapm_routes->control) {
+			dev_err(module->dev, "%d:%d:%d:%d - Invalid control\n",
+				curr->source_id, curr->destination_id,
+				curr->control_id, curr->index);
+			ret = -EINVAL;
+			goto error;
+		}
+		dev_dbg(module->dev, "Route {%s, %s, %s}\n", dapm_routes->sink,
+			(dapm_routes->control) ? dapm_routes->control:"NULL",
+			dapm_routes->source);
+		dapm_routes++;
+		curr++;
+	}
+
+	return 0;
+
+error:
+	devm_kfree(module->dev, module->dapm_routes);
+	return ret;
+}
+
+static int gbaudio_tplg_process_header(struct gbaudio_module_info *module,
+				 struct gb_audio_topology *tplg_data)
+{
+	/* fetch no. of kcontrols, widgets & routes */
+	module->num_controls = tplg_data->num_controls;
+	module->num_dapm_widgets = tplg_data->num_widgets;
+	module->num_dapm_routes = tplg_data->num_routes;
+
+	/* update block offset */
+	module->dai_offset = (unsigned long)&tplg_data->data;
+	module->control_offset = module->dai_offset + tplg_data->size_dais;
+	module->widget_offset = module->control_offset +
+		tplg_data->size_controls;
+	module->route_offset = module->widget_offset +
+		tplg_data->size_widgets;
+
+	dev_dbg(module->dev, "DAI offset is 0x%lx\n", module->dai_offset);
+	dev_dbg(module->dev, "control offset is %lx\n",
+		module->control_offset);
+	dev_dbg(module->dev, "widget offset is %lx\n", module->widget_offset);
+	dev_dbg(module->dev, "route offset is %lx\n", module->route_offset);
+
+	return 0;
+}
+
+int gbaudio_tplg_parse_data(struct gbaudio_module_info *module,
+			       struct gb_audio_topology *tplg_data)
+{
+	int ret;
+	struct gb_audio_control *controls;
+	struct gb_audio_widget *widgets;
+	struct gb_audio_route *routes;
+
+	if (!tplg_data)
+		return -EINVAL;
+
+	ret = gbaudio_tplg_process_header(module, tplg_data);
+	if (ret) {
+		dev_err(module->dev, "%d: Error in parsing topology header\n",
+			ret);
+		return ret;
+	}
+
+	/* process control */
+	controls = (struct gb_audio_control *)module->control_offset;
+	ret = gbaudio_tplg_process_kcontrols(module, controls);
+	if (ret) {
+		dev_err(module->dev,
+			"%d: Error in parsing controls data\n", ret);
+		return ret;
+	}
+	dev_dbg(module->dev, "Control parsing finished\n");
+
+	/* process widgets */
+	widgets = (struct gb_audio_widget *)module->widget_offset;
+	ret = gbaudio_tplg_process_widgets(module, widgets);
+	if (ret) {
+		dev_err(module->dev,
+			"%d: Error in parsing widgets data\n", ret);
+		return ret;
+	}
+	dev_dbg(module->dev, "Widget parsing finished\n");
+
+	/* process route */
+	routes = (struct gb_audio_route *)module->route_offset;
+	ret = gbaudio_tplg_process_routes(module, routes);
+	if (ret) {
+		dev_err(module->dev,
+			"%d: Error in parsing routes data\n", ret);
+		return ret;
+	}
+	dev_dbg(module->dev, "Route parsing finished\n");
+
+	/* parse jack capabilities */
+	if (tplg_data->jack_type) {
+		module->jack_mask = tplg_data->jack_type & GBCODEC_JACK_MASK;
+		module->button_mask = tplg_data->jack_type &
+			GBCODEC_JACK_BUTTON_MASK;
+	}
+
+	return ret;
+}
+
+void gbaudio_tplg_release(struct gbaudio_module_info *module)
+{
+	struct gbaudio_control *control, *_control;
+	struct gbaudio_widget *widget, *_widget;
+
+	if (!module->topology)
+		return;
+
+	/* release kcontrols */
+	list_for_each_entry_safe(control, _control, &module->ctl_list,
+				 list) {
+		list_del(&control->list);
+		devm_kfree(module->dev, control);
+	}
+	if (module->controls)
+		devm_kfree(module->dev, module->controls);
+
+	/* release widget controls */
+	list_for_each_entry_safe(control, _control, &module->widget_ctl_list,
+				 list) {
+		list_del(&control->list);
+		devm_kfree(module->dev, control);
+	}
+
+	/* release widgets */
+	list_for_each_entry_safe(widget, _widget, &module->widget_list,
+				 list) {
+		list_del(&widget->list);
+		devm_kfree(module->dev, widget);
+	}
+	if (module->dapm_widgets)
+		devm_kfree(module->dev, module->dapm_widgets);
+
+	/* release routes */
+	if (module->dapm_routes)
+		devm_kfree(module->dev, module->dapm_routes);
+}
diff --git a/drivers/staging/greybus/authentication.c b/drivers/staging/greybus/authentication.c
new file mode 100644
index 000000000000..168626ba0c03
--- /dev/null
+++ b/drivers/staging/greybus/authentication.c
@@ -0,0 +1,429 @@
+/*
+ * Greybus Component Authentication Protocol (CAP) Driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/uaccess.h>
+
+#include "greybus_authentication.h"
+#include "firmware.h"
+#include "greybus.h"
+
+#define CAP_TIMEOUT_MS		1000
+
+/*
+ * Number of minor devices this driver supports.
+ * There will be exactly one required per Interface.
+ */
+#define NUM_MINORS		U8_MAX
+
+struct gb_cap {
+	struct device		*parent;
+	struct gb_connection	*connection;
+	struct kref		kref;
+	struct list_head	node;
+	bool			disabled; /* connection getting disabled */
+
+	struct mutex		mutex;
+	struct cdev		cdev;
+	struct device		*class_device;
+	dev_t			dev_num;
+};
+
+static struct class *cap_class;
+static dev_t cap_dev_num;
+static DEFINE_IDA(cap_minors_map);
+static LIST_HEAD(cap_list);
+static DEFINE_MUTEX(list_mutex);
+
+static void cap_kref_release(struct kref *kref)
+{
+	struct gb_cap *cap = container_of(kref, struct gb_cap, kref);
+
+	kfree(cap);
+}
+
+/*
+ * All users of cap take a reference (from within list_mutex lock), before
+ * they get a pointer to play with. And the structure will be freed only after
+ * the last user has put the reference to it.
+ */
+static void put_cap(struct gb_cap *cap)
+{
+	kref_put(&cap->kref, cap_kref_release);
+}
+
+/* Caller must call put_cap() after using struct gb_cap */
+static struct gb_cap *get_cap(struct cdev *cdev)
+{
+	struct gb_cap *cap;
+
+	mutex_lock(&list_mutex);
+
+	list_for_each_entry(cap, &cap_list, node) {
+		if (&cap->cdev == cdev) {
+			kref_get(&cap->kref);
+			goto unlock;
+		}
+	}
+
+	cap = NULL;
+
+unlock:
+	mutex_unlock(&list_mutex);
+
+	return cap;
+}
+
+static int cap_get_endpoint_uid(struct gb_cap *cap, u8 *euid)
+{
+	struct gb_connection *connection = cap->connection;
+	struct gb_cap_get_endpoint_uid_response response;
+	int ret;
+
+	ret = gb_operation_sync(connection, GB_CAP_TYPE_GET_ENDPOINT_UID, NULL,
+				0, &response, sizeof(response));
+	if (ret) {
+		dev_err(cap->parent, "failed to get endpoint uid (%d)\n", ret);
+		return ret;
+	}
+
+	memcpy(euid, response.uid, sizeof(response.uid));
+
+	return 0;
+}
+
+static int cap_get_ims_certificate(struct gb_cap *cap, u32 class, u32 id,
+				   u8 *certificate, u32 *size, u8 *result)
+{
+	struct gb_connection *connection = cap->connection;
+	struct gb_cap_get_ims_certificate_request *request;
+	struct gb_cap_get_ims_certificate_response *response;
+	size_t max_size = gb_operation_get_payload_size_max(connection);
+	struct gb_operation *op;
+	int ret;
+
+	op = gb_operation_create_flags(connection,
+				       GB_CAP_TYPE_GET_IMS_CERTIFICATE,
+				       sizeof(*request), max_size,
+				       GB_OPERATION_FLAG_SHORT_RESPONSE,
+				       GFP_KERNEL);
+	if (!op)
+		return -ENOMEM;
+
+	request = op->request->payload;
+	request->certificate_class = cpu_to_le32(class);
+	request->certificate_id = cpu_to_le32(id);
+
+	ret = gb_operation_request_send_sync(op);
+	if (ret) {
+		dev_err(cap->parent, "failed to get certificate (%d)\n", ret);
+		goto done;
+	}
+
+	response = op->response->payload;
+	*result = response->result_code;
+	*size = op->response->payload_size - sizeof(*response);
+	memcpy(certificate, response->certificate, *size);
+
+done:
+	gb_operation_put(op);
+	return ret;
+}
+
+static int cap_authenticate(struct gb_cap *cap, u32 auth_type, u8 *uid,
+			    u8 *challenge, u8 *result, u8 *auth_response,
+			    u32 *signature_size, u8 *signature)
+{
+	struct gb_connection *connection = cap->connection;
+	struct gb_cap_authenticate_request *request;
+	struct gb_cap_authenticate_response *response;
+	size_t max_size = gb_operation_get_payload_size_max(connection);
+	struct gb_operation *op;
+	int ret;
+
+	op = gb_operation_create_flags(connection, GB_CAP_TYPE_AUTHENTICATE,
+				       sizeof(*request), max_size,
+				       GB_OPERATION_FLAG_SHORT_RESPONSE,
+				       GFP_KERNEL);
+	if (!op)
+		return -ENOMEM;
+
+	request = op->request->payload;
+	request->auth_type = cpu_to_le32(auth_type);
+	memcpy(request->uid, uid, sizeof(request->uid));
+	memcpy(request->challenge, challenge, sizeof(request->challenge));
+
+	ret = gb_operation_request_send_sync(op);
+	if (ret) {
+		dev_err(cap->parent, "failed to authenticate (%d)\n", ret);
+		goto done;
+	}
+
+	response = op->response->payload;
+	*result = response->result_code;
+	*signature_size = op->response->payload_size - sizeof(*response);
+	memcpy(auth_response, response->response, sizeof(response->response));
+	memcpy(signature, response->signature, *signature_size);
+
+done:
+	gb_operation_put(op);
+	return ret;
+}
+
+/* Char device fops */
+
+static int cap_open(struct inode *inode, struct file *file)
+{
+	struct gb_cap *cap = get_cap(inode->i_cdev);
+
+	/* cap structure can't get freed until file descriptor is closed */
+	if (cap) {
+		file->private_data = cap;
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static int cap_release(struct inode *inode, struct file *file)
+{
+	struct gb_cap *cap = file->private_data;
+
+	put_cap(cap);
+	return 0;
+}
+
+static int cap_ioctl(struct gb_cap *cap, unsigned int cmd,
+			 void __user *buf)
+{
+	struct cap_ioc_get_endpoint_uid endpoint_uid;
+	struct cap_ioc_get_ims_certificate *ims_cert;
+	struct cap_ioc_authenticate *authenticate;
+	size_t size;
+	int ret;
+
+	switch (cmd) {
+	case CAP_IOC_GET_ENDPOINT_UID:
+		ret = cap_get_endpoint_uid(cap, endpoint_uid.uid);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(buf, &endpoint_uid, sizeof(endpoint_uid)))
+			return -EFAULT;
+
+		return 0;
+	case CAP_IOC_GET_IMS_CERTIFICATE:
+		size = sizeof(*ims_cert);
+		ims_cert = memdup_user(buf, size);
+		if (IS_ERR(ims_cert))
+			return PTR_ERR(ims_cert);
+
+		ret = cap_get_ims_certificate(cap, ims_cert->certificate_class,
+					      ims_cert->certificate_id,
+					      ims_cert->certificate,
+					      &ims_cert->cert_size,
+					      &ims_cert->result_code);
+		if (!ret && copy_to_user(buf, ims_cert, size))
+			ret = -EFAULT;
+		kfree(ims_cert);
+
+		return ret;
+	case CAP_IOC_AUTHENTICATE:
+		size = sizeof(*authenticate);
+		authenticate = memdup_user(buf, size);
+		if (IS_ERR(authenticate))
+			return PTR_ERR(authenticate);
+
+		ret = cap_authenticate(cap, authenticate->auth_type,
+				       authenticate->uid,
+				       authenticate->challenge,
+				       &authenticate->result_code,
+				       authenticate->response,
+				       &authenticate->signature_size,
+				       authenticate->signature);
+		if (!ret && copy_to_user(buf, authenticate, size))
+			ret = -EFAULT;
+		kfree(authenticate);
+
+		return ret;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static long cap_ioctl_unlocked(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct gb_cap *cap = file->private_data;
+	struct gb_bundle *bundle = cap->connection->bundle;
+	int ret = -ENODEV;
+
+	/*
+	 * Serialize ioctls.
+	 *
+	 * We don't want the user to do multiple authentication operations in
+	 * parallel.
+	 *
+	 * This is also used to protect ->disabled, which is used to check if
+	 * the connection is getting disconnected, so that we don't start any
+	 * new operations.
+	 */
+	mutex_lock(&cap->mutex);
+	if (!cap->disabled) {
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (!ret) {
+			ret = cap_ioctl(cap, cmd, (void __user *)arg);
+			gb_pm_runtime_put_autosuspend(bundle);
+		}
+	}
+	mutex_unlock(&cap->mutex);
+
+	return ret;
+}
+
+static const struct file_operations cap_fops = {
+	.owner		= THIS_MODULE,
+	.open		= cap_open,
+	.release	= cap_release,
+	.unlocked_ioctl	= cap_ioctl_unlocked,
+};
+
+int gb_cap_connection_init(struct gb_connection *connection)
+{
+	struct gb_cap *cap;
+	int ret, minor;
+
+	if (!connection)
+		return 0;
+
+	cap = kzalloc(sizeof(*cap), GFP_KERNEL);
+	if (!cap)
+		return -ENOMEM;
+
+	cap->parent = &connection->bundle->dev;
+	cap->connection = connection;
+	mutex_init(&cap->mutex);
+	gb_connection_set_data(connection, cap);
+	kref_init(&cap->kref);
+
+	mutex_lock(&list_mutex);
+	list_add(&cap->node, &cap_list);
+	mutex_unlock(&list_mutex);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_list_del;
+
+	minor = ida_simple_get(&cap_minors_map, 0, NUM_MINORS, GFP_KERNEL);
+	if (minor < 0) {
+		ret = minor;
+		goto err_connection_disable;
+	}
+
+	/* Add a char device to allow userspace to interact with cap */
+	cap->dev_num = MKDEV(MAJOR(cap_dev_num), minor);
+	cdev_init(&cap->cdev, &cap_fops);
+
+	ret = cdev_add(&cap->cdev, cap->dev_num, 1);
+	if (ret)
+		goto err_remove_ida;
+
+	/* Add a soft link to the previously added char-dev within the bundle */
+	cap->class_device = device_create(cap_class, cap->parent, cap->dev_num,
+					  NULL, "gb-authenticate-%d", minor);
+	if (IS_ERR(cap->class_device)) {
+		ret = PTR_ERR(cap->class_device);
+		goto err_del_cdev;
+	}
+
+	return 0;
+
+err_del_cdev:
+	cdev_del(&cap->cdev);
+err_remove_ida:
+	ida_simple_remove(&cap_minors_map, minor);
+err_connection_disable:
+	gb_connection_disable(connection);
+err_list_del:
+	mutex_lock(&list_mutex);
+	list_del(&cap->node);
+	mutex_unlock(&list_mutex);
+
+	put_cap(cap);
+
+	return ret;
+}
+
+void gb_cap_connection_exit(struct gb_connection *connection)
+{
+	struct gb_cap *cap;
+
+	if (!connection)
+		return;
+
+	cap = gb_connection_get_data(connection);
+
+	device_destroy(cap_class, cap->dev_num);
+	cdev_del(&cap->cdev);
+	ida_simple_remove(&cap_minors_map, MINOR(cap->dev_num));
+
+	/*
+	 * Disallow any new ioctl operations on the char device and wait for
+	 * existing ones to finish.
+	 */
+	mutex_lock(&cap->mutex);
+	cap->disabled = true;
+	mutex_unlock(&cap->mutex);
+
+	/* All pending greybus operations should have finished by now */
+	gb_connection_disable(cap->connection);
+
+	/* Disallow new users to get access to the cap structure */
+	mutex_lock(&list_mutex);
+	list_del(&cap->node);
+	mutex_unlock(&list_mutex);
+
+	/*
+	 * All current users of cap would have taken a reference to it by
+	 * now, we can drop our reference and wait the last user will get
+	 * cap freed.
+	 */
+	put_cap(cap);
+}
+
+int cap_init(void)
+{
+	int ret;
+
+	cap_class = class_create(THIS_MODULE, "gb_authenticate");
+	if (IS_ERR(cap_class))
+		return PTR_ERR(cap_class);
+
+	ret = alloc_chrdev_region(&cap_dev_num, 0, NUM_MINORS,
+				  "gb_authenticate");
+	if (ret)
+		goto err_remove_class;
+
+	return 0;
+
+err_remove_class:
+	class_destroy(cap_class);
+	return ret;
+}
+
+void cap_exit(void)
+{
+	unregister_chrdev_region(cap_dev_num, NUM_MINORS);
+	class_destroy(cap_class);
+	ida_destroy(&cap_minors_map);
+}
diff --git a/drivers/staging/greybus/bootrom.c b/drivers/staging/greybus/bootrom.c
new file mode 100644
index 000000000000..5f90721bcc51
--- /dev/null
+++ b/drivers/staging/greybus/bootrom.c
@@ -0,0 +1,524 @@
+/*
+ * BOOTROM Greybus driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/firmware.h>
+#include <linux/jiffies.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+#include "greybus.h"
+#include "firmware.h"
+
+/* Timeout, in jiffies, within which the next request must be received */
+#define NEXT_REQ_TIMEOUT_MS	1000
+
+/*
+ * FIXME: Reduce this timeout once svc core handles parallel processing of
+ * events from the SVC, which are handled sequentially today.
+ */
+#define MODE_SWITCH_TIMEOUT_MS	10000
+
+enum next_request_type {
+	NEXT_REQ_FIRMWARE_SIZE,
+	NEXT_REQ_GET_FIRMWARE,
+	NEXT_REQ_READY_TO_BOOT,
+	NEXT_REQ_MODE_SWITCH,
+};
+
+struct gb_bootrom {
+	struct gb_connection	*connection;
+	const struct firmware	*fw;
+	u8			protocol_major;
+	u8			protocol_minor;
+	enum next_request_type	next_request;
+	struct delayed_work	dwork;
+	struct mutex		mutex; /* Protects bootrom->fw */
+};
+
+static void free_firmware(struct gb_bootrom *bootrom)
+{
+	if (!bootrom->fw)
+		return;
+
+	release_firmware(bootrom->fw);
+	bootrom->fw = NULL;
+}
+
+static void gb_bootrom_timedout(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct gb_bootrom *bootrom = container_of(dwork, struct gb_bootrom, dwork);
+	struct device *dev = &bootrom->connection->bundle->dev;
+	const char *reason;
+
+	switch (bootrom->next_request) {
+	case NEXT_REQ_FIRMWARE_SIZE:
+		reason = "Firmware Size Request";
+		break;
+	case NEXT_REQ_GET_FIRMWARE:
+		reason = "Get Firmware Request";
+		break;
+	case NEXT_REQ_READY_TO_BOOT:
+		reason = "Ready to Boot Request";
+		break;
+	case NEXT_REQ_MODE_SWITCH:
+		reason = "Interface Mode Switch";
+		break;
+	default:
+		reason = NULL;
+		dev_err(dev, "Invalid next-request: %u", bootrom->next_request);
+		break;
+	}
+
+	dev_err(dev, "Timed out waiting for %s from the Module\n", reason);
+
+	mutex_lock(&bootrom->mutex);
+	free_firmware(bootrom);
+	mutex_unlock(&bootrom->mutex);
+
+	/* TODO: Power-off Module ? */
+}
+
+static void gb_bootrom_set_timeout(struct gb_bootrom *bootrom,
+			enum next_request_type next, unsigned long timeout)
+{
+	bootrom->next_request = next;
+	schedule_delayed_work(&bootrom->dwork, msecs_to_jiffies(timeout));
+}
+
+static void gb_bootrom_cancel_timeout(struct gb_bootrom *bootrom)
+{
+	cancel_delayed_work_sync(&bootrom->dwork);
+}
+
+/*
+ * The es2 chip doesn't have VID/PID programmed into the hardware and we need to
+ * hack that up to distinguish different modules and their firmware blobs.
+ *
+ * This fetches VID/PID (over bootrom protocol) for es2 chip only, when VID/PID
+ * already sent during hotplug are 0.
+ *
+ * Otherwise, we keep intf->vendor_id/product_id same as what's passed
+ * during hotplug.
+ */
+static void bootrom_es2_fixup_vid_pid(struct gb_bootrom *bootrom)
+{
+	struct gb_bootrom_get_vid_pid_response response;
+	struct gb_connection *connection = bootrom->connection;
+	struct gb_interface *intf = connection->bundle->intf;
+	int ret;
+
+	if (!(intf->quirks & GB_INTERFACE_QUIRK_NO_GMP_IDS))
+		return;
+
+	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_GET_VID_PID,
+				NULL, 0, &response, sizeof(response));
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"Bootrom get vid/pid operation failed (%d)\n", ret);
+		return;
+	}
+
+	/*
+	 * NOTE: This is hacked, so that the same values of VID/PID can be used
+	 * by next firmware level as well. The uevent for bootrom will still
+	 * have VID/PID as 0, though after this point the sysfs files will start
+	 * showing the updated values. But yeah, that's a bit racy as the same
+	 * sysfs files would be showing 0 before this point.
+	 */
+	intf->vendor_id = le32_to_cpu(response.vendor_id);
+	intf->product_id = le32_to_cpu(response.product_id);
+
+	dev_dbg(&connection->bundle->dev, "Bootrom got vid (0x%x)/pid (0x%x)\n",
+		intf->vendor_id, intf->product_id);
+}
+
+/* This returns path of the firmware blob on the disk */
+static int find_firmware(struct gb_bootrom *bootrom, u8 stage)
+{
+	struct gb_connection *connection = bootrom->connection;
+	struct gb_interface *intf = connection->bundle->intf;
+	char firmware_name[49];
+	int rc;
+
+	/* Already have a firmware, free it */
+	free_firmware(bootrom);
+
+	/* Bootrom protocol is only supported for loading Stage 2 firmware */
+	if (stage != 2) {
+		dev_err(&connection->bundle->dev, "Invalid boot stage: %u\n",
+			stage);
+		return -EINVAL;
+	}
+
+	/*
+	 * Create firmware name
+	 *
+	 * XXX Name it properly..
+	 */
+	snprintf(firmware_name, sizeof(firmware_name),
+		 FW_NAME_PREFIX "%08x_%08x_%08x_%08x_s2l.tftf",
+		 intf->ddbl1_manufacturer_id, intf->ddbl1_product_id,
+		 intf->vendor_id, intf->product_id);
+
+	// FIXME:
+	// Turn to dev_dbg later after everyone has valid bootloaders with good
+	// ids, but leave this as dev_info for now to make it easier to track
+	// down "empty" vid/pid modules.
+	dev_info(&connection->bundle->dev, "Firmware file '%s' requested\n",
+		 firmware_name);
+
+	rc = request_firmware(&bootrom->fw, firmware_name,
+		&connection->bundle->dev);
+	if (rc) {
+		dev_err(&connection->bundle->dev,
+			"failed to find %s firmware (%d)\n", firmware_name, rc);
+	}
+
+	return rc;
+}
+
+static int gb_bootrom_firmware_size_request(struct gb_operation *op)
+{
+	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
+	struct gb_bootrom_firmware_size_request *size_request = op->request->payload;
+	struct gb_bootrom_firmware_size_response *size_response;
+	struct device *dev = &op->connection->bundle->dev;
+	int ret;
+
+	/* Disable timeouts */
+	gb_bootrom_cancel_timeout(bootrom);
+
+	if (op->request->payload_size != sizeof(*size_request)) {
+		dev_err(dev, "%s: illegal size of firmware size request (%zu != %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*size_request));
+		ret = -EINVAL;
+		goto queue_work;
+	}
+
+	mutex_lock(&bootrom->mutex);
+
+	ret = find_firmware(bootrom, size_request->stage);
+	if (ret)
+		goto unlock;
+
+	if (!gb_operation_response_alloc(op, sizeof(*size_response),
+					 GFP_KERNEL)) {
+		dev_err(dev, "%s: error allocating response\n", __func__);
+		free_firmware(bootrom);
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	size_response = op->response->payload;
+	size_response->size = cpu_to_le32(bootrom->fw->size);
+
+	dev_dbg(dev, "%s: firmware size %d bytes\n", __func__, size_response->size);
+
+unlock:
+	mutex_unlock(&bootrom->mutex);
+
+queue_work:
+	if (!ret) {
+		/* Refresh timeout */
+		gb_bootrom_set_timeout(bootrom, NEXT_REQ_GET_FIRMWARE,
+				       NEXT_REQ_TIMEOUT_MS);
+	}
+
+	return ret;
+}
+
+static int gb_bootrom_get_firmware(struct gb_operation *op)
+{
+	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
+	const struct firmware *fw;
+	struct gb_bootrom_get_firmware_request *firmware_request;
+	struct gb_bootrom_get_firmware_response *firmware_response;
+	struct device *dev = &op->connection->bundle->dev;
+	unsigned int offset, size;
+	enum next_request_type next_request;
+	int ret = 0;
+
+	/* Disable timeouts */
+	gb_bootrom_cancel_timeout(bootrom);
+
+	if (op->request->payload_size != sizeof(*firmware_request)) {
+		dev_err(dev, "%s: Illegal size of get firmware request (%zu %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*firmware_request));
+		ret = -EINVAL;
+		goto queue_work;
+	}
+
+	mutex_lock(&bootrom->mutex);
+
+	fw = bootrom->fw;
+	if (!fw) {
+		dev_err(dev, "%s: firmware not available\n", __func__);
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	firmware_request = op->request->payload;
+	offset = le32_to_cpu(firmware_request->offset);
+	size = le32_to_cpu(firmware_request->size);
+
+	if (offset >= fw->size || size > fw->size - offset) {
+		dev_warn(dev, "bad firmware request (offs = %u, size = %u)\n",
+				offset, size);
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	if (!gb_operation_response_alloc(op, sizeof(*firmware_response) + size,
+					 GFP_KERNEL)) {
+		dev_err(dev, "%s: error allocating response\n", __func__);
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	firmware_response = op->response->payload;
+	memcpy(firmware_response->data, fw->data + offset, size);
+
+	dev_dbg(dev, "responding with firmware (offs = %u, size = %u)\n", offset,
+		size);
+
+unlock:
+	mutex_unlock(&bootrom->mutex);
+
+queue_work:
+	/* Refresh timeout */
+	if (!ret && (offset + size == fw->size))
+		next_request = NEXT_REQ_READY_TO_BOOT;
+	else
+		next_request = NEXT_REQ_GET_FIRMWARE;
+
+	gb_bootrom_set_timeout(bootrom, next_request, NEXT_REQ_TIMEOUT_MS);
+
+	return ret;
+}
+
+static int gb_bootrom_ready_to_boot(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_bootrom *bootrom = gb_connection_get_data(connection);
+	struct gb_bootrom_ready_to_boot_request *rtb_request;
+	struct device *dev = &connection->bundle->dev;
+	u8 status;
+	int ret = 0;
+
+	/* Disable timeouts */
+	gb_bootrom_cancel_timeout(bootrom);
+
+	if (op->request->payload_size != sizeof(*rtb_request)) {
+		dev_err(dev, "%s: Illegal size of ready to boot request (%zu %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*rtb_request));
+		ret = -EINVAL;
+		goto queue_work;
+	}
+
+	rtb_request = op->request->payload;
+	status = rtb_request->status;
+
+	/* Return error if the blob was invalid */
+	if (status == GB_BOOTROM_BOOT_STATUS_INVALID) {
+		ret = -EINVAL;
+		goto queue_work;
+	}
+
+	/*
+	 * XXX Should we return error for insecure firmware?
+	 */
+	dev_dbg(dev, "ready to boot: 0x%x, 0\n", status);
+
+queue_work:
+	/*
+	 * Refresh timeout, the Interface shall load the new personality and
+	 * send a new hotplug request, which shall get rid of the bootrom
+	 * connection. As that can take some time, increase the timeout a bit.
+	 */
+	gb_bootrom_set_timeout(bootrom, NEXT_REQ_MODE_SWITCH,
+			       MODE_SWITCH_TIMEOUT_MS);
+
+	return ret;
+}
+
+static int gb_bootrom_request_handler(struct gb_operation *op)
+{
+	u8 type = op->type;
+
+	switch (type) {
+	case GB_BOOTROM_TYPE_FIRMWARE_SIZE:
+		return gb_bootrom_firmware_size_request(op);
+	case GB_BOOTROM_TYPE_GET_FIRMWARE:
+		return gb_bootrom_get_firmware(op);
+	case GB_BOOTROM_TYPE_READY_TO_BOOT:
+		return gb_bootrom_ready_to_boot(op);
+	default:
+		dev_err(&op->connection->bundle->dev,
+			"unsupported request: %u\n", type);
+		return -EINVAL;
+	}
+}
+
+static int gb_bootrom_get_version(struct gb_bootrom *bootrom)
+{
+	struct gb_bundle *bundle = bootrom->connection->bundle;
+	struct gb_bootrom_version_request request;
+	struct gb_bootrom_version_response response;
+	int ret;
+
+	request.major = GB_BOOTROM_VERSION_MAJOR;
+	request.minor = GB_BOOTROM_VERSION_MINOR;
+
+	ret = gb_operation_sync(bootrom->connection,
+				GB_BOOTROM_TYPE_VERSION,
+				&request, sizeof(request), &response,
+				sizeof(response));
+	if (ret) {
+		dev_err(&bundle->dev,
+				"failed to get protocol version: %d\n",
+				ret);
+		return ret;
+	}
+
+	if (response.major > request.major) {
+		dev_err(&bundle->dev,
+				"unsupported major protocol version (%u > %u)\n",
+				response.major, request.major);
+		return -ENOTSUPP;
+	}
+
+	bootrom->protocol_major = response.major;
+	bootrom->protocol_minor = response.minor;
+
+	dev_dbg(&bundle->dev, "%s - %u.%u\n", __func__, response.major,
+			response.minor);
+
+	return 0;
+}
+
+static int gb_bootrom_probe(struct gb_bundle *bundle,
+					const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_bootrom *bootrom;
+	int ret;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_BOOTROM)
+		return -ENODEV;
+
+	bootrom = kzalloc(sizeof(*bootrom), GFP_KERNEL);
+	if (!bootrom)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle,
+						le16_to_cpu(cport_desc->id),
+						gb_bootrom_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto err_free_bootrom;
+	}
+
+	gb_connection_set_data(connection, bootrom);
+
+	bootrom->connection = connection;
+
+	mutex_init(&bootrom->mutex);
+	INIT_DELAYED_WORK(&bootrom->dwork, gb_bootrom_timedout);
+	greybus_set_drvdata(bundle, bootrom);
+
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto err_connection_destroy;
+
+	ret = gb_bootrom_get_version(bootrom);
+	if (ret)
+		goto err_connection_disable;
+
+	bootrom_es2_fixup_vid_pid(bootrom);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_connection_disable;
+
+	/* Refresh timeout */
+	gb_bootrom_set_timeout(bootrom, NEXT_REQ_FIRMWARE_SIZE,
+			       NEXT_REQ_TIMEOUT_MS);
+
+	/* Tell bootrom we're ready. */
+	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_AP_READY, NULL, 0,
+				NULL, 0);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+				"failed to send AP READY: %d\n", ret);
+		goto err_cancel_timeout;
+	}
+
+	dev_dbg(&bundle->dev, "AP_READY sent\n");
+
+	return 0;
+
+err_cancel_timeout:
+	gb_bootrom_cancel_timeout(bootrom);
+err_connection_disable:
+	gb_connection_disable(connection);
+err_connection_destroy:
+	gb_connection_destroy(connection);
+err_free_bootrom:
+	kfree(bootrom);
+
+	return ret;
+}
+
+static void gb_bootrom_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_bootrom *bootrom = greybus_get_drvdata(bundle);
+
+	dev_dbg(&bundle->dev, "%s\n", __func__);
+
+	gb_connection_disable(bootrom->connection);
+
+	/* Disable timeouts */
+	gb_bootrom_cancel_timeout(bootrom);
+
+	/*
+	 * Release firmware:
+	 *
+	 * As the connection and the delayed work are already disabled, we don't
+	 * need to lock access to bootrom->fw here.
+	 */
+	free_firmware(bootrom);
+
+	gb_connection_destroy(bootrom->connection);
+	kfree(bootrom);
+}
+
+static const struct greybus_bundle_id gb_bootrom_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_BOOTROM) },
+	{ }
+};
+
+static struct greybus_driver gb_bootrom_driver = {
+	.name		= "bootrom",
+	.probe		= gb_bootrom_probe,
+	.disconnect	= gb_bootrom_disconnect,
+	.id_table	= gb_bootrom_id_table,
+};
+
+module_greybus_driver(gb_bootrom_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/bundle.c b/drivers/staging/greybus/bundle.c
new file mode 100644
index 000000000000..d2ef57d090be
--- /dev/null
+++ b/drivers/staging/greybus/bundle.c
@@ -0,0 +1,253 @@
+/*
+ * Greybus bundles
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+static ssize_t bundle_class_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	return sprintf(buf, "0x%02x\n", bundle->class);
+}
+static DEVICE_ATTR_RO(bundle_class);
+
+static ssize_t bundle_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	return sprintf(buf, "%u\n", bundle->id);
+}
+static DEVICE_ATTR_RO(bundle_id);
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	if (bundle->state == NULL)
+		return sprintf(buf, "\n");
+
+	return sprintf(buf, "%s\n", bundle->state);
+}
+
+static ssize_t state_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t size)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	kfree(bundle->state);
+	bundle->state = kstrdup(buf, GFP_KERNEL);
+	if (!bundle->state)
+		return -ENOMEM;
+
+	/* Tell userspace that the file contents changed */
+	sysfs_notify(&bundle->dev.kobj, NULL, "state");
+
+	return size;
+}
+static DEVICE_ATTR_RW(state);
+
+static struct attribute *bundle_attrs[] = {
+	&dev_attr_bundle_class.attr,
+	&dev_attr_bundle_id.attr,
+	&dev_attr_state.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(bundle);
+
+static struct gb_bundle *gb_bundle_find(struct gb_interface *intf,
+							u8 bundle_id)
+{
+	struct gb_bundle *bundle;
+
+	list_for_each_entry(bundle, &intf->bundles, links) {
+		if (bundle->id == bundle_id)
+			return bundle;
+	}
+
+	return NULL;
+}
+
+static void gb_bundle_release(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	trace_gb_bundle_release(bundle);
+
+	kfree(bundle->state);
+	kfree(bundle->cport_desc);
+	kfree(bundle);
+}
+
+#ifdef CONFIG_PM
+static void gb_bundle_disable_all_connections(struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &bundle->connections, bundle_links)
+		gb_connection_disable(connection);
+}
+
+static void gb_bundle_enable_all_connections(struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &bundle->connections, bundle_links)
+		gb_connection_enable(connection);
+}
+
+static int gb_bundle_suspend(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	const struct dev_pm_ops *pm = dev->driver->pm;
+	int ret;
+
+	if (pm && pm->runtime_suspend) {
+		ret = pm->runtime_suspend(&bundle->dev);
+		if (ret)
+			return ret;
+	} else {
+		gb_bundle_disable_all_connections(bundle);
+	}
+
+	ret = gb_control_bundle_suspend(bundle->intf->control, bundle->id);
+	if (ret) {
+		if (pm && pm->runtime_resume)
+			ret = pm->runtime_resume(dev);
+		else
+			gb_bundle_enable_all_connections(bundle);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_bundle_resume(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	const struct dev_pm_ops *pm = dev->driver->pm;
+	int ret;
+
+	ret = gb_control_bundle_resume(bundle->intf->control, bundle->id);
+	if (ret)
+		return ret;
+
+	if (pm && pm->runtime_resume) {
+		ret = pm->runtime_resume(dev);
+		if (ret)
+			return ret;
+	} else {
+		gb_bundle_enable_all_connections(bundle);
+	}
+
+	return 0;
+}
+
+static int gb_bundle_idle(struct device *dev)
+{
+	pm_runtime_mark_last_busy(dev);
+	pm_request_autosuspend(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_bundle_pm_ops = {
+	SET_RUNTIME_PM_OPS(gb_bundle_suspend, gb_bundle_resume, gb_bundle_idle)
+};
+
+struct device_type greybus_bundle_type = {
+	.name =		"greybus_bundle",
+	.release =	gb_bundle_release,
+	.pm =		&gb_bundle_pm_ops,
+};
+
+/*
+ * Create a gb_bundle structure to represent a discovered
+ * bundle.  Returns a pointer to the new bundle or a null
+ * pointer if a failure occurs due to memory exhaustion.
+ */
+struct gb_bundle *gb_bundle_create(struct gb_interface *intf, u8 bundle_id,
+				   u8 class)
+{
+	struct gb_bundle *bundle;
+
+	if (bundle_id == BUNDLE_ID_NONE) {
+		dev_err(&intf->dev, "can't use bundle id %u\n", bundle_id);
+		return NULL;
+	}
+
+	/*
+	 * Reject any attempt to reuse a bundle id.  We initialize
+	 * these serially, so there's no need to worry about keeping
+	 * the interface bundle list locked here.
+	 */
+	if (gb_bundle_find(intf, bundle_id)) {
+		dev_err(&intf->dev, "duplicate bundle id %u\n", bundle_id);
+		return NULL;
+	}
+
+	bundle = kzalloc(sizeof(*bundle), GFP_KERNEL);
+	if (!bundle)
+		return NULL;
+
+	bundle->intf = intf;
+	bundle->id = bundle_id;
+	bundle->class = class;
+	INIT_LIST_HEAD(&bundle->connections);
+
+	bundle->dev.parent = &intf->dev;
+	bundle->dev.bus = &greybus_bus_type;
+	bundle->dev.type = &greybus_bundle_type;
+	bundle->dev.groups = bundle_groups;
+	bundle->dev.dma_mask = intf->dev.dma_mask;
+	device_initialize(&bundle->dev);
+	dev_set_name(&bundle->dev, "%s.%d", dev_name(&intf->dev), bundle_id);
+
+	list_add(&bundle->links, &intf->bundles);
+
+	trace_gb_bundle_create(bundle);
+
+	return bundle;
+}
+
+int gb_bundle_add(struct gb_bundle *bundle)
+{
+	int ret;
+
+	ret = device_add(&bundle->dev);
+	if (ret) {
+		dev_err(&bundle->dev, "failed to register bundle: %d\n", ret);
+		return ret;
+	}
+
+	trace_gb_bundle_add(bundle);
+
+	return 0;
+}
+
+/*
+ * Tear down a previously set up bundle.
+ */
+void gb_bundle_destroy(struct gb_bundle *bundle)
+{
+	trace_gb_bundle_destroy(bundle);
+
+	if (device_is_registered(&bundle->dev))
+		device_del(&bundle->dev);
+
+	list_del(&bundle->links);
+
+	put_device(&bundle->dev);
+}
diff --git a/drivers/staging/greybus/bundle.h b/drivers/staging/greybus/bundle.h
new file mode 100644
index 000000000000..0c3491def96c
--- /dev/null
+++ b/drivers/staging/greybus/bundle.h
@@ -0,0 +1,90 @@
+/*
+ * Greybus bundles
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __BUNDLE_H
+#define __BUNDLE_H
+
+#include <linux/list.h>
+
+#define	BUNDLE_ID_NONE	U8_MAX
+
+/* Greybus "public" definitions" */
+struct gb_bundle {
+	struct device		dev;
+	struct gb_interface	*intf;
+
+	u8			id;
+	u8			class;
+	u8			class_major;
+	u8			class_minor;
+
+	size_t			num_cports;
+	struct greybus_descriptor_cport *cport_desc;
+
+	struct list_head	connections;
+	u8			*state;
+
+	struct list_head	links;	/* interface->bundles */
+};
+#define to_gb_bundle(d) container_of(d, struct gb_bundle, dev)
+
+/* Greybus "private" definitions" */
+struct gb_bundle *gb_bundle_create(struct gb_interface *intf, u8 bundle_id,
+				   u8 class);
+int gb_bundle_add(struct gb_bundle *bundle);
+void gb_bundle_destroy(struct gb_bundle *bundle);
+
+/* Bundle Runtime PM wrappers */
+#ifdef CONFIG_PM
+static inline int gb_pm_runtime_get_sync(struct gb_bundle *bundle)
+{
+	int retval;
+
+	retval = pm_runtime_get_sync(&bundle->dev);
+	if (retval < 0) {
+		dev_err(&bundle->dev,
+			"pm_runtime_get_sync failed: %d\n", retval);
+		pm_runtime_put_noidle(&bundle->dev);
+		return retval;
+	}
+
+	return 0;
+}
+
+static inline int gb_pm_runtime_put_autosuspend(struct gb_bundle *bundle)
+{
+	int retval;
+
+	pm_runtime_mark_last_busy(&bundle->dev);
+	retval = pm_runtime_put_autosuspend(&bundle->dev);
+
+	return retval;
+}
+
+static inline void gb_pm_runtime_get_noresume(struct gb_bundle *bundle)
+{
+	pm_runtime_get_noresume(&bundle->dev);
+}
+
+static inline void gb_pm_runtime_put_noidle(struct gb_bundle *bundle)
+{
+	pm_runtime_put_noidle(&bundle->dev);
+}
+
+#else
+static inline int gb_pm_runtime_get_sync(struct gb_bundle *bundle)
+{ return 0; }
+static inline int gb_pm_runtime_put_autosuspend(struct gb_bundle *bundle)
+{ return 0; }
+
+static inline void gb_pm_runtime_get_noresume(struct gb_bundle *bundle) {}
+static inline void gb_pm_runtime_put_noidle(struct gb_bundle *bundle) {}
+#endif
+
+#endif /* __BUNDLE_H */
diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
new file mode 100644
index 000000000000..46d2e8a9e490
--- /dev/null
+++ b/drivers/staging/greybus/camera.c
@@ -0,0 +1,1400 @@
+/*
+ * Greybus Camera protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+
+#include "gb-camera.h"
+#include "greybus.h"
+#include "greybus_protocols.h"
+
+enum gb_camera_debugs_buffer_id {
+	GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES,
+	GB_CAMERA_DEBUGFS_BUFFER_STREAMS,
+	GB_CAMERA_DEBUGFS_BUFFER_CAPTURE,
+	GB_CAMERA_DEBUGFS_BUFFER_FLUSH,
+	GB_CAMERA_DEBUGFS_BUFFER_MAX,
+};
+
+struct gb_camera_debugfs_buffer {
+	char data[PAGE_SIZE];
+	size_t length;
+};
+
+enum gb_camera_state {
+	GB_CAMERA_STATE_UNCONFIGURED,
+	GB_CAMERA_STATE_CONFIGURED,
+};
+
+/**
+ * struct gb_camera - A Greybus Camera Device
+ * @connection: the greybus connection for camera management
+ * @data_connection: the greybus connection for camera data
+ * @data_cport_id: the data CPort ID on the module side
+ * @mutex: protects the connection and state fields
+ * @state: the current module state
+ * @debugfs: debugfs entries for camera protocol operations testing
+ * @module: Greybus camera module registered to HOST processor.
+ */
+struct gb_camera {
+	struct gb_bundle *bundle;
+	struct gb_connection *connection;
+	struct gb_connection *data_connection;
+	u16 data_cport_id;
+
+	struct mutex mutex;
+	enum gb_camera_state state;
+
+	struct {
+		struct dentry *root;
+		struct gb_camera_debugfs_buffer *buffers;
+	} debugfs;
+
+	struct gb_camera_module module;
+};
+
+struct gb_camera_stream_config {
+	unsigned int width;
+	unsigned int height;
+	unsigned int format;
+	unsigned int vc;
+	unsigned int dt[2];
+	unsigned int max_size;
+};
+
+struct gb_camera_fmt_info {
+	enum v4l2_mbus_pixelcode mbus_code;
+	unsigned int gb_format;
+	unsigned int bpp;
+};
+
+/* GB format to media code map */
+static const struct gb_camera_fmt_info gb_fmt_info[] = {
+	{
+		.mbus_code = V4L2_MBUS_FMT_UYVY8_1X16,
+		.gb_format = 0x01,
+		.bpp	   = 16,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_NV12_1x8,
+		.gb_format = 0x12,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_NV21_1x8,
+		.gb_format = 0x13,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_YU12_1x8,
+		.gb_format = 0x16,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_YV12_1x8,
+		.gb_format = 0x17,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_JPEG_1X8,
+		.gb_format = 0x40,
+		.bpp	   = 0,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_GB_CAM_METADATA_1X8,
+		.gb_format = 0x41,
+		.bpp	   = 0,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_GB_CAM_DEBUG_DATA_1X8,
+		.gb_format = 0x42,
+		.bpp	   = 0,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SBGGR10_1X10,
+		.gb_format = 0x80,
+		.bpp	   = 10,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SGBRG10_1X10,
+		.gb_format = 0x81,
+		.bpp	   = 10,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SGRBG10_1X10,
+		.gb_format = 0x82,
+		.bpp	   = 10,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SRGGB10_1X10,
+		.gb_format = 0x83,
+		.bpp	   = 10,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SBGGR12_1X12,
+		.gb_format = 0x84,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SGBRG12_1X12,
+		.gb_format = 0x85,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SGRBG12_1X12,
+		.gb_format = 0x86,
+		.bpp	   = 12,
+	},
+	{
+		.mbus_code = V4L2_MBUS_FMT_SRGGB12_1X12,
+		.gb_format = 0x87,
+		.bpp	   = 12,
+	},
+};
+
+static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+		if (gb_fmt_info[i].gb_format == gb_fmt)
+			return &gb_fmt_info[i];
+	}
+
+	return NULL;
+}
+
+#define ES2_APB_CDSI0_CPORT		16
+#define ES2_APB_CDSI1_CPORT		17
+
+#define GB_CAMERA_MAX_SETTINGS_SIZE	8192
+
+#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
+#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
+#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
+
+static int gb_camera_operation_sync_flags(struct gb_connection *connection,
+					  int type, unsigned int flags,
+					  void *request, size_t request_size,
+					  void *response, size_t *response_size)
+{
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_operation_create_flags(connection, type, request_size,
+					      *response_size, flags,
+					      GFP_KERNEL);
+	if (!operation)
+		return  -ENOMEM;
+
+	if (request_size)
+		memcpy(operation->request->payload, request, request_size);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: synchronous operation of type 0x%02x failed: %d\n",
+			connection->name, type, ret);
+	} else {
+		*response_size = operation->response->payload_size;
+
+		if (operation->response->payload_size)
+			memcpy(response, operation->response->payload,
+			       operation->response->payload_size);
+	}
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int gb_camera_get_max_pkt_size(struct gb_camera *gcam,
+		struct gb_camera_configure_streams_response *resp)
+{
+	unsigned int max_pkt_size = 0;
+	unsigned int i;
+
+	for (i = 0; i < resp->num_streams; i++) {
+		struct gb_camera_stream_config_response *cfg = &resp->config[i];
+		const struct gb_camera_fmt_info *fmt_info;
+		unsigned int pkt_size;
+
+		fmt_info = gb_camera_get_format_info(cfg->format);
+		if (!fmt_info) {
+			gcam_err(gcam, "unsupported greybus image format: %d\n",
+				 cfg->format);
+			return -EIO;
+		}
+
+		if (fmt_info->bpp == 0) {
+			pkt_size = le32_to_cpu(cfg->max_pkt_size);
+
+			if (pkt_size == 0) {
+				gcam_err(gcam,
+					 "Stream %u: invalid zero maximum packet size\n",
+					 i);
+				return -EIO;
+			}
+		} else {
+			pkt_size = le16_to_cpu(cfg->width) * fmt_info->bpp / 8;
+
+			if (pkt_size != le32_to_cpu(cfg->max_pkt_size)) {
+				gcam_err(gcam,
+					 "Stream %u: maximum packet size mismatch (%u/%u)\n",
+					 i, pkt_size, cfg->max_pkt_size);
+				return -EIO;
+			}
+		}
+
+		max_pkt_size = max(pkt_size, max_pkt_size);
+	}
+
+	return max_pkt_size;
+}
+
+/*
+ * Validate the stream configuration response verifying padding is correctly
+ * set and the returned number of streams is supported
+ */
+static const int gb_camera_configure_streams_validate_response(
+		struct gb_camera *gcam,
+		struct gb_camera_configure_streams_response *resp,
+		unsigned int nstreams)
+{
+	unsigned int i;
+
+	/* Validate the returned response structure */
+	if (resp->padding[0] || resp->padding[1]) {
+		gcam_err(gcam, "response padding != 0\n");
+		return -EIO;
+	}
+
+	if (resp->num_streams > nstreams) {
+		gcam_err(gcam, "got #streams %u > request %u\n",
+			 resp->num_streams, nstreams);
+		return -EIO;
+	}
+
+	for (i = 0; i < resp->num_streams; i++) {
+		struct gb_camera_stream_config_response *cfg = &resp->config[i];
+		if (cfg->padding) {
+			gcam_err(gcam, "stream #%u padding != 0\n", i);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Hardware Configuration
+ */
+
+static int gb_camera_set_intf_power_mode(struct gb_camera *gcam, u8 intf_id,
+					 bool hs)
+{
+	struct gb_svc *svc = gcam->connection->hd->svc;
+	int ret;
+
+	if (hs)
+		ret = gb_svc_intf_set_power_mode(svc, intf_id,
+						 GB_SVC_UNIPRO_HS_SERIES_A,
+						 GB_SVC_UNIPRO_FAST_MODE, 2, 2,
+						 GB_SVC_SMALL_AMPLITUDE,
+						 GB_SVC_NO_DE_EMPHASIS,
+						 GB_SVC_UNIPRO_FAST_MODE, 2, 2,
+						 GB_SVC_PWRM_RXTERMINATION |
+						 GB_SVC_PWRM_TXTERMINATION, 0,
+						 NULL, NULL);
+	else
+		ret = gb_svc_intf_set_power_mode(svc, intf_id,
+						 GB_SVC_UNIPRO_HS_SERIES_A,
+						 GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+						 2, 1,
+						 GB_SVC_SMALL_AMPLITUDE,
+						 GB_SVC_NO_DE_EMPHASIS,
+						 GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+						 2, 1,
+						 0, 0,
+						 NULL, NULL);
+
+	return ret;
+}
+
+static int gb_camera_set_power_mode(struct gb_camera *gcam, bool hs)
+{
+	struct gb_interface *intf = gcam->connection->intf;
+	struct gb_svc *svc = gcam->connection->hd->svc;
+	int ret;
+
+	ret = gb_camera_set_intf_power_mode(gcam, intf->interface_id, hs);
+	if (ret < 0) {
+		gcam_err(gcam, "failed to set module interface to %s (%d)\n",
+			 hs ? "HS" : "PWM", ret);
+		return ret;
+	}
+
+	ret = gb_camera_set_intf_power_mode(gcam, svc->ap_intf_id, hs);
+	if (ret < 0) {
+		gb_camera_set_intf_power_mode(gcam, intf->interface_id, !hs);
+		gcam_err(gcam, "failed to set AP interface to %s (%d)\n",
+			 hs ? "HS" : "PWM", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+struct ap_csi_config_request {
+	__u8 csi_id;
+	__u8 flags;
+#define GB_CAMERA_CSI_FLAG_CLOCK_CONTINUOUS 0x01
+	__u8 num_lanes;
+	__u8 padding;
+	__le32 csi_clk_freq;
+	__le32 max_pkt_size;
+} __packed;
+
+/*
+ * TODO: Compute the number of lanes dynamically based on bandwidth
+ * requirements.
+ */
+#define GB_CAMERA_CSI_NUM_DATA_LANES		4
+
+#define GB_CAMERA_CSI_CLK_FREQ_MAX		999000000U
+#define GB_CAMERA_CSI_CLK_FREQ_MIN		100000000U
+#define GB_CAMERA_CSI_CLK_FREQ_MARGIN		150000000U
+
+static int gb_camera_setup_data_connection(struct gb_camera *gcam,
+		struct gb_camera_configure_streams_response *resp,
+		struct gb_camera_csi_params *csi_params)
+{
+	struct ap_csi_config_request csi_cfg;
+	struct gb_connection *conn;
+	unsigned int clk_freq;
+	int ret;
+
+	/*
+	 * Create the data connection between the camera module data CPort and
+	 * APB CDSI1. The CDSI1 CPort ID is hardcoded by the ES2 bridge.
+	 */
+	conn = gb_connection_create_offloaded(gcam->bundle, gcam->data_cport_id,
+					      GB_CONNECTION_FLAG_NO_FLOWCTRL |
+					      GB_CONNECTION_FLAG_CDSI1);
+	if (IS_ERR(conn))
+		return PTR_ERR(conn);
+
+	gcam->data_connection = conn;
+	gb_connection_set_data(conn, gcam);
+
+	ret = gb_connection_enable(conn);
+	if (ret)
+		goto error_conn_destroy;
+
+	/* Set the UniPro link to high speed mode. */
+	ret = gb_camera_set_power_mode(gcam, true);
+	if (ret < 0)
+		goto error_conn_disable;
+
+	/*
+	 * Configure the APB-A CSI-2 transmitter.
+	 *
+	 * Hardcode the number of lanes to 4 and compute the bus clock frequency
+	 * based on the module bandwidth requirements with a safety margin.
+	 */
+	memset(&csi_cfg, 0, sizeof(csi_cfg));
+	csi_cfg.csi_id = 1;
+	csi_cfg.flags = 0;
+	csi_cfg.num_lanes = GB_CAMERA_CSI_NUM_DATA_LANES;
+
+	clk_freq = resp->data_rate / 2 / GB_CAMERA_CSI_NUM_DATA_LANES;
+	clk_freq = clamp(clk_freq + GB_CAMERA_CSI_CLK_FREQ_MARGIN,
+			 GB_CAMERA_CSI_CLK_FREQ_MIN,
+			 GB_CAMERA_CSI_CLK_FREQ_MAX);
+	csi_cfg.csi_clk_freq = clk_freq;
+
+	ret = gb_camera_get_max_pkt_size(gcam, resp);
+	if (ret < 0) {
+		ret = -EIO;
+		goto error_power;
+	}
+	csi_cfg.max_pkt_size = ret;
+
+	ret = gb_hd_output(gcam->connection->hd, &csi_cfg,
+			   sizeof(csi_cfg),
+			   GB_APB_REQUEST_CSI_TX_CONTROL, false);
+	if (ret < 0) {
+		gcam_err(gcam, "failed to start the CSI transmitter\n");
+		goto error_power;
+	}
+
+	if (csi_params) {
+		csi_params->clk_freq = csi_cfg.csi_clk_freq;
+		csi_params->num_lanes = csi_cfg.num_lanes;
+	}
+
+	return 0;
+
+error_power:
+	gb_camera_set_power_mode(gcam, false);
+error_conn_disable:
+	gb_connection_disable(gcam->data_connection);
+error_conn_destroy:
+	gb_connection_destroy(gcam->data_connection);
+	gcam->data_connection = NULL;
+	return ret;
+}
+
+static void gb_camera_teardown_data_connection(struct gb_camera *gcam)
+{
+	struct ap_csi_config_request csi_cfg;
+	int ret;
+
+	/* Stop the APB1 CSI transmitter. */
+	memset(&csi_cfg, 0, sizeof(csi_cfg));
+	csi_cfg.csi_id = 1;
+
+	ret = gb_hd_output(gcam->connection->hd, &csi_cfg,
+			   sizeof(csi_cfg),
+			   GB_APB_REQUEST_CSI_TX_CONTROL, false);
+
+	if (ret < 0)
+		gcam_err(gcam, "failed to stop the CSI transmitter\n");
+
+	/* Set the UniPro link to low speed mode. */
+	gb_camera_set_power_mode(gcam, false);
+
+	/* Destroy the data connection. */
+	gb_connection_disable(gcam->data_connection);
+	gb_connection_destroy(gcam->data_connection);
+	gcam->data_connection = NULL;
+}
+
+/* -----------------------------------------------------------------------------
+ * Camera Protocol Operations
+ */
+
+static int gb_camera_capabilities(struct gb_camera *gcam,
+				  u8 *capabilities, size_t *size)
+{
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(gcam->bundle);
+	if (ret)
+		return ret;
+
+	mutex_lock(&gcam->mutex);
+
+	if (!gcam->connection) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = gb_camera_operation_sync_flags(gcam->connection,
+					     GB_CAMERA_TYPE_CAPABILITIES,
+					     GB_OPERATION_FLAG_SHORT_RESPONSE,
+					     NULL, 0,
+					     (void *)capabilities, size);
+	if (ret)
+		gcam_err(gcam, "failed to retrieve capabilities: %d\n", ret);
+
+done:
+	mutex_unlock(&gcam->mutex);
+
+	gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+	return ret;
+}
+
+static int gb_camera_configure_streams(struct gb_camera *gcam,
+				       unsigned int *num_streams,
+				       unsigned int *flags,
+				       struct gb_camera_stream_config *streams,
+				       struct gb_camera_csi_params *csi_params)
+{
+	struct gb_camera_configure_streams_request *req;
+	struct gb_camera_configure_streams_response *resp;
+	unsigned int nstreams = *num_streams;
+	unsigned int i;
+	size_t req_size;
+	size_t resp_size;
+	int ret;
+
+	if (nstreams > GB_CAMERA_MAX_STREAMS)
+		return -EINVAL;
+
+	req_size = sizeof(*req) + nstreams * sizeof(req->config[0]);
+	resp_size = sizeof(*resp) + nstreams * sizeof(resp->config[0]);
+
+	req = kmalloc(req_size, GFP_KERNEL);
+	resp = kmalloc(resp_size, GFP_KERNEL);
+	if (!req || !resp) {
+		kfree(req);
+		kfree(resp);
+		return -ENOMEM;
+	}
+
+	req->num_streams = nstreams;
+	req->flags = *flags;
+	req->padding = 0;
+
+	for (i = 0; i < nstreams; ++i) {
+		struct gb_camera_stream_config_request *cfg = &req->config[i];
+
+		cfg->width = cpu_to_le16(streams[i].width);
+		cfg->height = cpu_to_le16(streams[i].height);
+		cfg->format = cpu_to_le16(streams[i].format);
+		cfg->padding = 0;
+	}
+
+	mutex_lock(&gcam->mutex);
+
+	ret = gb_pm_runtime_get_sync(gcam->bundle);
+	if (ret)
+		goto done_skip_pm_put;
+
+	if (!gcam->connection) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = gb_camera_operation_sync_flags(gcam->connection,
+					     GB_CAMERA_TYPE_CONFIGURE_STREAMS,
+					     GB_OPERATION_FLAG_SHORT_RESPONSE,
+					     req, req_size,
+					     resp, &resp_size);
+	if (ret < 0)
+		goto done;
+
+	ret = gb_camera_configure_streams_validate_response(gcam, resp,
+							    nstreams);
+	if (ret < 0)
+		goto done;
+
+	*flags = resp->flags;
+	*num_streams = resp->num_streams;
+
+	for (i = 0; i < resp->num_streams; ++i) {
+		struct gb_camera_stream_config_response *cfg = &resp->config[i];
+
+		streams[i].width = le16_to_cpu(cfg->width);
+		streams[i].height = le16_to_cpu(cfg->height);
+		streams[i].format = le16_to_cpu(cfg->format);
+		streams[i].vc = cfg->virtual_channel;
+		streams[i].dt[0] = cfg->data_type[0];
+		streams[i].dt[1] = cfg->data_type[1];
+		streams[i].max_size = le32_to_cpu(cfg->max_size);
+	}
+
+	if ((resp->flags & GB_CAMERA_CONFIGURE_STREAMS_ADJUSTED) ||
+	    (req->flags & GB_CAMERA_CONFIGURE_STREAMS_TEST_ONLY))
+		goto done;
+
+	if (gcam->state == GB_CAMERA_STATE_CONFIGURED) {
+		gb_camera_teardown_data_connection(gcam);
+		gcam->state = GB_CAMERA_STATE_UNCONFIGURED;
+
+		/*
+		 * When unconfiguring streams release the PM runtime reference
+		 * that was acquired when streams were configured. The bundle
+		 * won't be suspended until the PM runtime reference acquired at
+		 * the beginning of this function gets released right before
+		 * returning.
+		 */
+		gb_pm_runtime_put_noidle(gcam->bundle);
+	}
+
+	if (resp->num_streams == 0)
+		goto done;
+
+	/*
+	 * Make sure the bundle won't be suspended until streams get
+	 * unconfigured after the stream is configured successfully
+	 */
+	gb_pm_runtime_get_noresume(gcam->bundle);
+
+	/* Setup CSI-2 connection from APB-A to AP */
+	ret = gb_camera_setup_data_connection(gcam, resp, csi_params);
+	if (ret < 0) {
+		memset(req, 0, sizeof(*req));
+		gb_operation_sync(gcam->connection,
+				  GB_CAMERA_TYPE_CONFIGURE_STREAMS,
+				  req, sizeof(*req),
+				  resp, sizeof(*resp));
+		*flags = 0;
+		*num_streams = 0;
+		gb_pm_runtime_put_noidle(gcam->bundle);
+		goto done;
+	}
+
+	gcam->state = GB_CAMERA_STATE_CONFIGURED;
+
+done:
+	gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+done_skip_pm_put:
+	mutex_unlock(&gcam->mutex);
+	kfree(req);
+	kfree(resp);
+	return ret;
+}
+
+static int gb_camera_capture(struct gb_camera *gcam, u32 request_id,
+			     unsigned int streams, unsigned int num_frames,
+			     size_t settings_size, const void *settings)
+{
+	struct gb_camera_capture_request *req;
+	size_t req_size;
+	int ret;
+
+	if (settings_size > GB_CAMERA_MAX_SETTINGS_SIZE)
+		return -EINVAL;
+
+	req_size = sizeof(*req) + settings_size;
+	req = kmalloc(req_size, GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	req->request_id = cpu_to_le32(request_id);
+	req->streams = streams;
+	req->padding = 0;
+	req->num_frames = cpu_to_le16(num_frames);
+	memcpy(req->settings, settings, settings_size);
+
+	mutex_lock(&gcam->mutex);
+
+	if (!gcam->connection) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = gb_operation_sync(gcam->connection, GB_CAMERA_TYPE_CAPTURE,
+				req, req_size, NULL, 0);
+done:
+	mutex_unlock(&gcam->mutex);
+
+	kfree(req);
+
+	return ret;
+}
+
+static int gb_camera_flush(struct gb_camera *gcam, u32 *request_id)
+{
+	struct gb_camera_flush_response resp;
+	int ret;
+
+	mutex_lock(&gcam->mutex);
+
+	if (!gcam->connection) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = gb_operation_sync(gcam->connection, GB_CAMERA_TYPE_FLUSH, NULL, 0,
+				&resp, sizeof(resp));
+
+	if (ret < 0)
+		goto done;
+
+	if (request_id)
+		*request_id = le32_to_cpu(resp.request_id);
+
+done:
+	mutex_unlock(&gcam->mutex);
+
+	return ret;
+}
+
+static int gb_camera_request_handler(struct gb_operation *op)
+{
+	struct gb_camera *gcam = gb_connection_get_data(op->connection);
+	struct gb_camera_metadata_request *payload;
+	struct gb_message *request;
+
+	if (op->type != GB_CAMERA_TYPE_METADATA) {
+		gcam_err(gcam, "Unsupported unsolicited event: %u\n", op->type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*payload)) {
+		gcam_err(gcam, "Wrong event size received (%zu < %zu)\n",
+			 request->payload_size, sizeof(*payload));
+		return -EINVAL;
+	}
+
+	payload = request->payload;
+
+	gcam_dbg(gcam, "received metadata for request %u, frame %u, stream %u\n",
+		 payload->request_id, payload->frame_number, payload->stream);
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Interface with HOST gmp camera.
+ */
+static unsigned int gb_camera_mbus_to_gb(enum v4l2_mbus_pixelcode mbus_code)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+		if (gb_fmt_info[i].mbus_code == mbus_code)
+			return gb_fmt_info[i].gb_format;
+	}
+	return gb_fmt_info[0].gb_format;
+}
+
+static enum v4l2_mbus_pixelcode gb_camera_gb_to_mbus(u16 gb_fmt)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+		if (gb_fmt_info[i].gb_format == gb_fmt)
+			return gb_fmt_info[i].mbus_code;
+	}
+	return gb_fmt_info[0].mbus_code;
+}
+
+static ssize_t gb_camera_op_capabilities(void *priv, char *data, size_t len)
+{
+	struct gb_camera *gcam = priv;
+	size_t capabilities_len = len;
+	int ret;
+
+	ret = gb_camera_capabilities(gcam, data, &capabilities_len);
+	if (ret)
+		return ret;
+
+	return capabilities_len;
+}
+
+static int gb_camera_op_configure_streams(void *priv, unsigned int *nstreams,
+		unsigned int *flags, struct gb_camera_stream *streams,
+		struct gb_camera_csi_params *csi_params)
+{
+	struct gb_camera *gcam = priv;
+	struct gb_camera_stream_config *gb_streams;
+	unsigned int gb_flags = 0;
+	unsigned int gb_nstreams = *nstreams;
+	unsigned int i;
+	int ret;
+
+	if (gb_nstreams > GB_CAMERA_MAX_STREAMS)
+		return -EINVAL;
+
+	gb_streams = kzalloc(gb_nstreams * sizeof(*gb_streams), GFP_KERNEL);
+	if (!gb_streams)
+		return -ENOMEM;
+
+	for (i = 0; i < gb_nstreams; i++) {
+		gb_streams[i].width = streams[i].width;
+		gb_streams[i].height = streams[i].height;
+		gb_streams[i].format =
+			gb_camera_mbus_to_gb(streams[i].pixel_code);
+	}
+
+	if (*flags & GB_CAMERA_IN_FLAG_TEST)
+		gb_flags |= GB_CAMERA_CONFIGURE_STREAMS_TEST_ONLY;
+
+	ret = gb_camera_configure_streams(gcam, &gb_nstreams,
+					  &gb_flags, gb_streams, csi_params);
+	if (ret < 0)
+		goto done;
+	if (gb_nstreams > *nstreams) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	*flags = 0;
+	if (gb_flags & GB_CAMERA_CONFIGURE_STREAMS_ADJUSTED)
+		*flags |= GB_CAMERA_OUT_FLAG_ADJUSTED;
+
+	for (i = 0; i < gb_nstreams; i++) {
+		streams[i].width = gb_streams[i].width;
+		streams[i].height = gb_streams[i].height;
+		streams[i].vc = gb_streams[i].vc;
+		streams[i].dt[0] = gb_streams[i].dt[0];
+		streams[i].dt[1] = gb_streams[i].dt[1];
+		streams[i].max_size = gb_streams[i].max_size;
+		streams[i].pixel_code =
+			gb_camera_gb_to_mbus(gb_streams[i].format);
+	}
+	*nstreams = gb_nstreams;
+
+done:
+	kfree(gb_streams);
+	return ret;
+}
+
+static int gb_camera_op_capture(void *priv, u32 request_id,
+		unsigned int streams, unsigned int num_frames,
+		size_t settings_size, const void *settings)
+{
+	struct gb_camera *gcam = priv;
+
+	return gb_camera_capture(gcam, request_id, streams, num_frames,
+				 settings_size, settings);
+}
+
+static int gb_camera_op_flush(void *priv, u32 *request_id)
+{
+	struct gb_camera *gcam = priv;
+
+	return gb_camera_flush(gcam, request_id);
+}
+
+static const struct gb_camera_ops gb_cam_ops = {
+	.capabilities = gb_camera_op_capabilities,
+	.configure_streams = gb_camera_op_configure_streams,
+	.capture = gb_camera_op_capture,
+	.flush = gb_camera_op_flush,
+};
+
+/* -----------------------------------------------------------------------------
+ * DebugFS
+ */
+
+static ssize_t gb_camera_debugfs_capabilities(struct gb_camera *gcam,
+		char *buf, size_t len)
+{
+	struct gb_camera_debugfs_buffer *buffer =
+		&gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES];
+	size_t size = 1024;
+	unsigned int i;
+	u8 *caps;
+	int ret;
+
+	caps = kmalloc(size, GFP_KERNEL);
+	if (!caps)
+		return -ENOMEM;
+
+	ret = gb_camera_capabilities(gcam, caps, &size);
+	if (ret < 0)
+		goto done;
+
+	/*
+	 * hex_dump_to_buffer() doesn't return the number of bytes dumped prior
+	 * to v4.0, we need our own implementation :-(
+	 */
+	buffer->length = 0;
+
+	for (i = 0; i < size; i += 16) {
+		unsigned int nbytes = min_t(unsigned int, size - i, 16);
+
+		buffer->length += sprintf(buffer->data + buffer->length,
+					  "%*ph\n", nbytes, caps + i);
+	}
+
+done:
+	kfree(caps);
+	return ret;
+}
+
+static ssize_t gb_camera_debugfs_configure_streams(struct gb_camera *gcam,
+		char *buf, size_t len)
+{
+	struct gb_camera_debugfs_buffer *buffer =
+		&gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_STREAMS];
+	struct gb_camera_stream_config *streams;
+	unsigned int nstreams;
+	unsigned int flags;
+	unsigned int i;
+	char *token;
+	int ret;
+
+	/* Retrieve number of streams to configure */
+	token = strsep(&buf, ";");
+	if (token == NULL)
+		return -EINVAL;
+
+	ret = kstrtouint(token, 10, &nstreams);
+	if (ret < 0)
+		return ret;
+
+	if (nstreams > GB_CAMERA_MAX_STREAMS)
+		return -EINVAL;
+
+	token = strsep(&buf, ";");
+	if (token == NULL)
+		return -EINVAL;
+
+	ret = kstrtouint(token, 10, &flags);
+	if (ret < 0)
+		return ret;
+
+	/* For each stream to configure parse width, height and format */
+	streams = kzalloc(nstreams * sizeof(*streams), GFP_KERNEL);
+	if (!streams)
+		return -ENOMEM;
+
+	for (i = 0; i < nstreams; ++i) {
+		struct gb_camera_stream_config *stream = &streams[i];
+
+		/* width */
+		token = strsep(&buf, ";");
+		if (token == NULL) {
+			ret = -EINVAL;
+			goto done;
+		}
+		ret = kstrtouint(token, 10, &stream->width);
+		if (ret < 0)
+			goto done;
+
+		/* height */
+		token = strsep(&buf, ";");
+		if (token == NULL)
+			goto done;
+
+		ret = kstrtouint(token, 10, &stream->height);
+		if (ret < 0)
+			goto done;
+
+		/* Image format code */
+		token = strsep(&buf, ";");
+		if (token == NULL)
+			goto done;
+
+		ret = kstrtouint(token, 16, &stream->format);
+		if (ret < 0)
+			goto done;
+	}
+
+	ret = gb_camera_configure_streams(gcam, &nstreams, &flags, streams,
+					  NULL);
+	if (ret < 0)
+		goto done;
+
+	buffer->length = sprintf(buffer->data, "%u;%u;", nstreams, flags);
+
+	for (i = 0; i < nstreams; ++i) {
+		struct gb_camera_stream_config *stream = &streams[i];
+
+		buffer->length += sprintf(buffer->data + buffer->length,
+					  "%u;%u;%u;%u;%u;%u;%u;",
+					  stream->width, stream->height,
+					  stream->format, stream->vc,
+					  stream->dt[0], stream->dt[1],
+					  stream->max_size);
+	}
+
+	ret = len;
+
+done:
+	kfree(streams);
+	return ret;
+};
+
+static ssize_t gb_camera_debugfs_capture(struct gb_camera *gcam,
+		char *buf, size_t len)
+{
+	unsigned int request_id;
+	unsigned int streams_mask;
+	unsigned int num_frames;
+	char *token;
+	int ret;
+
+	/* Request id */
+	token = strsep(&buf, ";");
+	if (token == NULL)
+		return -EINVAL;
+	ret = kstrtouint(token, 10, &request_id);
+	if (ret < 0)
+		return ret;
+
+	/* Stream mask */
+	token = strsep(&buf, ";");
+	if (token == NULL)
+		return -EINVAL;
+	ret = kstrtouint(token, 16, &streams_mask);
+	if (ret < 0)
+		return ret;
+
+	/* number of frames */
+	token = strsep(&buf, ";");
+	if (token == NULL)
+		return -EINVAL;
+	ret = kstrtouint(token, 10, &num_frames);
+	if (ret < 0)
+		return ret;
+
+	ret = gb_camera_capture(gcam, request_id, streams_mask, num_frames, 0,
+				NULL);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t gb_camera_debugfs_flush(struct gb_camera *gcam,
+		char *buf, size_t len)
+{
+	struct gb_camera_debugfs_buffer *buffer =
+		&gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_FLUSH];
+	unsigned int req_id;
+	int ret;
+
+	ret = gb_camera_flush(gcam, &req_id);
+	if (ret < 0)
+		return ret;
+
+	buffer->length = sprintf(buffer->data, "%u", req_id);
+
+	return len;
+}
+
+struct gb_camera_debugfs_entry {
+	const char *name;
+	unsigned int mask;
+	unsigned int buffer;
+	ssize_t (*execute)(struct gb_camera *gcam, char *buf, size_t len);
+};
+
+static const struct gb_camera_debugfs_entry gb_camera_debugfs_entries[] = {
+	{
+		.name = "capabilities",
+		.mask = S_IFREG | S_IRUGO,
+		.buffer = GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES,
+		.execute = gb_camera_debugfs_capabilities,
+	}, {
+		.name = "configure_streams",
+		.mask = S_IFREG | S_IRUGO | S_IWUGO,
+		.buffer = GB_CAMERA_DEBUGFS_BUFFER_STREAMS,
+		.execute = gb_camera_debugfs_configure_streams,
+	}, {
+		.name = "capture",
+		.mask = S_IFREG | S_IRUGO | S_IWUGO,
+		.buffer = GB_CAMERA_DEBUGFS_BUFFER_CAPTURE,
+		.execute = gb_camera_debugfs_capture,
+	}, {
+		.name = "flush",
+		.mask = S_IFREG | S_IRUGO | S_IWUGO,
+		.buffer = GB_CAMERA_DEBUGFS_BUFFER_FLUSH,
+		.execute = gb_camera_debugfs_flush,
+	},
+};
+
+static ssize_t gb_camera_debugfs_read(struct file *file, char __user *buf,
+				      size_t len, loff_t *offset)
+{
+	const struct gb_camera_debugfs_entry *op = file->private_data;
+	struct gb_camera *gcam = file->f_inode->i_private;
+	struct gb_camera_debugfs_buffer *buffer;
+	ssize_t ret;
+
+	/* For read-only entries the operation is triggered by a read. */
+	if (!(op->mask & S_IWUGO)) {
+		ret = op->execute(gcam, NULL, 0);
+		if (ret < 0)
+			return ret;
+	}
+
+	buffer = &gcam->debugfs.buffers[op->buffer];
+
+	return simple_read_from_buffer(buf, len, offset, buffer->data,
+				       buffer->length);
+}
+
+static ssize_t gb_camera_debugfs_write(struct file *file,
+				       const char __user *buf, size_t len,
+				       loff_t *offset)
+{
+	const struct gb_camera_debugfs_entry *op = file->private_data;
+	struct gb_camera *gcam = file->f_inode->i_private;
+	ssize_t ret;
+	char *kbuf;
+
+	if (len > 1024)
+	       return -EINVAL;
+
+	kbuf = kmalloc(len + 1, GFP_KERNEL);
+	if (kbuf == NULL)
+		return -ENOMEM;
+
+	if (copy_from_user(kbuf, buf, len)) {
+		ret = -EFAULT;
+		goto done;
+	}
+
+	kbuf[len] = '\0';
+
+	ret = op->execute(gcam, kbuf, len);
+
+done:
+	kfree(kbuf);
+	return ret;
+}
+
+static int gb_camera_debugfs_open(struct inode *inode, struct file *file)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gb_camera_debugfs_entries); ++i) {
+		const struct gb_camera_debugfs_entry *entry =
+			&gb_camera_debugfs_entries[i];
+
+		if (!strcmp(file->f_path.dentry->d_iname, entry->name)) {
+			file->private_data = (void *)entry;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static const struct file_operations gb_camera_debugfs_ops = {
+	.open = gb_camera_debugfs_open,
+	.read = gb_camera_debugfs_read,
+	.write = gb_camera_debugfs_write,
+};
+
+static int gb_camera_debugfs_init(struct gb_camera *gcam)
+{
+	struct gb_connection *connection = gcam->connection;
+	char dirname[27];
+	unsigned int i;
+
+	/*
+	 * Create root debugfs entry and a file entry for each camera operation.
+	 */
+	snprintf(dirname, 27, "camera-%u.%u", connection->intf->interface_id,
+		 gcam->bundle->id);
+
+	gcam->debugfs.root = debugfs_create_dir(dirname, gb_debugfs_get());
+	if (IS_ERR(gcam->debugfs.root)) {
+		gcam_err(gcam, "debugfs root create failed (%ld)\n",
+			 PTR_ERR(gcam->debugfs.root));
+		return PTR_ERR(gcam->debugfs.root);
+	}
+
+	gcam->debugfs.buffers = vmalloc(sizeof(*gcam->debugfs.buffers) *
+					GB_CAMERA_DEBUGFS_BUFFER_MAX);
+	if (!gcam->debugfs.buffers)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(gb_camera_debugfs_entries); ++i) {
+		const struct gb_camera_debugfs_entry *entry =
+			&gb_camera_debugfs_entries[i];
+		struct dentry *dentry;
+
+		gcam->debugfs.buffers[i].length = 0;
+
+		dentry = debugfs_create_file(entry->name, entry->mask,
+					     gcam->debugfs.root, gcam,
+					     &gb_camera_debugfs_ops);
+		if (IS_ERR(dentry)) {
+			gcam_err(gcam,
+				 "debugfs operation %s create failed (%ld)\n",
+				 entry->name, PTR_ERR(dentry));
+			return PTR_ERR(dentry);
+		}
+	}
+
+	return 0;
+}
+
+static void gb_camera_debugfs_cleanup(struct gb_camera *gcam)
+{
+	debugfs_remove_recursive(gcam->debugfs.root);
+
+	vfree(gcam->debugfs.buffers);
+}
+
+/* -----------------------------------------------------------------------------
+ * Init & Cleanup
+ */
+
+static void gb_camera_cleanup(struct gb_camera *gcam)
+{
+	gb_camera_debugfs_cleanup(gcam);
+
+	mutex_lock(&gcam->mutex);
+	if (gcam->data_connection) {
+		gb_connection_disable(gcam->data_connection);
+		gb_connection_destroy(gcam->data_connection);
+		gcam->data_connection = NULL;
+	}
+
+	if (gcam->connection) {
+		gb_connection_disable(gcam->connection);
+		gb_connection_destroy(gcam->connection);
+		gcam->connection = NULL;
+	}
+	mutex_unlock(&gcam->mutex);
+}
+
+static void gb_camera_release_module(struct kref *ref)
+{
+	struct gb_camera_module *cam_mod =
+		container_of(ref, struct gb_camera_module, refcount);
+	kfree(cam_mod->priv);
+}
+
+static int gb_camera_probe(struct gb_bundle *bundle,
+			   const struct greybus_bundle_id *id)
+{
+	struct gb_connection *conn;
+	struct gb_camera *gcam;
+	u16 mgmt_cport_id = 0;
+	u16 data_cport_id = 0;
+	unsigned int i;
+	int ret;
+
+	/*
+	 * The camera bundle must contain exactly two CPorts, one for the
+	 * camera management protocol and one for the camera data protocol.
+	 */
+	if (bundle->num_cports != 2)
+		return -ENODEV;
+
+	for (i = 0; i < bundle->num_cports; ++i) {
+		struct greybus_descriptor_cport *desc = &bundle->cport_desc[i];
+
+		switch (desc->protocol_id) {
+		case GREYBUS_PROTOCOL_CAMERA_MGMT:
+			mgmt_cport_id = le16_to_cpu(desc->id);
+			break;
+		case GREYBUS_PROTOCOL_CAMERA_DATA:
+			data_cport_id = le16_to_cpu(desc->id);
+			break;
+		default:
+			return -ENODEV;
+		}
+	}
+
+	if (!mgmt_cport_id || !data_cport_id)
+		return -ENODEV;
+
+	gcam = kzalloc(sizeof(*gcam), GFP_KERNEL);
+	if (!gcam)
+		return -ENOMEM;
+
+	mutex_init(&gcam->mutex);
+
+	gcam->bundle = bundle;
+	gcam->state = GB_CAMERA_STATE_UNCONFIGURED;
+	gcam->data_cport_id = data_cport_id;
+
+	conn = gb_connection_create(bundle, mgmt_cport_id,
+				    gb_camera_request_handler);
+	if (IS_ERR(conn)) {
+		ret = PTR_ERR(conn);
+		goto error;
+	}
+
+	gcam->connection = conn;
+	gb_connection_set_data(conn, gcam);
+
+	ret = gb_connection_enable(conn);
+	if (ret)
+		goto error;
+
+	ret = gb_camera_debugfs_init(gcam);
+	if (ret < 0)
+		goto error;
+
+	gcam->module.priv = gcam;
+	gcam->module.ops = &gb_cam_ops;
+	gcam->module.interface_id = gcam->connection->intf->interface_id;
+	gcam->module.release = gb_camera_release_module;
+	ret = gb_camera_register(&gcam->module);
+	if (ret < 0)
+		goto error;
+
+	greybus_set_drvdata(bundle, gcam);
+
+	gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+	return 0;
+
+error:
+	gb_camera_cleanup(gcam);
+	kfree(gcam);
+	return ret;
+}
+
+static void gb_camera_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_camera *gcam = greybus_get_drvdata(bundle);
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		gb_pm_runtime_get_noresume(bundle);
+
+	gb_camera_cleanup(gcam);
+	gb_camera_unregister(&gcam->module);
+}
+
+static const struct greybus_bundle_id gb_camera_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_CAMERA) },
+	{ },
+};
+
+#ifdef CONFIG_PM
+static int gb_camera_suspend(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gb_camera *gcam = greybus_get_drvdata(bundle);
+
+	if (gcam->data_connection)
+		gb_connection_disable(gcam->data_connection);
+
+	gb_connection_disable(gcam->connection);
+
+	return 0;
+}
+
+static int gb_camera_resume(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gb_camera *gcam = greybus_get_drvdata(bundle);
+	int ret;
+
+	ret = gb_connection_enable(gcam->connection);
+	if (ret) {
+		gcam_err(gcam, "failed to enable connection: %d\n", ret);
+		return ret;
+	}
+
+	if (gcam->data_connection) {
+		ret = gb_connection_enable(gcam->data_connection);
+		if (ret) {
+			gcam_err(gcam,
+				 "failed to enable data connection: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_camera_pm_ops = {
+	SET_RUNTIME_PM_OPS(gb_camera_suspend, gb_camera_resume, NULL)
+};
+
+static struct greybus_driver gb_camera_driver = {
+	.name		= "camera",
+	.probe		= gb_camera_probe,
+	.disconnect	= gb_camera_disconnect,
+	.id_table	= gb_camera_id_table,
+	.driver.pm	= &gb_camera_pm_ops,
+};
+
+module_greybus_driver(gb_camera_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c
new file mode 100644
index 000000000000..557075147f2d
--- /dev/null
+++ b/drivers/staging/greybus/connection.c
@@ -0,0 +1,938 @@
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/workqueue.h>
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+
+#define GB_CONNECTION_CPORT_QUIESCE_TIMEOUT	1000
+
+
+static void gb_connection_kref_release(struct kref *kref);
+
+
+static DEFINE_SPINLOCK(gb_connections_lock);
+static DEFINE_MUTEX(gb_connection_mutex);
+
+
+/* Caller holds gb_connection_mutex. */
+static bool gb_connection_cport_in_use(struct gb_interface *intf, u16 cport_id)
+{
+	struct gb_host_device *hd = intf->hd;
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &hd->connections, hd_links) {
+		if (connection->intf == intf &&
+				connection->intf_cport_id == cport_id)
+			return true;
+	}
+
+	return false;
+}
+
+static void gb_connection_get(struct gb_connection *connection)
+{
+	kref_get(&connection->kref);
+
+	trace_gb_connection_get(connection);
+}
+
+static void gb_connection_put(struct gb_connection *connection)
+{
+	trace_gb_connection_put(connection);
+
+	kref_put(&connection->kref, gb_connection_kref_release);
+}
+
+/*
+ * Returns a reference-counted pointer to the connection if found.
+ */
+static struct gb_connection *
+gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
+{
+	struct gb_connection *connection;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gb_connections_lock, flags);
+	list_for_each_entry(connection, &hd->connections, hd_links)
+		if (connection->hd_cport_id == cport_id) {
+			gb_connection_get(connection);
+			goto found;
+		}
+	connection = NULL;
+found:
+	spin_unlock_irqrestore(&gb_connections_lock, flags);
+
+	return connection;
+}
+
+/*
+ * Callback from the host driver to let us know that data has been
+ * received on the bundle.
+ */
+void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
+			u8 *data, size_t length)
+{
+	struct gb_connection *connection;
+
+	trace_gb_hd_in(hd);
+
+	connection = gb_connection_hd_find(hd, cport_id);
+	if (!connection) {
+		dev_err(&hd->dev,
+			"nonexistent connection (%zu bytes dropped)\n", length);
+		return;
+	}
+	gb_connection_recv(connection, data, length);
+	gb_connection_put(connection);
+}
+EXPORT_SYMBOL_GPL(greybus_data_rcvd);
+
+static void gb_connection_kref_release(struct kref *kref)
+{
+	struct gb_connection *connection;
+
+	connection = container_of(kref, struct gb_connection, kref);
+
+	trace_gb_connection_release(connection);
+
+	kfree(connection);
+}
+
+static void gb_connection_init_name(struct gb_connection *connection)
+{
+	u16 hd_cport_id = connection->hd_cport_id;
+	u16 cport_id = 0;
+	u8 intf_id = 0;
+
+	if (connection->intf) {
+		intf_id = connection->intf->interface_id;
+		cport_id = connection->intf_cport_id;
+	}
+
+	snprintf(connection->name, sizeof(connection->name),
+			"%u/%u:%u", hd_cport_id, intf_id, cport_id);
+}
+
+/*
+ * _gb_connection_create() - create a Greybus connection
+ * @hd:			host device of the connection
+ * @hd_cport_id:	host-device cport id, or -1 for dynamic allocation
+ * @intf:		remote interface, or NULL for static connections
+ * @bundle:		remote-interface bundle (may be NULL)
+ * @cport_id:		remote-interface cport id, or 0 for static connections
+ * @handler:		request handler (may be NULL)
+ * @flags:		connection flags
+ *
+ * Create a Greybus connection, representing the bidirectional link
+ * between a CPort on a (local) Greybus host device and a CPort on
+ * another Greybus interface.
+ *
+ * A connection also maintains the state of operations sent over the
+ * connection.
+ *
+ * Serialised against concurrent create and destroy using the
+ * gb_connection_mutex.
+ *
+ * Return: A pointer to the new connection if successful, or an ERR_PTR
+ * otherwise.
+ */
+static struct gb_connection *
+_gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
+				struct gb_interface *intf,
+				struct gb_bundle *bundle, int cport_id,
+				gb_request_handler_t handler,
+				unsigned long flags)
+{
+	struct gb_connection *connection;
+	int ret;
+
+	mutex_lock(&gb_connection_mutex);
+
+	if (intf && gb_connection_cport_in_use(intf, cport_id)) {
+		dev_err(&intf->dev, "cport %u already in use\n", cport_id);
+		ret = -EBUSY;
+		goto err_unlock;
+	}
+
+	ret = gb_hd_cport_allocate(hd, hd_cport_id, flags);
+	if (ret < 0) {
+		dev_err(&hd->dev, "failed to allocate cport: %d\n", ret);
+		goto err_unlock;
+	}
+	hd_cport_id = ret;
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection) {
+		ret = -ENOMEM;
+		goto err_hd_cport_release;
+	}
+
+	connection->hd_cport_id = hd_cport_id;
+	connection->intf_cport_id = cport_id;
+	connection->hd = hd;
+	connection->intf = intf;
+	connection->bundle = bundle;
+	connection->handler = handler;
+	connection->flags = flags;
+	if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
+		connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+
+	atomic_set(&connection->op_cycle, 0);
+	mutex_init(&connection->mutex);
+	spin_lock_init(&connection->lock);
+	INIT_LIST_HEAD(&connection->operations);
+
+	connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
+					 dev_name(&hd->dev), hd_cport_id);
+	if (!connection->wq) {
+		ret = -ENOMEM;
+		goto err_free_connection;
+	}
+
+	kref_init(&connection->kref);
+
+	gb_connection_init_name(connection);
+
+	spin_lock_irq(&gb_connections_lock);
+	list_add(&connection->hd_links, &hd->connections);
+
+	if (bundle)
+		list_add(&connection->bundle_links, &bundle->connections);
+	else
+		INIT_LIST_HEAD(&connection->bundle_links);
+
+	spin_unlock_irq(&gb_connections_lock);
+
+	mutex_unlock(&gb_connection_mutex);
+
+	trace_gb_connection_create(connection);
+
+	return connection;
+
+err_free_connection:
+	kfree(connection);
+err_hd_cport_release:
+	gb_hd_cport_release(hd, hd_cport_id);
+err_unlock:
+	mutex_unlock(&gb_connection_mutex);
+
+	return ERR_PTR(ret);
+}
+
+struct gb_connection *
+gb_connection_create_static(struct gb_host_device *hd, u16 hd_cport_id,
+					gb_request_handler_t handler)
+{
+	return _gb_connection_create(hd, hd_cport_id, NULL, NULL, 0, handler,
+					GB_CONNECTION_FLAG_HIGH_PRIO);
+}
+
+struct gb_connection *
+gb_connection_create_control(struct gb_interface *intf)
+{
+	return _gb_connection_create(intf->hd, -1, intf, NULL, 0, NULL,
+					GB_CONNECTION_FLAG_CONTROL |
+					GB_CONNECTION_FLAG_HIGH_PRIO);
+}
+
+struct gb_connection *
+gb_connection_create(struct gb_bundle *bundle, u16 cport_id,
+					gb_request_handler_t handler)
+{
+	struct gb_interface *intf = bundle->intf;
+
+	return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
+					handler, 0);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create);
+
+struct gb_connection *
+gb_connection_create_flags(struct gb_bundle *bundle, u16 cport_id,
+					gb_request_handler_t handler,
+					unsigned long flags)
+{
+	struct gb_interface *intf = bundle->intf;
+
+	if (WARN_ON_ONCE(flags & GB_CONNECTION_FLAG_CORE_MASK))
+		flags &= ~GB_CONNECTION_FLAG_CORE_MASK;
+
+	return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
+					handler, flags);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create_flags);
+
+struct gb_connection *
+gb_connection_create_offloaded(struct gb_bundle *bundle, u16 cport_id,
+					unsigned long flags)
+{
+	flags |= GB_CONNECTION_FLAG_OFFLOADED;
+
+	return gb_connection_create_flags(bundle, cport_id, NULL, flags);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create_offloaded);
+
+static int gb_connection_hd_cport_enable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_enable)
+		return 0;
+
+	ret = hd->driver->cport_enable(hd, connection->hd_cport_id,
+					connection->flags);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to enable host cport: %d\n",
+				connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void gb_connection_hd_cport_disable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_disable)
+		return;
+
+	ret = hd->driver->cport_disable(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to disable host cport: %d\n",
+				connection->name, ret);
+	}
+}
+
+static int gb_connection_hd_cport_connected(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_connected)
+		return 0;
+
+	ret = hd->driver->cport_connected(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to set connected state: %d\n",
+				connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_flush(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_flush)
+		return 0;
+
+	ret = hd->driver->cport_flush(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to flush host cport: %d\n",
+				connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_quiesce(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	size_t peer_space;
+	int ret;
+
+	peer_space = sizeof(struct gb_operation_msg_hdr) +
+			sizeof(struct gb_cport_shutdown_request);
+
+	if (connection->mode_switch)
+		peer_space += sizeof(struct gb_operation_msg_hdr);
+
+	ret = hd->driver->cport_quiesce(hd, connection->hd_cport_id,
+					peer_space,
+					GB_CONNECTION_CPORT_QUIESCE_TIMEOUT);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to quiesce host cport: %d\n",
+				connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_clear(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	ret = hd->driver->cport_clear(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to clear host cport: %d\n",
+				connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Request the SVC to create a connection from AP's cport to interface's
+ * cport.
+ */
+static int
+gb_connection_svc_connection_create(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	struct gb_interface *intf;
+	u8 cport_flags;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	intf = connection->intf;
+
+	/*
+	 * Enable either E2EFC or CSD, unless no flow control is requested.
+	 */
+	cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
+	if (gb_connection_flow_control_disabled(connection)) {
+		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
+	} else if (gb_connection_e2efc_enabled(connection)) {
+		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |
+				GB_SVC_CPORT_FLAG_E2EFC;
+	}
+
+	ret = gb_svc_connection_create(hd->svc,
+			hd->svc->ap_intf_id,
+			connection->hd_cport_id,
+			intf->interface_id,
+			connection->intf_cport_id,
+			cport_flags);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to create svc connection: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void
+gb_connection_svc_connection_destroy(struct gb_connection *connection)
+{
+	if (gb_connection_is_static(connection))
+		return;
+
+	gb_svc_connection_destroy(connection->hd->svc,
+				  connection->hd->svc->ap_intf_id,
+				  connection->hd_cport_id,
+				  connection->intf->interface_id,
+				  connection->intf_cport_id);
+}
+
+/* Inform Interface about active CPorts */
+static int gb_connection_control_connected(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	if (gb_connection_is_control(connection))
+		return 0;
+
+	control = connection->intf->control;
+
+	ret = gb_control_connected_operation(control, cport_id);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to connect cport: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void
+gb_connection_control_disconnecting(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return;
+
+	control = connection->intf->control;
+
+	ret = gb_control_disconnecting_operation(control, cport_id);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+				"%s: failed to send disconnecting: %d\n",
+				connection->name, ret);
+	}
+}
+
+static void
+gb_connection_control_disconnected(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return;
+
+	control = connection->intf->control;
+
+	if (gb_connection_is_control(connection)) {
+		if (connection->mode_switch) {
+			ret = gb_control_mode_switch_operation(control);
+			if (ret) {
+				/*
+				 * Allow mode switch to time out waiting for
+				 * mailbox event.
+				 */
+				return;
+			}
+		}
+
+		return;
+	}
+
+	ret = gb_control_disconnected_operation(control, cport_id);
+	if (ret) {
+		dev_warn(&connection->bundle->dev,
+			 "failed to disconnect cport: %d\n", ret);
+	}
+}
+
+static int gb_connection_shutdown_operation(struct gb_connection *connection,
+						u8 phase)
+{
+	struct gb_cport_shutdown_request *req;
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_operation_create_core(connection,
+						GB_REQUEST_TYPE_CPORT_SHUTDOWN,
+						sizeof(*req), 0, 0,
+						GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	req = operation->request->payload;
+	req->phase = phase;
+
+	ret = gb_operation_request_send_sync(operation);
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int gb_connection_cport_shutdown(struct gb_connection *connection,
+					u8 phase)
+{
+	struct gb_host_device *hd = connection->hd;
+	const struct gb_hd_driver *drv = hd->driver;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	if (gb_connection_is_offloaded(connection)) {
+		if (!drv->cport_shutdown)
+			return 0;
+
+		ret = drv->cport_shutdown(hd, connection->hd_cport_id, phase,
+						GB_OPERATION_TIMEOUT_DEFAULT);
+	} else {
+		ret = gb_connection_shutdown_operation(connection, phase);
+	}
+
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to send cport shutdown (phase %d): %d\n",
+				connection->name, phase, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int
+gb_connection_cport_shutdown_phase_1(struct gb_connection *connection)
+{
+	return gb_connection_cport_shutdown(connection, 1);
+}
+
+static int
+gb_connection_cport_shutdown_phase_2(struct gb_connection *connection)
+{
+	return gb_connection_cport_shutdown(connection, 2);
+}
+
+/*
+ * Cancel all active operations on a connection.
+ *
+ * Locking: Called with connection lock held and state set to DISABLED or
+ * DISCONNECTING.
+ */
+static void gb_connection_cancel_operations(struct gb_connection *connection,
+						int errno)
+	__must_hold(&connection->lock)
+{
+	struct gb_operation *operation;
+
+	while (!list_empty(&connection->operations)) {
+		operation = list_last_entry(&connection->operations,
+						struct gb_operation, links);
+		gb_operation_get(operation);
+		spin_unlock_irq(&connection->lock);
+
+		if (gb_operation_is_incoming(operation))
+			gb_operation_cancel_incoming(operation, errno);
+		else
+			gb_operation_cancel(operation, errno);
+
+		gb_operation_put(operation);
+
+		spin_lock_irq(&connection->lock);
+	}
+}
+
+/*
+ * Cancel all active incoming operations on a connection.
+ *
+ * Locking: Called with connection lock held and state set to ENABLED_TX.
+ */
+static void
+gb_connection_flush_incoming_operations(struct gb_connection *connection,
+						int errno)
+	__must_hold(&connection->lock)
+{
+	struct gb_operation *operation;
+	bool incoming;
+
+	while (!list_empty(&connection->operations)) {
+		incoming = false;
+		list_for_each_entry(operation, &connection->operations,
+								links) {
+			if (gb_operation_is_incoming(operation)) {
+				gb_operation_get(operation);
+				incoming = true;
+				break;
+			}
+		}
+
+		if (!incoming)
+			break;
+
+		spin_unlock_irq(&connection->lock);
+
+		/* FIXME: flush, not cancel? */
+		gb_operation_cancel_incoming(operation, errno);
+		gb_operation_put(operation);
+
+		spin_lock_irq(&connection->lock);
+	}
+}
+
+/*
+ * _gb_connection_enable() - enable a connection
+ * @connection:		connection to enable
+ * @rx:			whether to enable incoming requests
+ *
+ * Connection-enable helper for DISABLED->ENABLED, DISABLED->ENABLED_TX, and
+ * ENABLED_TX->ENABLED state transitions.
+ *
+ * Locking: Caller holds connection->mutex.
+ */
+static int _gb_connection_enable(struct gb_connection *connection, bool rx)
+{
+	int ret;
+
+	/* Handle ENABLED_TX -> ENABLED transitions. */
+	if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
+		if (!(connection->handler && rx))
+			return 0;
+
+		spin_lock_irq(&connection->lock);
+		connection->state = GB_CONNECTION_STATE_ENABLED;
+		spin_unlock_irq(&connection->lock);
+
+		return 0;
+	}
+
+	ret = gb_connection_hd_cport_enable(connection);
+	if (ret)
+		return ret;
+
+	ret = gb_connection_svc_connection_create(connection);
+	if (ret)
+		goto err_hd_cport_clear;
+
+	ret = gb_connection_hd_cport_connected(connection);
+	if (ret)
+		goto err_svc_connection_destroy;
+
+	spin_lock_irq(&connection->lock);
+	if (connection->handler && rx)
+		connection->state = GB_CONNECTION_STATE_ENABLED;
+	else
+		connection->state = GB_CONNECTION_STATE_ENABLED_TX;
+	spin_unlock_irq(&connection->lock);
+
+	ret = gb_connection_control_connected(connection);
+	if (ret)
+		goto err_control_disconnecting;
+
+	return 0;
+
+err_control_disconnecting:
+	spin_lock_irq(&connection->lock);
+	connection->state = GB_CONNECTION_STATE_DISCONNECTING;
+	gb_connection_cancel_operations(connection, -ESHUTDOWN);
+	spin_unlock_irq(&connection->lock);
+
+	/* Transmit queue should already be empty. */
+	gb_connection_hd_cport_flush(connection);
+
+	gb_connection_control_disconnecting(connection);
+	gb_connection_cport_shutdown_phase_1(connection);
+	gb_connection_hd_cport_quiesce(connection);
+	gb_connection_cport_shutdown_phase_2(connection);
+	gb_connection_control_disconnected(connection);
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+err_svc_connection_destroy:
+	gb_connection_svc_connection_destroy(connection);
+err_hd_cport_clear:
+	gb_connection_hd_cport_clear(connection);
+
+	gb_connection_hd_cport_disable(connection);
+
+	return ret;
+}
+
+int gb_connection_enable(struct gb_connection *connection)
+{
+	int ret = 0;
+
+	mutex_lock(&connection->mutex);
+
+	if (connection->state == GB_CONNECTION_STATE_ENABLED)
+		goto out_unlock;
+
+	ret = _gb_connection_enable(connection, true);
+	if (!ret)
+		trace_gb_connection_enable(connection);
+
+out_unlock:
+	mutex_unlock(&connection->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_connection_enable);
+
+int gb_connection_enable_tx(struct gb_connection *connection)
+{
+	int ret = 0;
+
+	mutex_lock(&connection->mutex);
+
+	if (connection->state == GB_CONNECTION_STATE_ENABLED) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (connection->state == GB_CONNECTION_STATE_ENABLED_TX)
+		goto out_unlock;
+
+	ret = _gb_connection_enable(connection, false);
+	if (!ret)
+		trace_gb_connection_enable(connection);
+
+out_unlock:
+	mutex_unlock(&connection->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_connection_enable_tx);
+
+void gb_connection_disable_rx(struct gb_connection *connection)
+{
+	mutex_lock(&connection->mutex);
+
+	spin_lock_irq(&connection->lock);
+	if (connection->state != GB_CONNECTION_STATE_ENABLED) {
+		spin_unlock_irq(&connection->lock);
+		goto out_unlock;
+	}
+	connection->state = GB_CONNECTION_STATE_ENABLED_TX;
+	gb_connection_flush_incoming_operations(connection, -ESHUTDOWN);
+	spin_unlock_irq(&connection->lock);
+
+	trace_gb_connection_disable(connection);
+
+out_unlock:
+	mutex_unlock(&connection->mutex);
+}
+EXPORT_SYMBOL_GPL(gb_connection_disable_rx);
+
+void gb_connection_mode_switch_prepare(struct gb_connection *connection)
+{
+	connection->mode_switch = true;
+}
+
+void gb_connection_mode_switch_complete(struct gb_connection *connection)
+{
+	gb_connection_svc_connection_destroy(connection);
+	gb_connection_hd_cport_clear(connection);
+
+	gb_connection_hd_cport_disable(connection);
+
+	connection->mode_switch = false;
+}
+
+void gb_connection_disable(struct gb_connection *connection)
+{
+	mutex_lock(&connection->mutex);
+
+	if (connection->state == GB_CONNECTION_STATE_DISABLED)
+		goto out_unlock;
+
+	trace_gb_connection_disable(connection);
+
+	spin_lock_irq(&connection->lock);
+	connection->state = GB_CONNECTION_STATE_DISCONNECTING;
+	gb_connection_cancel_operations(connection, -ESHUTDOWN);
+	spin_unlock_irq(&connection->lock);
+
+	gb_connection_hd_cport_flush(connection);
+
+	gb_connection_control_disconnecting(connection);
+	gb_connection_cport_shutdown_phase_1(connection);
+	gb_connection_hd_cport_quiesce(connection);
+	gb_connection_cport_shutdown_phase_2(connection);
+	gb_connection_control_disconnected(connection);
+
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+
+	/* control-connection tear down is deferred when mode switching */
+	if (!connection->mode_switch) {
+		gb_connection_svc_connection_destroy(connection);
+		gb_connection_hd_cport_clear(connection);
+
+		gb_connection_hd_cport_disable(connection);
+	}
+
+out_unlock:
+	mutex_unlock(&connection->mutex);
+}
+EXPORT_SYMBOL_GPL(gb_connection_disable);
+
+/* Disable a connection without communicating with the remote end. */
+void gb_connection_disable_forced(struct gb_connection *connection)
+{
+	mutex_lock(&connection->mutex);
+
+	if (connection->state == GB_CONNECTION_STATE_DISABLED)
+		goto out_unlock;
+
+	trace_gb_connection_disable(connection);
+
+	spin_lock_irq(&connection->lock);
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+	gb_connection_cancel_operations(connection, -ESHUTDOWN);
+	spin_unlock_irq(&connection->lock);
+
+	gb_connection_hd_cport_flush(connection);
+
+	gb_connection_svc_connection_destroy(connection);
+	gb_connection_hd_cport_clear(connection);
+
+	gb_connection_hd_cport_disable(connection);
+out_unlock:
+	mutex_unlock(&connection->mutex);
+}
+EXPORT_SYMBOL_GPL(gb_connection_disable_forced);
+
+/* Caller must have disabled the connection before destroying it. */
+void gb_connection_destroy(struct gb_connection *connection)
+{
+	if (!connection)
+		return;
+
+	if (WARN_ON(connection->state != GB_CONNECTION_STATE_DISABLED))
+		gb_connection_disable(connection);
+
+	mutex_lock(&gb_connection_mutex);
+
+	spin_lock_irq(&gb_connections_lock);
+	list_del(&connection->bundle_links);
+	list_del(&connection->hd_links);
+	spin_unlock_irq(&gb_connections_lock);
+
+	destroy_workqueue(connection->wq);
+
+	gb_hd_cport_release(connection->hd, connection->hd_cport_id);
+	connection->hd_cport_id = CPORT_ID_BAD;
+
+	mutex_unlock(&gb_connection_mutex);
+
+	gb_connection_put(connection);
+}
+EXPORT_SYMBOL_GPL(gb_connection_destroy);
+
+void gb_connection_latency_tag_enable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->latency_tag_enable)
+		return;
+
+	ret = hd->driver->latency_tag_enable(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to enable latency tag: %d\n",
+			connection->name, ret);
+	}
+}
+EXPORT_SYMBOL_GPL(gb_connection_latency_tag_enable);
+
+void gb_connection_latency_tag_disable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->latency_tag_disable)
+		return;
+
+	ret = hd->driver->latency_tag_disable(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to disable latency tag: %d\n",
+			connection->name, ret);
+	}
+}
+EXPORT_SYMBOL_GPL(gb_connection_latency_tag_disable);
diff --git a/drivers/staging/greybus/connection.h b/drivers/staging/greybus/connection.h
new file mode 100644
index 000000000000..4d9f4c64176c
--- /dev/null
+++ b/drivers/staging/greybus/connection.h
@@ -0,0 +1,129 @@
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __CONNECTION_H
+#define __CONNECTION_H
+
+#include <linux/list.h>
+#include <linux/kfifo.h>
+
+#define GB_CONNECTION_FLAG_CSD		BIT(0)
+#define GB_CONNECTION_FLAG_NO_FLOWCTRL	BIT(1)
+#define GB_CONNECTION_FLAG_OFFLOADED	BIT(2)
+#define GB_CONNECTION_FLAG_CDSI1	BIT(3)
+#define GB_CONNECTION_FLAG_CONTROL	BIT(4)
+#define GB_CONNECTION_FLAG_HIGH_PRIO	BIT(5)
+
+#define GB_CONNECTION_FLAG_CORE_MASK	GB_CONNECTION_FLAG_CONTROL
+
+enum gb_connection_state {
+	GB_CONNECTION_STATE_DISABLED		= 0,
+	GB_CONNECTION_STATE_ENABLED_TX		= 1,
+	GB_CONNECTION_STATE_ENABLED		= 2,
+	GB_CONNECTION_STATE_DISCONNECTING	= 3,
+};
+
+struct gb_operation;
+
+typedef int (*gb_request_handler_t)(struct gb_operation *);
+
+struct gb_connection {
+	struct gb_host_device		*hd;
+	struct gb_interface		*intf;
+	struct gb_bundle		*bundle;
+	struct kref			kref;
+	u16				hd_cport_id;
+	u16				intf_cport_id;
+
+	struct list_head		hd_links;
+	struct list_head		bundle_links;
+
+	gb_request_handler_t		handler;
+	unsigned long			flags;
+
+	struct mutex			mutex;
+	spinlock_t			lock;
+	enum gb_connection_state	state;
+	struct list_head		operations;
+
+	char				name[16];
+	struct workqueue_struct		*wq;
+
+	atomic_t			op_cycle;
+
+	void				*private;
+
+	bool				mode_switch;
+};
+
+struct gb_connection *gb_connection_create_static(struct gb_host_device *hd,
+				u16 hd_cport_id, gb_request_handler_t handler);
+struct gb_connection *gb_connection_create_control(struct gb_interface *intf);
+struct gb_connection *gb_connection_create(struct gb_bundle *bundle,
+				u16 cport_id, gb_request_handler_t handler);
+struct gb_connection *gb_connection_create_flags(struct gb_bundle *bundle,
+				u16 cport_id, gb_request_handler_t handler,
+				unsigned long flags);
+struct gb_connection *gb_connection_create_offloaded(struct gb_bundle *bundle,
+				u16 cport_id, unsigned long flags);
+void gb_connection_destroy(struct gb_connection *connection);
+
+static inline bool gb_connection_is_static(struct gb_connection *connection)
+{
+	return !connection->intf;
+}
+
+int gb_connection_enable(struct gb_connection *connection);
+int gb_connection_enable_tx(struct gb_connection *connection);
+void gb_connection_disable_rx(struct gb_connection *connection);
+void gb_connection_disable(struct gb_connection *connection);
+void gb_connection_disable_forced(struct gb_connection *connection);
+
+void gb_connection_mode_switch_prepare(struct gb_connection *connection);
+void gb_connection_mode_switch_complete(struct gb_connection *connection);
+
+void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
+			u8 *data, size_t length);
+
+void gb_connection_latency_tag_enable(struct gb_connection *connection);
+void gb_connection_latency_tag_disable(struct gb_connection *connection);
+
+static inline bool gb_connection_e2efc_enabled(struct gb_connection *connection)
+{
+	return !(connection->flags & GB_CONNECTION_FLAG_CSD);
+}
+
+static inline bool
+gb_connection_flow_control_disabled(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_NO_FLOWCTRL;
+}
+
+static inline bool gb_connection_is_offloaded(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_OFFLOADED;
+}
+
+static inline bool gb_connection_is_control(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_CONTROL;
+}
+
+static inline void *gb_connection_get_data(struct gb_connection *connection)
+{
+	return connection->private;
+}
+
+static inline void gb_connection_set_data(struct gb_connection *connection,
+					  void *data)
+{
+	connection->private = data;
+}
+
+#endif /* __CONNECTION_H */
diff --git a/drivers/staging/greybus/control.c b/drivers/staging/greybus/control.c
new file mode 100644
index 000000000000..4716190e740a
--- /dev/null
+++ b/drivers/staging/greybus/control.c
@@ -0,0 +1,635 @@
+/*
+ * Greybus CPort control protocol.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "greybus.h"
+
+/* Highest control-protocol version supported */
+#define GB_CONTROL_VERSION_MAJOR	0
+#define GB_CONTROL_VERSION_MINOR	1
+
+
+static int gb_control_get_version(struct gb_control *control)
+{
+	struct gb_interface *intf = control->connection->intf;
+	struct gb_control_version_request request;
+	struct gb_control_version_response response;
+	int ret;
+
+	request.major = GB_CONTROL_VERSION_MAJOR;
+	request.minor = GB_CONTROL_VERSION_MINOR;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_VERSION,
+				&request, sizeof(request), &response,
+				sizeof(response));
+	if (ret) {
+		dev_err(&intf->dev,
+				"failed to get control-protocol version: %d\n",
+				ret);
+		return ret;
+	}
+
+	if (response.major > request.major) {
+		dev_err(&intf->dev,
+				"unsupported major control-protocol version (%u > %u)\n",
+				response.major, request.major);
+		return -ENOTSUPP;
+	}
+
+	control->protocol_major = response.major;
+	control->protocol_minor = response.minor;
+
+	dev_dbg(&intf->dev, "%s - %u.%u\n", __func__, response.major,
+			response.minor);
+
+	return 0;
+}
+
+static int gb_control_get_bundle_version(struct gb_control *control,
+						struct gb_bundle *bundle)
+{
+	struct gb_interface *intf = control->connection->intf;
+	struct gb_control_bundle_version_request request;
+	struct gb_control_bundle_version_response response;
+	int ret;
+
+	request.bundle_id = bundle->id;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_BUNDLE_VERSION,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&intf->dev,
+				"failed to get bundle %u class version: %d\n",
+				bundle->id, ret);
+		return ret;
+	}
+
+	bundle->class_major = response.major;
+	bundle->class_minor = response.minor;
+
+	dev_dbg(&intf->dev, "%s - %u: %u.%u\n", __func__, bundle->id,
+			response.major, response.minor);
+
+	return 0;
+}
+
+int gb_control_get_bundle_versions(struct gb_control *control)
+{
+	struct gb_interface *intf = control->connection->intf;
+	struct gb_bundle *bundle;
+	int ret;
+
+	if (!control->has_bundle_version)
+		return 0;
+
+	list_for_each_entry(bundle, &intf->bundles, links) {
+		ret = gb_control_get_bundle_version(control, bundle);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* Get Manifest's size from the interface */
+int gb_control_get_manifest_size_operation(struct gb_interface *intf)
+{
+	struct gb_control_get_manifest_size_response response;
+	struct gb_connection *connection = intf->control->connection;
+	int ret;
+
+	ret = gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST_SIZE,
+				NULL, 0, &response, sizeof(response));
+	if (ret) {
+		dev_err(&connection->intf->dev,
+				"failed to get manifest size: %d\n", ret);
+		return ret;
+	}
+
+	return le16_to_cpu(response.size);
+}
+
+/* Reads Manifest from the interface */
+int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
+				      size_t size)
+{
+	struct gb_connection *connection = intf->control->connection;
+
+	return gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST,
+				NULL, 0, manifest, size);
+}
+
+int gb_control_connected_operation(struct gb_control *control, u16 cport_id)
+{
+	struct gb_control_connected_request request;
+
+	request.cport_id = cpu_to_le16(cport_id);
+	return gb_operation_sync(control->connection, GB_CONTROL_TYPE_CONNECTED,
+				 &request, sizeof(request), NULL, 0);
+}
+
+int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id)
+{
+	struct gb_control_disconnected_request request;
+
+	request.cport_id = cpu_to_le16(cport_id);
+	return gb_operation_sync(control->connection,
+				 GB_CONTROL_TYPE_DISCONNECTED, &request,
+				 sizeof(request), NULL, 0);
+}
+
+int gb_control_disconnecting_operation(struct gb_control *control,
+					u16 cport_id)
+{
+	struct gb_control_disconnecting_request *request;
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_operation_create_core(control->connection,
+					GB_CONTROL_TYPE_DISCONNECTING,
+					sizeof(*request), 0, 0,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	request = operation->request->payload;
+	request->cport_id = cpu_to_le16(cport_id);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret) {
+		dev_err(&control->dev, "failed to send disconnecting: %d\n",
+				ret);
+	}
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+int gb_control_mode_switch_operation(struct gb_control *control)
+{
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_operation_create_core(control->connection,
+					GB_CONTROL_TYPE_MODE_SWITCH,
+					0, 0, GB_OPERATION_FLAG_UNIDIRECTIONAL,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret)
+		dev_err(&control->dev, "failed to send mode switch: %d\n", ret);
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+int gb_control_timesync_enable(struct gb_control *control, u8 count,
+			       u64 frame_time, u32 strobe_delay, u32 refclk)
+{
+	struct gb_control_timesync_enable_request request;
+
+	request.count = count;
+	request.frame_time = cpu_to_le64(frame_time);
+	request.strobe_delay = cpu_to_le32(strobe_delay);
+	request.refclk = cpu_to_le32(refclk);
+	return gb_operation_sync(control->connection,
+				 GB_CONTROL_TYPE_TIMESYNC_ENABLE, &request,
+				 sizeof(request), NULL, 0);
+}
+
+int gb_control_timesync_disable(struct gb_control *control)
+{
+	return gb_operation_sync(control->connection,
+				 GB_CONTROL_TYPE_TIMESYNC_DISABLE, NULL, 0,
+				 NULL, 0);
+}
+
+int gb_control_timesync_get_last_event(struct gb_control *control,
+				       u64 *frame_time)
+{
+	struct gb_control_timesync_get_last_event_response response;
+	int ret;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_TIMESYNC_GET_LAST_EVENT,
+				NULL, 0, &response, sizeof(response));
+	if (!ret)
+		*frame_time = le64_to_cpu(response.frame_time);
+	return ret;
+}
+
+int gb_control_timesync_authoritative(struct gb_control *control,
+				      u64 *frame_time)
+{
+	struct gb_control_timesync_authoritative_request request;
+	int i;
+
+	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
+		request.frame_time[i] = cpu_to_le64(frame_time[i]);
+
+	return gb_operation_sync(control->connection,
+				 GB_CONTROL_TYPE_TIMESYNC_AUTHORITATIVE,
+				 &request, sizeof(request),
+				 NULL, 0);
+}
+
+static int gb_control_bundle_pm_status_map(u8 status)
+{
+	switch (status) {
+	case GB_CONTROL_BUNDLE_PM_INVAL:
+		return -EINVAL;
+	case GB_CONTROL_BUNDLE_PM_BUSY:
+		return -EBUSY;
+	case GB_CONTROL_BUNDLE_PM_NA:
+		return -ENOMSG;
+	case GB_CONTROL_BUNDLE_PM_FAIL:
+	default:
+		return -EREMOTEIO;
+	}
+}
+
+int gb_control_bundle_suspend(struct gb_control *control, u8 bundle_id)
+{
+	struct gb_control_bundle_pm_request request;
+	struct gb_control_bundle_pm_response response;
+	int ret;
+
+	request.bundle_id = bundle_id;
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_BUNDLE_SUSPEND, &request,
+				sizeof(request), &response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev, "failed to send bundle %u suspend: %d\n",
+			bundle_id, ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
+		dev_err(&control->dev, "failed to suspend bundle %u: %d\n",
+			bundle_id, response.status);
+		return gb_control_bundle_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+int gb_control_bundle_resume(struct gb_control *control, u8 bundle_id)
+{
+	struct gb_control_bundle_pm_request request;
+	struct gb_control_bundle_pm_response response;
+	int ret;
+
+	request.bundle_id = bundle_id;
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_BUNDLE_RESUME, &request,
+				sizeof(request), &response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev, "failed to send bundle %u resume: %d\n",
+			bundle_id, ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
+		dev_err(&control->dev, "failed to resume bundle %u: %d\n",
+			bundle_id, response.status);
+		return gb_control_bundle_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+int gb_control_bundle_deactivate(struct gb_control *control, u8 bundle_id)
+{
+	struct gb_control_bundle_pm_request request;
+	struct gb_control_bundle_pm_response response;
+	int ret;
+
+	request.bundle_id = bundle_id;
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_BUNDLE_DEACTIVATE, &request,
+				sizeof(request), &response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev,
+			"failed to send bundle %u deactivate: %d\n", bundle_id,
+			ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
+		dev_err(&control->dev, "failed to deactivate bundle %u: %d\n",
+			bundle_id, response.status);
+		return gb_control_bundle_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+int gb_control_bundle_activate(struct gb_control *control, u8 bundle_id)
+{
+	struct gb_control_bundle_pm_request request;
+	struct gb_control_bundle_pm_response response;
+	int ret;
+
+	if (!control->has_bundle_activate)
+		return 0;
+
+	request.bundle_id = bundle_id;
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_BUNDLE_ACTIVATE, &request,
+				sizeof(request), &response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev,
+			"failed to send bundle %u activate: %d\n", bundle_id,
+			ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
+		dev_err(&control->dev, "failed to activate bundle %u: %d\n",
+			bundle_id, response.status);
+		return gb_control_bundle_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+static int gb_control_interface_pm_status_map(u8 status)
+{
+	switch (status) {
+	case GB_CONTROL_INTF_PM_BUSY:
+		return -EBUSY;
+	case GB_CONTROL_INTF_PM_NA:
+		return -ENOMSG;
+	default:
+		return -EREMOTEIO;
+	}
+}
+
+int gb_control_interface_suspend_prepare(struct gb_control *control)
+{
+	struct gb_control_intf_pm_response response;
+	int ret;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_INTF_SUSPEND_PREPARE, NULL, 0,
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev,
+			"failed to send interface suspend prepare: %d\n", ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_INTF_PM_OK) {
+		dev_err(&control->dev, "interface error while preparing suspend: %d\n",
+			response.status);
+		return gb_control_interface_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+int gb_control_interface_deactivate_prepare(struct gb_control *control)
+{
+	struct gb_control_intf_pm_response response;
+	int ret;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_INTF_DEACTIVATE_PREPARE, NULL,
+				0, &response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev, "failed to send interface deactivate prepare: %d\n",
+			ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_INTF_PM_OK) {
+		dev_err(&control->dev, "interface error while preparing deactivate: %d\n",
+			response.status);
+		return gb_control_interface_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+int gb_control_interface_hibernate_abort(struct gb_control *control)
+{
+	struct gb_control_intf_pm_response response;
+	int ret;
+
+	ret = gb_operation_sync(control->connection,
+				GB_CONTROL_TYPE_INTF_HIBERNATE_ABORT, NULL, 0,
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&control->dev,
+			"failed to send interface aborting hibernate: %d\n",
+			ret);
+		return ret;
+	}
+
+	if (response.status != GB_CONTROL_INTF_PM_OK) {
+		dev_err(&control->dev, "interface error while aborting hibernate: %d\n",
+			response.status);
+		return gb_control_interface_pm_status_map(response.status);
+	}
+
+	return 0;
+}
+
+static ssize_t vendor_string_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct gb_control *control = to_gb_control(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", control->vendor_string);
+}
+static DEVICE_ATTR_RO(vendor_string);
+
+static ssize_t product_string_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct gb_control *control = to_gb_control(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", control->product_string);
+}
+static DEVICE_ATTR_RO(product_string);
+
+static struct attribute *control_attrs[] = {
+	&dev_attr_vendor_string.attr,
+	&dev_attr_product_string.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(control);
+
+static void gb_control_release(struct device *dev)
+{
+	struct gb_control *control = to_gb_control(dev);
+
+	gb_connection_destroy(control->connection);
+
+	kfree(control->vendor_string);
+	kfree(control->product_string);
+
+	kfree(control);
+}
+
+struct device_type greybus_control_type = {
+	.name =		"greybus_control",
+	.release =	gb_control_release,
+};
+
+struct gb_control *gb_control_create(struct gb_interface *intf)
+{
+	struct gb_connection *connection;
+	struct gb_control *control;
+
+	control = kzalloc(sizeof(*control), GFP_KERNEL);
+	if (!control)
+		return ERR_PTR(-ENOMEM);
+
+	control->intf = intf;
+
+	connection = gb_connection_create_control(intf);
+	if (IS_ERR(connection)) {
+		dev_err(&intf->dev,
+				"failed to create control connection: %ld\n",
+				PTR_ERR(connection));
+		kfree(control);
+		return ERR_CAST(connection);
+	}
+
+	control->connection = connection;
+
+	control->dev.parent = &intf->dev;
+	control->dev.bus = &greybus_bus_type;
+	control->dev.type = &greybus_control_type;
+	control->dev.groups = control_groups;
+	control->dev.dma_mask = intf->dev.dma_mask;
+	device_initialize(&control->dev);
+	dev_set_name(&control->dev, "%s.ctrl", dev_name(&intf->dev));
+
+	gb_connection_set_data(control->connection, control);
+
+	return control;
+}
+
+int gb_control_enable(struct gb_control *control)
+{
+	int ret;
+
+	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
+
+	ret = gb_connection_enable_tx(control->connection);
+	if (ret) {
+		dev_err(&control->connection->intf->dev,
+				"failed to enable control connection: %d\n",
+				ret);
+		return ret;
+	}
+
+	ret = gb_control_get_version(control);
+	if (ret)
+		goto err_disable_connection;
+
+	if (control->protocol_major > 0 || control->protocol_minor > 1)
+		control->has_bundle_version = true;
+
+	/* FIXME: use protocol version instead */
+	if (!(control->intf->quirks & GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE))
+		control->has_bundle_activate = true;
+
+	return 0;
+
+err_disable_connection:
+	gb_connection_disable(control->connection);
+
+	return ret;
+}
+
+void gb_control_disable(struct gb_control *control)
+{
+	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
+
+	if (control->intf->disconnected)
+		gb_connection_disable_forced(control->connection);
+	else
+		gb_connection_disable(control->connection);
+}
+
+int gb_control_suspend(struct gb_control *control)
+{
+	gb_connection_disable(control->connection);
+
+	return 0;
+}
+
+int gb_control_resume(struct gb_control *control)
+{
+	int ret;
+
+	ret = gb_connection_enable_tx(control->connection);
+	if (ret) {
+		dev_err(&control->connection->intf->dev,
+			"failed to enable control connection: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int gb_control_add(struct gb_control *control)
+{
+	int ret;
+
+	ret = device_add(&control->dev);
+	if (ret) {
+		dev_err(&control->dev,
+				"failed to register control device: %d\n",
+				ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+void gb_control_del(struct gb_control *control)
+{
+	if (device_is_registered(&control->dev))
+		device_del(&control->dev);
+}
+
+struct gb_control *gb_control_get(struct gb_control *control)
+{
+	get_device(&control->dev);
+
+	return control;
+}
+
+void gb_control_put(struct gb_control *control)
+{
+	put_device(&control->dev);
+}
+
+void gb_control_mode_switch_prepare(struct gb_control *control)
+{
+	gb_connection_mode_switch_prepare(control->connection);
+}
+
+void gb_control_mode_switch_complete(struct gb_control *control)
+{
+	gb_connection_mode_switch_complete(control->connection);
+}
diff --git a/drivers/staging/greybus/control.h b/drivers/staging/greybus/control.h
new file mode 100644
index 000000000000..f9a60daf9a72
--- /dev/null
+++ b/drivers/staging/greybus/control.h
@@ -0,0 +1,65 @@
+/*
+ * Greybus CPort control protocol
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __CONTROL_H
+#define __CONTROL_H
+
+struct gb_control {
+	struct device dev;
+	struct gb_interface *intf;
+
+	struct gb_connection *connection;
+
+	u8 protocol_major;
+	u8 protocol_minor;
+
+	bool has_bundle_activate;
+	bool has_bundle_version;
+
+	char *vendor_string;
+	char *product_string;
+};
+#define to_gb_control(d) container_of(d, struct gb_control, dev)
+
+struct gb_control *gb_control_create(struct gb_interface *intf);
+int gb_control_enable(struct gb_control *control);
+void gb_control_disable(struct gb_control *control);
+int gb_control_suspend(struct gb_control *control);
+int gb_control_resume(struct gb_control *control);
+int gb_control_add(struct gb_control *control);
+void gb_control_del(struct gb_control *control);
+struct gb_control *gb_control_get(struct gb_control *control);
+void gb_control_put(struct gb_control *control);
+
+int gb_control_get_bundle_versions(struct gb_control *control);
+int gb_control_connected_operation(struct gb_control *control, u16 cport_id);
+int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id);
+int gb_control_disconnecting_operation(struct gb_control *control,
+					u16 cport_id);
+int gb_control_mode_switch_operation(struct gb_control *control);
+void gb_control_mode_switch_prepare(struct gb_control *control);
+void gb_control_mode_switch_complete(struct gb_control *control);
+int gb_control_get_manifest_size_operation(struct gb_interface *intf);
+int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
+				      size_t size);
+int gb_control_timesync_enable(struct gb_control *control, u8 count,
+			       u64 frame_time, u32 strobe_delay, u32 refclk);
+int gb_control_timesync_disable(struct gb_control *control);
+int gb_control_timesync_get_last_event(struct gb_control *control,
+				       u64 *frame_time);
+int gb_control_timesync_authoritative(struct gb_control *control,
+				      u64 *frame_time);
+int gb_control_bundle_suspend(struct gb_control *control, u8 bundle_id);
+int gb_control_bundle_resume(struct gb_control *control, u8 bundle_id);
+int gb_control_bundle_deactivate(struct gb_control *control, u8 bundle_id);
+int gb_control_bundle_activate(struct gb_control *control, u8 bundle_id);
+int gb_control_interface_suspend_prepare(struct gb_control *control);
+int gb_control_interface_deactivate_prepare(struct gb_control *control);
+int gb_control_interface_hibernate_abort(struct gb_control *control);
+#endif /* __CONTROL_H */
diff --git a/drivers/staging/greybus/core.c b/drivers/staging/greybus/core.c
new file mode 100644
index 000000000000..1049e9c0edb0
--- /dev/null
+++ b/drivers/staging/greybus/core.c
@@ -0,0 +1,361 @@
+/*
+ * Greybus "Core"
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define CREATE_TRACE_POINTS
+#include "greybus.h"
+#include "greybus_trace.h"
+
+#define GB_BUNDLE_AUTOSUSPEND_MS	3000
+
+/* Allow greybus to be disabled at boot if needed */
+static bool nogreybus;
+#ifdef MODULE
+module_param(nogreybus, bool, 0444);
+#else
+core_param(nogreybus, nogreybus, bool, 0444);
+#endif
+int greybus_disabled(void)
+{
+	return nogreybus;
+}
+EXPORT_SYMBOL_GPL(greybus_disabled);
+
+static bool greybus_match_one_id(struct gb_bundle *bundle,
+				     const struct greybus_bundle_id *id)
+{
+	if ((id->match_flags & GREYBUS_ID_MATCH_VENDOR) &&
+	    (id->vendor != bundle->intf->vendor_id))
+		return false;
+
+	if ((id->match_flags & GREYBUS_ID_MATCH_PRODUCT) &&
+	    (id->product != bundle->intf->product_id))
+		return false;
+
+	if ((id->match_flags & GREYBUS_ID_MATCH_CLASS) &&
+	    (id->class != bundle->class))
+		return false;
+
+	return true;
+}
+
+static const struct greybus_bundle_id *
+greybus_match_id(struct gb_bundle *bundle, const struct greybus_bundle_id *id)
+{
+	if (id == NULL)
+		return NULL;
+
+	for (; id->vendor || id->product || id->class || id->driver_info;
+									id++) {
+		if (greybus_match_one_id(bundle, id))
+			return id;
+	}
+
+	return NULL;
+}
+
+static int greybus_match_device(struct device *dev, struct device_driver *drv)
+{
+	struct greybus_driver *driver = to_greybus_driver(drv);
+	struct gb_bundle *bundle;
+	const struct greybus_bundle_id *id;
+
+	if (!is_gb_bundle(dev))
+		return 0;
+
+	bundle = to_gb_bundle(dev);
+
+	id = greybus_match_id(bundle, driver->id_table);
+	if (id)
+		return 1;
+	/* FIXME - Dynamic ids? */
+	return 0;
+}
+
+static int greybus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct gb_host_device *hd;
+	struct gb_module *module = NULL;
+	struct gb_interface *intf = NULL;
+	struct gb_control *control = NULL;
+	struct gb_bundle *bundle = NULL;
+	struct gb_svc *svc = NULL;
+
+	if (is_gb_host_device(dev)) {
+		hd = to_gb_host_device(dev);
+	} else if (is_gb_module(dev)) {
+		module = to_gb_module(dev);
+		hd = module->hd;
+	} else if (is_gb_interface(dev)) {
+		intf = to_gb_interface(dev);
+		module = intf->module;
+		hd = intf->hd;
+	} else if (is_gb_control(dev)) {
+		control = to_gb_control(dev);
+		intf = control->intf;
+		module = intf->module;
+		hd = intf->hd;
+	} else if (is_gb_bundle(dev)) {
+		bundle = to_gb_bundle(dev);
+		intf = bundle->intf;
+		module = intf->module;
+		hd = intf->hd;
+	} else if (is_gb_svc(dev)) {
+		svc = to_gb_svc(dev);
+		hd = svc->hd;
+	} else {
+		dev_WARN(dev, "uevent for unknown greybus device \"type\"!\n");
+		return -EINVAL;
+	}
+
+	if (add_uevent_var(env, "BUS=%u", hd->bus_id))
+		return -ENOMEM;
+
+	if (module) {
+		if (add_uevent_var(env, "MODULE=%u", module->module_id))
+			return -ENOMEM;
+	}
+
+	if (intf) {
+		if (add_uevent_var(env, "INTERFACE=%u", intf->interface_id))
+			return -ENOMEM;
+		if (add_uevent_var(env, "GREYBUS_ID=%08x/%08x",
+				   intf->vendor_id, intf->product_id))
+			return -ENOMEM;
+	}
+
+	if (bundle) {
+		// FIXME
+		// add a uevent that can "load" a bundle type
+		// This is what we need to bind a driver to so use the info
+		// in gmod here as well
+
+		if (add_uevent_var(env, "BUNDLE=%u", bundle->id))
+			return -ENOMEM;
+		if (add_uevent_var(env, "BUNDLE_CLASS=%02x", bundle->class))
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void greybus_shutdown(struct device *dev)
+{
+	if (is_gb_host_device(dev)) {
+		struct gb_host_device *hd;
+
+		hd = to_gb_host_device(dev);
+		gb_hd_shutdown(hd);
+	}
+}
+
+struct bus_type greybus_bus_type = {
+	.name =		"greybus",
+	.match =	greybus_match_device,
+	.uevent =	greybus_uevent,
+	.shutdown =	greybus_shutdown,
+};
+
+static int greybus_probe(struct device *dev)
+{
+	struct greybus_driver *driver = to_greybus_driver(dev->driver);
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	const struct greybus_bundle_id *id;
+	int retval;
+
+	/* match id */
+	id = greybus_match_id(bundle, driver->id_table);
+	if (!id)
+		return -ENODEV;
+
+	retval = pm_runtime_get_sync(&bundle->intf->dev);
+	if (retval < 0) {
+		pm_runtime_put_noidle(&bundle->intf->dev);
+		return retval;
+	}
+
+	retval = gb_control_bundle_activate(bundle->intf->control, bundle->id);
+	if (retval) {
+		pm_runtime_put(&bundle->intf->dev);
+		return retval;
+	}
+
+	/*
+	 * Unbound bundle devices are always deactivated. During probe, the
+	 * Runtime PM is set to enabled and active and the usage count is
+	 * incremented. If the driver supports runtime PM, it should call
+	 * pm_runtime_put() in its probe routine and pm_runtime_get_sync()
+	 * in remove routine.
+	 */
+	pm_runtime_set_autosuspend_delay(dev, GB_BUNDLE_AUTOSUSPEND_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	retval = driver->probe(bundle, id);
+	if (retval) {
+		/*
+		 * Catch buggy drivers that fail to destroy their connections.
+		 */
+		WARN_ON(!list_empty(&bundle->connections));
+
+		gb_control_bundle_deactivate(bundle->intf->control, bundle->id);
+
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_put_noidle(dev);
+		pm_runtime_dont_use_autosuspend(dev);
+		pm_runtime_put(&bundle->intf->dev);
+
+		return retval;
+	}
+
+	gb_timesync_schedule_synchronous(bundle->intf);
+
+	pm_runtime_put(&bundle->intf->dev);
+
+	return 0;
+}
+
+static int greybus_remove(struct device *dev)
+{
+	struct greybus_driver *driver = to_greybus_driver(dev->driver);
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gb_connection *connection;
+	int retval;
+
+	retval = pm_runtime_get_sync(dev);
+	if (retval < 0)
+		dev_err(dev, "failed to resume bundle: %d\n", retval);
+
+	/*
+	 * Disable (non-offloaded) connections early in case the interface is
+	 * already gone to avoid unceccessary operation timeouts during
+	 * driver disconnect. Otherwise, only disable incoming requests.
+	 */
+	list_for_each_entry(connection, &bundle->connections, bundle_links) {
+		if (gb_connection_is_offloaded(connection))
+			continue;
+
+		if (bundle->intf->disconnected)
+			gb_connection_disable_forced(connection);
+		else
+			gb_connection_disable_rx(connection);
+	}
+
+	driver->disconnect(bundle);
+
+	/* Catch buggy drivers that fail to destroy their connections. */
+	WARN_ON(!list_empty(&bundle->connections));
+
+	if (!bundle->intf->disconnected)
+		gb_control_bundle_deactivate(bundle->intf->control, bundle->id);
+
+	pm_runtime_put_noidle(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+	pm_runtime_put_noidle(dev);
+
+	return 0;
+}
+
+int greybus_register_driver(struct greybus_driver *driver, struct module *owner,
+		const char *mod_name)
+{
+	int retval;
+
+	if (greybus_disabled())
+		return -ENODEV;
+
+	driver->driver.bus = &greybus_bus_type;
+	driver->driver.name = driver->name;
+	driver->driver.probe = greybus_probe;
+	driver->driver.remove = greybus_remove;
+	driver->driver.owner = owner;
+	driver->driver.mod_name = mod_name;
+
+	retval = driver_register(&driver->driver);
+	if (retval)
+		return retval;
+
+	pr_info("registered new driver %s\n", driver->name);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(greybus_register_driver);
+
+void greybus_deregister_driver(struct greybus_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(greybus_deregister_driver);
+
+static int __init gb_init(void)
+{
+	int retval;
+
+	if (greybus_disabled())
+		return -ENODEV;
+
+	BUILD_BUG_ON(CPORT_ID_MAX >= (long)CPORT_ID_BAD);
+
+	gb_debugfs_init();
+
+	retval = bus_register(&greybus_bus_type);
+	if (retval) {
+		pr_err("bus_register failed (%d)\n", retval);
+		goto error_bus;
+	}
+
+	retval = gb_hd_init();
+	if (retval) {
+		pr_err("gb_hd_init failed (%d)\n", retval);
+		goto error_hd;
+	}
+
+	retval = gb_operation_init();
+	if (retval) {
+		pr_err("gb_operation_init failed (%d)\n", retval);
+		goto error_operation;
+	}
+
+	retval = gb_timesync_init();
+	if (retval) {
+		pr_err("gb_timesync_init failed\n");
+		goto error_timesync;
+	}
+	return 0;	/* Success */
+
+error_timesync:
+	gb_operation_exit();
+error_operation:
+	gb_hd_exit();
+error_hd:
+	bus_unregister(&greybus_bus_type);
+error_bus:
+	gb_debugfs_cleanup();
+
+	return retval;
+}
+module_init(gb_init);
+
+static void __exit gb_exit(void)
+{
+	gb_timesync_exit();
+	gb_operation_exit();
+	gb_hd_exit();
+	bus_unregister(&greybus_bus_type);
+	gb_debugfs_cleanup();
+	tracepoint_synchronize_unregister();
+}
+module_exit(gb_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");
diff --git a/drivers/staging/greybus/debugfs.c b/drivers/staging/greybus/debugfs.c
new file mode 100644
index 000000000000..a9d4d3da99a0
--- /dev/null
+++ b/drivers/staging/greybus/debugfs.c
@@ -0,0 +1,31 @@
+/*
+ * Greybus debugfs code
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/debugfs.h>
+
+#include "greybus.h"
+
+static struct dentry *gb_debug_root;
+
+void __init gb_debugfs_init(void)
+{
+	gb_debug_root = debugfs_create_dir("greybus", NULL);
+}
+
+void gb_debugfs_cleanup(void)
+{
+	debugfs_remove_recursive(gb_debug_root);
+	gb_debug_root = NULL;
+}
+
+struct dentry *gb_debugfs_get(void)
+{
+	return gb_debug_root;
+}
+EXPORT_SYMBOL_GPL(gb_debugfs_get);
diff --git a/drivers/staging/greybus/es2.c b/drivers/staging/greybus/es2.c
new file mode 100644
index 000000000000..071bb1cfd3ae
--- /dev/null
+++ b/drivers/staging/greybus/es2.c
@@ -0,0 +1,1597 @@
+/*
+ * Greybus "AP" USB driver for "ES2" controller chips
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kthread.h>
+#include <linux/sizes.h>
+#include <linux/usb.h>
+#include <linux/kfifo.h>
+#include <linux/debugfs.h>
+#include <linux/list.h>
+#include <asm/unaligned.h>
+
+#include "arpc.h"
+#include "greybus.h"
+#include "greybus_trace.h"
+#include "connection.h"
+
+
+/* Default timeout for USB vendor requests. */
+#define ES2_USB_CTRL_TIMEOUT	500
+
+/* Default timeout for ARPC CPort requests */
+#define ES2_ARPC_CPORT_TIMEOUT	500
+
+/* Fixed CPort numbers */
+#define ES2_CPORT_CDSI0		16
+#define ES2_CPORT_CDSI1		17
+
+/* Memory sizes for the buffers sent to/from the ES2 controller */
+#define ES2_GBUF_MSG_SIZE_MAX	2048
+
+/* Memory sizes for the ARPC buffers */
+#define ARPC_OUT_SIZE_MAX	U16_MAX
+#define ARPC_IN_SIZE_MAX	128
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x18d1, 0x1eaf) },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+#define APB1_LOG_SIZE		SZ_16K
+
+/*
+ * Number of CPort IN urbs in flight at any point in time.
+ * Adjust if we are having stalls in the USB buffer due to not enough urbs in
+ * flight.
+ */
+#define NUM_CPORT_IN_URB	4
+
+/* Number of CPort OUT urbs in flight at any point in time.
+ * Adjust if we get messages saying we are out of urbs in the system log.
+ */
+#define NUM_CPORT_OUT_URB	8
+
+/*
+ * Number of ARPC in urbs in flight at any point in time.
+ */
+#define NUM_ARPC_IN_URB		2
+
+/*
+ * @endpoint: bulk in endpoint for CPort data
+ * @urb: array of urbs for the CPort in messages
+ * @buffer: array of buffers for the @cport_in_urb urbs
+ */
+struct es2_cport_in {
+	__u8 endpoint;
+	struct urb *urb[NUM_CPORT_IN_URB];
+	u8 *buffer[NUM_CPORT_IN_URB];
+};
+
+/**
+ * es2_ap_dev - ES2 USB Bridge to AP structure
+ * @usb_dev: pointer to the USB device we are.
+ * @usb_intf: pointer to the USB interface we are bound to.
+ * @hd: pointer to our gb_host_device structure
+
+ * @cport_in: endpoint, urbs and buffer for cport in messages
+ * @cport_out_endpoint: endpoint for for cport out messages
+ * @cport_out_urb: array of urbs for the CPort out messages
+ * @cport_out_urb_busy: array of flags to see if the @cport_out_urb is busy or
+ *			not.
+ * @cport_out_urb_cancelled: array of flags indicating whether the
+ *			corresponding @cport_out_urb is being cancelled
+ * @cport_out_urb_lock: locks the @cport_out_urb_busy "list"
+ *
+ * @apb_log_task: task pointer for logging thread
+ * @apb_log_dentry: file system entry for the log file interface
+ * @apb_log_enable_dentry: file system entry for enabling logging
+ * @apb_log_fifo: kernel FIFO to carry logged data
+ * @arpc_urb: array of urbs for the ARPC in messages
+ * @arpc_buffer: array of buffers for the @arpc_urb urbs
+ * @arpc_endpoint_in: bulk in endpoint for APBridgeA RPC
+ * @arpc_id_cycle: gives an unique id to ARPC
+ * @arpc_lock: locks ARPC list
+ * @arpcs: list of in progress ARPCs
+ */
+struct es2_ap_dev {
+	struct usb_device *usb_dev;
+	struct usb_interface *usb_intf;
+	struct gb_host_device *hd;
+
+	struct es2_cport_in cport_in;
+	__u8 cport_out_endpoint;
+	struct urb *cport_out_urb[NUM_CPORT_OUT_URB];
+	bool cport_out_urb_busy[NUM_CPORT_OUT_URB];
+	bool cport_out_urb_cancelled[NUM_CPORT_OUT_URB];
+	spinlock_t cport_out_urb_lock;
+
+	bool cdsi1_in_use;
+
+	struct task_struct *apb_log_task;
+	struct dentry *apb_log_dentry;
+	struct dentry *apb_log_enable_dentry;
+	DECLARE_KFIFO(apb_log_fifo, char, APB1_LOG_SIZE);
+
+	__u8 arpc_endpoint_in;
+	struct urb *arpc_urb[NUM_ARPC_IN_URB];
+	u8 *arpc_buffer[NUM_ARPC_IN_URB];
+
+	int arpc_id_cycle;
+	spinlock_t arpc_lock;
+	struct list_head arpcs;
+};
+
+/**
+ * timesync_enable_request - Enable timesync in an APBridge
+ * @count: number of TimeSync Pulses to expect
+ * @frame_time: the initial FrameTime at the first TimeSync Pulse
+ * @strobe_delay: the expected delay in microseconds between each TimeSync Pulse
+ * @refclk: The AP mandated reference clock to run FrameTime at
+ */
+struct timesync_enable_request {
+	__u8	count;
+	__le64	frame_time;
+	__le32	strobe_delay;
+	__le32	refclk;
+} __packed;
+
+/**
+ * timesync_authoritative_request - Transmit authoritative FrameTime to APBridge
+ * @frame_time: An array of authoritative FrameTimes provided by the SVC
+ *              and relayed to the APBridge by the AP
+ */
+struct timesync_authoritative_request {
+	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
+} __packed;
+
+struct arpc {
+	struct list_head list;
+	struct arpc_request_message *req;
+	struct arpc_response_message *resp;
+	struct completion response_received;
+	bool active;
+};
+
+static inline struct es2_ap_dev *hd_to_es2(struct gb_host_device *hd)
+{
+	return (struct es2_ap_dev *)&hd->hd_priv;
+}
+
+static void cport_out_callback(struct urb *urb);
+static void usb_log_enable(struct es2_ap_dev *es2);
+static void usb_log_disable(struct es2_ap_dev *es2);
+static int arpc_sync(struct es2_ap_dev *es2, u8 type, void *payload,
+		     size_t size, int *result, unsigned int timeout);
+
+static int output_sync(struct es2_ap_dev *es2, void *req, u16 size, u8 cmd)
+{
+	struct usb_device *udev = es2->usb_dev;
+	u8 *data;
+	int retval;
+
+	data = kmalloc(size, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	memcpy(data, req, size);
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 cmd,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE,
+				 0, 0, data, size, ES2_USB_CTRL_TIMEOUT);
+	if (retval < 0)
+		dev_err(&udev->dev, "%s: return error %d\n", __func__, retval);
+	else
+		retval = 0;
+
+	kfree(data);
+	return retval;
+}
+
+static void ap_urb_complete(struct urb *urb)
+{
+	struct usb_ctrlrequest *dr = urb->context;
+
+	kfree(dr);
+	usb_free_urb(urb);
+}
+
+static int output_async(struct es2_ap_dev *es2, void *req, u16 size, u8 cmd)
+{
+	struct usb_device *udev = es2->usb_dev;
+	struct urb *urb;
+	struct usb_ctrlrequest *dr;
+	u8 *buf;
+	int retval;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb)
+		return -ENOMEM;
+
+	dr = kmalloc(sizeof(*dr) + size, GFP_ATOMIC);
+	if (!dr) {
+		usb_free_urb(urb);
+		return -ENOMEM;
+	}
+
+	buf = (u8 *)dr + sizeof(*dr);
+	memcpy(buf, req, size);
+
+	dr->bRequest = cmd;
+	dr->bRequestType = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE;
+	dr->wValue = 0;
+	dr->wIndex = 0;
+	dr->wLength = cpu_to_le16(size);
+
+	usb_fill_control_urb(urb, udev, usb_sndctrlpipe(udev, 0),
+			     (unsigned char *)dr, buf, size,
+			     ap_urb_complete, dr);
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval) {
+		usb_free_urb(urb);
+		kfree(dr);
+	}
+	return retval;
+}
+
+static int output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
+		     bool async)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+
+	if (async)
+		return output_async(es2, req, size, cmd);
+
+	return output_sync(es2, req, size, cmd);
+}
+
+static int es2_cport_in_enable(struct es2_ap_dev *es2,
+				struct es2_cport_in *cport_in)
+{
+	struct urb *urb;
+	int ret;
+	int i;
+
+	for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
+		urb = cport_in->urb[i];
+
+		ret = usb_submit_urb(urb, GFP_KERNEL);
+		if (ret) {
+			dev_err(&es2->usb_dev->dev,
+					"failed to submit in-urb: %d\n", ret);
+			goto err_kill_urbs;
+		}
+	}
+
+	return 0;
+
+err_kill_urbs:
+	for (--i; i >= 0; --i) {
+		urb = cport_in->urb[i];
+		usb_kill_urb(urb);
+	}
+
+	return ret;
+}
+
+static void es2_cport_in_disable(struct es2_ap_dev *es2,
+				struct es2_cport_in *cport_in)
+{
+	struct urb *urb;
+	int i;
+
+	for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
+		urb = cport_in->urb[i];
+		usb_kill_urb(urb);
+	}
+}
+
+static int es2_arpc_in_enable(struct es2_ap_dev *es2)
+{
+	struct urb *urb;
+	int ret;
+	int i;
+
+	for (i = 0; i < NUM_ARPC_IN_URB; ++i) {
+		urb = es2->arpc_urb[i];
+
+		ret = usb_submit_urb(urb, GFP_KERNEL);
+		if (ret) {
+			dev_err(&es2->usb_dev->dev,
+				"failed to submit arpc in-urb: %d\n", ret);
+			goto err_kill_urbs;
+		}
+	}
+
+	return 0;
+
+err_kill_urbs:
+	for (--i; i >= 0; --i) {
+		urb = es2->arpc_urb[i];
+		usb_kill_urb(urb);
+	}
+
+	return ret;
+}
+
+static void es2_arpc_in_disable(struct es2_ap_dev *es2)
+{
+	struct urb *urb;
+	int i;
+
+	for (i = 0; i < NUM_ARPC_IN_URB; ++i) {
+		urb = es2->arpc_urb[i];
+		usb_kill_urb(urb);
+	}
+}
+
+static struct urb *next_free_urb(struct es2_ap_dev *es2, gfp_t gfp_mask)
+{
+	struct urb *urb = NULL;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&es2->cport_out_urb_lock, flags);
+
+	/* Look in our pool of allocated urbs first, as that's the "fastest" */
+	for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
+		if (es2->cport_out_urb_busy[i] == false &&
+				es2->cport_out_urb_cancelled[i] == false) {
+			es2->cport_out_urb_busy[i] = true;
+			urb = es2->cport_out_urb[i];
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&es2->cport_out_urb_lock, flags);
+	if (urb)
+		return urb;
+
+	/*
+	 * Crap, pool is empty, complain to the syslog and go allocate one
+	 * dynamically as we have to succeed.
+	 */
+	dev_dbg(&es2->usb_dev->dev,
+		"No free CPort OUT urbs, having to dynamically allocate one!\n");
+	return usb_alloc_urb(0, gfp_mask);
+}
+
+static void free_urb(struct es2_ap_dev *es2, struct urb *urb)
+{
+	unsigned long flags;
+	int i;
+	/*
+	 * See if this was an urb in our pool, if so mark it "free", otherwise
+	 * we need to free it ourselves.
+	 */
+	spin_lock_irqsave(&es2->cport_out_urb_lock, flags);
+	for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
+		if (urb == es2->cport_out_urb[i]) {
+			es2->cport_out_urb_busy[i] = false;
+			urb = NULL;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&es2->cport_out_urb_lock, flags);
+
+	/* If urb is not NULL, then we need to free this urb */
+	usb_free_urb(urb);
+}
+
+/*
+ * We (ab)use the operation-message header pad bytes to transfer the
+ * cport id in order to minimise overhead.
+ */
+static void
+gb_message_cport_pack(struct gb_operation_msg_hdr *header, u16 cport_id)
+{
+	header->pad[0] = cport_id;
+}
+
+/* Clear the pad bytes used for the CPort id */
+static void gb_message_cport_clear(struct gb_operation_msg_hdr *header)
+{
+	header->pad[0] = 0;
+}
+
+/* Extract the CPort id packed into the header, and clear it */
+static u16 gb_message_cport_unpack(struct gb_operation_msg_hdr *header)
+{
+	u16 cport_id = header->pad[0];
+
+	gb_message_cport_clear(header);
+
+	return cport_id;
+}
+
+/*
+ * Returns zero if the message was successfully queued, or a negative errno
+ * otherwise.
+ */
+static int message_send(struct gb_host_device *hd, u16 cport_id,
+			struct gb_message *message, gfp_t gfp_mask)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+	size_t buffer_size;
+	int retval;
+	struct urb *urb;
+	unsigned long flags;
+
+	/*
+	 * The data actually transferred will include an indication
+	 * of where the data should be sent.  Do one last check of
+	 * the target CPort id before filling it in.
+	 */
+	if (!cport_id_valid(hd, cport_id)) {
+		dev_err(&udev->dev, "invalid cport %u\n", cport_id);
+		return -EINVAL;
+	}
+
+	/* Find a free urb */
+	urb = next_free_urb(es2, gfp_mask);
+	if (!urb)
+		return -ENOMEM;
+
+	spin_lock_irqsave(&es2->cport_out_urb_lock, flags);
+	message->hcpriv = urb;
+	spin_unlock_irqrestore(&es2->cport_out_urb_lock, flags);
+
+	/* Pack the cport id into the message header */
+	gb_message_cport_pack(message->header, cport_id);
+
+	buffer_size = sizeof(*message->header) + message->payload_size;
+
+	usb_fill_bulk_urb(urb, udev,
+			  usb_sndbulkpipe(udev,
+					  es2->cport_out_endpoint),
+			  message->buffer, buffer_size,
+			  cport_out_callback, message);
+	urb->transfer_flags |= URB_ZERO_PACKET;
+
+	trace_gb_message_submit(message);
+
+	retval = usb_submit_urb(urb, gfp_mask);
+	if (retval) {
+		dev_err(&udev->dev, "failed to submit out-urb: %d\n", retval);
+
+		spin_lock_irqsave(&es2->cport_out_urb_lock, flags);
+		message->hcpriv = NULL;
+		spin_unlock_irqrestore(&es2->cport_out_urb_lock, flags);
+
+		free_urb(es2, urb);
+		gb_message_cport_clear(message->header);
+
+		return retval;
+	}
+
+	return 0;
+}
+
+/*
+ * Can not be called in atomic context.
+ */
+static void message_cancel(struct gb_message *message)
+{
+	struct gb_host_device *hd = message->operation->connection->hd;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct urb *urb;
+	int i;
+
+	might_sleep();
+
+	spin_lock_irq(&es2->cport_out_urb_lock);
+	urb = message->hcpriv;
+
+	/* Prevent dynamically allocated urb from being deallocated. */
+	usb_get_urb(urb);
+
+	/* Prevent pre-allocated urb from being reused. */
+	for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
+		if (urb == es2->cport_out_urb[i]) {
+			es2->cport_out_urb_cancelled[i] = true;
+			break;
+		}
+	}
+	spin_unlock_irq(&es2->cport_out_urb_lock);
+
+	usb_kill_urb(urb);
+
+	if (i < NUM_CPORT_OUT_URB) {
+		spin_lock_irq(&es2->cport_out_urb_lock);
+		es2->cport_out_urb_cancelled[i] = false;
+		spin_unlock_irq(&es2->cport_out_urb_lock);
+	}
+
+	usb_free_urb(urb);
+}
+
+static int es2_cport_allocate(struct gb_host_device *hd, int cport_id,
+				unsigned long flags)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct ida *id_map = &hd->cport_id_map;
+	int ida_start, ida_end;
+
+	switch (cport_id) {
+	case ES2_CPORT_CDSI0:
+	case ES2_CPORT_CDSI1:
+		dev_err(&hd->dev, "cport %d not available\n", cport_id);
+		return -EBUSY;
+	}
+
+	if (flags & GB_CONNECTION_FLAG_OFFLOADED &&
+			flags & GB_CONNECTION_FLAG_CDSI1) {
+		if (es2->cdsi1_in_use) {
+			dev_err(&hd->dev, "CDSI1 already in use\n");
+			return -EBUSY;
+		}
+
+		es2->cdsi1_in_use = true;
+
+		return ES2_CPORT_CDSI1;
+	}
+
+	if (cport_id < 0) {
+		ida_start = 0;
+		ida_end = hd->num_cports;
+	} else if (cport_id < hd->num_cports) {
+		ida_start = cport_id;
+		ida_end = cport_id + 1;
+	} else {
+		dev_err(&hd->dev, "cport %d not available\n", cport_id);
+		return -EINVAL;
+	}
+
+	return ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
+}
+
+static void es2_cport_release(struct gb_host_device *hd, u16 cport_id)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+
+	switch (cport_id) {
+	case ES2_CPORT_CDSI1:
+		es2->cdsi1_in_use = false;
+		return;
+	}
+
+	ida_simple_remove(&hd->cport_id_map, cport_id);
+}
+
+static int cport_enable(struct gb_host_device *hd, u16 cport_id,
+			unsigned long flags)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+	struct gb_apb_request_cport_flags *req;
+	u32 connection_flags;
+	int ret;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	connection_flags = 0;
+	if (flags & GB_CONNECTION_FLAG_CONTROL)
+		connection_flags |= GB_APB_CPORT_FLAG_CONTROL;
+	if (flags & GB_CONNECTION_FLAG_HIGH_PRIO)
+		connection_flags |= GB_APB_CPORT_FLAG_HIGH_PRIO;
+
+	req->flags = cpu_to_le32(connection_flags);
+
+	dev_dbg(&hd->dev, "%s - cport = %u, flags = %02x\n", __func__,
+			cport_id, connection_flags);
+
+	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				GB_APB_REQUEST_CPORT_FLAGS,
+				USB_DIR_OUT | USB_TYPE_VENDOR |
+				USB_RECIP_INTERFACE, cport_id, 0,
+				req, sizeof(*req), ES2_USB_CTRL_TIMEOUT);
+	if (ret != sizeof(*req)) {
+		dev_err(&udev->dev, "failed to set cport flags for port %d\n",
+				cport_id);
+		if (ret >= 0)
+			ret = -EIO;
+
+		goto out;
+	}
+
+	ret = 0;
+out:
+	kfree(req);
+
+	return ret;
+}
+
+static int es2_cport_connected(struct gb_host_device *hd, u16 cport_id)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct device *dev = &es2->usb_dev->dev;
+	struct arpc_cport_connected_req req;
+	int ret;
+
+	req.cport_id = cpu_to_le16(cport_id);
+	ret = arpc_sync(es2, ARPC_TYPE_CPORT_CONNECTED, &req, sizeof(req),
+			NULL, ES2_ARPC_CPORT_TIMEOUT);
+	if (ret) {
+		dev_err(dev, "failed to set connected state for cport %u: %d\n",
+				cport_id, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int es2_cport_flush(struct gb_host_device *hd, u16 cport_id)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct device *dev = &es2->usb_dev->dev;
+	struct arpc_cport_flush_req req;
+	int ret;
+
+	req.cport_id = cpu_to_le16(cport_id);
+	ret = arpc_sync(es2, ARPC_TYPE_CPORT_FLUSH, &req, sizeof(req),
+			NULL, ES2_ARPC_CPORT_TIMEOUT);
+	if (ret) {
+		dev_err(dev, "failed to flush cport %u: %d\n", cport_id, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int es2_cport_shutdown(struct gb_host_device *hd, u16 cport_id,
+				u8 phase, unsigned int timeout)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct device *dev = &es2->usb_dev->dev;
+	struct arpc_cport_shutdown_req req;
+	int result;
+	int ret;
+
+	if (timeout > U16_MAX)
+		return -EINVAL;
+
+	req.cport_id = cpu_to_le16(cport_id);
+	req.timeout = cpu_to_le16(timeout);
+	req.phase = phase;
+	ret = arpc_sync(es2, ARPC_TYPE_CPORT_SHUTDOWN, &req, sizeof(req),
+			&result, ES2_ARPC_CPORT_TIMEOUT + timeout);
+	if (ret) {
+		dev_err(dev, "failed to send shutdown over cport %u: %d (%d)\n",
+				cport_id, ret, result);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int es2_cport_quiesce(struct gb_host_device *hd, u16 cport_id,
+				size_t peer_space, unsigned int timeout)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct device *dev = &es2->usb_dev->dev;
+	struct arpc_cport_quiesce_req req;
+	int result;
+	int ret;
+
+	if (peer_space > U16_MAX)
+		return -EINVAL;
+
+	if (timeout > U16_MAX)
+		return -EINVAL;
+
+	req.cport_id = cpu_to_le16(cport_id);
+	req.peer_space = cpu_to_le16(peer_space);
+	req.timeout = cpu_to_le16(timeout);
+	ret = arpc_sync(es2, ARPC_TYPE_CPORT_QUIESCE, &req, sizeof(req),
+			&result, ES2_ARPC_CPORT_TIMEOUT + timeout);
+	if (ret) {
+		dev_err(dev, "failed to quiesce cport %u: %d (%d)\n",
+				cport_id, ret, result);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int es2_cport_clear(struct gb_host_device *hd, u16 cport_id)
+{
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct device *dev = &es2->usb_dev->dev;
+	struct arpc_cport_clear_req req;
+	int ret;
+
+	req.cport_id = cpu_to_le16(cport_id);
+	ret = arpc_sync(es2, ARPC_TYPE_CPORT_CLEAR, &req, sizeof(req),
+			NULL, ES2_ARPC_CPORT_TIMEOUT);
+	if (ret) {
+		dev_err(dev, "failed to clear cport %u: %d\n", cport_id, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int latency_tag_enable(struct gb_host_device *hd, u16 cport_id)
+{
+	int retval;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_LATENCY_TAG_EN,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, cport_id, 0, NULL,
+				 0, ES2_USB_CTRL_TIMEOUT);
+
+	if (retval < 0)
+		dev_err(&udev->dev, "Cannot enable latency tag for cport %d\n",
+			cport_id);
+	return retval;
+}
+
+static int latency_tag_disable(struct gb_host_device *hd, u16 cport_id)
+{
+	int retval;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_LATENCY_TAG_DIS,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, cport_id, 0, NULL,
+				 0, ES2_USB_CTRL_TIMEOUT);
+
+	if (retval < 0)
+		dev_err(&udev->dev, "Cannot disable latency tag for cport %d\n",
+			cport_id);
+	return retval;
+}
+
+static int timesync_enable(struct gb_host_device *hd, u8 count,
+			   u64 frame_time, u32 strobe_delay, u32 refclk)
+{
+	int retval;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+	struct gb_control_timesync_enable_request *request;
+
+	request = kzalloc(sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->count = count;
+	request->frame_time = cpu_to_le64(frame_time);
+	request->strobe_delay = cpu_to_le32(strobe_delay);
+	request->refclk = cpu_to_le32(refclk);
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_TIMESYNC_ENABLE,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, 0, 0, request,
+				 sizeof(*request), ES2_USB_CTRL_TIMEOUT);
+	if (retval < 0)
+		dev_err(&udev->dev, "Cannot enable timesync %d\n", retval);
+
+	kfree(request);
+	return retval;
+}
+
+static int timesync_disable(struct gb_host_device *hd)
+{
+	int retval;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_TIMESYNC_DISABLE,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, 0, 0, NULL,
+				 0, ES2_USB_CTRL_TIMEOUT);
+	if (retval < 0)
+		dev_err(&udev->dev, "Cannot disable timesync %d\n", retval);
+
+	return retval;
+}
+
+static int timesync_authoritative(struct gb_host_device *hd, u64 *frame_time)
+{
+	int retval, i;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+	struct timesync_authoritative_request *request;
+
+	request = kzalloc(sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
+		request->frame_time[i] = cpu_to_le64(frame_time[i]);
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_TIMESYNC_AUTHORITATIVE,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, 0, 0, request,
+				 sizeof(*request), ES2_USB_CTRL_TIMEOUT);
+	if (retval < 0)
+		dev_err(&udev->dev, "Cannot timesync authoritative out %d\n", retval);
+
+	kfree(request);
+	return retval;
+}
+
+static int timesync_get_last_event(struct gb_host_device *hd, u64 *frame_time)
+{
+	int retval;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	struct usb_device *udev = es2->usb_dev;
+	__le64 *response_frame_time;
+
+	response_frame_time = kzalloc(sizeof(*response_frame_time), GFP_KERNEL);
+	if (!response_frame_time)
+		return -ENOMEM;
+
+	retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+				 GB_APB_REQUEST_TIMESYNC_GET_LAST_EVENT,
+				 USB_DIR_IN | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, 0, 0, response_frame_time,
+				 sizeof(*response_frame_time),
+				 ES2_USB_CTRL_TIMEOUT);
+
+	if (retval != sizeof(*response_frame_time)) {
+		dev_err(&udev->dev, "Cannot get last TimeSync event: %d\n",
+			retval);
+
+		if (retval >= 0)
+			retval = -EIO;
+
+		goto out;
+	}
+	*frame_time = le64_to_cpu(*response_frame_time);
+	retval = 0;
+out:
+	kfree(response_frame_time);
+	return retval;
+}
+
+static struct gb_hd_driver es2_driver = {
+	.hd_priv_size			= sizeof(struct es2_ap_dev),
+	.message_send			= message_send,
+	.message_cancel			= message_cancel,
+	.cport_allocate			= es2_cport_allocate,
+	.cport_release			= es2_cport_release,
+	.cport_enable			= cport_enable,
+	.cport_connected		= es2_cport_connected,
+	.cport_flush			= es2_cport_flush,
+	.cport_shutdown			= es2_cport_shutdown,
+	.cport_quiesce			= es2_cport_quiesce,
+	.cport_clear			= es2_cport_clear,
+	.latency_tag_enable		= latency_tag_enable,
+	.latency_tag_disable		= latency_tag_disable,
+	.output				= output,
+	.timesync_enable		= timesync_enable,
+	.timesync_disable		= timesync_disable,
+	.timesync_authoritative		= timesync_authoritative,
+	.timesync_get_last_event	= timesync_get_last_event,
+};
+
+/* Common function to report consistent warnings based on URB status */
+static int check_urb_status(struct urb *urb)
+{
+	struct device *dev = &urb->dev->dev;
+	int status = urb->status;
+
+	switch (status) {
+	case 0:
+		return 0;
+
+	case -EOVERFLOW:
+		dev_err(dev, "%s: overflow actual length is %d\n",
+			__func__, urb->actual_length);
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+	case -EILSEQ:
+	case -EPROTO:
+		/* device is gone, stop sending */
+		return status;
+	}
+	dev_err(dev, "%s: unknown status %d\n", __func__, status);
+
+	return -EAGAIN;
+}
+
+static void es2_destroy(struct es2_ap_dev *es2)
+{
+	struct usb_device *udev;
+	struct urb *urb;
+	int i;
+
+	debugfs_remove(es2->apb_log_enable_dentry);
+	usb_log_disable(es2);
+
+	/* Tear down everything! */
+	for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
+		urb = es2->cport_out_urb[i];
+		usb_kill_urb(urb);
+		usb_free_urb(urb);
+		es2->cport_out_urb[i] = NULL;
+		es2->cport_out_urb_busy[i] = false;	/* just to be anal */
+	}
+
+	for (i = 0; i < NUM_ARPC_IN_URB; ++i) {
+		usb_free_urb(es2->arpc_urb[i]);
+		kfree(es2->arpc_buffer[i]);
+		es2->arpc_buffer[i] = NULL;
+	}
+
+	for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
+		usb_free_urb(es2->cport_in.urb[i]);
+		kfree(es2->cport_in.buffer[i]);
+		es2->cport_in.buffer[i] = NULL;
+	}
+
+	/* release reserved CDSI0 and CDSI1 cports */
+	gb_hd_cport_release_reserved(es2->hd, ES2_CPORT_CDSI1);
+	gb_hd_cport_release_reserved(es2->hd, ES2_CPORT_CDSI0);
+
+	udev = es2->usb_dev;
+	gb_hd_put(es2->hd);
+
+	usb_put_dev(udev);
+}
+
+static void cport_in_callback(struct urb *urb)
+{
+	struct gb_host_device *hd = urb->context;
+	struct device *dev = &urb->dev->dev;
+	struct gb_operation_msg_hdr *header;
+	int status = check_urb_status(urb);
+	int retval;
+	u16 cport_id;
+
+	if (status) {
+		if ((status == -EAGAIN) || (status == -EPROTO))
+			goto exit;
+
+		/* The urb is being unlinked */
+		if (status == -ENOENT || status == -ESHUTDOWN)
+			return;
+
+		dev_err(dev, "urb cport in error %d (dropped)\n", status);
+		return;
+	}
+
+	if (urb->actual_length < sizeof(*header)) {
+		dev_err(dev, "short message received\n");
+		goto exit;
+	}
+
+	/* Extract the CPort id, which is packed in the message header */
+	header = urb->transfer_buffer;
+	cport_id = gb_message_cport_unpack(header);
+
+	if (cport_id_valid(hd, cport_id)) {
+		greybus_data_rcvd(hd, cport_id, urb->transfer_buffer,
+							urb->actual_length);
+	} else {
+		dev_err(dev, "invalid cport id %u received\n", cport_id);
+	}
+exit:
+	/* put our urb back in the request pool */
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(dev, "failed to resubmit in-urb: %d\n", retval);
+}
+
+static void cport_out_callback(struct urb *urb)
+{
+	struct gb_message *message = urb->context;
+	struct gb_host_device *hd = message->operation->connection->hd;
+	struct es2_ap_dev *es2 = hd_to_es2(hd);
+	int status = check_urb_status(urb);
+	unsigned long flags;
+
+	gb_message_cport_clear(message->header);
+
+	spin_lock_irqsave(&es2->cport_out_urb_lock, flags);
+	message->hcpriv = NULL;
+	spin_unlock_irqrestore(&es2->cport_out_urb_lock, flags);
+
+	/*
+	 * Tell the submitter that the message send (attempt) is
+	 * complete, and report the status.
+	 */
+	greybus_message_sent(hd, message, status);
+
+	free_urb(es2, urb);
+}
+
+static struct arpc *arpc_alloc(void *payload, u16 size, u8 type)
+{
+	struct arpc *rpc;
+
+	if (size + sizeof(*rpc->req) > ARPC_OUT_SIZE_MAX)
+		return NULL;
+
+	rpc = kzalloc(sizeof(*rpc), GFP_KERNEL);
+	if (!rpc)
+		return NULL;
+
+	INIT_LIST_HEAD(&rpc->list);
+	rpc->req = kzalloc(sizeof(*rpc->req) + size, GFP_KERNEL);
+	if (!rpc->req)
+		goto err_free_rpc;
+
+	rpc->resp = kzalloc(sizeof(*rpc->resp), GFP_KERNEL);
+	if (!rpc->resp)
+		goto err_free_req;
+
+	rpc->req->type = type;
+	rpc->req->size = cpu_to_le16(sizeof(rpc->req) + size);
+	memcpy(rpc->req->data, payload, size);
+
+	init_completion(&rpc->response_received);
+
+	return rpc;
+
+err_free_req:
+	kfree(rpc->req);
+err_free_rpc:
+	kfree(rpc);
+
+	return NULL;
+}
+
+static void arpc_free(struct arpc *rpc)
+{
+	kfree(rpc->req);
+	kfree(rpc->resp);
+	kfree(rpc);
+}
+
+static struct arpc *arpc_find(struct es2_ap_dev *es2, __le16 id)
+{
+	struct arpc *rpc;
+
+	list_for_each_entry(rpc, &es2->arpcs, list) {
+		if (rpc->req->id == id)
+			return rpc;
+	}
+
+	return NULL;
+}
+
+static void arpc_add(struct es2_ap_dev *es2, struct arpc *rpc)
+{
+	rpc->active = true;
+	rpc->req->id = cpu_to_le16(es2->arpc_id_cycle++);
+	list_add_tail(&rpc->list, &es2->arpcs);
+}
+
+static void arpc_del(struct es2_ap_dev *es2, struct arpc *rpc)
+{
+	if (rpc->active) {
+		rpc->active = false;
+		list_del(&rpc->list);
+	}
+}
+
+static int arpc_send(struct es2_ap_dev *es2, struct arpc *rpc, int timeout)
+{
+	struct usb_device *udev = es2->usb_dev;
+	int retval;
+
+	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				 GB_APB_REQUEST_ARPC_RUN,
+				 USB_DIR_OUT | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE,
+				 0, 0,
+				 rpc->req, le16_to_cpu(rpc->req->size),
+				 ES2_USB_CTRL_TIMEOUT);
+	if (retval != le16_to_cpu(rpc->req->size)) {
+		dev_err(&udev->dev,
+			"failed to send ARPC request %d: %d\n",
+			rpc->req->type, retval);
+		if (retval > 0)
+			retval = -EIO;
+		return retval;
+	}
+
+	return 0;
+}
+
+static int arpc_sync(struct es2_ap_dev *es2, u8 type, void *payload,
+		     size_t size, int *result, unsigned int timeout)
+{
+	struct arpc *rpc;
+	unsigned long flags;
+	int retval;
+
+	if (result)
+		*result = 0;
+
+	rpc = arpc_alloc(payload, size, type);
+	if (!rpc)
+		return -ENOMEM;
+
+	spin_lock_irqsave(&es2->arpc_lock, flags);
+	arpc_add(es2, rpc);
+	spin_unlock_irqrestore(&es2->arpc_lock, flags);
+
+	retval = arpc_send(es2, rpc, timeout);
+	if (retval)
+		goto out_arpc_del;
+
+	retval = wait_for_completion_interruptible_timeout(
+						&rpc->response_received,
+						msecs_to_jiffies(timeout));
+	if (retval <= 0) {
+		if (!retval)
+			retval = -ETIMEDOUT;
+		goto out_arpc_del;
+	}
+
+	if (rpc->resp->result) {
+		retval = -EREMOTEIO;
+		if (result)
+			*result = rpc->resp->result;
+	} else {
+		retval = 0;
+	}
+
+out_arpc_del:
+	spin_lock_irqsave(&es2->arpc_lock, flags);
+	arpc_del(es2, rpc);
+	spin_unlock_irqrestore(&es2->arpc_lock, flags);
+	arpc_free(rpc);
+
+	if (retval < 0 && retval != -EREMOTEIO) {
+		dev_err(&es2->usb_dev->dev,
+			"failed to execute ARPC: %d\n", retval);
+	}
+
+	return retval;
+}
+
+static void arpc_in_callback(struct urb *urb)
+{
+	struct es2_ap_dev *es2 = urb->context;
+	struct device *dev = &urb->dev->dev;
+	int status = check_urb_status(urb);
+	struct arpc *rpc;
+	struct arpc_response_message *resp;
+	unsigned long flags;
+	int retval;
+
+	if (status) {
+		if ((status == -EAGAIN) || (status == -EPROTO))
+			goto exit;
+
+		/* The urb is being unlinked */
+		if (status == -ENOENT || status == -ESHUTDOWN)
+			return;
+
+		dev_err(dev, "arpc in-urb error %d (dropped)\n", status);
+		return;
+	}
+
+	if (urb->actual_length < sizeof(*resp)) {
+		dev_err(dev, "short aprc response received\n");
+		goto exit;
+	}
+
+	resp = urb->transfer_buffer;
+	spin_lock_irqsave(&es2->arpc_lock, flags);
+	rpc = arpc_find(es2, resp->id);
+	if (!rpc) {
+		dev_err(dev, "invalid arpc response id received: %u\n",
+			le16_to_cpu(resp->id));
+		spin_unlock_irqrestore(&es2->arpc_lock, flags);
+		goto exit;
+	}
+
+	arpc_del(es2, rpc);
+	memcpy(rpc->resp, resp, sizeof(*resp));
+	complete(&rpc->response_received);
+	spin_unlock_irqrestore(&es2->arpc_lock, flags);
+
+exit:
+	/* put our urb back in the request pool */
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(dev, "failed to resubmit arpc in-urb: %d\n", retval);
+}
+
+#define APB1_LOG_MSG_SIZE	64
+static void apb_log_get(struct es2_ap_dev *es2, char *buf)
+{
+	int retval;
+
+	do {
+		retval = usb_control_msg(es2->usb_dev,
+					usb_rcvctrlpipe(es2->usb_dev, 0),
+					GB_APB_REQUEST_LOG,
+					USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
+					0x00, 0x00,
+					buf,
+					APB1_LOG_MSG_SIZE,
+					ES2_USB_CTRL_TIMEOUT);
+		if (retval > 0)
+			kfifo_in(&es2->apb_log_fifo, buf, retval);
+	} while (retval > 0);
+}
+
+static int apb_log_poll(void *data)
+{
+	struct es2_ap_dev *es2 = data;
+	char *buf;
+
+	buf = kmalloc(APB1_LOG_MSG_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	while (!kthread_should_stop()) {
+		msleep(1000);
+		apb_log_get(es2, buf);
+	}
+
+	kfree(buf);
+
+	return 0;
+}
+
+static ssize_t apb_log_read(struct file *f, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct es2_ap_dev *es2 = f->f_inode->i_private;
+	ssize_t ret;
+	size_t copied;
+	char *tmp_buf;
+
+	if (count > APB1_LOG_SIZE)
+		count = APB1_LOG_SIZE;
+
+	tmp_buf = kmalloc(count, GFP_KERNEL);
+	if (!tmp_buf)
+		return -ENOMEM;
+
+	copied = kfifo_out(&es2->apb_log_fifo, tmp_buf, count);
+	ret = simple_read_from_buffer(buf, count, ppos, tmp_buf, copied);
+
+	kfree(tmp_buf);
+
+	return ret;
+}
+
+static const struct file_operations apb_log_fops = {
+	.read	= apb_log_read,
+};
+
+static void usb_log_enable(struct es2_ap_dev *es2)
+{
+	if (!IS_ERR_OR_NULL(es2->apb_log_task))
+		return;
+
+	/* get log from APB1 */
+	es2->apb_log_task = kthread_run(apb_log_poll, es2, "apb_log");
+	if (IS_ERR(es2->apb_log_task))
+		return;
+	/* XXX We will need to rename this per APB */
+	es2->apb_log_dentry = debugfs_create_file("apb_log", S_IRUGO,
+						gb_debugfs_get(), es2,
+						&apb_log_fops);
+}
+
+static void usb_log_disable(struct es2_ap_dev *es2)
+{
+	if (IS_ERR_OR_NULL(es2->apb_log_task))
+		return;
+
+	debugfs_remove(es2->apb_log_dentry);
+	es2->apb_log_dentry = NULL;
+
+	kthread_stop(es2->apb_log_task);
+	es2->apb_log_task = NULL;
+}
+
+static ssize_t apb_log_enable_read(struct file *f, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct es2_ap_dev *es2 = f->f_inode->i_private;
+	int enable = !IS_ERR_OR_NULL(es2->apb_log_task);
+	char tmp_buf[3];
+
+	sprintf(tmp_buf, "%d\n", enable);
+	return simple_read_from_buffer(buf, count, ppos, tmp_buf, 3);
+}
+
+static ssize_t apb_log_enable_write(struct file *f, const char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	int enable;
+	ssize_t retval;
+	struct es2_ap_dev *es2 = f->f_inode->i_private;
+
+	retval = kstrtoint_from_user(buf, count, 10, &enable);
+	if (retval)
+		return retval;
+
+	if (enable)
+		usb_log_enable(es2);
+	else
+		usb_log_disable(es2);
+
+	return count;
+}
+
+static const struct file_operations apb_log_enable_fops = {
+	.read	= apb_log_enable_read,
+	.write	= apb_log_enable_write,
+};
+
+static int apb_get_cport_count(struct usb_device *udev)
+{
+	int retval;
+	__le16 *cport_count;
+
+	cport_count = kzalloc(sizeof(*cport_count), GFP_KERNEL);
+	if (!cport_count)
+		return -ENOMEM;
+
+	retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+				 GB_APB_REQUEST_CPORT_COUNT,
+				 USB_DIR_IN | USB_TYPE_VENDOR |
+				 USB_RECIP_INTERFACE, 0, 0, cport_count,
+				 sizeof(*cport_count), ES2_USB_CTRL_TIMEOUT);
+	if (retval != sizeof(*cport_count)) {
+		dev_err(&udev->dev, "Cannot retrieve CPort count: %d\n",
+			retval);
+
+		if (retval >= 0)
+			retval = -EIO;
+
+		goto out;
+	}
+
+	retval = le16_to_cpu(*cport_count);
+
+	/* We need to fit a CPort ID in one byte of a message header */
+	if (retval > U8_MAX) {
+		retval = U8_MAX;
+		dev_warn(&udev->dev, "Limiting number of CPorts to U8_MAX\n");
+	}
+
+out:
+	kfree(cport_count);
+	return retval;
+}
+
+/*
+ * The ES2 USB Bridge device has 15 endpoints
+ * 1 Control - usual USB stuff + AP -> APBridgeA messages
+ * 7 Bulk IN - CPort data in
+ * 7 Bulk OUT - CPort data out
+ */
+static int ap_probe(struct usb_interface *interface,
+		    const struct usb_device_id *id)
+{
+	struct es2_ap_dev *es2;
+	struct gb_host_device *hd;
+	struct usb_device *udev;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint;
+	__u8 ep_addr;
+	int retval;
+	int i;
+	int num_cports;
+	bool bulk_out_found = false;
+	bool bulk_in_found = false;
+	bool arpc_in_found = false;
+
+	udev = usb_get_dev(interface_to_usbdev(interface));
+
+	num_cports = apb_get_cport_count(udev);
+	if (num_cports < 0) {
+		usb_put_dev(udev);
+		dev_err(&udev->dev, "Cannot retrieve CPort count: %d\n",
+			num_cports);
+		return num_cports;
+	}
+
+	hd = gb_hd_create(&es2_driver, &udev->dev, ES2_GBUF_MSG_SIZE_MAX,
+				num_cports);
+	if (IS_ERR(hd)) {
+		usb_put_dev(udev);
+		return PTR_ERR(hd);
+	}
+
+	es2 = hd_to_es2(hd);
+	es2->hd = hd;
+	es2->usb_intf = interface;
+	es2->usb_dev = udev;
+	spin_lock_init(&es2->cport_out_urb_lock);
+	INIT_KFIFO(es2->apb_log_fifo);
+	usb_set_intfdata(interface, es2);
+
+	/*
+	 * Reserve the CDSI0 and CDSI1 CPorts so they won't be allocated
+	 * dynamically.
+	 */
+	retval = gb_hd_cport_reserve(hd, ES2_CPORT_CDSI0);
+	if (retval)
+		goto error;
+	retval = gb_hd_cport_reserve(hd, ES2_CPORT_CDSI1);
+	if (retval)
+		goto error;
+
+	/* find all bulk endpoints */
+	iface_desc = interface->cur_altsetting;
+	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+		endpoint = &iface_desc->endpoint[i].desc;
+		ep_addr = endpoint->bEndpointAddress;
+
+		if (usb_endpoint_is_bulk_in(endpoint)) {
+			if (!bulk_in_found) {
+				es2->cport_in.endpoint = ep_addr;
+				bulk_in_found = true;
+			} else if (!arpc_in_found) {
+				es2->arpc_endpoint_in = ep_addr;
+				arpc_in_found = true;
+			} else {
+				dev_warn(&udev->dev,
+					 "Unused bulk IN endpoint found: 0x%02x\n",
+					 ep_addr);
+			}
+			continue;
+		}
+		if (usb_endpoint_is_bulk_out(endpoint)) {
+			if (!bulk_out_found) {
+				es2->cport_out_endpoint = ep_addr;
+				bulk_out_found = true;
+			} else {
+				dev_warn(&udev->dev,
+					 "Unused bulk OUT endpoint found: 0x%02x\n",
+					 ep_addr);
+			}
+			continue;
+		}
+		dev_warn(&udev->dev,
+			 "Unknown endpoint type found, address 0x%02x\n",
+			 ep_addr);
+	}
+	if (!bulk_in_found || !arpc_in_found || !bulk_out_found) {
+		dev_err(&udev->dev, "Not enough endpoints found in device, aborting!\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* Allocate buffers for our cport in messages */
+	for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
+		struct urb *urb;
+		u8 *buffer;
+
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			retval = -ENOMEM;
+			goto error;
+		}
+		es2->cport_in.urb[i] = urb;
+
+		buffer = kmalloc(ES2_GBUF_MSG_SIZE_MAX, GFP_KERNEL);
+		if (!buffer) {
+			retval = -ENOMEM;
+			goto error;
+		}
+
+		usb_fill_bulk_urb(urb, udev,
+				  usb_rcvbulkpipe(udev, es2->cport_in.endpoint),
+				  buffer, ES2_GBUF_MSG_SIZE_MAX,
+				  cport_in_callback, hd);
+
+		es2->cport_in.buffer[i] = buffer;
+	}
+
+	/* Allocate buffers for ARPC in messages */
+	for (i = 0; i < NUM_ARPC_IN_URB; ++i) {
+		struct urb *urb;
+		u8 *buffer;
+
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			retval = -ENOMEM;
+			goto error;
+		}
+		es2->arpc_urb[i] = urb;
+
+		buffer = kmalloc(ARPC_IN_SIZE_MAX, GFP_KERNEL);
+		if (!buffer) {
+			retval = -ENOMEM;
+			goto error;
+		}
+
+		usb_fill_bulk_urb(urb, udev,
+				  usb_rcvbulkpipe(udev,
+						  es2->arpc_endpoint_in),
+				  buffer, ARPC_IN_SIZE_MAX,
+				  arpc_in_callback, es2);
+
+		es2->arpc_buffer[i] = buffer;
+	}
+
+	/* Allocate urbs for our CPort OUT messages */
+	for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
+		struct urb *urb;
+
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			retval = -ENOMEM;
+			goto error;
+		}
+
+		es2->cport_out_urb[i] = urb;
+		es2->cport_out_urb_busy[i] = false;	/* just to be anal */
+	}
+
+	/* XXX We will need to rename this per APB */
+	es2->apb_log_enable_dentry = debugfs_create_file("apb_log_enable",
+							(S_IWUSR | S_IRUGO),
+							gb_debugfs_get(), es2,
+							&apb_log_enable_fops);
+
+	INIT_LIST_HEAD(&es2->arpcs);
+	spin_lock_init(&es2->arpc_lock);
+
+	if (es2_arpc_in_enable(es2))
+		goto error;
+
+	retval = gb_hd_add(hd);
+	if (retval)
+		goto err_disable_arpc_in;
+
+	retval = es2_cport_in_enable(es2, &es2->cport_in);
+	if (retval)
+		goto err_hd_del;
+
+	return 0;
+
+err_hd_del:
+	gb_hd_del(hd);
+err_disable_arpc_in:
+	es2_arpc_in_disable(es2);
+error:
+	es2_destroy(es2);
+
+	return retval;
+}
+
+static void ap_disconnect(struct usb_interface *interface)
+{
+	struct es2_ap_dev *es2 = usb_get_intfdata(interface);
+
+	gb_hd_del(es2->hd);
+
+	es2_cport_in_disable(es2, &es2->cport_in);
+	es2_arpc_in_disable(es2);
+
+	es2_destroy(es2);
+}
+
+static struct usb_driver es2_ap_driver = {
+	.name =		"es2_ap_driver",
+	.probe =	ap_probe,
+	.disconnect =	ap_disconnect,
+	.id_table =	id_table,
+	.soft_unbind =	1,
+};
+
+module_usb_driver(es2_ap_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");
diff --git a/drivers/staging/greybus/firmware.h b/drivers/staging/greybus/firmware.h
new file mode 100644
index 000000000000..f4f0db1cefe8
--- /dev/null
+++ b/drivers/staging/greybus/firmware.h
@@ -0,0 +1,42 @@
+/*
+ * Greybus Firmware Management Header
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __FIRMWARE_H
+#define __FIRMWARE_H
+
+#include "greybus.h"
+
+#define FW_NAME_PREFIX	"gmp_"
+
+/*
+ * Length of the string in format: "FW_NAME_PREFIX""%08x_%08x_%08x_%08x_%s.tftf"
+ *                                  (3 + 1 + 4 * (8 + 1) + 10 + 1 + 4 + 1)
+ */
+#define FW_NAME_SIZE		56
+
+/* Firmware Management Protocol specific functions */
+int fw_mgmt_init(void);
+void fw_mgmt_exit(void);
+struct gb_connection *to_fw_mgmt_connection(struct device *dev);
+int gb_fw_mgmt_request_handler(struct gb_operation *op);
+int gb_fw_mgmt_connection_init(struct gb_connection *connection);
+void gb_fw_mgmt_connection_exit(struct gb_connection *connection);
+
+/* Firmware Download Protocol specific functions */
+int gb_fw_download_request_handler(struct gb_operation *op);
+int gb_fw_download_connection_init(struct gb_connection *connection);
+void gb_fw_download_connection_exit(struct gb_connection *connection);
+
+/* CAP Protocol specific functions */
+int cap_init(void);
+void cap_exit(void);
+int gb_cap_connection_init(struct gb_connection *connection);
+void gb_cap_connection_exit(struct gb_connection *connection);
+
+#endif /* __FIRMWARE_H */
diff --git a/drivers/staging/greybus/fw-core.c b/drivers/staging/greybus/fw-core.c
new file mode 100644
index 000000000000..454a98957ba5
--- /dev/null
+++ b/drivers/staging/greybus/fw-core.c
@@ -0,0 +1,312 @@
+/*
+ * Greybus Firmware Core Bundle Driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/firmware.h>
+#include "firmware.h"
+#include "greybus.h"
+#include "spilib.h"
+
+struct gb_fw_core {
+	struct gb_connection	*download_connection;
+	struct gb_connection	*mgmt_connection;
+	struct gb_connection	*spi_connection;
+	struct gb_connection	*cap_connection;
+};
+
+static struct spilib_ops *spilib_ops;
+
+struct gb_connection *to_fw_mgmt_connection(struct device *dev)
+{
+	struct gb_fw_core *fw_core = dev_get_drvdata(dev);
+
+	return fw_core->mgmt_connection;
+}
+
+static int gb_fw_spi_connection_init(struct gb_connection *connection)
+{
+	int ret;
+
+	if (!connection)
+		return 0;
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		return ret;
+
+	ret = gb_spilib_master_init(connection, &connection->bundle->dev,
+				    spilib_ops);
+	if (ret) {
+		gb_connection_disable(connection);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void gb_fw_spi_connection_exit(struct gb_connection *connection)
+{
+	if (!connection)
+		return;
+
+	gb_spilib_master_exit(connection);
+	gb_connection_disable(connection);
+}
+
+static int gb_fw_core_probe(struct gb_bundle *bundle,
+			    const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_fw_core *fw_core;
+	int ret, i;
+	u16 cport_id;
+	u8 protocol_id;
+
+	fw_core = kzalloc(sizeof(*fw_core), GFP_KERNEL);
+	if (!fw_core)
+		return -ENOMEM;
+
+	/* Parse CPorts and create connections */
+	for (i = 0; i < bundle->num_cports; i++) {
+		cport_desc = &bundle->cport_desc[i];
+		cport_id = le16_to_cpu(cport_desc->id);
+		protocol_id = cport_desc->protocol_id;
+
+		switch (protocol_id) {
+		case GREYBUS_PROTOCOL_FW_MANAGEMENT:
+			/* Disallow multiple Firmware Management CPorts */
+			if (fw_core->mgmt_connection) {
+				dev_err(&bundle->dev,
+					"multiple management CPorts found\n");
+				ret = -EINVAL;
+				goto err_destroy_connections;
+			}
+
+			connection = gb_connection_create(bundle, cport_id,
+						gb_fw_mgmt_request_handler);
+			if (IS_ERR(connection)) {
+				ret = PTR_ERR(connection);
+				dev_err(&bundle->dev,
+					"failed to create management connection (%d)\n",
+					ret);
+				goto err_destroy_connections;
+			}
+
+			fw_core->mgmt_connection = connection;
+			break;
+		case GREYBUS_PROTOCOL_FW_DOWNLOAD:
+			/* Disallow multiple Firmware Download CPorts */
+			if (fw_core->download_connection) {
+				dev_err(&bundle->dev,
+					"multiple download CPorts found\n");
+				ret = -EINVAL;
+				goto err_destroy_connections;
+			}
+
+			connection = gb_connection_create(bundle, cport_id,
+						gb_fw_download_request_handler);
+			if (IS_ERR(connection)) {
+				dev_err(&bundle->dev, "failed to create download connection (%ld)\n",
+					PTR_ERR(connection));
+			} else {
+				fw_core->download_connection = connection;
+			}
+
+			break;
+		case GREYBUS_PROTOCOL_SPI:
+			/* Disallow multiple SPI CPorts */
+			if (fw_core->spi_connection) {
+				dev_err(&bundle->dev,
+					"multiple SPI CPorts found\n");
+				ret = -EINVAL;
+				goto err_destroy_connections;
+			}
+
+			connection = gb_connection_create(bundle, cport_id,
+							  NULL);
+			if (IS_ERR(connection)) {
+				dev_err(&bundle->dev, "failed to create SPI connection (%ld)\n",
+					PTR_ERR(connection));
+			} else {
+				fw_core->spi_connection = connection;
+			}
+
+			break;
+		case GREYBUS_PROTOCOL_AUTHENTICATION:
+			/* Disallow multiple CAP CPorts */
+			if (fw_core->cap_connection) {
+				dev_err(&bundle->dev, "multiple Authentication CPorts found\n");
+				ret = -EINVAL;
+				goto err_destroy_connections;
+			}
+
+			connection = gb_connection_create(bundle, cport_id,
+							  NULL);
+			if (IS_ERR(connection)) {
+				dev_err(&bundle->dev, "failed to create Authentication connection (%ld)\n",
+					PTR_ERR(connection));
+			} else {
+				fw_core->cap_connection = connection;
+			}
+
+			break;
+		default:
+			dev_err(&bundle->dev, "invalid protocol id (0x%02x)\n",
+				protocol_id);
+			ret = -EINVAL;
+			goto err_destroy_connections;
+		}
+	}
+
+	/* Firmware Management connection is mandatory */
+	if (!fw_core->mgmt_connection) {
+		dev_err(&bundle->dev, "missing management connection\n");
+		ret = -ENODEV;
+		goto err_destroy_connections;
+	}
+
+	ret = gb_fw_download_connection_init(fw_core->download_connection);
+	if (ret) {
+		/* We may still be able to work with the Interface */
+		dev_err(&bundle->dev, "failed to initialize firmware download connection, disable it (%d)\n",
+			ret);
+		gb_connection_destroy(fw_core->download_connection);
+		fw_core->download_connection = NULL;
+	}
+
+	ret = gb_fw_spi_connection_init(fw_core->spi_connection);
+	if (ret) {
+		/* We may still be able to work with the Interface */
+		dev_err(&bundle->dev, "failed to initialize SPI connection, disable it (%d)\n",
+			ret);
+		gb_connection_destroy(fw_core->spi_connection);
+		fw_core->spi_connection = NULL;
+	}
+
+	ret = gb_cap_connection_init(fw_core->cap_connection);
+	if (ret) {
+		/* We may still be able to work with the Interface */
+		dev_err(&bundle->dev, "failed to initialize CAP connection, disable it (%d)\n",
+			ret);
+		gb_connection_destroy(fw_core->cap_connection);
+		fw_core->cap_connection = NULL;
+	}
+
+	ret = gb_fw_mgmt_connection_init(fw_core->mgmt_connection);
+	if (ret) {
+		/* We may still be able to work with the Interface */
+		dev_err(&bundle->dev, "failed to initialize firmware management connection, disable it (%d)\n",
+			ret);
+		goto err_exit_connections;
+	}
+
+	greybus_set_drvdata(bundle, fw_core);
+
+	/* FIXME: Remove this after S2 Loader gets runtime PM support */
+	if (!(bundle->intf->quirks & GB_INTERFACE_QUIRK_NO_PM))
+		gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+err_exit_connections:
+	gb_cap_connection_exit(fw_core->cap_connection);
+	gb_fw_spi_connection_exit(fw_core->spi_connection);
+	gb_fw_download_connection_exit(fw_core->download_connection);
+err_destroy_connections:
+	gb_connection_destroy(fw_core->mgmt_connection);
+	gb_connection_destroy(fw_core->cap_connection);
+	gb_connection_destroy(fw_core->spi_connection);
+	gb_connection_destroy(fw_core->download_connection);
+	kfree(fw_core);
+
+	return ret;
+}
+
+static void gb_fw_core_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_fw_core *fw_core = greybus_get_drvdata(bundle);
+	int ret;
+
+	/* FIXME: Remove this after S2 Loader gets runtime PM support */
+	if (!(bundle->intf->quirks & GB_INTERFACE_QUIRK_NO_PM)) {
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (ret)
+			gb_pm_runtime_get_noresume(bundle);
+	}
+
+	gb_fw_mgmt_connection_exit(fw_core->mgmt_connection);
+	gb_cap_connection_exit(fw_core->cap_connection);
+	gb_fw_spi_connection_exit(fw_core->spi_connection);
+	gb_fw_download_connection_exit(fw_core->download_connection);
+
+	gb_connection_destroy(fw_core->mgmt_connection);
+	gb_connection_destroy(fw_core->cap_connection);
+	gb_connection_destroy(fw_core->spi_connection);
+	gb_connection_destroy(fw_core->download_connection);
+
+	kfree(fw_core);
+}
+
+static const struct greybus_bundle_id gb_fw_core_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_FW_MANAGEMENT) },
+	{ }
+};
+
+static struct greybus_driver gb_fw_core_driver = {
+	.name		= "gb-firmware",
+	.probe		= gb_fw_core_probe,
+	.disconnect	= gb_fw_core_disconnect,
+	.id_table	= gb_fw_core_id_table,
+};
+
+static int fw_core_init(void)
+{
+	int ret;
+
+	ret = fw_mgmt_init();
+	if (ret) {
+		pr_err("Failed to initialize fw-mgmt core (%d)\n", ret);
+		return ret;
+	}
+
+	ret = cap_init();
+	if (ret) {
+		pr_err("Failed to initialize component authentication core (%d)\n",
+		       ret);
+		goto fw_mgmt_exit;
+	}
+
+	ret = greybus_register(&gb_fw_core_driver);
+	if (ret)
+		goto cap_exit;
+
+	return 0;
+
+cap_exit:
+	cap_exit();
+fw_mgmt_exit:
+	fw_mgmt_exit();
+
+	return ret;
+}
+module_init(fw_core_init);
+
+static void __exit fw_core_exit(void)
+{
+	greybus_deregister(&gb_fw_core_driver);
+	cap_exit();
+	fw_mgmt_exit();
+}
+module_exit(fw_core_exit);
+
+MODULE_ALIAS("greybus:firmware");
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_DESCRIPTION("Greybus Firmware Bundle Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/fw-download.c b/drivers/staging/greybus/fw-download.c
new file mode 100644
index 000000000000..2d7246887547
--- /dev/null
+++ b/drivers/staging/greybus/fw-download.c
@@ -0,0 +1,465 @@
+/*
+ * Greybus Firmware Download Protocol Driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/firmware.h>
+#include <linux/jiffies.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+#include "firmware.h"
+#include "greybus.h"
+
+/* Estimated minimum buffer size, actual size can be smaller than this */
+#define MIN_FETCH_SIZE		512
+/* Timeout, in jiffies, within which fetch or release firmware must be called */
+#define NEXT_REQ_TIMEOUT_J	msecs_to_jiffies(1000)
+
+struct fw_request {
+	u8			firmware_id;
+	bool			disabled;
+	bool			timedout;
+	char			name[FW_NAME_SIZE];
+	const struct firmware	*fw;
+	struct list_head	node;
+
+	struct delayed_work	dwork;
+	/* Timeout, in jiffies, within which the firmware shall download */
+	unsigned long		release_timeout_j;
+	struct kref		kref;
+	struct fw_download	*fw_download;
+};
+
+struct fw_download {
+	struct device		*parent;
+	struct gb_connection	*connection;
+	struct list_head	fw_requests;
+	struct ida		id_map;
+	struct mutex		mutex;
+};
+
+static void fw_req_release(struct kref *kref)
+{
+	struct fw_request *fw_req = container_of(kref, struct fw_request, kref);
+
+	dev_dbg(fw_req->fw_download->parent, "firmware %s released\n",
+		fw_req->name);
+
+	release_firmware(fw_req->fw);
+
+	/*
+	 * The request timed out and the module may send a fetch-fw or
+	 * release-fw request later. Lets block the id we allocated for this
+	 * request, so that the AP doesn't refer to a later fw-request (with
+	 * same firmware_id) for the old timedout fw-request.
+	 *
+	 * NOTE:
+	 *
+	 * This also means that after 255 timeouts we will fail to service new
+	 * firmware downloads. But what else can we do in that case anyway? Lets
+	 * just hope that it never happens.
+	 */
+	if (!fw_req->timedout)
+		ida_simple_remove(&fw_req->fw_download->id_map,
+				  fw_req->firmware_id);
+
+	kfree(fw_req);
+}
+
+/*
+ * Incoming requests are serialized for a connection, and the only race possible
+ * is between the timeout handler freeing this and an incoming request.
+ *
+ * The operations on the fw-request list are protected by the mutex and
+ * get_fw_req() increments the reference count before returning a fw_req pointer
+ * to the users.
+ *
+ * free_firmware() also takes the mutex while removing an entry from the list,
+ * it guarantees that every user of fw_req has taken a kref-reference by now and
+ * we wouldn't have any new users.
+ *
+ * Once the last user drops the reference, the fw_req structure is freed.
+ */
+static void put_fw_req(struct fw_request *fw_req)
+{
+	kref_put(&fw_req->kref, fw_req_release);
+}
+
+/* Caller must call put_fw_req() after using struct fw_request */
+static struct fw_request *get_fw_req(struct fw_download *fw_download,
+				     u8 firmware_id)
+{
+	struct fw_request *fw_req;
+
+	mutex_lock(&fw_download->mutex);
+
+	list_for_each_entry(fw_req, &fw_download->fw_requests, node) {
+		if (fw_req->firmware_id == firmware_id) {
+			kref_get(&fw_req->kref);
+			goto unlock;
+		}
+	}
+
+	fw_req = NULL;
+
+unlock:
+	mutex_unlock(&fw_download->mutex);
+
+	return fw_req;
+}
+
+static void free_firmware(struct fw_download *fw_download,
+			  struct fw_request *fw_req)
+{
+	/* Already disabled from timeout handlers */
+	if (fw_req->disabled)
+		return;
+
+	mutex_lock(&fw_download->mutex);
+	list_del(&fw_req->node);
+	mutex_unlock(&fw_download->mutex);
+
+	fw_req->disabled = true;
+	put_fw_req(fw_req);
+}
+
+static void fw_request_timedout(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct fw_request *fw_req = container_of(dwork, struct fw_request, dwork);
+	struct fw_download *fw_download = fw_req->fw_download;
+
+	dev_err(fw_download->parent,
+		"Timed out waiting for fetch / release firmware requests: %u\n",
+		fw_req->firmware_id);
+
+	fw_req->timedout = true;
+	free_firmware(fw_download, fw_req);
+}
+
+static int exceeds_release_timeout(struct fw_request *fw_req)
+{
+	struct fw_download *fw_download = fw_req->fw_download;
+
+	if (time_before(jiffies, fw_req->release_timeout_j))
+		return 0;
+
+	dev_err(fw_download->parent,
+		"Firmware download didn't finish in time, abort: %d\n",
+		fw_req->firmware_id);
+
+	fw_req->timedout = true;
+	free_firmware(fw_download, fw_req);
+
+	return -ETIMEDOUT;
+}
+
+/* This returns path of the firmware blob on the disk */
+static struct fw_request *find_firmware(struct fw_download *fw_download,
+					const char *tag)
+{
+	struct gb_interface *intf = fw_download->connection->bundle->intf;
+	struct fw_request *fw_req;
+	int ret, req_count;
+
+	fw_req = kzalloc(sizeof(*fw_req), GFP_KERNEL);
+	if (!fw_req)
+		return ERR_PTR(-ENOMEM);
+
+	/* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
+	ret = ida_simple_get(&fw_download->id_map, 1, 256, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(fw_download->parent,
+			"failed to allocate firmware id (%d)\n", ret);
+		goto err_free_req;
+	}
+	fw_req->firmware_id = ret;
+
+	snprintf(fw_req->name, sizeof(fw_req->name),
+		 FW_NAME_PREFIX "%08x_%08x_%08x_%08x_%s.tftf",
+		 intf->ddbl1_manufacturer_id, intf->ddbl1_product_id,
+		 intf->vendor_id, intf->product_id, tag);
+
+	dev_info(fw_download->parent, "Requested firmware package '%s'\n",
+		 fw_req->name);
+
+	ret = request_firmware(&fw_req->fw, fw_req->name, fw_download->parent);
+	if (ret) {
+		dev_err(fw_download->parent,
+			"firmware request failed for %s (%d)\n", fw_req->name,
+			ret);
+		goto err_free_id;
+	}
+
+	fw_req->fw_download = fw_download;
+	kref_init(&fw_req->kref);
+
+	mutex_lock(&fw_download->mutex);
+	list_add(&fw_req->node, &fw_download->fw_requests);
+	mutex_unlock(&fw_download->mutex);
+
+	/* Timeout, in jiffies, within which firmware should get loaded */
+	req_count = DIV_ROUND_UP(fw_req->fw->size, MIN_FETCH_SIZE);
+	fw_req->release_timeout_j = jiffies + req_count * NEXT_REQ_TIMEOUT_J;
+
+	INIT_DELAYED_WORK(&fw_req->dwork, fw_request_timedout);
+	schedule_delayed_work(&fw_req->dwork, NEXT_REQ_TIMEOUT_J);
+
+	return fw_req;
+
+err_free_id:
+	ida_simple_remove(&fw_download->id_map, fw_req->firmware_id);
+err_free_req:
+	kfree(fw_req);
+
+	return ERR_PTR(ret);
+}
+
+static int fw_download_find_firmware(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct fw_download *fw_download = gb_connection_get_data(connection);
+	struct gb_fw_download_find_firmware_request *request;
+	struct gb_fw_download_find_firmware_response *response;
+	struct fw_request *fw_req;
+	const char *tag;
+
+	if (op->request->payload_size != sizeof(*request)) {
+		dev_err(fw_download->parent,
+			"illegal size of find firmware request (%zu != %zu)\n",
+			op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+	tag = (const char *)request->firmware_tag;
+
+	/* firmware_tag must be null-terminated */
+	if (strnlen(tag, GB_FIRMWARE_TAG_MAX_SIZE) == GB_FIRMWARE_TAG_MAX_SIZE) {
+		dev_err(fw_download->parent,
+			"firmware-tag is not null-terminated\n");
+		return -EINVAL;
+	}
+
+	fw_req = find_firmware(fw_download, tag);
+	if (IS_ERR(fw_req))
+		return PTR_ERR(fw_req);
+
+	if (!gb_operation_response_alloc(op, sizeof(*response), GFP_KERNEL)) {
+		dev_err(fw_download->parent, "error allocating response\n");
+		free_firmware(fw_download, fw_req);
+		return -ENOMEM;
+	}
+
+	response = op->response->payload;
+	response->firmware_id = fw_req->firmware_id;
+	response->size = cpu_to_le32(fw_req->fw->size);
+
+	dev_dbg(fw_download->parent,
+		"firmware size is %zu bytes\n", fw_req->fw->size);
+
+	return 0;
+}
+
+static int fw_download_fetch_firmware(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct fw_download *fw_download = gb_connection_get_data(connection);
+	struct gb_fw_download_fetch_firmware_request *request;
+	struct gb_fw_download_fetch_firmware_response *response;
+	struct fw_request *fw_req;
+	const struct firmware *fw;
+	unsigned int offset, size;
+	u8 firmware_id;
+	int ret = 0;
+
+	if (op->request->payload_size != sizeof(*request)) {
+		dev_err(fw_download->parent,
+			"Illegal size of fetch firmware request (%zu %zu)\n",
+			op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+	offset = le32_to_cpu(request->offset);
+	size = le32_to_cpu(request->size);
+	firmware_id = request->firmware_id;
+
+	fw_req = get_fw_req(fw_download, firmware_id);
+	if (!fw_req) {
+		dev_err(fw_download->parent,
+			"firmware not available for id: %02u\n", firmware_id);
+		return -EINVAL;
+	}
+
+	/* Make sure work handler isn't running in parallel */
+	cancel_delayed_work_sync(&fw_req->dwork);
+
+	/* We timed-out before reaching here ? */
+	if (fw_req->disabled) {
+		ret = -ETIMEDOUT;
+		goto put_fw;
+	}
+
+	/*
+	 * Firmware download must finish within a limited time interval. If it
+	 * doesn't, then we might have a buggy Module on the other side. Abort
+	 * download.
+	 */
+	ret = exceeds_release_timeout(fw_req);
+	if (ret)
+		goto put_fw;
+
+	fw = fw_req->fw;
+
+	if (offset >= fw->size || size > fw->size - offset) {
+		dev_err(fw_download->parent,
+			"bad fetch firmware request (offs = %u, size = %u)\n",
+			offset, size);
+		ret = -EINVAL;
+		goto put_fw;
+	}
+
+	if (!gb_operation_response_alloc(op, sizeof(*response) + size,
+					 GFP_KERNEL)) {
+		dev_err(fw_download->parent,
+			"error allocating fetch firmware response\n");
+		ret = -ENOMEM;
+		goto put_fw;
+	}
+
+	response = op->response->payload;
+	memcpy(response->data, fw->data + offset, size);
+
+	dev_dbg(fw_download->parent,
+		"responding with firmware (offs = %u, size = %u)\n", offset,
+		size);
+
+	/* Refresh timeout */
+	schedule_delayed_work(&fw_req->dwork, NEXT_REQ_TIMEOUT_J);
+
+put_fw:
+	put_fw_req(fw_req);
+
+	return ret;
+}
+
+static int fw_download_release_firmware(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct fw_download *fw_download = gb_connection_get_data(connection);
+	struct gb_fw_download_release_firmware_request *request;
+	struct fw_request *fw_req;
+	u8 firmware_id;
+
+	if (op->request->payload_size != sizeof(*request)) {
+		dev_err(fw_download->parent,
+			"Illegal size of release firmware request (%zu %zu)\n",
+			op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+	firmware_id = request->firmware_id;
+
+	fw_req = get_fw_req(fw_download, firmware_id);
+	if (!fw_req) {
+		dev_err(fw_download->parent,
+			"firmware not available for id: %02u\n", firmware_id);
+		return -EINVAL;
+	}
+
+	cancel_delayed_work_sync(&fw_req->dwork);
+
+	free_firmware(fw_download, fw_req);
+	put_fw_req(fw_req);
+
+	dev_dbg(fw_download->parent, "release firmware\n");
+
+	return 0;
+}
+
+int gb_fw_download_request_handler(struct gb_operation *op)
+{
+	u8 type = op->type;
+
+	switch (type) {
+	case GB_FW_DOWNLOAD_TYPE_FIND_FIRMWARE:
+		return fw_download_find_firmware(op);
+	case GB_FW_DOWNLOAD_TYPE_FETCH_FIRMWARE:
+		return fw_download_fetch_firmware(op);
+	case GB_FW_DOWNLOAD_TYPE_RELEASE_FIRMWARE:
+		return fw_download_release_firmware(op);
+	default:
+		dev_err(&op->connection->bundle->dev,
+			"unsupported request: %u\n", type);
+		return -EINVAL;
+	}
+}
+
+int gb_fw_download_connection_init(struct gb_connection *connection)
+{
+	struct fw_download *fw_download;
+	int ret;
+
+	if (!connection)
+		return 0;
+
+	fw_download = kzalloc(sizeof(*fw_download), GFP_KERNEL);
+	if (!fw_download)
+		return -ENOMEM;
+
+	fw_download->parent = &connection->bundle->dev;
+	INIT_LIST_HEAD(&fw_download->fw_requests);
+	ida_init(&fw_download->id_map);
+	gb_connection_set_data(connection, fw_download);
+	fw_download->connection = connection;
+	mutex_init(&fw_download->mutex);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_destroy_id_map;
+
+	return 0;
+
+err_destroy_id_map:
+	ida_destroy(&fw_download->id_map);
+	kfree(fw_download);
+
+	return ret;
+}
+
+void gb_fw_download_connection_exit(struct gb_connection *connection)
+{
+	struct fw_download *fw_download;
+	struct fw_request *fw_req, *tmp;
+
+	if (!connection)
+		return;
+
+	fw_download = gb_connection_get_data(connection);
+	gb_connection_disable(fw_download->connection);
+
+	/*
+	 * Make sure we have a reference to the pending requests, before they
+	 * are freed from the timeout handler.
+	 */
+	mutex_lock(&fw_download->mutex);
+	list_for_each_entry(fw_req, &fw_download->fw_requests, node)
+		kref_get(&fw_req->kref);
+	mutex_unlock(&fw_download->mutex);
+
+	/* Release pending firmware packages */
+	list_for_each_entry_safe(fw_req, tmp, &fw_download->fw_requests, node) {
+		cancel_delayed_work_sync(&fw_req->dwork);
+		free_firmware(fw_download, fw_req);
+		put_fw_req(fw_req);
+	}
+
+	ida_destroy(&fw_download->id_map);
+	kfree(fw_download);
+}
diff --git a/drivers/staging/greybus/fw-management.c b/drivers/staging/greybus/fw-management.c
new file mode 100644
index 000000000000..3cd6cf0a656b
--- /dev/null
+++ b/drivers/staging/greybus/fw-management.c
@@ -0,0 +1,721 @@
+/*
+ * Greybus Firmware Management Protocol Driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/cdev.h>
+#include <linux/completion.h>
+#include <linux/firmware.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/ioctl.h>
+#include <linux/uaccess.h>
+
+#include "firmware.h"
+#include "greybus_firmware.h"
+#include "greybus.h"
+
+#define FW_MGMT_TIMEOUT_MS		1000
+
+struct fw_mgmt {
+	struct device		*parent;
+	struct gb_connection	*connection;
+	struct kref		kref;
+	struct list_head	node;
+
+	/* Common id-map for interface and backend firmware requests */
+	struct ida		id_map;
+	struct mutex		mutex;
+	struct completion	completion;
+	struct cdev		cdev;
+	struct device		*class_device;
+	dev_t			dev_num;
+	unsigned int		timeout_jiffies;
+	bool			disabled; /* connection getting disabled */
+
+	/* Interface Firmware specific fields */
+	bool			mode_switch_started;
+	bool			intf_fw_loaded;
+	u8			intf_fw_request_id;
+	u8			intf_fw_status;
+	u16			intf_fw_major;
+	u16			intf_fw_minor;
+
+	/* Backend Firmware specific fields */
+	u8			backend_fw_request_id;
+	u8			backend_fw_status;
+};
+
+/*
+ * Number of minor devices this driver supports.
+ * There will be exactly one required per Interface.
+ */
+#define NUM_MINORS		U8_MAX
+
+static struct class *fw_mgmt_class;
+static dev_t fw_mgmt_dev_num;
+static DEFINE_IDA(fw_mgmt_minors_map);
+static LIST_HEAD(fw_mgmt_list);
+static DEFINE_MUTEX(list_mutex);
+
+static void fw_mgmt_kref_release(struct kref *kref)
+{
+	struct fw_mgmt *fw_mgmt = container_of(kref, struct fw_mgmt, kref);
+
+	ida_destroy(&fw_mgmt->id_map);
+	kfree(fw_mgmt);
+}
+
+/*
+ * All users of fw_mgmt take a reference (from within list_mutex lock), before
+ * they get a pointer to play with. And the structure will be freed only after
+ * the last user has put the reference to it.
+ */
+static void put_fw_mgmt(struct fw_mgmt *fw_mgmt)
+{
+	kref_put(&fw_mgmt->kref, fw_mgmt_kref_release);
+}
+
+/* Caller must call put_fw_mgmt() after using struct fw_mgmt */
+static struct fw_mgmt *get_fw_mgmt(struct cdev *cdev)
+{
+	struct fw_mgmt *fw_mgmt;
+
+	mutex_lock(&list_mutex);
+
+	list_for_each_entry(fw_mgmt, &fw_mgmt_list, node) {
+		if (&fw_mgmt->cdev == cdev) {
+			kref_get(&fw_mgmt->kref);
+			goto unlock;
+		}
+	}
+
+	fw_mgmt = NULL;
+
+unlock:
+	mutex_unlock(&list_mutex);
+
+	return fw_mgmt;
+}
+
+static int fw_mgmt_interface_fw_version_operation(struct fw_mgmt *fw_mgmt,
+		struct fw_mgmt_ioc_get_intf_version *fw_info)
+{
+	struct gb_connection *connection = fw_mgmt->connection;
+	struct gb_fw_mgmt_interface_fw_version_response response;
+	int ret;
+
+	ret = gb_operation_sync(connection,
+				GB_FW_MGMT_TYPE_INTERFACE_FW_VERSION, NULL, 0,
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(fw_mgmt->parent,
+			"failed to get interface firmware version (%d)\n", ret);
+		return ret;
+	}
+
+	fw_info->major = le16_to_cpu(response.major);
+	fw_info->minor = le16_to_cpu(response.minor);
+
+	strncpy(fw_info->firmware_tag, response.firmware_tag,
+		GB_FIRMWARE_TAG_MAX_SIZE);
+
+	/*
+	 * The firmware-tag should be NULL terminated, otherwise throw error but
+	 * don't fail.
+	 */
+	if (fw_info->firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
+		dev_err(fw_mgmt->parent,
+			"fw-version: firmware-tag is not NULL terminated\n");
+		fw_info->firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] = '\0';
+	}
+
+	return 0;
+}
+
+static int fw_mgmt_load_and_validate_operation(struct fw_mgmt *fw_mgmt,
+					       u8 load_method, const char *tag)
+{
+	struct gb_fw_mgmt_load_and_validate_fw_request request;
+	int ret;
+
+	if (load_method != GB_FW_LOAD_METHOD_UNIPRO &&
+	    load_method != GB_FW_LOAD_METHOD_INTERNAL) {
+		dev_err(fw_mgmt->parent,
+			"invalid load-method (%d)\n", load_method);
+		return -EINVAL;
+	}
+
+	request.load_method = load_method;
+	strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
+
+	/*
+	 * The firmware-tag should be NULL terminated, otherwise throw error and
+	 * fail.
+	 */
+	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
+		dev_err(fw_mgmt->parent, "load-and-validate: firmware-tag is not NULL terminated\n");
+		return -EINVAL;
+	}
+
+	/* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
+	ret = ida_simple_get(&fw_mgmt->id_map, 1, 256, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(fw_mgmt->parent, "failed to allocate request id (%d)\n",
+			ret);
+		return ret;
+	}
+
+	fw_mgmt->intf_fw_request_id = ret;
+	fw_mgmt->intf_fw_loaded = false;
+	request.request_id = ret;
+
+	ret = gb_operation_sync(fw_mgmt->connection,
+				GB_FW_MGMT_TYPE_LOAD_AND_VALIDATE_FW, &request,
+				sizeof(request), NULL, 0);
+	if (ret) {
+		ida_simple_remove(&fw_mgmt->id_map,
+				  fw_mgmt->intf_fw_request_id);
+		fw_mgmt->intf_fw_request_id = 0;
+		dev_err(fw_mgmt->parent,
+			"load and validate firmware request failed (%d)\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int fw_mgmt_interface_fw_loaded_operation(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct fw_mgmt *fw_mgmt = gb_connection_get_data(connection);
+	struct gb_fw_mgmt_loaded_fw_request *request;
+
+	/* No pending load and validate request ? */
+	if (!fw_mgmt->intf_fw_request_id) {
+		dev_err(fw_mgmt->parent,
+			"unexpected firmware loaded request received\n");
+		return -ENODEV;
+	}
+
+	if (op->request->payload_size != sizeof(*request)) {
+		dev_err(fw_mgmt->parent, "illegal size of firmware loaded request (%zu != %zu)\n",
+			op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	/* Invalid request-id ? */
+	if (request->request_id != fw_mgmt->intf_fw_request_id) {
+		dev_err(fw_mgmt->parent, "invalid request id for firmware loaded request (%02u != %02u)\n",
+			fw_mgmt->intf_fw_request_id, request->request_id);
+		return -ENODEV;
+	}
+
+	ida_simple_remove(&fw_mgmt->id_map, fw_mgmt->intf_fw_request_id);
+	fw_mgmt->intf_fw_request_id = 0;
+	fw_mgmt->intf_fw_status = request->status;
+	fw_mgmt->intf_fw_major = le16_to_cpu(request->major);
+	fw_mgmt->intf_fw_minor = le16_to_cpu(request->minor);
+
+	if (fw_mgmt->intf_fw_status == GB_FW_LOAD_STATUS_FAILED)
+		dev_err(fw_mgmt->parent,
+			"failed to load interface firmware, status:%02x\n",
+			fw_mgmt->intf_fw_status);
+	else if (fw_mgmt->intf_fw_status == GB_FW_LOAD_STATUS_VALIDATION_FAILED)
+		dev_err(fw_mgmt->parent,
+			"failed to validate interface firmware, status:%02x\n",
+			fw_mgmt->intf_fw_status);
+	else
+		fw_mgmt->intf_fw_loaded = true;
+
+	complete(&fw_mgmt->completion);
+
+	return 0;
+}
+
+static int fw_mgmt_backend_fw_version_operation(struct fw_mgmt *fw_mgmt,
+		struct fw_mgmt_ioc_get_backend_version *fw_info)
+{
+	struct gb_connection *connection = fw_mgmt->connection;
+	struct gb_fw_mgmt_backend_fw_version_request request;
+	struct gb_fw_mgmt_backend_fw_version_response response;
+	int ret;
+
+	strncpy(request.firmware_tag, fw_info->firmware_tag,
+		GB_FIRMWARE_TAG_MAX_SIZE);
+
+	/*
+	 * The firmware-tag should be NULL terminated, otherwise throw error and
+	 * fail.
+	 */
+	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
+		dev_err(fw_mgmt->parent, "backend-version: firmware-tag is not NULL terminated\n");
+		return -EINVAL;
+	}
+
+	ret = gb_operation_sync(connection,
+				GB_FW_MGMT_TYPE_BACKEND_FW_VERSION, &request,
+				sizeof(request), &response, sizeof(response));
+	if (ret) {
+		dev_err(fw_mgmt->parent, "failed to get version of %s backend firmware (%d)\n",
+			fw_info->firmware_tag, ret);
+		return ret;
+	}
+
+	fw_info->status = response.status;
+
+	/* Reset version as that should be non-zero only for success case */
+	fw_info->major = 0;
+	fw_info->minor = 0;
+
+	switch (fw_info->status) {
+	case GB_FW_BACKEND_VERSION_STATUS_SUCCESS:
+		fw_info->major = le16_to_cpu(response.major);
+		fw_info->minor = le16_to_cpu(response.minor);
+		break;
+	case GB_FW_BACKEND_VERSION_STATUS_NOT_AVAILABLE:
+	case GB_FW_BACKEND_VERSION_STATUS_RETRY:
+		break;
+	case GB_FW_BACKEND_VERSION_STATUS_NOT_SUPPORTED:
+		dev_err(fw_mgmt->parent,
+			"Firmware with tag %s is not supported by Interface\n",
+			fw_info->firmware_tag);
+		break;
+	default:
+		dev_err(fw_mgmt->parent, "Invalid status received: %u\n",
+			fw_info->status);
+	}
+
+	return 0;
+}
+
+static int fw_mgmt_backend_fw_update_operation(struct fw_mgmt *fw_mgmt,
+					       char *tag)
+{
+	struct gb_fw_mgmt_backend_fw_update_request request;
+	int ret;
+
+	strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
+
+	/*
+	 * The firmware-tag should be NULL terminated, otherwise throw error and
+	 * fail.
+	 */
+	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
+		dev_err(fw_mgmt->parent, "backend-update: firmware-tag is not NULL terminated\n");
+		return -EINVAL;
+	}
+
+	/* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
+	ret = ida_simple_get(&fw_mgmt->id_map, 1, 256, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(fw_mgmt->parent, "failed to allocate request id (%d)\n",
+			ret);
+		return ret;
+	}
+
+	fw_mgmt->backend_fw_request_id = ret;
+	request.request_id = ret;
+
+	ret = gb_operation_sync(fw_mgmt->connection,
+				GB_FW_MGMT_TYPE_BACKEND_FW_UPDATE, &request,
+				sizeof(request), NULL, 0);
+	if (ret) {
+		ida_simple_remove(&fw_mgmt->id_map,
+				  fw_mgmt->backend_fw_request_id);
+		fw_mgmt->backend_fw_request_id = 0;
+		dev_err(fw_mgmt->parent,
+			"backend %s firmware update request failed (%d)\n", tag,
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int fw_mgmt_backend_fw_updated_operation(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct fw_mgmt *fw_mgmt = gb_connection_get_data(connection);
+	struct gb_fw_mgmt_backend_fw_updated_request *request;
+
+	/* No pending load and validate request ? */
+	if (!fw_mgmt->backend_fw_request_id) {
+		dev_err(fw_mgmt->parent, "unexpected backend firmware updated request received\n");
+		return -ENODEV;
+	}
+
+	if (op->request->payload_size != sizeof(*request)) {
+		dev_err(fw_mgmt->parent, "illegal size of backend firmware updated request (%zu != %zu)\n",
+			op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	/* Invalid request-id ? */
+	if (request->request_id != fw_mgmt->backend_fw_request_id) {
+		dev_err(fw_mgmt->parent, "invalid request id for backend firmware updated request (%02u != %02u)\n",
+			fw_mgmt->backend_fw_request_id, request->request_id);
+		return -ENODEV;
+	}
+
+	ida_simple_remove(&fw_mgmt->id_map, fw_mgmt->backend_fw_request_id);
+	fw_mgmt->backend_fw_request_id = 0;
+	fw_mgmt->backend_fw_status = request->status;
+
+	if ((fw_mgmt->backend_fw_status != GB_FW_BACKEND_FW_STATUS_SUCCESS) &&
+	    (fw_mgmt->backend_fw_status != GB_FW_BACKEND_FW_STATUS_RETRY))
+		dev_err(fw_mgmt->parent,
+			"failed to load backend firmware: %02x\n",
+			fw_mgmt->backend_fw_status);
+
+	complete(&fw_mgmt->completion);
+
+	return 0;
+}
+
+/* Char device fops */
+
+static int fw_mgmt_open(struct inode *inode, struct file *file)
+{
+	struct fw_mgmt *fw_mgmt = get_fw_mgmt(inode->i_cdev);
+
+	/* fw_mgmt structure can't get freed until file descriptor is closed */
+	if (fw_mgmt) {
+		file->private_data = fw_mgmt;
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static int fw_mgmt_release(struct inode *inode, struct file *file)
+{
+	struct fw_mgmt *fw_mgmt = file->private_data;
+
+	put_fw_mgmt(fw_mgmt);
+	return 0;
+}
+
+static int fw_mgmt_ioctl(struct fw_mgmt *fw_mgmt, unsigned int cmd,
+			 void __user *buf)
+{
+	struct fw_mgmt_ioc_get_intf_version intf_fw_info;
+	struct fw_mgmt_ioc_get_backend_version backend_fw_info;
+	struct fw_mgmt_ioc_intf_load_and_validate intf_load;
+	struct fw_mgmt_ioc_backend_fw_update backend_update;
+	unsigned int timeout;
+	int ret;
+
+	/* Reject any operations after mode-switch has started */
+	if (fw_mgmt->mode_switch_started)
+		return -EBUSY;
+
+	switch (cmd) {
+	case FW_MGMT_IOC_GET_INTF_FW:
+		ret = fw_mgmt_interface_fw_version_operation(fw_mgmt,
+							     &intf_fw_info);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(buf, &intf_fw_info, sizeof(intf_fw_info)))
+			return -EFAULT;
+
+		return 0;
+	case FW_MGMT_IOC_GET_BACKEND_FW:
+		if (copy_from_user(&backend_fw_info, buf,
+				   sizeof(backend_fw_info)))
+			return -EFAULT;
+
+		ret = fw_mgmt_backend_fw_version_operation(fw_mgmt,
+							   &backend_fw_info);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(buf, &backend_fw_info,
+				 sizeof(backend_fw_info)))
+			return -EFAULT;
+
+		return 0;
+	case FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE:
+		if (copy_from_user(&intf_load, buf, sizeof(intf_load)))
+			return -EFAULT;
+
+		ret = fw_mgmt_load_and_validate_operation(fw_mgmt,
+				intf_load.load_method, intf_load.firmware_tag);
+		if (ret)
+			return ret;
+
+		if (!wait_for_completion_timeout(&fw_mgmt->completion,
+						 fw_mgmt->timeout_jiffies)) {
+			dev_err(fw_mgmt->parent, "timed out waiting for firmware load and validation to finish\n");
+			return -ETIMEDOUT;
+		}
+
+		intf_load.status = fw_mgmt->intf_fw_status;
+		intf_load.major = fw_mgmt->intf_fw_major;
+		intf_load.minor = fw_mgmt->intf_fw_minor;
+
+		if (copy_to_user(buf, &intf_load, sizeof(intf_load)))
+			return -EFAULT;
+
+		return 0;
+	case FW_MGMT_IOC_INTF_BACKEND_FW_UPDATE:
+		if (copy_from_user(&backend_update, buf,
+				   sizeof(backend_update)))
+			return -EFAULT;
+
+		ret = fw_mgmt_backend_fw_update_operation(fw_mgmt,
+				backend_update.firmware_tag);
+		if (ret)
+			return ret;
+
+		if (!wait_for_completion_timeout(&fw_mgmt->completion,
+						 fw_mgmt->timeout_jiffies)) {
+			dev_err(fw_mgmt->parent, "timed out waiting for backend firmware update to finish\n");
+			return -ETIMEDOUT;
+		}
+
+		backend_update.status = fw_mgmt->backend_fw_status;
+
+		if (copy_to_user(buf, &backend_update, sizeof(backend_update)))
+			return -EFAULT;
+
+		return 0;
+	case FW_MGMT_IOC_SET_TIMEOUT_MS:
+		if (get_user(timeout, (unsigned int __user *)buf))
+			return -EFAULT;
+
+		if (!timeout) {
+			dev_err(fw_mgmt->parent, "timeout can't be zero\n");
+			return -EINVAL;
+		}
+
+		fw_mgmt->timeout_jiffies = msecs_to_jiffies(timeout);
+
+		return 0;
+	case FW_MGMT_IOC_MODE_SWITCH:
+		if (!fw_mgmt->intf_fw_loaded) {
+			dev_err(fw_mgmt->parent,
+				"Firmware not loaded for mode-switch\n");
+			return -EPERM;
+		}
+
+		/*
+		 * Disallow new ioctls as the fw-core bundle driver is going to
+		 * get disconnected soon and the character device will get
+		 * removed.
+		 */
+		fw_mgmt->mode_switch_started = true;
+
+		ret = gb_interface_request_mode_switch(fw_mgmt->connection->intf);
+		if (ret) {
+			dev_err(fw_mgmt->parent, "Mode-switch failed: %d\n",
+				ret);
+			fw_mgmt->mode_switch_started = false;
+			return ret;
+		}
+
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static long fw_mgmt_ioctl_unlocked(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	struct fw_mgmt *fw_mgmt = file->private_data;
+	struct gb_bundle *bundle = fw_mgmt->connection->bundle;
+	int ret = -ENODEV;
+
+	/*
+	 * Serialize ioctls.
+	 *
+	 * We don't want the user to do few operations in parallel. For example,
+	 * updating Interface firmware in parallel for the same Interface. There
+	 * is no need to do things in parallel for speed and we can avoid having
+	 * complicated code for now.
+	 *
+	 * This is also used to protect ->disabled, which is used to check if
+	 * the connection is getting disconnected, so that we don't start any
+	 * new operations.
+	 */
+	mutex_lock(&fw_mgmt->mutex);
+	if (!fw_mgmt->disabled) {
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (!ret) {
+			ret = fw_mgmt_ioctl(fw_mgmt, cmd, (void __user *)arg);
+			gb_pm_runtime_put_autosuspend(bundle);
+		}
+	}
+	mutex_unlock(&fw_mgmt->mutex);
+
+	return ret;
+}
+
+static const struct file_operations fw_mgmt_fops = {
+	.owner		= THIS_MODULE,
+	.open		= fw_mgmt_open,
+	.release	= fw_mgmt_release,
+	.unlocked_ioctl	= fw_mgmt_ioctl_unlocked,
+};
+
+int gb_fw_mgmt_request_handler(struct gb_operation *op)
+{
+	u8 type = op->type;
+
+	switch (type) {
+	case GB_FW_MGMT_TYPE_LOADED_FW:
+		return fw_mgmt_interface_fw_loaded_operation(op);
+	case GB_FW_MGMT_TYPE_BACKEND_FW_UPDATED:
+		return fw_mgmt_backend_fw_updated_operation(op);
+	default:
+		dev_err(&op->connection->bundle->dev,
+			"unsupported request: %u\n", type);
+		return -EINVAL;
+	}
+}
+
+int gb_fw_mgmt_connection_init(struct gb_connection *connection)
+{
+	struct fw_mgmt *fw_mgmt;
+	int ret, minor;
+
+	if (!connection)
+		return 0;
+
+	fw_mgmt = kzalloc(sizeof(*fw_mgmt), GFP_KERNEL);
+	if (!fw_mgmt)
+		return -ENOMEM;
+
+	fw_mgmt->parent = &connection->bundle->dev;
+	fw_mgmt->timeout_jiffies = msecs_to_jiffies(FW_MGMT_TIMEOUT_MS);
+	fw_mgmt->connection = connection;
+
+	gb_connection_set_data(connection, fw_mgmt);
+	init_completion(&fw_mgmt->completion);
+	ida_init(&fw_mgmt->id_map);
+	mutex_init(&fw_mgmt->mutex);
+	kref_init(&fw_mgmt->kref);
+
+	mutex_lock(&list_mutex);
+	list_add(&fw_mgmt->node, &fw_mgmt_list);
+	mutex_unlock(&list_mutex);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_list_del;
+
+	minor = ida_simple_get(&fw_mgmt_minors_map, 0, NUM_MINORS, GFP_KERNEL);
+	if (minor < 0) {
+		ret = minor;
+		goto err_connection_disable;
+	}
+
+	/* Add a char device to allow userspace to interact with fw-mgmt */
+	fw_mgmt->dev_num = MKDEV(MAJOR(fw_mgmt_dev_num), minor);
+	cdev_init(&fw_mgmt->cdev, &fw_mgmt_fops);
+
+	ret = cdev_add(&fw_mgmt->cdev, fw_mgmt->dev_num, 1);
+	if (ret)
+		goto err_remove_ida;
+
+	/* Add a soft link to the previously added char-dev within the bundle */
+	fw_mgmt->class_device = device_create(fw_mgmt_class, fw_mgmt->parent,
+					      fw_mgmt->dev_num, NULL,
+					      "gb-fw-mgmt-%d", minor);
+	if (IS_ERR(fw_mgmt->class_device)) {
+		ret = PTR_ERR(fw_mgmt->class_device);
+		goto err_del_cdev;
+	}
+
+	return 0;
+
+err_del_cdev:
+	cdev_del(&fw_mgmt->cdev);
+err_remove_ida:
+	ida_simple_remove(&fw_mgmt_minors_map, minor);
+err_connection_disable:
+	gb_connection_disable(connection);
+err_list_del:
+	mutex_lock(&list_mutex);
+	list_del(&fw_mgmt->node);
+	mutex_unlock(&list_mutex);
+
+	put_fw_mgmt(fw_mgmt);
+
+	return ret;
+}
+
+void gb_fw_mgmt_connection_exit(struct gb_connection *connection)
+{
+	struct fw_mgmt *fw_mgmt;
+
+	if (!connection)
+		return;
+
+	fw_mgmt = gb_connection_get_data(connection);
+
+	device_destroy(fw_mgmt_class, fw_mgmt->dev_num);
+	cdev_del(&fw_mgmt->cdev);
+	ida_simple_remove(&fw_mgmt_minors_map, MINOR(fw_mgmt->dev_num));
+
+	/*
+	 * Disallow any new ioctl operations on the char device and wait for
+	 * existing ones to finish.
+	 */
+	mutex_lock(&fw_mgmt->mutex);
+	fw_mgmt->disabled = true;
+	mutex_unlock(&fw_mgmt->mutex);
+
+	/* All pending greybus operations should have finished by now */
+	gb_connection_disable(fw_mgmt->connection);
+
+	/* Disallow new users to get access to the fw_mgmt structure */
+	mutex_lock(&list_mutex);
+	list_del(&fw_mgmt->node);
+	mutex_unlock(&list_mutex);
+
+	/*
+	 * All current users of fw_mgmt would have taken a reference to it by
+	 * now, we can drop our reference and wait the last user will get
+	 * fw_mgmt freed.
+	 */
+	put_fw_mgmt(fw_mgmt);
+}
+
+int fw_mgmt_init(void)
+{
+	int ret;
+
+	fw_mgmt_class = class_create(THIS_MODULE, "gb_fw_mgmt");
+	if (IS_ERR(fw_mgmt_class))
+		return PTR_ERR(fw_mgmt_class);
+
+	ret = alloc_chrdev_region(&fw_mgmt_dev_num, 0, NUM_MINORS,
+				  "gb_fw_mgmt");
+	if (ret)
+		goto err_remove_class;
+
+	return 0;
+
+err_remove_class:
+	class_destroy(fw_mgmt_class);
+	return ret;
+}
+
+void fw_mgmt_exit(void)
+{
+	unregister_chrdev_region(fw_mgmt_dev_num, NUM_MINORS);
+	class_destroy(fw_mgmt_class);
+	ida_destroy(&fw_mgmt_minors_map);
+}
diff --git a/drivers/staging/greybus/gb-camera.h b/drivers/staging/greybus/gb-camera.h
new file mode 100644
index 000000000000..d45dabc5b367
--- /dev/null
+++ b/drivers/staging/greybus/gb-camera.h
@@ -0,0 +1,127 @@
+/*
+ * Greybus Camera protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+#ifndef __GB_CAMERA_H
+#define __GB_CAMERA_H
+
+#include <linux/v4l2-mediabus.h>
+
+/* Input flags need to be set from the caller */
+#define GB_CAMERA_IN_FLAG_TEST		(1 << 0)
+/* Output flags returned */
+#define GB_CAMERA_OUT_FLAG_ADJUSTED	(1 << 0)
+
+/**
+ * struct gb_camera_stream - Represents greybus camera stream.
+ * @width: Stream width in pixels.
+ * @height: Stream height in pixels.
+ * @pixel_code: Media bus pixel code.
+ * @vc: MIPI CSI virtual channel.
+ * @dt: MIPI CSI data types. Most formats use a single data type, in which case
+ *      the second element will be ignored.
+ * @max_size: Maximum size of a frame in bytes. The camera module guarantees
+ *            that all data between the Frame Start and Frame End packet for
+ *            the associated virtual channel and data type(s) will not exceed
+ *            this size.
+ */
+struct gb_camera_stream {
+	unsigned int width;
+	unsigned int height;
+	enum v4l2_mbus_pixelcode pixel_code;
+	unsigned int vc;
+	unsigned int dt[2];
+	unsigned int max_size;
+};
+
+/**
+ * struct gb_camera_csi_params - CSI configuration parameters
+ * @num_lanes: number of CSI data lanes
+ * @clk_freq: CSI clock frequency in Hz
+ */
+struct gb_camera_csi_params {
+	unsigned int num_lanes;
+	unsigned int clk_freq;
+};
+
+/**
+ * struct gb_camera_ops - Greybus camera operations, used by the Greybus camera
+ *                        driver to expose operations to the host camera driver.
+ * @capabilities: Retrieve camera capabilities and store them in the buffer
+ *                'buf' capabilities. The buffer maximum size is specified by
+ *                the caller in the 'size' parameter, and the effective
+ *                capabilities size is returned from the function. If the buffer
+ *                size is too small to hold the capabilities an error is
+ *                returned and the buffer is left untouched.
+ *
+ * @configure_streams: Negotiate configuration and prepare the module for video
+ *                     capture. The caller specifies the number of streams it
+ *                     requests in the 'nstreams' argument and the associated
+ *                     streams configurations in the 'streams' argument. The
+ *                     GB_CAMERA_IN_FLAG_TEST 'flag' can be set to test a
+ *                     configuration without applying it, otherwise the
+ *                     configuration is applied by the module. The module can
+ *                     decide to modify the requested configuration, including
+ *                     using a different number of streams. In that case the
+ *                     modified configuration won't be applied, the
+ *                     GB_CAMERA_OUT_FLAG_ADJUSTED 'flag' will be set upon
+ *                     return, and the modified configuration and number of
+ *                     streams stored in 'streams' and 'array'. The module
+ *                     returns its CSI-2 bus parameters in the 'csi_params'
+ *                     structure in all cases.
+ *
+ * @capture: Submit a capture request. The supplied 'request_id' must be unique
+ *           and higher than the IDs of all the previously submitted requests.
+ *           The 'streams' argument specifies which streams are affected by the
+ *           request in the form of a bitmask, with bits corresponding to the
+ *           configured streams indexes. If the request contains settings, the
+ *           'settings' argument points to the settings buffer and its size is
+ *           specified by the 'settings_size' argument. Otherwise the 'settings'
+ *           argument should be set to NULL and 'settings_size' to 0.
+ *
+ * @flush: Flush the capture requests queue. Return the ID of the last request
+ *         that will processed by the device before it stops transmitting video
+ *         frames. All queued capture requests with IDs higher than the returned
+ *         ID will be dropped without being processed.
+ */
+struct gb_camera_ops {
+	ssize_t (*capabilities)(void *priv, char *buf, size_t len);
+	int (*configure_streams)(void *priv, unsigned int *nstreams,
+			unsigned int *flags, struct gb_camera_stream *streams,
+			struct gb_camera_csi_params *csi_params);
+	int (*capture)(void *priv, u32 request_id,
+			unsigned int streams, unsigned int num_frames,
+			size_t settings_size, const void *settings);
+	int (*flush)(void *priv, u32 *request_id);
+};
+
+/**
+ * struct gb_camera_module - Represents greybus camera module.
+ * @priv: Module private data, passed to all camera operations.
+ * @ops: Greybus camera operation callbacks.
+ * @interface_id: Interface id of the module.
+ * @refcount: Reference counting object.
+ * @release: Module release function.
+ * @list: List entry in the camera modules list.
+ */
+struct gb_camera_module {
+	void *priv;
+	const struct gb_camera_ops *ops;
+
+	unsigned int interface_id;
+	struct kref refcount;
+	void (*release)(struct kref *kref);
+	struct list_head list; /* Global list */
+};
+
+#define gb_camera_call(f, op, args...)      \
+	(!(f) ? -ENODEV : (((f)->ops->op) ?  \
+	(f)->ops->op((f)->priv, ##args) : -ENOIOCTLCMD))
+
+int gb_camera_register(struct gb_camera_module *module);
+int gb_camera_unregister(struct gb_camera_module *module);
+
+#endif /* __GB_CAMERA_H */
diff --git a/drivers/staging/greybus/gbphy.c b/drivers/staging/greybus/gbphy.c
new file mode 100644
index 000000000000..bcde7c9a0f17
--- /dev/null
+++ b/drivers/staging/greybus/gbphy.c
@@ -0,0 +1,360 @@
+/*
+ * Greybus Bridged-Phy Bus driver
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+#define GB_GBPHY_AUTOSUSPEND_MS	3000
+
+struct gbphy_host {
+	struct gb_bundle *bundle;
+	struct list_head devices;
+};
+
+static DEFINE_IDA(gbphy_id);
+
+static ssize_t protocol_id_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+
+	return sprintf(buf, "0x%02x\n", gbphy_dev->cport_desc->protocol_id);
+}
+static DEVICE_ATTR_RO(protocol_id);
+
+static struct attribute *gbphy_dev_attrs[] = {
+	&dev_attr_protocol_id.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(gbphy_dev);
+
+static void gbphy_dev_release(struct device *dev)
+{
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+
+	ida_simple_remove(&gbphy_id, gbphy_dev->id);
+	kfree(gbphy_dev);
+}
+
+#ifdef CONFIG_PM
+static int gb_gbphy_idle(struct device *dev)
+{
+	pm_runtime_mark_last_busy(dev);
+	pm_request_autosuspend(dev);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_gbphy_pm_ops = {
+	SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend,
+			   pm_generic_runtime_resume,
+			   gb_gbphy_idle)
+};
+
+static struct device_type greybus_gbphy_dev_type = {
+	.name	 =	"gbphy_device",
+	.release =	gbphy_dev_release,
+	.pm	=	&gb_gbphy_pm_ops,
+};
+
+static int gbphy_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+	struct greybus_descriptor_cport *cport_desc = gbphy_dev->cport_desc;
+	struct gb_bundle *bundle = gbphy_dev->bundle;
+	struct gb_interface *intf = bundle->intf;
+	struct gb_module *module = intf->module;
+	struct gb_host_device *hd = intf->hd;
+
+	if (add_uevent_var(env, "BUS=%u", hd->bus_id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "MODULE=%u", module->module_id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "INTERFACE=%u", intf->interface_id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "GREYBUS_ID=%08x/%08x",
+			   intf->vendor_id, intf->product_id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "BUNDLE=%u", gbphy_dev->bundle->id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "BUNDLE_CLASS=%02x", bundle->class))
+		return -ENOMEM;
+	if (add_uevent_var(env, "GBPHY=%u", gbphy_dev->id))
+		return -ENOMEM;
+	if (add_uevent_var(env, "PROTOCOL_ID=%02x", cport_desc->protocol_id))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static const struct gbphy_device_id *
+gbphy_dev_match_id(struct gbphy_device *gbphy_dev, struct gbphy_driver *gbphy_drv)
+{
+	const struct gbphy_device_id *id = gbphy_drv->id_table;
+
+	if (!id)
+		return NULL;
+
+	for (; id->protocol_id; id++)
+		if (id->protocol_id == gbphy_dev->cport_desc->protocol_id)
+			return id;
+
+	return NULL;
+}
+
+static int gbphy_dev_match(struct device *dev, struct device_driver *drv)
+{
+	struct gbphy_driver *gbphy_drv = to_gbphy_driver(drv);
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+	const struct gbphy_device_id *id;
+
+	id = gbphy_dev_match_id(gbphy_dev, gbphy_drv);
+	if (id)
+		return 1;
+
+	return 0;
+}
+
+static int gbphy_dev_probe(struct device *dev)
+{
+	struct gbphy_driver *gbphy_drv = to_gbphy_driver(dev->driver);
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+	const struct gbphy_device_id *id;
+	int ret;
+
+	id = gbphy_dev_match_id(gbphy_dev, gbphy_drv);
+	if (!id)
+		return -ENODEV;
+
+	/* for old kernels we need get_sync to resume parent devices */
+	ret = gb_pm_runtime_get_sync(gbphy_dev->bundle);
+	if (ret < 0)
+		return ret;
+
+	pm_runtime_set_autosuspend_delay(dev, GB_GBPHY_AUTOSUSPEND_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	/*
+	 * Drivers should call put on the gbphy dev before returning
+	 * from probe if they support runtime pm.
+	 */
+	ret = gbphy_drv->probe(gbphy_dev, id);
+	if (ret) {
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_put_noidle(dev);
+		pm_runtime_dont_use_autosuspend(dev);
+	}
+
+	gb_pm_runtime_put_autosuspend(gbphy_dev->bundle);
+
+	return ret;
+}
+
+static int gbphy_dev_remove(struct device *dev)
+{
+	struct gbphy_driver *gbphy_drv = to_gbphy_driver(dev->driver);
+	struct gbphy_device *gbphy_dev = to_gbphy_dev(dev);
+
+	gbphy_drv->remove(gbphy_dev);
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+
+	return 0;
+}
+
+static struct bus_type gbphy_bus_type = {
+	.name =		"gbphy",
+	.match =	gbphy_dev_match,
+	.probe =	gbphy_dev_probe,
+	.remove =	gbphy_dev_remove,
+	.uevent =	gbphy_dev_uevent,
+};
+
+int gb_gbphy_register_driver(struct gbphy_driver *driver,
+			     struct module *owner, const char *mod_name)
+{
+	int retval;
+
+	if (greybus_disabled())
+		return -ENODEV;
+
+	driver->driver.bus = &gbphy_bus_type;
+	driver->driver.name = driver->name;
+	driver->driver.owner = owner;
+	driver->driver.mod_name = mod_name;
+
+	retval = driver_register(&driver->driver);
+	if (retval)
+		return retval;
+
+	pr_info("registered new driver %s\n", driver->name);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_gbphy_register_driver);
+
+void gb_gbphy_deregister_driver(struct gbphy_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(gb_gbphy_deregister_driver);
+
+static struct gbphy_device *gb_gbphy_create_dev(struct gb_bundle *bundle,
+				struct greybus_descriptor_cport *cport_desc)
+{
+	struct gbphy_device *gbphy_dev;
+	int retval;
+	int id;
+
+	id = ida_simple_get(&gbphy_id, 1, 0, GFP_KERNEL);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	gbphy_dev = kzalloc(sizeof(*gbphy_dev), GFP_KERNEL);
+	if (!gbphy_dev) {
+		ida_simple_remove(&gbphy_id, id);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	gbphy_dev->id = id;
+	gbphy_dev->bundle = bundle;
+	gbphy_dev->cport_desc = cport_desc;
+	gbphy_dev->dev.parent = &bundle->dev;
+	gbphy_dev->dev.bus = &gbphy_bus_type;
+	gbphy_dev->dev.type = &greybus_gbphy_dev_type;
+	gbphy_dev->dev.groups = gbphy_dev_groups;
+	gbphy_dev->dev.dma_mask = bundle->dev.dma_mask;
+	dev_set_name(&gbphy_dev->dev, "gbphy%d", id);
+
+	retval = device_register(&gbphy_dev->dev);
+	if (retval) {
+		put_device(&gbphy_dev->dev);
+		return ERR_PTR(retval);
+	}
+
+	return gbphy_dev;
+}
+
+static void gb_gbphy_disconnect(struct gb_bundle *bundle)
+{
+	struct gbphy_host *gbphy_host = greybus_get_drvdata(bundle);
+	struct gbphy_device *gbphy_dev, *temp;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		gb_pm_runtime_get_noresume(bundle);
+
+	list_for_each_entry_safe(gbphy_dev, temp, &gbphy_host->devices, list) {
+		list_del(&gbphy_dev->list);
+		device_unregister(&gbphy_dev->dev);
+	}
+
+	kfree(gbphy_host);
+}
+
+static int gb_gbphy_probe(struct gb_bundle *bundle,
+			  const struct greybus_bundle_id *id)
+{
+	struct gbphy_host *gbphy_host;
+	struct gbphy_device *gbphy_dev;
+	int i;
+
+	if (bundle->num_cports == 0)
+		return -ENODEV;
+
+	gbphy_host = kzalloc(sizeof(*gbphy_host), GFP_KERNEL);
+	if (!gbphy_host)
+		return -ENOMEM;
+
+	gbphy_host->bundle = bundle;
+	INIT_LIST_HEAD(&gbphy_host->devices);
+	greybus_set_drvdata(bundle, gbphy_host);
+
+	/*
+	 * Create a bunch of children devices, one per cport, and bind the
+	 * bridged phy drivers to them.
+	 */
+	for (i = 0; i < bundle->num_cports; ++i) {
+		gbphy_dev = gb_gbphy_create_dev(bundle, &bundle->cport_desc[i]);
+		if (IS_ERR(gbphy_dev)) {
+			gb_gbphy_disconnect(bundle);
+			return PTR_ERR(gbphy_dev);
+		}
+		list_add(&gbphy_dev->list, &gbphy_host->devices);
+	}
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+}
+
+static const struct greybus_bundle_id gb_gbphy_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_BRIDGED_PHY) },
+	{ },
+};
+MODULE_DEVICE_TABLE(greybus, gb_gbphy_id_table);
+
+static struct greybus_driver gb_gbphy_driver = {
+	.name		= "gbphy",
+	.probe		= gb_gbphy_probe,
+	.disconnect	= gb_gbphy_disconnect,
+	.id_table	= gb_gbphy_id_table,
+};
+
+static int __init gbphy_init(void)
+{
+	int retval;
+
+	retval = bus_register(&gbphy_bus_type);
+	if (retval) {
+		pr_err("gbphy bus register failed (%d)\n", retval);
+		return retval;
+	}
+
+	retval = greybus_register(&gb_gbphy_driver);
+	if (retval) {
+		pr_err("error registering greybus driver\n");
+		goto error_gbphy;
+	}
+
+	return 0;
+
+error_gbphy:
+	bus_unregister(&gbphy_bus_type);
+	ida_destroy(&gbphy_id);
+	return retval;
+}
+module_init(gbphy_init);
+
+static void __exit gbphy_exit(void)
+{
+	greybus_deregister(&gb_gbphy_driver);
+	bus_unregister(&gbphy_bus_type);
+	ida_destroy(&gbphy_id);
+}
+module_exit(gbphy_exit);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/gbphy.h b/drivers/staging/greybus/gbphy.h
new file mode 100644
index 000000000000..8ee68055ccc4
--- /dev/null
+++ b/drivers/staging/greybus/gbphy.h
@@ -0,0 +1,110 @@
+/*
+ * Greybus Bridged-Phy Bus driver
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __GBPHY_H
+#define __GBPHY_H
+
+struct gbphy_device {
+	u32 id;
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_bundle *bundle;
+	struct list_head list;
+	struct device dev;
+};
+#define to_gbphy_dev(d) container_of(d, struct gbphy_device, dev)
+
+static inline void *gb_gbphy_get_data(struct gbphy_device *gdev)
+{
+	return dev_get_drvdata(&gdev->dev);
+}
+
+static inline void gb_gbphy_set_data(struct gbphy_device *gdev, void *data)
+{
+	dev_set_drvdata(&gdev->dev, data);
+}
+
+struct gbphy_device_id {
+	__u8 protocol_id;
+};
+
+#define GBPHY_PROTOCOL(p)		\
+	.protocol_id	= (p),
+
+struct gbphy_driver {
+	const char *name;
+	int (*probe)(struct gbphy_device *,
+		     const struct gbphy_device_id *id);
+	void (*remove)(struct gbphy_device *);
+	const struct gbphy_device_id *id_table;
+
+	struct device_driver driver;
+};
+#define to_gbphy_driver(d) container_of(d, struct gbphy_driver, driver)
+
+int gb_gbphy_register_driver(struct gbphy_driver *driver,
+			     struct module *owner, const char *mod_name);
+void gb_gbphy_deregister_driver(struct gbphy_driver *driver);
+
+#define gb_gbphy_register(driver) \
+	gb_gbphy_register_driver(driver, THIS_MODULE, KBUILD_MODNAME)
+#define gb_gbphy_deregister(driver) \
+	gb_gbphy_deregister_driver(driver)
+
+/**
+ * module_gbphy_driver() - Helper macro for registering a gbphy driver
+ * @__gbphy_driver: gbphy_driver structure
+ *
+ * Helper macro for gbphy drivers to set up proper module init / exit
+ * functions.  Replaces module_init() and module_exit() and keeps people from
+ * printing pointless things to the kernel log when their driver is loaded.
+ */
+#define module_gbphy_driver(__gbphy_driver)	\
+	module_driver(__gbphy_driver, gb_gbphy_register, gb_gbphy_deregister)
+
+#ifdef CONFIG_PM
+static inline int gbphy_runtime_get_sync(struct gbphy_device *gbphy_dev)
+{
+	struct device *dev = &gbphy_dev->dev;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm_runtime_get_sync failed: %d\n", ret);
+		pm_runtime_put_noidle(dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static inline void gbphy_runtime_put_autosuspend(struct gbphy_device *gbphy_dev)
+{
+	struct device *dev = &gbphy_dev->dev;
+
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+}
+
+static inline void gbphy_runtime_get_noresume(struct gbphy_device *gbphy_dev)
+{
+	pm_runtime_get_noresume(&gbphy_dev->dev);
+}
+
+static inline void gbphy_runtime_put_noidle(struct gbphy_device *gbphy_dev)
+{
+	pm_runtime_put_noidle(&gbphy_dev->dev);
+}
+#else
+static inline int gbphy_runtime_get_sync(struct gbphy_device *gbphy_dev) { return 0; }
+static inline void gbphy_runtime_put_autosuspend(struct gbphy_device *gbphy_dev) {}
+static inline void gbphy_runtime_get_noresume(struct gbphy_device *gbphy_dev) {}
+static inline void gbphy_runtime_put_noidle(struct gbphy_device *gbphy_dev) {}
+#endif
+
+#endif /* __GBPHY_H */
+
diff --git a/drivers/staging/greybus/gpio.c b/drivers/staging/greybus/gpio.c
new file mode 100644
index 000000000000..ea8234abf185
--- /dev/null
+++ b/drivers/staging/greybus/gpio.c
@@ -0,0 +1,767 @@
+/*
+ * GPIO Greybus driver.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mutex.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+struct gb_gpio_line {
+	/* The following has to be an array of line_max entries */
+	/* --> make them just a flags field */
+	u8			active:    1,
+				direction: 1,	/* 0 = output, 1 = input */
+				value:     1;	/* 0 = low, 1 = high */
+	u16			debounce_usec;
+
+	u8			irq_type;
+	bool			irq_type_pending;
+	bool			masked;
+	bool			masked_pending;
+};
+
+struct gb_gpio_controller {
+	struct gbphy_device	*gbphy_dev;
+	struct gb_connection	*connection;
+	u8			line_max;	/* max line number */
+	struct gb_gpio_line	*lines;
+
+	struct gpio_chip	chip;
+	struct irq_chip		irqc;
+	struct irq_chip		*irqchip;
+	struct irq_domain	*irqdomain;
+	unsigned int		irq_base;
+	irq_flow_handler_t	irq_handler;
+	unsigned int		irq_default_type;
+	struct mutex		irq_lock;
+};
+#define gpio_chip_to_gb_gpio_controller(chip) \
+	container_of(chip, struct gb_gpio_controller, chip)
+#define irq_data_to_gpio_chip(d) (d->domain->host_data)
+
+static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
+{
+	struct gb_gpio_line_count_response response;
+	int ret;
+
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
+				NULL, 0, &response, sizeof(response));
+	if (!ret)
+		ggc->line_max = response.count;
+	return ret;
+}
+
+static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
+{
+	struct gb_gpio_activate_request request;
+	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
+				 &request, sizeof(request), NULL, 0);
+	if (ret) {
+		gbphy_runtime_put_autosuspend(gbphy_dev);
+		return ret;
+	}
+
+	ggc->lines[which].active = true;
+
+	return 0;
+}
+
+static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
+	struct device *dev = &gbphy_dev->dev;
+	struct gb_gpio_deactivate_request request;
+	int ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
+				 &request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(dev, "failed to deactivate gpio %u\n", which);
+		goto out_pm_put;
+	}
+
+	ggc->lines[which].active = false;
+
+out_pm_put:
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+}
+
+static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_get_direction_request request;
+	struct gb_gpio_get_direction_response response;
+	int ret;
+	u8 direction;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret)
+		return ret;
+
+	direction = response.direction;
+	if (direction && direction != 1) {
+		dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
+			 which, direction);
+	}
+	ggc->lines[which].direction = direction ? 1 : 0;
+	return 0;
+}
+
+static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct gb_gpio_direction_in_request request;
+	int ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].direction = 1;
+	return ret;
+}
+
+static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
+					u8 which, bool value_high)
+{
+	struct gb_gpio_direction_out_request request;
+	int ret;
+
+	request.which = which;
+	request.value = value_high ? 1 : 0;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].direction = 0;
+	return ret;
+}
+
+static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_get_value_request request;
+	struct gb_gpio_get_value_response response;
+	int ret;
+	u8 value;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(dev, "failed to get value of gpio %u\n", which);
+		return ret;
+	}
+
+	value = response.value;
+	if (value && value != 1) {
+		dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
+			 which, value);
+	}
+	ggc->lines[which].value = value ? 1 : 0;
+	return 0;
+}
+
+static void gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
+					u8 which, bool value_high)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_set_value_request request;
+	int ret;
+
+	if (ggc->lines[which].direction == 1) {
+		dev_warn(dev, "refusing to set value of input gpio %u\n",
+			 which);
+		return;
+	}
+
+	request.which = which;
+	request.value = value_high ? 1 : 0;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
+				&request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(dev, "failed to set value of gpio %u\n", which);
+		return;
+	}
+
+	ggc->lines[which].value = request.value;
+}
+
+static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc,
+					u8 which, u16 debounce_usec)
+{
+	struct gb_gpio_set_debounce_request request;
+	int ret;
+
+	request.which = which;
+	request.usec = cpu_to_le16(debounce_usec);
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].debounce_usec = debounce_usec;
+	return ret;
+}
+
+static void _gb_gpio_irq_mask(struct gb_gpio_controller *ggc, u8 hwirq)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_mask_request request;
+	int ret;
+
+	request.which = hwirq;
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_MASK,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to mask irq: %d\n", ret);
+}
+
+static void _gb_gpio_irq_unmask(struct gb_gpio_controller *ggc, u8 hwirq)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_unmask_request request;
+	int ret;
+
+	request.which = hwirq;
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_UNMASK,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to unmask irq: %d\n", ret);
+}
+
+static void _gb_gpio_irq_set_type(struct gb_gpio_controller *ggc,
+					u8 hwirq, u8 type)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_type_request request;
+	int ret;
+
+	request.which = hwirq;
+	request.type = type;
+
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_TYPE,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to set irq type: %d\n", ret);
+}
+
+static void gb_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	line->masked = true;
+	line->masked_pending = true;
+}
+
+static void gb_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	line->masked = false;
+	line->masked_pending = true;
+}
+
+static int gb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+	struct device *dev = &ggc->gbphy_dev->dev;
+	u8 irq_type;
+
+	switch (type) {
+	case IRQ_TYPE_NONE:
+		irq_type = GB_GPIO_IRQ_TYPE_NONE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_LOW;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_HIGH;
+		break;
+	default:
+		dev_err(dev, "unsupported irq type: %u\n", type);
+		return -EINVAL;
+	}
+
+	line->irq_type = irq_type;
+	line->irq_type_pending = true;
+
+	return 0;
+}
+
+static void gb_gpio_irq_bus_lock(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	mutex_lock(&ggc->irq_lock);
+}
+
+static void gb_gpio_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	if (line->irq_type_pending) {
+		_gb_gpio_irq_set_type(ggc, d->hwirq, line->irq_type);
+		line->irq_type_pending = false;
+	}
+
+	if (line->masked_pending) {
+		if (line->masked)
+			_gb_gpio_irq_mask(ggc, d->hwirq);
+		else
+			_gb_gpio_irq_unmask(ggc, d->hwirq);
+		line->masked_pending = false;
+	}
+
+	mutex_unlock(&ggc->irq_lock);
+}
+
+static int gb_gpio_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_gpio_controller *ggc = gb_connection_get_data(connection);
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_message *request;
+	struct gb_gpio_irq_event_request *event;
+	u8 type = op->type;
+	int irq;
+	struct irq_desc *desc;
+
+	if (type != GB_GPIO_TYPE_IRQ_EVENT) {
+		dev_err(dev, "unsupported unsolicited request: %u\n", type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*event)) {
+		dev_err(dev, "short event received (%zu < %zu)\n",
+			request->payload_size, sizeof(*event));
+		return -EINVAL;
+	}
+
+	event = request->payload;
+	if (event->which > ggc->line_max) {
+		dev_err(dev, "invalid hw irq: %d\n", event->which);
+		return -EINVAL;
+	}
+
+	irq = irq_find_mapping(ggc->irqdomain, event->which);
+	if (!irq) {
+		dev_err(dev, "failed to find IRQ\n");
+		return -EINVAL;
+	}
+	desc = irq_to_desc(irq);
+	if (!desc) {
+		dev_err(dev, "failed to look up irq\n");
+		return -EINVAL;
+	}
+
+	local_irq_disable();
+	generic_handle_irq_desc(desc);
+	local_irq_enable();
+
+	return 0;
+}
+
+static int gb_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_activate_operation(ggc, (u8)offset);
+}
+
+static void gb_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	gb_gpio_deactivate_operation(ggc, (u8)offset);
+}
+
+static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u8 which;
+	int ret;
+
+	which = (u8)offset;
+	ret = gb_gpio_get_direction_operation(ggc, which);
+	if (ret)
+		return ret;
+
+	return ggc->lines[which].direction ? 1 : 0;
+}
+
+static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_direction_in_operation(ggc, (u8)offset);
+}
+
+static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+					int value)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_direction_out_operation(ggc, (u8)offset, !!value);
+}
+
+static int gb_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u8 which;
+	int ret;
+
+	which = (u8)offset;
+	ret = gb_gpio_get_value_operation(ggc, which);
+	if (ret)
+		return ret;
+
+	return ggc->lines[which].value;
+}
+
+static void gb_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	gb_gpio_set_value_operation(ggc, (u8)offset, !!value);
+}
+
+static int gb_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+					unsigned debounce)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u16 usec;
+
+	if (debounce > U16_MAX)
+		return -EINVAL;
+	usec = (u16)debounce;
+
+	return gb_gpio_set_debounce_operation(ggc, (u8)offset, usec);
+}
+
+static int gb_gpio_controller_setup(struct gb_gpio_controller *ggc)
+{
+	int ret;
+
+	/* Now find out how many lines there are */
+	ret = gb_gpio_line_count_operation(ggc);
+	if (ret)
+		return ret;
+
+	ggc->lines = kcalloc(ggc->line_max + 1, sizeof(*ggc->lines),
+			     GFP_KERNEL);
+	if (!ggc->lines)
+		return -ENOMEM;
+
+	return ret;
+}
+
+/**
+ * gb_gpio_irq_map() - maps an IRQ into a GB gpio irqchip
+ * @d: the irqdomain used by this irqchip
+ * @irq: the global irq number used by this GB gpio irqchip irq
+ * @hwirq: the local IRQ/GPIO line offset on this GB gpio
+ *
+ * This function will set up the mapping for a certain IRQ line on a
+ * GB gpio by assigning the GB gpio as chip data, and using the irqchip
+ * stored inside the GB gpio.
+ */
+static int gb_gpio_irq_map(struct irq_domain *domain, unsigned int irq,
+			   irq_hw_number_t hwirq)
+{
+	struct gpio_chip *chip = domain->host_data;
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	irq_set_chip_data(irq, ggc);
+	irq_set_chip_and_handler(irq, ggc->irqchip, ggc->irq_handler);
+	irq_set_noprobe(irq);
+	/*
+	 * No set-up of the hardware will happen if IRQ_TYPE_NONE
+	 * is passed as default type.
+	 */
+	if (ggc->irq_default_type != IRQ_TYPE_NONE)
+		irq_set_irq_type(irq, ggc->irq_default_type);
+
+	return 0;
+}
+
+static void gb_gpio_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+}
+
+static const struct irq_domain_ops gb_gpio_domain_ops = {
+	.map	= gb_gpio_irq_map,
+	.unmap	= gb_gpio_irq_unmap,
+};
+
+/**
+ * gb_gpio_irqchip_remove() - removes an irqchip added to a gb_gpio_controller
+ * @ggc: the gb_gpio_controller to remove the irqchip from
+ *
+ * This is called only from gb_gpio_remove()
+ */
+static void gb_gpio_irqchip_remove(struct gb_gpio_controller *ggc)
+{
+	unsigned int offset;
+
+	/* Remove all IRQ mappings and delete the domain */
+	if (ggc->irqdomain) {
+		for (offset = 0; offset < (ggc->line_max + 1); offset++)
+			irq_dispose_mapping(irq_find_mapping(ggc->irqdomain, offset));
+		irq_domain_remove(ggc->irqdomain);
+	}
+
+	if (ggc->irqchip) {
+		ggc->irqchip = NULL;
+	}
+}
+
+/**
+ * gb_gpio_irqchip_add() - adds an irqchip to a gpio chip
+ * @chip: the gpio chip to add the irqchip to
+ * @irqchip: the irqchip to add to the adapter
+ * @first_irq: if not dynamically assigned, the base (first) IRQ to
+ * allocate gpio irqs from
+ * @handler: the irq handler to use (often a predefined irq core function)
+ * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
+ * to have the core avoid setting up any default type in the hardware.
+ *
+ * This function closely associates a certain irqchip with a certain
+ * gpio chip, providing an irq domain to translate the local IRQs to
+ * global irqs, and making sure that the gpio chip
+ * is passed as chip data to all related functions. Driver callbacks
+ * need to use container_of() to get their local state containers back
+ * from the gpio chip passed as chip data. An irqdomain will be stored
+ * in the gpio chip that shall be used by the driver to handle IRQ number
+ * translation. The gpio chip will need to be initialized and registered
+ * before calling this function.
+ */
+static int gb_gpio_irqchip_add(struct gpio_chip *chip,
+			 struct irq_chip *irqchip,
+			 unsigned int first_irq,
+			 irq_flow_handler_t handler,
+			 unsigned int type)
+{
+	struct gb_gpio_controller *ggc;
+	unsigned int offset;
+	unsigned irq_base;
+
+	if (!chip || !irqchip)
+		return -EINVAL;
+
+	ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	ggc->irqchip = irqchip;
+	ggc->irq_handler = handler;
+	ggc->irq_default_type = type;
+	ggc->irqdomain = irq_domain_add_simple(NULL,
+					ggc->line_max + 1, first_irq,
+					&gb_gpio_domain_ops, chip);
+	if (!ggc->irqdomain) {
+		ggc->irqchip = NULL;
+		return -EINVAL;
+	}
+
+	/*
+	 * Prepare the mapping since the irqchip shall be orthogonal to
+	 * any gpio calls. If the first_irq was zero, this is
+	 * necessary to allocate descriptors for all IRQs.
+	 */
+	for (offset = 0; offset < (ggc->line_max + 1); offset++) {
+		irq_base = irq_create_mapping(ggc->irqdomain, offset);
+		if (offset == 0)
+			ggc->irq_base = irq_base;
+	}
+
+	return 0;
+}
+
+static int gb_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return irq_find_mapping(ggc->irqdomain, offset);
+}
+
+static int gb_gpio_probe(struct gbphy_device *gbphy_dev,
+			 const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct gb_gpio_controller *ggc;
+	struct gpio_chip *gpio;
+	struct irq_chip *irqc;
+	int ret;
+
+	ggc = kzalloc(sizeof(*ggc), GFP_KERNEL);
+	if (!ggc)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  gb_gpio_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto exit_ggc_free;
+	}
+
+	ggc->connection = connection;
+	gb_connection_set_data(connection, ggc);
+	ggc->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, ggc);
+
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	ret = gb_gpio_controller_setup(ggc);
+	if (ret)
+		goto exit_connection_disable;
+
+	irqc = &ggc->irqc;
+	irqc->irq_mask = gb_gpio_irq_mask;
+	irqc->irq_unmask = gb_gpio_irq_unmask;
+	irqc->irq_set_type = gb_gpio_irq_set_type;
+	irqc->irq_bus_lock = gb_gpio_irq_bus_lock;
+	irqc->irq_bus_sync_unlock = gb_gpio_irq_bus_sync_unlock;
+	irqc->name = "greybus_gpio";
+
+	mutex_init(&ggc->irq_lock);
+
+	gpio = &ggc->chip;
+
+	gpio->label = "greybus_gpio";
+	gpio->parent = &gbphy_dev->dev;
+	gpio->owner = THIS_MODULE;
+
+	gpio->request = gb_gpio_request;
+	gpio->free = gb_gpio_free;
+	gpio->get_direction = gb_gpio_get_direction;
+	gpio->direction_input = gb_gpio_direction_input;
+	gpio->direction_output = gb_gpio_direction_output;
+	gpio->get = gb_gpio_get;
+	gpio->set = gb_gpio_set;
+	gpio->set_debounce = gb_gpio_set_debounce;
+	gpio->to_irq = gb_gpio_to_irq;
+	gpio->base = -1;		/* Allocate base dynamically */
+	gpio->ngpio = ggc->line_max + 1;
+	gpio->can_sleep = true;
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_line_free;
+
+	ret = gb_gpio_irqchip_add(gpio, irqc, 0,
+				   handle_level_irq, IRQ_TYPE_NONE);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to add irq chip: %d\n", ret);
+		goto exit_line_free;
+	}
+
+	ret = gpiochip_add(gpio);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to add gpio chip: %d\n", ret);
+		goto exit_gpio_irqchip_remove;
+	}
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_gpio_irqchip_remove:
+	gb_gpio_irqchip_remove(ggc);
+exit_line_free:
+	kfree(ggc->lines);
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_ggc_free:
+	kfree(ggc);
+	return ret;
+}
+
+static void gb_gpio_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_gpio_controller *ggc = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = ggc->connection;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	gb_connection_disable_rx(connection);
+	gpiochip_remove(&ggc->chip);
+	gb_gpio_irqchip_remove(ggc);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	kfree(ggc->lines);
+	kfree(ggc);
+}
+
+static const struct gbphy_device_id gb_gpio_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_GPIO) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_gpio_id_table);
+
+static struct gbphy_driver gpio_driver = {
+	.name		= "gpio",
+	.probe		= gb_gpio_probe,
+	.remove		= gb_gpio_remove,
+	.id_table	= gb_gpio_id_table,
+};
+
+module_gbphy_driver(gpio_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/greybus.h b/drivers/staging/greybus/greybus.h
new file mode 100644
index 000000000000..12526887ae2e
--- /dev/null
+++ b/drivers/staging/greybus/greybus.h
@@ -0,0 +1,154 @@
+/*
+ * Greybus driver and device API
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __LINUX_GREYBUS_H
+#define __LINUX_GREYBUS_H
+
+#ifdef __KERNEL__
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/idr.h>
+
+#include "greybus_id.h"
+#include "greybus_manifest.h"
+#include "greybus_protocols.h"
+#include "manifest.h"
+#include "hd.h"
+#include "svc.h"
+#include "control.h"
+#include "module.h"
+#include "interface.h"
+#include "bundle.h"
+#include "connection.h"
+#include "operation.h"
+#include "timesync.h"
+
+/* Matches up with the Greybus Protocol specification document */
+#define GREYBUS_VERSION_MAJOR	0x00
+#define GREYBUS_VERSION_MINOR	0x01
+
+#define GREYBUS_ID_MATCH_DEVICE \
+	(GREYBUS_ID_MATCH_VENDOR | GREYBUS_ID_MATCH_PRODUCT)
+
+#define GREYBUS_DEVICE(v, p)					\
+	.match_flags	= GREYBUS_ID_MATCH_DEVICE,		\
+	.vendor		= (v),					\
+	.product	= (p),
+
+#define GREYBUS_DEVICE_CLASS(c)					\
+	.match_flags	= GREYBUS_ID_MATCH_CLASS,		\
+	.class		= (c),
+
+/* Maximum number of CPorts */
+#define CPORT_ID_MAX	4095		/* UniPro max id is 4095 */
+#define CPORT_ID_BAD	U16_MAX
+
+struct greybus_driver {
+	const char *name;
+
+	int (*probe)(struct gb_bundle *bundle,
+		     const struct greybus_bundle_id *id);
+	void (*disconnect)(struct gb_bundle *bundle);
+
+	const struct greybus_bundle_id *id_table;
+
+	struct device_driver driver;
+};
+#define to_greybus_driver(d) container_of(d, struct greybus_driver, driver)
+
+static inline void greybus_set_drvdata(struct gb_bundle *bundle, void *data)
+{
+	dev_set_drvdata(&bundle->dev, data);
+}
+
+static inline void *greybus_get_drvdata(struct gb_bundle *bundle)
+{
+	return dev_get_drvdata(&bundle->dev);
+}
+
+/* Don't call these directly, use the module_greybus_driver() macro instead */
+int greybus_register_driver(struct greybus_driver *driver,
+			    struct module *module, const char *mod_name);
+void greybus_deregister_driver(struct greybus_driver *driver);
+
+/* define to get proper THIS_MODULE and KBUILD_MODNAME values */
+#define greybus_register(driver) \
+	greybus_register_driver(driver, THIS_MODULE, KBUILD_MODNAME)
+#define greybus_deregister(driver) \
+	greybus_deregister_driver(driver)
+
+/**
+ * module_greybus_driver() - Helper macro for registering a Greybus driver
+ * @__greybus_driver: greybus_driver structure
+ *
+ * Helper macro for Greybus drivers to set up proper module init / exit
+ * functions.  Replaces module_init() and module_exit() and keeps people from
+ * printing pointless things to the kernel log when their driver is loaded.
+ */
+#define module_greybus_driver(__greybus_driver)	\
+	module_driver(__greybus_driver, greybus_register, greybus_deregister)
+
+int greybus_disabled(void);
+
+void gb_debugfs_init(void);
+void gb_debugfs_cleanup(void);
+struct dentry *gb_debugfs_get(void);
+
+extern struct bus_type greybus_bus_type;
+
+extern struct device_type greybus_hd_type;
+extern struct device_type greybus_module_type;
+extern struct device_type greybus_interface_type;
+extern struct device_type greybus_control_type;
+extern struct device_type greybus_bundle_type;
+extern struct device_type greybus_svc_type;
+
+static inline int is_gb_host_device(const struct device *dev)
+{
+	return dev->type == &greybus_hd_type;
+}
+
+static inline int is_gb_module(const struct device *dev)
+{
+	return dev->type == &greybus_module_type;
+}
+
+static inline int is_gb_interface(const struct device *dev)
+{
+	return dev->type == &greybus_interface_type;
+}
+
+static inline int is_gb_control(const struct device *dev)
+{
+	return dev->type == &greybus_control_type;
+}
+
+static inline int is_gb_bundle(const struct device *dev)
+{
+	return dev->type == &greybus_bundle_type;
+}
+
+static inline int is_gb_svc(const struct device *dev)
+{
+	return dev->type == &greybus_svc_type;
+}
+
+static inline bool cport_id_valid(struct gb_host_device *hd, u16 cport_id)
+{
+	return cport_id != CPORT_ID_BAD && cport_id < hd->num_cports;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __LINUX_GREYBUS_H */
diff --git a/drivers/staging/greybus/greybus_authentication.h b/drivers/staging/greybus/greybus_authentication.h
new file mode 100644
index 000000000000..4784ed98e8a3
--- /dev/null
+++ b/drivers/staging/greybus/greybus_authentication.h
@@ -0,0 +1,120 @@
+/*
+ * Greybus Component Authentication User Header
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __GREYBUS_AUTHENTICATION_USER_H
+#define __GREYBUS_AUTHENTICATION_USER_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define CAP_CERTIFICATE_MAX_SIZE	1600
+#define CAP_SIGNATURE_MAX_SIZE		320
+
+/* Certificate class types */
+#define CAP_CERT_IMS_EAPC		0x00000001
+#define CAP_CERT_IMS_EASC		0x00000002
+#define CAP_CERT_IMS_EARC		0x00000003
+#define CAP_CERT_IMS_IAPC		0x00000004
+#define CAP_CERT_IMS_IASC		0x00000005
+#define CAP_CERT_IMS_IARC		0x00000006
+
+/* IMS Certificate response result codes */
+#define CAP_IMS_RESULT_CERT_FOUND	0x00
+#define CAP_IMS_RESULT_CERT_CLASS_INVAL	0x01
+#define CAP_IMS_RESULT_CERT_CORRUPT	0x02
+#define CAP_IMS_RESULT_CERT_NOT_FOUND	0x03
+
+/* Authentication types */
+#define CAP_AUTH_IMS_PRI		0x00000001
+#define CAP_AUTH_IMS_SEC		0x00000002
+#define CAP_AUTH_IMS_RSA		0x00000003
+
+/* Authenticate response result codes */
+#define CAP_AUTH_RESULT_CR_SUCCESS	0x00
+#define CAP_AUTH_RESULT_CR_BAD_TYPE	0x01
+#define CAP_AUTH_RESULT_CR_WRONG_EP	0x02
+#define CAP_AUTH_RESULT_CR_NO_KEY	0x03
+#define CAP_AUTH_RESULT_CR_SIG_FAIL	0x04
+
+
+/* IOCTL support */
+struct cap_ioc_get_endpoint_uid {
+	__u8			uid[8];
+} __attribute__ ((__packed__));
+
+struct cap_ioc_get_ims_certificate {
+	__u32			certificate_class;
+	__u32			certificate_id;
+
+	__u8			result_code;
+	__u32			cert_size;
+	__u8			certificate[CAP_CERTIFICATE_MAX_SIZE];
+} __attribute__ ((__packed__));
+
+struct cap_ioc_authenticate {
+	__u32			auth_type;
+	__u8			uid[8];
+	__u8			challenge[32];
+
+	__u8			result_code;
+	__u8			response[64];
+	__u32			signature_size;
+	__u8			signature[CAP_SIGNATURE_MAX_SIZE];
+} __attribute__ ((__packed__));
+
+#define CAP_IOCTL_BASE			'C'
+#define CAP_IOC_GET_ENDPOINT_UID	_IOR(CAP_IOCTL_BASE, 0, struct cap_ioc_get_endpoint_uid)
+#define CAP_IOC_GET_IMS_CERTIFICATE	_IOWR(CAP_IOCTL_BASE, 1, struct cap_ioc_get_ims_certificate)
+#define CAP_IOC_AUTHENTICATE		_IOWR(CAP_IOCTL_BASE, 2, struct cap_ioc_authenticate)
+
+#endif /* __GREYBUS_AUTHENTICATION_USER_H */
diff --git a/drivers/staging/greybus/greybus_firmware.h b/drivers/staging/greybus/greybus_firmware.h
new file mode 100644
index 000000000000..277a2acce6fd
--- /dev/null
+++ b/drivers/staging/greybus/greybus_firmware.h
@@ -0,0 +1,120 @@
+/*
+ * Greybus Firmware Management User Header
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2016 Google Inc. All rights reserved.
+ * Copyright(c) 2016 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __GREYBUS_FIRMWARE_USER_H
+#define __GREYBUS_FIRMWARE_USER_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define GB_FIRMWARE_U_TAG_MAX_SIZE		10
+
+#define GB_FW_U_LOAD_METHOD_UNIPRO		0x01
+#define GB_FW_U_LOAD_METHOD_INTERNAL		0x02
+
+#define GB_FW_U_LOAD_STATUS_FAILED		0x00
+#define GB_FW_U_LOAD_STATUS_UNVALIDATED		0x01
+#define GB_FW_U_LOAD_STATUS_VALIDATED		0x02
+#define GB_FW_U_LOAD_STATUS_VALIDATION_FAILED	0x03
+
+#define GB_FW_U_BACKEND_FW_STATUS_SUCCESS	0x01
+#define GB_FW_U_BACKEND_FW_STATUS_FAIL_FIND	0x02
+#define GB_FW_U_BACKEND_FW_STATUS_FAIL_FETCH	0x03
+#define GB_FW_U_BACKEND_FW_STATUS_FAIL_WRITE	0x04
+#define GB_FW_U_BACKEND_FW_STATUS_INT		0x05
+#define GB_FW_U_BACKEND_FW_STATUS_RETRY		0x06
+#define GB_FW_U_BACKEND_FW_STATUS_NOT_SUPPORTED	0x07
+
+#define GB_FW_U_BACKEND_VERSION_STATUS_SUCCESS		0x01
+#define GB_FW_U_BACKEND_VERSION_STATUS_NOT_AVAILABLE	0x02
+#define GB_FW_U_BACKEND_VERSION_STATUS_NOT_SUPPORTED	0x03
+#define GB_FW_U_BACKEND_VERSION_STATUS_RETRY		0x04
+#define GB_FW_U_BACKEND_VERSION_STATUS_FAIL_INT		0x05
+
+/* IOCTL support */
+struct fw_mgmt_ioc_get_intf_version {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u16 major;
+	__u16 minor;
+} __attribute__ ((__packed__));
+
+struct fw_mgmt_ioc_get_backend_version {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u16 major;
+	__u16 minor;
+	__u8 status;
+} __attribute__ ((__packed__));
+
+struct fw_mgmt_ioc_intf_load_and_validate {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u8 load_method;
+	__u8 status;
+	__u16 major;
+	__u16 minor;
+} __attribute__ ((__packed__));
+
+struct fw_mgmt_ioc_backend_fw_update {
+	__u8 firmware_tag[GB_FIRMWARE_U_TAG_MAX_SIZE];
+	__u8 status;
+} __attribute__ ((__packed__));
+
+#define FW_MGMT_IOCTL_BASE			'F'
+#define FW_MGMT_IOC_GET_INTF_FW			_IOR(FW_MGMT_IOCTL_BASE, 0, struct fw_mgmt_ioc_get_intf_version)
+#define FW_MGMT_IOC_GET_BACKEND_FW		_IOWR(FW_MGMT_IOCTL_BASE, 1, struct fw_mgmt_ioc_get_backend_version)
+#define FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE	_IOWR(FW_MGMT_IOCTL_BASE, 2, struct fw_mgmt_ioc_intf_load_and_validate)
+#define FW_MGMT_IOC_INTF_BACKEND_FW_UPDATE	_IOWR(FW_MGMT_IOCTL_BASE, 3, struct fw_mgmt_ioc_backend_fw_update)
+#define FW_MGMT_IOC_SET_TIMEOUT_MS		_IOW(FW_MGMT_IOCTL_BASE, 4, unsigned int)
+#define FW_MGMT_IOC_MODE_SWITCH			_IO(FW_MGMT_IOCTL_BASE, 5)
+
+#endif /* __GREYBUS_FIRMWARE_USER_H */
+
diff --git a/drivers/staging/greybus/greybus_id.h b/drivers/staging/greybus/greybus_id.h
new file mode 100644
index 000000000000..4bb1fc1b811d
--- /dev/null
+++ b/drivers/staging/greybus/greybus_id.h
@@ -0,0 +1,26 @@
+/* FIXME
+ * move this to include/linux/mod_devicetable.h when merging
+ */
+
+#ifndef __LINUX_GREYBUS_ID_H
+#define __LINUX_GREYBUS_ID_H
+
+#include <linux/types.h>
+#include <linux/mod_devicetable.h>
+
+
+struct greybus_bundle_id {
+	__u16	match_flags;
+	__u32	vendor;
+	__u32	product;
+	__u8	class;
+
+	kernel_ulong_t	driver_info __aligned(sizeof(kernel_ulong_t));
+};
+
+/* Used to match the greybus_bundle_id */
+#define GREYBUS_ID_MATCH_VENDOR		BIT(0)
+#define GREYBUS_ID_MATCH_PRODUCT	BIT(1)
+#define GREYBUS_ID_MATCH_CLASS		BIT(2)
+
+#endif /* __LINUX_GREYBUS_ID_H */
diff --git a/drivers/staging/greybus/greybus_manifest.h b/drivers/staging/greybus/greybus_manifest.h
new file mode 100644
index 000000000000..d135945cefe1
--- /dev/null
+++ b/drivers/staging/greybus/greybus_manifest.h
@@ -0,0 +1,177 @@
+/*
+ * Greybus manifest definition
+ *
+ * See "Greybus Application Protocol" document (version 0.1) for
+ * details on these values and structures.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 and BSD licenses.
+ */
+
+#ifndef __GREYBUS_MANIFEST_H
+#define __GREYBUS_MANIFEST_H
+
+enum greybus_descriptor_type {
+	GREYBUS_TYPE_INVALID		= 0x00,
+	GREYBUS_TYPE_INTERFACE		= 0x01,
+	GREYBUS_TYPE_STRING		= 0x02,
+	GREYBUS_TYPE_BUNDLE		= 0x03,
+	GREYBUS_TYPE_CPORT		= 0x04,
+};
+
+enum greybus_protocol {
+	GREYBUS_PROTOCOL_CONTROL	= 0x00,
+	/* 0x01 is unused */
+	GREYBUS_PROTOCOL_GPIO		= 0x02,
+	GREYBUS_PROTOCOL_I2C		= 0x03,
+	GREYBUS_PROTOCOL_UART		= 0x04,
+	GREYBUS_PROTOCOL_HID		= 0x05,
+	GREYBUS_PROTOCOL_USB		= 0x06,
+	GREYBUS_PROTOCOL_SDIO		= 0x07,
+	GREYBUS_PROTOCOL_POWER_SUPPLY	= 0x08,
+	GREYBUS_PROTOCOL_PWM		= 0x09,
+	/* 0x0a is unused */
+	GREYBUS_PROTOCOL_SPI		= 0x0b,
+	GREYBUS_PROTOCOL_DISPLAY	= 0x0c,
+	GREYBUS_PROTOCOL_CAMERA_MGMT	= 0x0d,
+	GREYBUS_PROTOCOL_SENSOR		= 0x0e,
+	GREYBUS_PROTOCOL_LIGHTS		= 0x0f,
+	GREYBUS_PROTOCOL_VIBRATOR	= 0x10,
+	GREYBUS_PROTOCOL_LOOPBACK	= 0x11,
+	GREYBUS_PROTOCOL_AUDIO_MGMT	= 0x12,
+	GREYBUS_PROTOCOL_AUDIO_DATA	= 0x13,
+	GREYBUS_PROTOCOL_SVC            = 0x14,
+	GREYBUS_PROTOCOL_BOOTROM	= 0x15,
+	GREYBUS_PROTOCOL_CAMERA_DATA	= 0x16,
+	GREYBUS_PROTOCOL_FW_DOWNLOAD	= 0x17,
+	GREYBUS_PROTOCOL_FW_MANAGEMENT	= 0x18,
+	GREYBUS_PROTOCOL_AUTHENTICATION	= 0x19,
+	GREYBUS_PROTOCOL_LOG		= 0x1a,
+		/* ... */
+	GREYBUS_PROTOCOL_RAW		= 0xfe,
+	GREYBUS_PROTOCOL_VENDOR		= 0xff,
+};
+
+enum greybus_class_type {
+	GREYBUS_CLASS_CONTROL		= 0x00,
+	/* 0x01 is unused */
+	/* 0x02 is unused */
+	/* 0x03 is unused */
+	/* 0x04 is unused */
+	GREYBUS_CLASS_HID		= 0x05,
+	/* 0x06 is unused */
+	/* 0x07 is unused */
+	GREYBUS_CLASS_POWER_SUPPLY	= 0x08,
+	/* 0x09 is unused */
+	GREYBUS_CLASS_BRIDGED_PHY	= 0x0a,
+	/* 0x0b is unused */
+	GREYBUS_CLASS_DISPLAY		= 0x0c,
+	GREYBUS_CLASS_CAMERA		= 0x0d,
+	GREYBUS_CLASS_SENSOR		= 0x0e,
+	GREYBUS_CLASS_LIGHTS		= 0x0f,
+	GREYBUS_CLASS_VIBRATOR		= 0x10,
+	GREYBUS_CLASS_LOOPBACK		= 0x11,
+	GREYBUS_CLASS_AUDIO		= 0x12,
+	/* 0x13 is unused */
+	/* 0x14 is unused */
+	GREYBUS_CLASS_BOOTROM		= 0x15,
+	GREYBUS_CLASS_FW_MANAGEMENT	= 0x16,
+	GREYBUS_CLASS_LOG		= 0x17,
+		/* ... */
+	GREYBUS_CLASS_RAW		= 0xfe,
+	GREYBUS_CLASS_VENDOR		= 0xff,
+};
+
+enum {
+	GREYBUS_INTERFACE_FEATURE_TIMESYNC = BIT(0),
+};
+
+/*
+ * The string in a string descriptor is not NUL-terminated.  The
+ * size of the descriptor will be rounded up to a multiple of 4
+ * bytes, by padding the string with 0x00 bytes if necessary.
+ */
+struct greybus_descriptor_string {
+	__u8	length;
+	__u8	id;
+	__u8	string[0];
+} __packed;
+
+/*
+ * An interface descriptor describes information about an interface as a whole,
+ * *not* the functions within it.
+ */
+struct greybus_descriptor_interface {
+	__u8	vendor_stringid;
+	__u8	product_stringid;
+	__u8	features;
+	__u8	pad;
+} __packed;
+
+/*
+ * An bundle descriptor defines an identification number and a class for
+ * each bundle.
+ *
+ * @id: Uniquely identifies a bundle within a interface, its sole purpose is to
+ * allow CPort descriptors to specify which bundle they are associated with.
+ * The first bundle will have id 0, second will have 1 and so on.
+ *
+ * The largest CPort id associated with an bundle (defined by a
+ * CPort descriptor in the manifest) is used to determine how to
+ * encode the device id and module number in UniPro packets
+ * that use the bundle.
+ *
+ * @class: It is used by kernel to know the functionality provided by the
+ * bundle and will be matched against drivers functinality while probing greybus
+ * driver. It should contain one of the values defined in
+ * 'enum greybus_class_type'.
+ *
+ */
+struct greybus_descriptor_bundle {
+	__u8	id;	/* interface-relative id (0..) */
+	__u8	class;
+	__u8	pad[2];
+} __packed;
+
+/*
+ * A CPort descriptor indicates the id of the bundle within the
+ * module it's associated with, along with the CPort id used to
+ * address the CPort.  The protocol id defines the format of messages
+ * exchanged using the CPort.
+ */
+struct greybus_descriptor_cport {
+	__le16	id;
+	__u8	bundle;
+	__u8	protocol_id;	/* enum greybus_protocol */
+} __packed;
+
+struct greybus_descriptor_header {
+	__le16	size;
+	__u8	type;		/* enum greybus_descriptor_type */
+	__u8	pad;
+} __packed;
+
+struct greybus_descriptor {
+	struct greybus_descriptor_header		header;
+	union {
+		struct greybus_descriptor_string	string;
+		struct greybus_descriptor_interface	interface;
+		struct greybus_descriptor_bundle	bundle;
+		struct greybus_descriptor_cport		cport;
+	};
+} __packed;
+
+struct greybus_manifest_header {
+	__le16	size;
+	__u8	version_major;
+	__u8	version_minor;
+} __packed;
+
+struct greybus_manifest {
+	struct greybus_manifest_header		header;
+	struct greybus_descriptor		descriptors[0];
+} __packed;
+
+#endif /* __GREYBUS_MANIFEST_H */
diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h
new file mode 100644
index 000000000000..639578309c2a
--- /dev/null
+++ b/drivers/staging/greybus/greybus_protocols.h
@@ -0,0 +1,2268 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2014 - 2015 Google Inc. All rights reserved.
+ * Copyright(c) 2014 - 2015 Linaro Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2014 - 2015 Google Inc. All rights reserved.
+ * Copyright(c) 2014 - 2015 Linaro Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google Inc. or Linaro Ltd. nor the names of
+ *    its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR
+ * LINARO LTD. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __GREYBUS_PROTOCOLS_H
+#define __GREYBUS_PROTOCOLS_H
+
+/* Fixed IDs for control/svc protocols */
+
+/* SVC switch-port device ids */
+#define GB_SVC_DEVICE_ID_SVC			0
+#define GB_SVC_DEVICE_ID_AP			1
+#define GB_SVC_DEVICE_ID_MIN			2
+#define GB_SVC_DEVICE_ID_MAX			31
+
+#define GB_SVC_CPORT_ID				0
+#define GB_CONTROL_BUNDLE_ID			0
+#define GB_CONTROL_CPORT_ID			0
+
+
+/*
+ * All operation messages (both requests and responses) begin with
+ * a header that encodes the size of the message (header included).
+ * This header also contains a unique identifier, that associates a
+ * response message with its operation.  The header contains an
+ * operation type field, whose interpretation is dependent on what
+ * type of protocol is used over the connection.  The high bit
+ * (0x80) of the operation type field is used to indicate whether
+ * the message is a request (clear) or a response (set).
+ *
+ * Response messages include an additional result byte, which
+ * communicates the result of the corresponding request.  A zero
+ * result value means the operation completed successfully.  Any
+ * other value indicates an error; in this case, the payload of the
+ * response message (if any) is ignored.  The result byte must be
+ * zero in the header for a request message.
+ *
+ * The wire format for all numeric fields in the header is little
+ * endian.  Any operation-specific data begins immediately after the
+ * header.
+ */
+struct gb_operation_msg_hdr {
+	__le16	size;		/* Size in bytes of header + payload */
+	__le16	operation_id;	/* Operation unique id */
+	__u8	type;		/* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */
+	__u8	result;		/* Result of request (in responses only) */
+	__u8	pad[2];		/* must be zero (ignore when read) */
+} __packed;
+
+
+/* Generic request types */
+#define GB_REQUEST_TYPE_CPORT_SHUTDOWN		0x00
+#define GB_REQUEST_TYPE_INVALID			0x7f
+
+struct gb_cport_shutdown_request {
+	__u8 phase;
+} __packed;
+
+
+/* Control Protocol */
+
+/* Greybus control request types */
+#define GB_CONTROL_TYPE_VERSION			0x01
+#define GB_CONTROL_TYPE_PROBE_AP		0x02
+#define GB_CONTROL_TYPE_GET_MANIFEST_SIZE	0x03
+#define GB_CONTROL_TYPE_GET_MANIFEST		0x04
+#define GB_CONTROL_TYPE_CONNECTED		0x05
+#define GB_CONTROL_TYPE_DISCONNECTED		0x06
+#define GB_CONTROL_TYPE_TIMESYNC_ENABLE		0x07
+#define GB_CONTROL_TYPE_TIMESYNC_DISABLE	0x08
+#define GB_CONTROL_TYPE_TIMESYNC_AUTHORITATIVE	0x09
+/*	Unused					0x0a */
+#define GB_CONTROL_TYPE_BUNDLE_VERSION		0x0b
+#define GB_CONTROL_TYPE_DISCONNECTING		0x0c
+#define GB_CONTROL_TYPE_TIMESYNC_GET_LAST_EVENT	0x0d
+#define GB_CONTROL_TYPE_MODE_SWITCH		0x0e
+#define GB_CONTROL_TYPE_BUNDLE_SUSPEND		0x0f
+#define GB_CONTROL_TYPE_BUNDLE_RESUME		0x10
+#define GB_CONTROL_TYPE_BUNDLE_DEACTIVATE	0x11
+#define GB_CONTROL_TYPE_BUNDLE_ACTIVATE		0x12
+#define GB_CONTROL_TYPE_INTF_SUSPEND_PREPARE		0x13
+#define GB_CONTROL_TYPE_INTF_DEACTIVATE_PREPARE	0x14
+#define GB_CONTROL_TYPE_INTF_HIBERNATE_ABORT	0x15
+
+struct gb_control_version_request {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+struct gb_control_version_response {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+struct gb_control_bundle_version_request {
+	__u8	bundle_id;
+} __packed;
+
+struct gb_control_bundle_version_response {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+/* Control protocol manifest get size request has no payload*/
+struct gb_control_get_manifest_size_response {
+	__le16			size;
+} __packed;
+
+/* Control protocol manifest get request has no payload */
+struct gb_control_get_manifest_response {
+	__u8			data[0];
+} __packed;
+
+/* Control protocol [dis]connected request */
+struct gb_control_connected_request {
+	__le16			cport_id;
+} __packed;
+
+struct gb_control_disconnecting_request {
+	__le16			cport_id;
+} __packed;
+/* disconnecting response has no payload */
+
+struct gb_control_disconnected_request {
+	__le16			cport_id;
+} __packed;
+/* Control protocol [dis]connected response has no payload */
+
+#define GB_TIMESYNC_MAX_STROBES			0x04
+
+struct gb_control_timesync_enable_request {
+	__u8	count;
+	__le64	frame_time;
+	__le32	strobe_delay;
+	__le32	refclk;
+} __packed;
+/* timesync enable response has no payload */
+
+struct gb_control_timesync_authoritative_request {
+	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
+} __packed;
+/* timesync authoritative response has no payload */
+
+/* timesync get_last_event_request has no payload */
+struct gb_control_timesync_get_last_event_response {
+	__le64	frame_time;
+} __packed;
+
+/*
+ * All Bundle power management operations use the same request and response
+ * layout and status codes.
+ */
+
+#define GB_CONTROL_BUNDLE_PM_OK		0x00
+#define GB_CONTROL_BUNDLE_PM_INVAL	0x01
+#define GB_CONTROL_BUNDLE_PM_BUSY	0x02
+#define GB_CONTROL_BUNDLE_PM_FAIL	0x03
+#define GB_CONTROL_BUNDLE_PM_NA		0x04
+
+struct gb_control_bundle_pm_request {
+	__u8	bundle_id;
+} __packed;
+
+struct gb_control_bundle_pm_response {
+	__u8	status;
+} __packed;
+
+/*
+ * Interface Suspend Prepare and Deactivate Prepare operations use the same
+ * response layout and error codes. Define a single response structure and reuse
+ * it. Both operations have no payload.
+ */
+
+#define GB_CONTROL_INTF_PM_OK		0x00
+#define GB_CONTROL_INTF_PM_BUSY		0x01
+#define GB_CONTROL_INTF_PM_NA		0x02
+
+struct gb_control_intf_pm_response {
+	__u8	status;
+} __packed;
+
+/* APBridge protocol */
+
+/* request APB1 log */
+#define GB_APB_REQUEST_LOG			0x02
+
+/* request to map a cport to bulk in and bulk out endpoints */
+#define GB_APB_REQUEST_EP_MAPPING		0x03
+
+/* request to get the number of cports available */
+#define GB_APB_REQUEST_CPORT_COUNT		0x04
+
+/* request to reset a cport state */
+#define GB_APB_REQUEST_RESET_CPORT		0x05
+
+/* request to time the latency of messages on a given cport */
+#define GB_APB_REQUEST_LATENCY_TAG_EN		0x06
+#define GB_APB_REQUEST_LATENCY_TAG_DIS		0x07
+
+/* request to control the CSI transmitter */
+#define GB_APB_REQUEST_CSI_TX_CONTROL		0x08
+
+/* request to control audio streaming */
+#define GB_APB_REQUEST_AUDIO_CONTROL		0x09
+
+/* TimeSync requests */
+#define GB_APB_REQUEST_TIMESYNC_ENABLE		0x0d
+#define GB_APB_REQUEST_TIMESYNC_DISABLE		0x0e
+#define GB_APB_REQUEST_TIMESYNC_AUTHORITATIVE	0x0f
+#define GB_APB_REQUEST_TIMESYNC_GET_LAST_EVENT	0x10
+
+/* requests to set Greybus CPort flags */
+#define GB_APB_REQUEST_CPORT_FLAGS		0x11
+
+/* ARPC request */
+#define GB_APB_REQUEST_ARPC_RUN			0x12
+
+struct gb_apb_request_cport_flags {
+	__le32	flags;
+#define GB_APB_CPORT_FLAG_CONTROL		0x01
+#define GB_APB_CPORT_FLAG_HIGH_PRIO		0x02
+} __packed;
+
+
+/* Firmware Download Protocol */
+
+/* Request Types */
+#define GB_FW_DOWNLOAD_TYPE_FIND_FIRMWARE	0x01
+#define GB_FW_DOWNLOAD_TYPE_FETCH_FIRMWARE	0x02
+#define GB_FW_DOWNLOAD_TYPE_RELEASE_FIRMWARE	0x03
+
+#define GB_FIRMWARE_TAG_MAX_SIZE		10
+
+/* firmware download find firmware request/response */
+struct gb_fw_download_find_firmware_request {
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+} __packed;
+
+struct gb_fw_download_find_firmware_response {
+	__u8			firmware_id;
+	__le32			size;
+} __packed;
+
+/* firmware download fetch firmware request/response */
+struct gb_fw_download_fetch_firmware_request {
+	__u8			firmware_id;
+	__le32			offset;
+	__le32			size;
+} __packed;
+
+struct gb_fw_download_fetch_firmware_response {
+	__u8			data[0];
+} __packed;
+
+/* firmware download release firmware request */
+struct gb_fw_download_release_firmware_request {
+	__u8			firmware_id;
+} __packed;
+/* firmware download release firmware response has no payload */
+
+
+/* Firmware Management Protocol */
+
+/* Request Types */
+#define GB_FW_MGMT_TYPE_INTERFACE_FW_VERSION	0x01
+#define GB_FW_MGMT_TYPE_LOAD_AND_VALIDATE_FW	0x02
+#define GB_FW_MGMT_TYPE_LOADED_FW		0x03
+#define GB_FW_MGMT_TYPE_BACKEND_FW_VERSION	0x04
+#define GB_FW_MGMT_TYPE_BACKEND_FW_UPDATE	0x05
+#define GB_FW_MGMT_TYPE_BACKEND_FW_UPDATED	0x06
+
+#define GB_FW_LOAD_METHOD_UNIPRO		0x01
+#define GB_FW_LOAD_METHOD_INTERNAL		0x02
+
+#define GB_FW_LOAD_STATUS_FAILED		0x00
+#define GB_FW_LOAD_STATUS_UNVALIDATED		0x01
+#define GB_FW_LOAD_STATUS_VALIDATED		0x02
+#define GB_FW_LOAD_STATUS_VALIDATION_FAILED	0x03
+
+#define GB_FW_BACKEND_FW_STATUS_SUCCESS		0x01
+#define GB_FW_BACKEND_FW_STATUS_FAIL_FIND	0x02
+#define GB_FW_BACKEND_FW_STATUS_FAIL_FETCH	0x03
+#define GB_FW_BACKEND_FW_STATUS_FAIL_WRITE	0x04
+#define GB_FW_BACKEND_FW_STATUS_INT		0x05
+#define GB_FW_BACKEND_FW_STATUS_RETRY		0x06
+#define GB_FW_BACKEND_FW_STATUS_NOT_SUPPORTED	0x07
+
+#define GB_FW_BACKEND_VERSION_STATUS_SUCCESS		0x01
+#define GB_FW_BACKEND_VERSION_STATUS_NOT_AVAILABLE	0x02
+#define GB_FW_BACKEND_VERSION_STATUS_NOT_SUPPORTED	0x03
+#define GB_FW_BACKEND_VERSION_STATUS_RETRY		0x04
+#define GB_FW_BACKEND_VERSION_STATUS_FAIL_INT		0x05
+
+/* firmware management interface firmware version request has no payload */
+struct gb_fw_mgmt_interface_fw_version_response {
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+	__le16			major;
+	__le16			minor;
+} __packed;
+
+/* firmware management load and validate firmware request/response */
+struct gb_fw_mgmt_load_and_validate_fw_request {
+	__u8			request_id;
+	__u8			load_method;
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+} __packed;
+/* firmware management load and validate firmware response has no payload*/
+
+/* firmware management loaded firmware request */
+struct gb_fw_mgmt_loaded_fw_request {
+	__u8			request_id;
+	__u8			status;
+	__le16			major;
+	__le16			minor;
+} __packed;
+/* firmware management loaded firmware response has no payload */
+
+/* firmware management backend firmware version request/response */
+struct gb_fw_mgmt_backend_fw_version_request {
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+} __packed;
+
+struct gb_fw_mgmt_backend_fw_version_response {
+	__le16			major;
+	__le16			minor;
+	__u8			status;
+} __packed;
+
+/* firmware management backend firmware update request */
+struct gb_fw_mgmt_backend_fw_update_request {
+	__u8			request_id;
+	__u8			firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE];
+} __packed;
+/* firmware management backend firmware update response has no payload */
+
+/* firmware management backend firmware updated request */
+struct gb_fw_mgmt_backend_fw_updated_request {
+	__u8			request_id;
+	__u8			status;
+} __packed;
+/* firmware management backend firmware updated response has no payload */
+
+
+/* Component Authentication Protocol (CAP) */
+
+/* Request Types */
+#define GB_CAP_TYPE_GET_ENDPOINT_UID	0x01
+#define GB_CAP_TYPE_GET_IMS_CERTIFICATE	0x02
+#define GB_CAP_TYPE_AUTHENTICATE	0x03
+
+/* CAP get endpoint uid request has no payload */
+struct gb_cap_get_endpoint_uid_response {
+	__u8			uid[8];
+} __packed;
+
+/* CAP get endpoint ims certificate request/response */
+struct gb_cap_get_ims_certificate_request {
+	__le32			certificate_class;
+	__le32			certificate_id;
+} __packed;
+
+struct gb_cap_get_ims_certificate_response {
+	__u8			result_code;
+	__u8			certificate[0];
+} __packed;
+
+/* CAP authenticate request/response */
+struct gb_cap_authenticate_request {
+	__le32			auth_type;
+	__u8			uid[8];
+	__u8			challenge[32];
+} __packed;
+
+struct gb_cap_authenticate_response {
+	__u8			result_code;
+	__u8			response[64];
+	__u8			signature[0];
+} __packed;
+
+
+/* Bootrom Protocol */
+
+/* Version of the Greybus bootrom protocol we support */
+#define GB_BOOTROM_VERSION_MAJOR		0x00
+#define GB_BOOTROM_VERSION_MINOR		0x01
+
+/* Greybus bootrom request types */
+#define GB_BOOTROM_TYPE_VERSION			0x01
+#define GB_BOOTROM_TYPE_FIRMWARE_SIZE		0x02
+#define GB_BOOTROM_TYPE_GET_FIRMWARE		0x03
+#define GB_BOOTROM_TYPE_READY_TO_BOOT		0x04
+#define GB_BOOTROM_TYPE_AP_READY		0x05	/* Request with no-payload */
+#define GB_BOOTROM_TYPE_GET_VID_PID		0x06	/* Request with no-payload */
+
+/* Greybus bootrom boot stages */
+#define GB_BOOTROM_BOOT_STAGE_ONE		0x01 /* Reserved for the boot ROM */
+#define GB_BOOTROM_BOOT_STAGE_TWO		0x02 /* Bootrom package to be loaded by the boot ROM */
+#define GB_BOOTROM_BOOT_STAGE_THREE		0x03 /* Module personality package loaded by Stage 2 firmware */
+
+/* Greybus bootrom ready to boot status */
+#define GB_BOOTROM_BOOT_STATUS_INVALID		0x00 /* Firmware blob could not be validated */
+#define GB_BOOTROM_BOOT_STATUS_INSECURE		0x01 /* Firmware blob is valid but insecure */
+#define GB_BOOTROM_BOOT_STATUS_SECURE		0x02 /* Firmware blob is valid and secure */
+
+/* Max bootrom data fetch size in bytes */
+#define GB_BOOTROM_FETCH_MAX			2000
+
+struct gb_bootrom_version_request {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+struct gb_bootrom_version_response {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+/* Bootrom protocol firmware size request/response */
+struct gb_bootrom_firmware_size_request {
+	__u8			stage;
+} __packed;
+
+struct gb_bootrom_firmware_size_response {
+	__le32			size;
+} __packed;
+
+/* Bootrom protocol get firmware request/response */
+struct gb_bootrom_get_firmware_request {
+	__le32			offset;
+	__le32			size;
+} __packed;
+
+struct gb_bootrom_get_firmware_response {
+	__u8			data[0];
+} __packed;
+
+/* Bootrom protocol Ready to boot request */
+struct gb_bootrom_ready_to_boot_request {
+	__u8			status;
+} __packed;
+/* Bootrom protocol Ready to boot response has no payload */
+
+/* Bootrom protocol get VID/PID request has no payload */
+struct gb_bootrom_get_vid_pid_response {
+	__le32			vendor_id;
+	__le32			product_id;
+} __packed;
+
+
+/* Power Supply */
+
+/* Greybus power supply request types */
+#define GB_POWER_SUPPLY_TYPE_GET_SUPPLIES		0x02
+#define GB_POWER_SUPPLY_TYPE_GET_DESCRIPTION		0x03
+#define GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS	0x04
+#define GB_POWER_SUPPLY_TYPE_GET_PROPERTY		0x05
+#define GB_POWER_SUPPLY_TYPE_SET_PROPERTY		0x06
+#define GB_POWER_SUPPLY_TYPE_EVENT			0x07
+
+/* Greybus power supply battery technologies types */
+#define GB_POWER_SUPPLY_TECH_UNKNOWN			0x0000
+#define GB_POWER_SUPPLY_TECH_NiMH			0x0001
+#define GB_POWER_SUPPLY_TECH_LION			0x0002
+#define GB_POWER_SUPPLY_TECH_LIPO			0x0003
+#define GB_POWER_SUPPLY_TECH_LiFe			0x0004
+#define GB_POWER_SUPPLY_TECH_NiCd			0x0005
+#define GB_POWER_SUPPLY_TECH_LiMn			0x0006
+
+/* Greybus power supply types */
+#define GB_POWER_SUPPLY_UNKNOWN_TYPE			0x0000
+#define GB_POWER_SUPPLY_BATTERY_TYPE			0x0001
+#define GB_POWER_SUPPLY_UPS_TYPE			0x0002
+#define GB_POWER_SUPPLY_MAINS_TYPE			0x0003
+#define GB_POWER_SUPPLY_USB_TYPE			0x0004
+#define GB_POWER_SUPPLY_USB_DCP_TYPE			0x0005
+#define GB_POWER_SUPPLY_USB_CDP_TYPE			0x0006
+#define GB_POWER_SUPPLY_USB_ACA_TYPE			0x0007
+
+/* Greybus power supply health values */
+#define GB_POWER_SUPPLY_HEALTH_UNKNOWN			0x0000
+#define GB_POWER_SUPPLY_HEALTH_GOOD			0x0001
+#define GB_POWER_SUPPLY_HEALTH_OVERHEAT			0x0002
+#define GB_POWER_SUPPLY_HEALTH_DEAD			0x0003
+#define GB_POWER_SUPPLY_HEALTH_OVERVOLTAGE		0x0004
+#define GB_POWER_SUPPLY_HEALTH_UNSPEC_FAILURE		0x0005
+#define GB_POWER_SUPPLY_HEALTH_COLD			0x0006
+#define GB_POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE	0x0007
+#define GB_POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE	0x0008
+
+/* Greybus power supply status values */
+#define GB_POWER_SUPPLY_STATUS_UNKNOWN			0x0000
+#define GB_POWER_SUPPLY_STATUS_CHARGING			0x0001
+#define GB_POWER_SUPPLY_STATUS_DISCHARGING		0x0002
+#define GB_POWER_SUPPLY_STATUS_NOT_CHARGING		0x0003
+#define GB_POWER_SUPPLY_STATUS_FULL			0x0004
+
+/* Greybus power supply capacity level values */
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN		0x0000
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL		0x0001
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_LOW		0x0002
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_NORMAL		0x0003
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_HIGH		0x0004
+#define GB_POWER_SUPPLY_CAPACITY_LEVEL_FULL		0x0005
+
+/* Greybus power supply scope values */
+#define GB_POWER_SUPPLY_SCOPE_UNKNOWN			0x0000
+#define GB_POWER_SUPPLY_SCOPE_SYSTEM			0x0001
+#define GB_POWER_SUPPLY_SCOPE_DEVICE			0x0002
+
+struct gb_power_supply_get_supplies_response {
+	__u8	supplies_count;
+} __packed;
+
+struct gb_power_supply_get_description_request {
+	__u8	psy_id;
+} __packed;
+
+struct gb_power_supply_get_description_response {
+	__u8	manufacturer[32];
+	__u8	model[32];
+	__u8	serial_number[32];
+	__le16	type;
+	__u8	properties_count;
+} __packed;
+
+struct gb_power_supply_props_desc {
+	__u8	property;
+#define GB_POWER_SUPPLY_PROP_STATUS				0x00
+#define GB_POWER_SUPPLY_PROP_CHARGE_TYPE			0x01
+#define GB_POWER_SUPPLY_PROP_HEALTH				0x02
+#define GB_POWER_SUPPLY_PROP_PRESENT				0x03
+#define GB_POWER_SUPPLY_PROP_ONLINE				0x04
+#define GB_POWER_SUPPLY_PROP_AUTHENTIC				0x05
+#define GB_POWER_SUPPLY_PROP_TECHNOLOGY				0x06
+#define GB_POWER_SUPPLY_PROP_CYCLE_COUNT			0x07
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_MAX			0x08
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_MIN			0x09
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN			0x0A
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN			0x0B
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_NOW			0x0C
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_AVG			0x0D
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_OCV			0x0E
+#define GB_POWER_SUPPLY_PROP_VOLTAGE_BOOT			0x0F
+#define GB_POWER_SUPPLY_PROP_CURRENT_MAX			0x10
+#define GB_POWER_SUPPLY_PROP_CURRENT_NOW			0x11
+#define GB_POWER_SUPPLY_PROP_CURRENT_AVG			0x12
+#define GB_POWER_SUPPLY_PROP_CURRENT_BOOT			0x13
+#define GB_POWER_SUPPLY_PROP_POWER_NOW				0x14
+#define GB_POWER_SUPPLY_PROP_POWER_AVG				0x15
+#define GB_POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN			0x16
+#define GB_POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN		0x17
+#define GB_POWER_SUPPLY_PROP_CHARGE_FULL			0x18
+#define GB_POWER_SUPPLY_PROP_CHARGE_EMPTY			0x19
+#define GB_POWER_SUPPLY_PROP_CHARGE_NOW				0x1A
+#define GB_POWER_SUPPLY_PROP_CHARGE_AVG				0x1B
+#define GB_POWER_SUPPLY_PROP_CHARGE_COUNTER			0x1C
+#define GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT		0x1D
+#define GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX	0x1E
+#define GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE		0x1F
+#define GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX	0x20
+#define GB_POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT		0x21
+#define GB_POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX		0x22
+#define GB_POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT		0x23
+#define GB_POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN			0x24
+#define GB_POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN		0x25
+#define GB_POWER_SUPPLY_PROP_ENERGY_FULL			0x26
+#define GB_POWER_SUPPLY_PROP_ENERGY_EMPTY			0x27
+#define GB_POWER_SUPPLY_PROP_ENERGY_NOW				0x28
+#define GB_POWER_SUPPLY_PROP_ENERGY_AVG				0x29
+#define GB_POWER_SUPPLY_PROP_CAPACITY				0x2A
+#define GB_POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN			0x2B
+#define GB_POWER_SUPPLY_PROP_CAPACITY_ALERT_MAX			0x2C
+#define GB_POWER_SUPPLY_PROP_CAPACITY_LEVEL			0x2D
+#define GB_POWER_SUPPLY_PROP_TEMP				0x2E
+#define GB_POWER_SUPPLY_PROP_TEMP_MAX				0x2F
+#define GB_POWER_SUPPLY_PROP_TEMP_MIN				0x30
+#define GB_POWER_SUPPLY_PROP_TEMP_ALERT_MIN			0x31
+#define GB_POWER_SUPPLY_PROP_TEMP_ALERT_MAX			0x32
+#define GB_POWER_SUPPLY_PROP_TEMP_AMBIENT			0x33
+#define GB_POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN		0x34
+#define GB_POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX		0x35
+#define GB_POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW			0x36
+#define GB_POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG			0x37
+#define GB_POWER_SUPPLY_PROP_TIME_TO_FULL_NOW			0x38
+#define GB_POWER_SUPPLY_PROP_TIME_TO_FULL_AVG			0x39
+#define GB_POWER_SUPPLY_PROP_TYPE				0x3A
+#define GB_POWER_SUPPLY_PROP_SCOPE				0x3B
+#define GB_POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT		0x3C
+#define GB_POWER_SUPPLY_PROP_CALIBRATE				0x3D
+	__u8	is_writeable;
+} __packed;
+
+struct gb_power_supply_get_property_descriptors_request {
+	__u8	psy_id;
+} __packed;
+
+struct gb_power_supply_get_property_descriptors_response {
+	__u8	properties_count;
+	struct gb_power_supply_props_desc props[];
+} __packed;
+
+struct gb_power_supply_get_property_request {
+	__u8	psy_id;
+	__u8	property;
+} __packed;
+
+struct gb_power_supply_get_property_response {
+	__le32	prop_val;
+};
+
+struct gb_power_supply_set_property_request {
+	__u8	psy_id;
+	__u8	property;
+	__le32	prop_val;
+} __packed;
+
+struct gb_power_supply_event_request {
+	__u8	psy_id;
+	__u8	event;
+#define GB_POWER_SUPPLY_UPDATE		0x01
+} __packed;
+
+
+/* HID */
+
+/* Greybus HID operation types */
+#define GB_HID_TYPE_GET_DESC		0x02
+#define GB_HID_TYPE_GET_REPORT_DESC	0x03
+#define GB_HID_TYPE_PWR_ON		0x04
+#define GB_HID_TYPE_PWR_OFF		0x05
+#define GB_HID_TYPE_GET_REPORT		0x06
+#define GB_HID_TYPE_SET_REPORT		0x07
+#define GB_HID_TYPE_IRQ_EVENT		0x08
+
+/* Report type */
+#define GB_HID_INPUT_REPORT		0
+#define GB_HID_OUTPUT_REPORT		1
+#define GB_HID_FEATURE_REPORT		2
+
+/* Different request/response structures */
+/* HID get descriptor response */
+struct gb_hid_desc_response {
+	__u8				bLength;
+	__le16				wReportDescLength;
+	__le16				bcdHID;
+	__le16				wProductID;
+	__le16				wVendorID;
+	__u8				bCountryCode;
+} __packed;
+
+/* HID get report request/response */
+struct gb_hid_get_report_request {
+	__u8				report_type;
+	__u8				report_id;
+} __packed;
+
+/* HID set report request */
+struct gb_hid_set_report_request {
+	__u8				report_type;
+	__u8				report_id;
+	__u8				report[0];
+} __packed;
+
+/* HID input report request, via interrupt pipe */
+struct gb_hid_input_report_request {
+	__u8				report[0];
+} __packed;
+
+
+/* I2C */
+
+/* Greybus i2c request types */
+#define GB_I2C_TYPE_FUNCTIONALITY	0x02
+#define GB_I2C_TYPE_TRANSFER		0x05
+
+/* functionality request has no payload */
+struct gb_i2c_functionality_response {
+	__le32	functionality;
+} __packed;
+
+/*
+ * Outgoing data immediately follows the op count and ops array.
+ * The data for each write (master -> slave) op in the array is sent
+ * in order, with no (e.g. pad) bytes separating them.
+ *
+ * Short reads cause the entire transfer request to fail So response
+ * payload consists only of bytes read, and the number of bytes is
+ * exactly what was specified in the corresponding op.  Like
+ * outgoing data, the incoming data is in order and contiguous.
+ */
+struct gb_i2c_transfer_op {
+	__le16	addr;
+	__le16	flags;
+	__le16	size;
+} __packed;
+
+struct gb_i2c_transfer_request {
+	__le16				op_count;
+	struct gb_i2c_transfer_op	ops[0];		/* op_count of these */
+} __packed;
+struct gb_i2c_transfer_response {
+	__u8				data[0];	/* inbound data */
+} __packed;
+
+
+/* GPIO */
+
+/* Greybus GPIO request types */
+#define GB_GPIO_TYPE_LINE_COUNT		0x02
+#define GB_GPIO_TYPE_ACTIVATE		0x03
+#define GB_GPIO_TYPE_DEACTIVATE		0x04
+#define GB_GPIO_TYPE_GET_DIRECTION	0x05
+#define GB_GPIO_TYPE_DIRECTION_IN	0x06
+#define GB_GPIO_TYPE_DIRECTION_OUT	0x07
+#define GB_GPIO_TYPE_GET_VALUE		0x08
+#define GB_GPIO_TYPE_SET_VALUE		0x09
+#define GB_GPIO_TYPE_SET_DEBOUNCE	0x0a
+#define GB_GPIO_TYPE_IRQ_TYPE		0x0b
+#define GB_GPIO_TYPE_IRQ_MASK		0x0c
+#define GB_GPIO_TYPE_IRQ_UNMASK		0x0d
+#define GB_GPIO_TYPE_IRQ_EVENT		0x0e
+
+#define GB_GPIO_IRQ_TYPE_NONE		0x00
+#define GB_GPIO_IRQ_TYPE_EDGE_RISING	0x01
+#define GB_GPIO_IRQ_TYPE_EDGE_FALLING	0x02
+#define GB_GPIO_IRQ_TYPE_EDGE_BOTH	0x03
+#define GB_GPIO_IRQ_TYPE_LEVEL_HIGH	0x04
+#define GB_GPIO_IRQ_TYPE_LEVEL_LOW	0x08
+
+/* line count request has no payload */
+struct gb_gpio_line_count_response {
+	__u8	count;
+} __packed;
+
+struct gb_gpio_activate_request {
+	__u8	which;
+} __packed;
+/* activate response has no payload */
+
+struct gb_gpio_deactivate_request {
+	__u8	which;
+} __packed;
+/* deactivate response has no payload */
+
+struct gb_gpio_get_direction_request {
+	__u8	which;
+} __packed;
+struct gb_gpio_get_direction_response {
+	__u8	direction;
+} __packed;
+
+struct gb_gpio_direction_in_request {
+	__u8	which;
+} __packed;
+/* direction in response has no payload */
+
+struct gb_gpio_direction_out_request {
+	__u8	which;
+	__u8	value;
+} __packed;
+/* direction out response has no payload */
+
+struct gb_gpio_get_value_request {
+	__u8	which;
+} __packed;
+struct gb_gpio_get_value_response {
+	__u8	value;
+} __packed;
+
+struct gb_gpio_set_value_request {
+	__u8	which;
+	__u8	value;
+} __packed;
+/* set value response has no payload */
+
+struct gb_gpio_set_debounce_request {
+	__u8	which;
+	__le16	usec;
+} __packed;
+/* debounce response has no payload */
+
+struct gb_gpio_irq_type_request {
+	__u8	which;
+	__u8	type;
+} __packed;
+/* irq type response has no payload */
+
+struct gb_gpio_irq_mask_request {
+	__u8	which;
+} __packed;
+/* irq mask response has no payload */
+
+struct gb_gpio_irq_unmask_request {
+	__u8	which;
+} __packed;
+/* irq unmask response has no payload */
+
+/* irq event requests originate on another module and are handled on the AP */
+struct gb_gpio_irq_event_request {
+	__u8	which;
+} __packed;
+/* irq event has no response */
+
+
+/* PWM */
+
+/* Greybus PWM operation types */
+#define GB_PWM_TYPE_PWM_COUNT		0x02
+#define GB_PWM_TYPE_ACTIVATE		0x03
+#define GB_PWM_TYPE_DEACTIVATE		0x04
+#define GB_PWM_TYPE_CONFIG		0x05
+#define GB_PWM_TYPE_POLARITY		0x06
+#define GB_PWM_TYPE_ENABLE		0x07
+#define GB_PWM_TYPE_DISABLE		0x08
+
+/* pwm count request has no payload */
+struct gb_pwm_count_response {
+	__u8	count;
+} __packed;
+
+struct gb_pwm_activate_request {
+	__u8	which;
+} __packed;
+
+struct gb_pwm_deactivate_request {
+	__u8	which;
+} __packed;
+
+struct gb_pwm_config_request {
+	__u8	which;
+	__le32	duty;
+	__le32	period;
+} __packed;
+
+struct gb_pwm_polarity_request {
+	__u8	which;
+	__u8	polarity;
+} __packed;
+
+struct gb_pwm_enable_request {
+	__u8	which;
+} __packed;
+
+struct gb_pwm_disable_request {
+	__u8	which;
+} __packed;
+
+/* SPI */
+
+/* Should match up with modes in linux/spi/spi.h */
+#define GB_SPI_MODE_CPHA		0x01		/* clock phase */
+#define GB_SPI_MODE_CPOL		0x02		/* clock polarity */
+#define GB_SPI_MODE_MODE_0		(0|0)		/* (original MicroWire) */
+#define GB_SPI_MODE_MODE_1		(0|GB_SPI_MODE_CPHA)
+#define GB_SPI_MODE_MODE_2		(GB_SPI_MODE_CPOL|0)
+#define GB_SPI_MODE_MODE_3		(GB_SPI_MODE_CPOL|GB_SPI_MODE_CPHA)
+#define GB_SPI_MODE_CS_HIGH		0x04		/* chipselect active high? */
+#define GB_SPI_MODE_LSB_FIRST		0x08		/* per-word bits-on-wire */
+#define GB_SPI_MODE_3WIRE		0x10		/* SI/SO signals shared */
+#define GB_SPI_MODE_LOOP		0x20		/* loopback mode */
+#define GB_SPI_MODE_NO_CS		0x40		/* 1 dev/bus, no chipselect */
+#define GB_SPI_MODE_READY		0x80		/* slave pulls low to pause */
+
+/* Should match up with flags in linux/spi/spi.h */
+#define GB_SPI_FLAG_HALF_DUPLEX		BIT(0)		/* can't do full duplex */
+#define GB_SPI_FLAG_NO_RX		BIT(1)		/* can't do buffer read */
+#define GB_SPI_FLAG_NO_TX		BIT(2)		/* can't do buffer write */
+
+/* Greybus spi operation types */
+#define GB_SPI_TYPE_MASTER_CONFIG	0x02
+#define GB_SPI_TYPE_DEVICE_CONFIG	0x03
+#define GB_SPI_TYPE_TRANSFER		0x04
+
+/* mode request has no payload */
+struct gb_spi_master_config_response {
+	__le32	bits_per_word_mask;
+	__le32	min_speed_hz;
+	__le32	max_speed_hz;
+	__le16	mode;
+	__le16	flags;
+	__u8	num_chipselect;
+} __packed;
+
+struct gb_spi_device_config_request {
+	__u8	chip_select;
+} __packed;
+
+struct gb_spi_device_config_response {
+	__le16	mode;
+	__u8	bits_per_word;
+	__le32	max_speed_hz;
+	__u8	device_type;
+#define GB_SPI_SPI_DEV		0x00
+#define GB_SPI_SPI_NOR		0x01
+#define GB_SPI_SPI_MODALIAS	0x02
+	__u8	name[32];
+} __packed;
+
+/**
+ * struct gb_spi_transfer - a read/write buffer pair
+ * @speed_hz: Select a speed other than the device default for this transfer. If
+ *	0 the default (from @spi_device) is used.
+ * @len: size of rx and tx buffers (in bytes)
+ * @delay_usecs: microseconds to delay after this transfer before (optionally)
+ * 	changing the chipselect status, then starting the next transfer or
+ * 	completing this spi_message.
+ * @cs_change: affects chipselect after this transfer completes
+ * @bits_per_word: select a bits_per_word other than the device default for this
+ *	transfer. If 0 the default (from @spi_device) is used.
+ */
+struct gb_spi_transfer {
+	__le32		speed_hz;
+	__le32		len;
+	__le16		delay_usecs;
+	__u8		cs_change;
+	__u8		bits_per_word;
+	__u8		xfer_flags;
+#define GB_SPI_XFER_READ	0x01
+#define GB_SPI_XFER_WRITE	0x02
+#define GB_SPI_XFER_INPROGRESS	0x04
+} __packed;
+
+struct gb_spi_transfer_request {
+	__u8			chip_select;	/* of the spi device */
+	__u8			mode;		/* of the spi device */
+	__le16			count;
+	struct gb_spi_transfer	transfers[0];	/* count of these */
+} __packed;
+
+struct gb_spi_transfer_response {
+	__u8			data[0];	/* inbound data */
+} __packed;
+
+/* Version of the Greybus SVC protocol we support */
+#define GB_SVC_VERSION_MAJOR		0x00
+#define GB_SVC_VERSION_MINOR		0x01
+
+/* Greybus SVC request types */
+#define GB_SVC_TYPE_PROTOCOL_VERSION		0x01
+#define GB_SVC_TYPE_SVC_HELLO			0x02
+#define GB_SVC_TYPE_INTF_DEVICE_ID		0x03
+#define GB_SVC_TYPE_INTF_RESET			0x06
+#define GB_SVC_TYPE_CONN_CREATE			0x07
+#define GB_SVC_TYPE_CONN_DESTROY		0x08
+#define GB_SVC_TYPE_DME_PEER_GET		0x09
+#define GB_SVC_TYPE_DME_PEER_SET		0x0a
+#define GB_SVC_TYPE_ROUTE_CREATE		0x0b
+#define GB_SVC_TYPE_ROUTE_DESTROY		0x0c
+#define GB_SVC_TYPE_TIMESYNC_ENABLE		0x0d
+#define GB_SVC_TYPE_TIMESYNC_DISABLE		0x0e
+#define GB_SVC_TYPE_TIMESYNC_AUTHORITATIVE	0x0f
+#define GB_SVC_TYPE_INTF_SET_PWRM		0x10
+#define GB_SVC_TYPE_INTF_EJECT			0x11
+#define GB_SVC_TYPE_PING			0x13
+#define GB_SVC_TYPE_PWRMON_RAIL_COUNT_GET	0x14
+#define GB_SVC_TYPE_PWRMON_RAIL_NAMES_GET	0x15
+#define GB_SVC_TYPE_PWRMON_SAMPLE_GET		0x16
+#define GB_SVC_TYPE_PWRMON_INTF_SAMPLE_GET	0x17
+#define GB_SVC_TYPE_TIMESYNC_WAKE_PINS_ACQUIRE	0x18
+#define GB_SVC_TYPE_TIMESYNC_WAKE_PINS_RELEASE	0x19
+#define GB_SVC_TYPE_TIMESYNC_PING		0x1a
+#define GB_SVC_TYPE_MODULE_INSERTED		0x1f
+#define GB_SVC_TYPE_MODULE_REMOVED		0x20
+#define GB_SVC_TYPE_INTF_VSYS_ENABLE		0x21
+#define GB_SVC_TYPE_INTF_VSYS_DISABLE		0x22
+#define GB_SVC_TYPE_INTF_REFCLK_ENABLE		0x23
+#define GB_SVC_TYPE_INTF_REFCLK_DISABLE		0x24
+#define GB_SVC_TYPE_INTF_UNIPRO_ENABLE		0x25
+#define GB_SVC_TYPE_INTF_UNIPRO_DISABLE		0x26
+#define GB_SVC_TYPE_INTF_ACTIVATE		0x27
+#define GB_SVC_TYPE_INTF_RESUME			0x28
+#define GB_SVC_TYPE_INTF_MAILBOX_EVENT		0x29
+#define GB_SVC_TYPE_INTF_OOPS			0x2a
+
+/* Greybus SVC protocol status values */
+#define GB_SVC_OP_SUCCESS			0x00
+#define GB_SVC_OP_UNKNOWN_ERROR			0x01
+#define GB_SVC_INTF_NOT_DETECTED		0x02
+#define GB_SVC_INTF_NO_UPRO_LINK		0x03
+#define GB_SVC_INTF_UPRO_NOT_DOWN		0x04
+#define GB_SVC_INTF_UPRO_NOT_HIBERNATED		0x05
+#define GB_SVC_INTF_NO_V_SYS			0x06
+#define GB_SVC_INTF_V_CHG			0x07
+#define GB_SVC_INTF_WAKE_BUSY			0x08
+#define GB_SVC_INTF_NO_REFCLK			0x09
+#define GB_SVC_INTF_RELEASING			0x0a
+#define GB_SVC_INTF_NO_ORDER			0x0b
+#define GB_SVC_INTF_MBOX_SET			0x0c
+#define GB_SVC_INTF_BAD_MBOX			0x0d
+#define GB_SVC_INTF_OP_TIMEOUT			0x0e
+#define GB_SVC_PWRMON_OP_NOT_PRESENT		0x0f
+
+struct gb_svc_version_request {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+struct gb_svc_version_response {
+	__u8	major;
+	__u8	minor;
+} __packed;
+
+/* SVC protocol hello request */
+struct gb_svc_hello_request {
+	__le16			endo_id;
+	__u8			interface_id;
+} __packed;
+/* hello response has no payload */
+
+struct gb_svc_intf_device_id_request {
+	__u8	intf_id;
+	__u8	device_id;
+} __packed;
+/* device id response has no payload */
+
+struct gb_svc_intf_reset_request {
+	__u8	intf_id;
+} __packed;
+/* interface reset response has no payload */
+
+struct gb_svc_intf_eject_request {
+	__u8	intf_id;
+} __packed;
+/* interface eject response has no payload */
+
+struct gb_svc_conn_create_request {
+	__u8	intf1_id;
+	__le16	cport1_id;
+	__u8	intf2_id;
+	__le16	cport2_id;
+	__u8	tc;
+	__u8	flags;
+} __packed;
+/* connection create response has no payload */
+
+struct gb_svc_conn_destroy_request {
+	__u8	intf1_id;
+	__le16	cport1_id;
+	__u8	intf2_id;
+	__le16	cport2_id;
+} __packed;
+/* connection destroy response has no payload */
+
+struct gb_svc_dme_peer_get_request {
+	__u8	intf_id;
+	__le16	attr;
+	__le16	selector;
+} __packed;
+
+struct gb_svc_dme_peer_get_response {
+	__le16	result_code;
+	__le32	attr_value;
+} __packed;
+
+struct gb_svc_dme_peer_set_request {
+	__u8	intf_id;
+	__le16	attr;
+	__le16	selector;
+	__le32	value;
+} __packed;
+
+struct gb_svc_dme_peer_set_response {
+	__le16	result_code;
+} __packed;
+
+/* Greybus init-status values, currently retrieved using DME peer gets. */
+#define GB_INIT_SPI_BOOT_STARTED			0x02
+#define GB_INIT_TRUSTED_SPI_BOOT_FINISHED		0x03
+#define GB_INIT_UNTRUSTED_SPI_BOOT_FINISHED		0x04
+#define GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED		0x06
+#define GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED	0x09
+#define GB_INIT_S2_LOADER_BOOT_STARTED			0x0D
+
+struct gb_svc_route_create_request {
+	__u8	intf1_id;
+	__u8	dev1_id;
+	__u8	intf2_id;
+	__u8	dev2_id;
+} __packed;
+/* route create response has no payload */
+
+struct gb_svc_route_destroy_request {
+	__u8	intf1_id;
+	__u8	intf2_id;
+} __packed;
+/* route destroy response has no payload */
+
+/* used for svc_intf_vsys_{enable,disable} */
+struct gb_svc_intf_vsys_request {
+	__u8	intf_id;
+} __packed;
+
+struct gb_svc_intf_vsys_response {
+	__u8	result_code;
+#define GB_SVC_INTF_VSYS_OK				0x00
+	/* 0x01 is reserved */
+#define GB_SVC_INTF_VSYS_FAIL				0x02
+} __packed;
+
+/* used for svc_intf_refclk_{enable,disable} */
+struct gb_svc_intf_refclk_request {
+	__u8	intf_id;
+} __packed;
+
+struct gb_svc_intf_refclk_response {
+	__u8	result_code;
+#define GB_SVC_INTF_REFCLK_OK				0x00
+	/* 0x01 is reserved */
+#define GB_SVC_INTF_REFCLK_FAIL				0x02
+} __packed;
+
+/* used for svc_intf_unipro_{enable,disable} */
+struct gb_svc_intf_unipro_request {
+	__u8	intf_id;
+} __packed;
+
+struct gb_svc_intf_unipro_response {
+	__u8	result_code;
+#define GB_SVC_INTF_UNIPRO_OK				0x00
+	/* 0x01 is reserved */
+#define GB_SVC_INTF_UNIPRO_FAIL				0x02
+#define GB_SVC_INTF_UNIPRO_NOT_OFF			0x03
+} __packed;
+
+struct gb_svc_timesync_enable_request {
+	__u8	count;
+	__le64	frame_time;
+	__le32	strobe_delay;
+	__le32	refclk;
+} __packed;
+/* timesync enable response has no payload */
+
+/* timesync authoritative request has no payload */
+struct gb_svc_timesync_authoritative_response {
+	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
+};
+
+struct gb_svc_timesync_wake_pins_acquire_request {
+	__le32	strobe_mask;
+};
+
+/* timesync wake pins acquire response has no payload */
+
+/* timesync wake pins release request has no payload */
+/* timesync wake pins release response has no payload */
+
+/* timesync svc ping request has no payload */
+struct gb_svc_timesync_ping_response {
+	__le64	frame_time;
+} __packed;
+
+#define GB_SVC_UNIPRO_FAST_MODE			0x01
+#define GB_SVC_UNIPRO_SLOW_MODE			0x02
+#define GB_SVC_UNIPRO_FAST_AUTO_MODE		0x04
+#define GB_SVC_UNIPRO_SLOW_AUTO_MODE		0x05
+#define GB_SVC_UNIPRO_MODE_UNCHANGED		0x07
+#define GB_SVC_UNIPRO_HIBERNATE_MODE		0x11
+#define GB_SVC_UNIPRO_OFF_MODE			0x12
+
+#define GB_SVC_SMALL_AMPLITUDE          0x01
+#define GB_SVC_LARGE_AMPLITUDE          0x02
+
+#define GB_SVC_NO_DE_EMPHASIS           0x00
+#define GB_SVC_SMALL_DE_EMPHASIS        0x01
+#define GB_SVC_LARGE_DE_EMPHASIS        0x02
+
+#define GB_SVC_PWRM_RXTERMINATION		0x01
+#define GB_SVC_PWRM_TXTERMINATION		0x02
+#define GB_SVC_PWRM_LINE_RESET			0x04
+#define GB_SVC_PWRM_SCRAMBLING			0x20
+
+#define GB_SVC_PWRM_QUIRK_HSSER			0x00000001
+
+#define GB_SVC_UNIPRO_HS_SERIES_A		0x01
+#define GB_SVC_UNIPRO_HS_SERIES_B		0x02
+
+#define GB_SVC_SETPWRM_PWR_OK           0x00
+#define GB_SVC_SETPWRM_PWR_LOCAL        0x01
+#define GB_SVC_SETPWRM_PWR_REMOTE       0x02
+#define GB_SVC_SETPWRM_PWR_BUSY         0x03
+#define GB_SVC_SETPWRM_PWR_ERROR_CAP    0x04
+#define GB_SVC_SETPWRM_PWR_FATAL_ERROR  0x05
+
+struct gb_svc_l2_timer_cfg {
+	__le16 tsb_fc0_protection_timeout;
+	__le16 tsb_tc0_replay_timeout;
+	__le16 tsb_afc0_req_timeout;
+	__le16 tsb_fc1_protection_timeout;
+	__le16 tsb_tc1_replay_timeout;
+	__le16 tsb_afc1_req_timeout;
+	__le16 reserved_for_tc2[3];
+	__le16 reserved_for_tc3[3];
+} __packed;
+
+struct gb_svc_intf_set_pwrm_request {
+	__u8	intf_id;
+	__u8	hs_series;
+	__u8	tx_mode;
+	__u8	tx_gear;
+	__u8	tx_nlanes;
+	__u8	tx_amplitude;
+	__u8	tx_hs_equalizer;
+	__u8	rx_mode;
+	__u8	rx_gear;
+	__u8	rx_nlanes;
+	__u8	flags;
+	__le32	quirks;
+	struct gb_svc_l2_timer_cfg local_l2timerdata, remote_l2timerdata;
+} __packed;
+
+struct gb_svc_intf_set_pwrm_response {
+	__u8	result_code;
+} __packed;
+
+struct gb_svc_key_event_request {
+	__le16  key_code;
+#define GB_KEYCODE_ARA         0x00
+
+	__u8    key_event;
+#define GB_SVC_KEY_RELEASED    0x00
+#define GB_SVC_KEY_PRESSED     0x01
+} __packed;
+
+#define GB_SVC_PWRMON_MAX_RAIL_COUNT		254
+
+struct gb_svc_pwrmon_rail_count_get_response {
+	__u8	rail_count;
+} __packed;
+
+#define GB_SVC_PWRMON_RAIL_NAME_BUFSIZE		32
+
+struct gb_svc_pwrmon_rail_names_get_response {
+	__u8	status;
+	__u8	name[0][GB_SVC_PWRMON_RAIL_NAME_BUFSIZE];
+} __packed;
+
+#define GB_SVC_PWRMON_TYPE_CURR			0x01
+#define GB_SVC_PWRMON_TYPE_VOL			0x02
+#define GB_SVC_PWRMON_TYPE_PWR			0x03
+
+#define GB_SVC_PWRMON_GET_SAMPLE_OK		0x00
+#define GB_SVC_PWRMON_GET_SAMPLE_INVAL		0x01
+#define GB_SVC_PWRMON_GET_SAMPLE_NOSUPP		0x02
+#define GB_SVC_PWRMON_GET_SAMPLE_HWERR		0x03
+
+struct gb_svc_pwrmon_sample_get_request {
+	__u8	rail_id;
+	__u8	measurement_type;
+} __packed;
+
+struct gb_svc_pwrmon_sample_get_response {
+	__u8	result;
+	__le32	measurement;
+} __packed;
+
+struct gb_svc_pwrmon_intf_sample_get_request {
+	__u8	intf_id;
+	__u8	measurement_type;
+} __packed;
+
+struct gb_svc_pwrmon_intf_sample_get_response {
+	__u8	result;
+	__le32	measurement;
+} __packed;
+
+#define GB_SVC_MODULE_INSERTED_FLAG_NO_PRIMARY	0x0001
+
+struct gb_svc_module_inserted_request {
+	__u8	primary_intf_id;
+	__u8	intf_count;
+	__le16	flags;
+} __packed;
+/* module_inserted response has no payload */
+
+struct gb_svc_module_removed_request {
+	__u8	primary_intf_id;
+} __packed;
+/* module_removed response has no payload */
+
+struct gb_svc_intf_activate_request {
+	__u8	intf_id;
+} __packed;
+
+#define GB_SVC_INTF_TYPE_UNKNOWN		0x00
+#define GB_SVC_INTF_TYPE_DUMMY			0x01
+#define GB_SVC_INTF_TYPE_UNIPRO			0x02
+#define GB_SVC_INTF_TYPE_GREYBUS		0x03
+
+struct gb_svc_intf_activate_response {
+	__u8	status;
+	__u8	intf_type;
+} __packed;
+
+struct gb_svc_intf_resume_request {
+	__u8	intf_id;
+} __packed;
+
+struct gb_svc_intf_resume_response {
+	__u8	status;
+} __packed;
+
+#define GB_SVC_INTF_MAILBOX_NONE		0x00
+#define GB_SVC_INTF_MAILBOX_AP			0x01
+#define GB_SVC_INTF_MAILBOX_GREYBUS		0x02
+
+struct gb_svc_intf_mailbox_event_request {
+	__u8	intf_id;
+	__le16	result_code;
+	__le32	mailbox;
+} __packed;
+/* intf_mailbox_event response has no payload */
+
+struct gb_svc_intf_oops_request {
+	__u8	intf_id;
+	__u8	reason;
+} __packed;
+/* intf_oops response has no payload */
+
+
+/* RAW */
+
+/* Greybus raw request types */
+#define	GB_RAW_TYPE_SEND			0x02
+
+struct gb_raw_send_request {
+	__le32	len;
+	__u8	data[0];
+} __packed;
+
+
+/* UART */
+
+/* Greybus UART operation types */
+#define GB_UART_TYPE_SEND_DATA			0x02
+#define GB_UART_TYPE_RECEIVE_DATA		0x03	/* Unsolicited data */
+#define GB_UART_TYPE_SET_LINE_CODING		0x04
+#define GB_UART_TYPE_SET_CONTROL_LINE_STATE	0x05
+#define GB_UART_TYPE_SEND_BREAK			0x06
+#define GB_UART_TYPE_SERIAL_STATE		0x07	/* Unsolicited data */
+#define GB_UART_TYPE_RECEIVE_CREDITS		0x08
+#define GB_UART_TYPE_FLUSH_FIFOS		0x09
+
+/* Represents data from AP -> Module */
+struct gb_uart_send_data_request {
+	__le16	size;
+	__u8	data[0];
+} __packed;
+
+/* recv-data-request flags */
+#define GB_UART_RECV_FLAG_FRAMING		0x01	/* Framing error */
+#define GB_UART_RECV_FLAG_PARITY		0x02	/* Parity error */
+#define GB_UART_RECV_FLAG_OVERRUN		0x04	/* Overrun error */
+#define GB_UART_RECV_FLAG_BREAK			0x08	/* Break */
+
+/* Represents data from Module -> AP */
+struct gb_uart_recv_data_request {
+	__le16	size;
+	__u8	flags;
+	__u8	data[0];
+} __packed;
+
+struct gb_uart_receive_credits_request {
+	__le16  count;
+} __packed;
+
+struct gb_uart_set_line_coding_request {
+	__le32	rate;
+	__u8	format;
+#define GB_SERIAL_1_STOP_BITS			0
+#define GB_SERIAL_1_5_STOP_BITS			1
+#define GB_SERIAL_2_STOP_BITS			2
+
+	__u8	parity;
+#define GB_SERIAL_NO_PARITY			0
+#define GB_SERIAL_ODD_PARITY			1
+#define GB_SERIAL_EVEN_PARITY			2
+#define GB_SERIAL_MARK_PARITY			3
+#define GB_SERIAL_SPACE_PARITY			4
+
+	__u8	data_bits;
+
+	__u8	flow_control;
+#define GB_SERIAL_AUTO_RTSCTS_EN		0x1
+} __packed;
+
+/* output control lines */
+#define GB_UART_CTRL_DTR			0x01
+#define GB_UART_CTRL_RTS			0x02
+
+struct gb_uart_set_control_line_state_request {
+	__u8	control;
+} __packed;
+
+struct gb_uart_set_break_request {
+	__u8	state;
+} __packed;
+
+/* input control lines and line errors */
+#define GB_UART_CTRL_DCD			0x01
+#define GB_UART_CTRL_DSR			0x02
+#define GB_UART_CTRL_RI				0x04
+
+struct gb_uart_serial_state_request {
+	__u8	control;
+} __packed;
+
+struct gb_uart_serial_flush_request {
+	__u8    flags;
+#define GB_SERIAL_FLAG_FLUSH_TRANSMITTER	0x01
+#define GB_SERIAL_FLAG_FLUSH_RECEIVER		0x02
+} __packed;
+
+/* Loopback */
+
+/* Greybus loopback request types */
+#define GB_LOOPBACK_TYPE_PING			0x02
+#define GB_LOOPBACK_TYPE_TRANSFER		0x03
+#define GB_LOOPBACK_TYPE_SINK			0x04
+
+/*
+ * Loopback request/response header format should be identical
+ * to simplify bandwidth and data movement analysis.
+ */
+struct gb_loopback_transfer_request {
+	__le32	len;
+	__le32  reserved0;
+	__le32  reserved1;
+	__u8	data[0];
+} __packed;
+
+struct gb_loopback_transfer_response {
+	__le32	len;
+	__le32	reserved0;
+	__le32	reserved1;
+	__u8	data[0];
+} __packed;
+
+/* SDIO */
+/* Greybus SDIO operation types */
+#define GB_SDIO_TYPE_GET_CAPABILITIES		0x02
+#define GB_SDIO_TYPE_SET_IOS			0x03
+#define GB_SDIO_TYPE_COMMAND			0x04
+#define GB_SDIO_TYPE_TRANSFER			0x05
+#define GB_SDIO_TYPE_EVENT			0x06
+
+/* get caps response: request has no payload */
+struct gb_sdio_get_caps_response {
+	__le32	caps;
+#define GB_SDIO_CAP_NONREMOVABLE	0x00000001
+#define GB_SDIO_CAP_4_BIT_DATA		0x00000002
+#define GB_SDIO_CAP_8_BIT_DATA		0x00000004
+#define GB_SDIO_CAP_MMC_HS		0x00000008
+#define GB_SDIO_CAP_SD_HS		0x00000010
+#define GB_SDIO_CAP_ERASE		0x00000020
+#define GB_SDIO_CAP_1_2V_DDR		0x00000040
+#define GB_SDIO_CAP_1_8V_DDR		0x00000080
+#define GB_SDIO_CAP_POWER_OFF_CARD	0x00000100
+#define GB_SDIO_CAP_UHS_SDR12		0x00000200
+#define GB_SDIO_CAP_UHS_SDR25		0x00000400
+#define GB_SDIO_CAP_UHS_SDR50		0x00000800
+#define GB_SDIO_CAP_UHS_SDR104		0x00001000
+#define GB_SDIO_CAP_UHS_DDR50		0x00002000
+#define GB_SDIO_CAP_DRIVER_TYPE_A	0x00004000
+#define GB_SDIO_CAP_DRIVER_TYPE_C	0x00008000
+#define GB_SDIO_CAP_DRIVER_TYPE_D	0x00010000
+#define GB_SDIO_CAP_HS200_1_2V		0x00020000
+#define GB_SDIO_CAP_HS200_1_8V		0x00040000
+#define GB_SDIO_CAP_HS400_1_2V		0x00080000
+#define GB_SDIO_CAP_HS400_1_8V		0x00100000
+
+	/* see possible values below at vdd */
+	__le32 ocr;
+	__le32 f_min;
+	__le32 f_max;
+	__le16 max_blk_count;
+	__le16 max_blk_size;
+} __packed;
+
+/* set ios request: response has no payload */
+struct gb_sdio_set_ios_request {
+	__le32	clock;
+	__le32	vdd;
+#define GB_SDIO_VDD_165_195	0x00000001
+#define GB_SDIO_VDD_20_21	0x00000002
+#define GB_SDIO_VDD_21_22	0x00000004
+#define GB_SDIO_VDD_22_23	0x00000008
+#define GB_SDIO_VDD_23_24	0x00000010
+#define GB_SDIO_VDD_24_25	0x00000020
+#define GB_SDIO_VDD_25_26	0x00000040
+#define GB_SDIO_VDD_26_27	0x00000080
+#define GB_SDIO_VDD_27_28	0x00000100
+#define GB_SDIO_VDD_28_29	0x00000200
+#define GB_SDIO_VDD_29_30	0x00000400
+#define GB_SDIO_VDD_30_31	0x00000800
+#define GB_SDIO_VDD_31_32	0x00001000
+#define GB_SDIO_VDD_32_33	0x00002000
+#define GB_SDIO_VDD_33_34	0x00004000
+#define GB_SDIO_VDD_34_35	0x00008000
+#define GB_SDIO_VDD_35_36	0x00010000
+
+	__u8	bus_mode;
+#define GB_SDIO_BUSMODE_OPENDRAIN	0x00
+#define GB_SDIO_BUSMODE_PUSHPULL	0x01
+
+	__u8	power_mode;
+#define GB_SDIO_POWER_OFF	0x00
+#define GB_SDIO_POWER_UP	0x01
+#define GB_SDIO_POWER_ON	0x02
+#define GB_SDIO_POWER_UNDEFINED	0x03
+
+	__u8	bus_width;
+#define GB_SDIO_BUS_WIDTH_1	0x00
+#define GB_SDIO_BUS_WIDTH_4	0x02
+#define GB_SDIO_BUS_WIDTH_8	0x03
+
+	__u8	timing;
+#define GB_SDIO_TIMING_LEGACY		0x00
+#define GB_SDIO_TIMING_MMC_HS		0x01
+#define GB_SDIO_TIMING_SD_HS		0x02
+#define GB_SDIO_TIMING_UHS_SDR12	0x03
+#define GB_SDIO_TIMING_UHS_SDR25	0x04
+#define GB_SDIO_TIMING_UHS_SDR50	0x05
+#define GB_SDIO_TIMING_UHS_SDR104	0x06
+#define GB_SDIO_TIMING_UHS_DDR50	0x07
+#define GB_SDIO_TIMING_MMC_DDR52	0x08
+#define GB_SDIO_TIMING_MMC_HS200	0x09
+#define GB_SDIO_TIMING_MMC_HS400	0x0A
+
+	__u8	signal_voltage;
+#define GB_SDIO_SIGNAL_VOLTAGE_330	0x00
+#define GB_SDIO_SIGNAL_VOLTAGE_180	0x01
+#define GB_SDIO_SIGNAL_VOLTAGE_120	0x02
+
+	__u8	drv_type;
+#define GB_SDIO_SET_DRIVER_TYPE_B	0x00
+#define GB_SDIO_SET_DRIVER_TYPE_A	0x01
+#define GB_SDIO_SET_DRIVER_TYPE_C	0x02
+#define GB_SDIO_SET_DRIVER_TYPE_D	0x03
+} __packed;
+
+/* command request */
+struct gb_sdio_command_request {
+	__u8	cmd;
+	__u8	cmd_flags;
+#define GB_SDIO_RSP_NONE		0x00
+#define GB_SDIO_RSP_PRESENT		0x01
+#define GB_SDIO_RSP_136			0x02
+#define GB_SDIO_RSP_CRC			0x04
+#define GB_SDIO_RSP_BUSY		0x08
+#define GB_SDIO_RSP_OPCODE		0x10
+
+	__u8	cmd_type;
+#define GB_SDIO_CMD_AC		0x00
+#define GB_SDIO_CMD_ADTC	0x01
+#define GB_SDIO_CMD_BC		0x02
+#define GB_SDIO_CMD_BCR		0x03
+
+	__le32	cmd_arg;
+	__le16	data_blocks;
+	__le16	data_blksz;
+} __packed;
+
+struct gb_sdio_command_response {
+	__le32	resp[4];
+} __packed;
+
+/* transfer request */
+struct gb_sdio_transfer_request {
+	__u8	data_flags;
+#define GB_SDIO_DATA_WRITE	0x01
+#define GB_SDIO_DATA_READ	0x02
+#define GB_SDIO_DATA_STREAM	0x04
+
+	__le16	data_blocks;
+	__le16	data_blksz;
+	__u8	data[0];
+} __packed;
+
+struct gb_sdio_transfer_response {
+	__le16	data_blocks;
+	__le16	data_blksz;
+	__u8	data[0];
+} __packed;
+
+/* event request: generated by module and is defined as unidirectional */
+struct gb_sdio_event_request {
+	__u8	event;
+#define GB_SDIO_CARD_INSERTED	0x01
+#define GB_SDIO_CARD_REMOVED	0x02
+#define GB_SDIO_WP		0x04
+} __packed;
+
+/* Camera */
+
+/* Greybus Camera request types */
+#define GB_CAMERA_TYPE_CAPABILITIES		0x02
+#define GB_CAMERA_TYPE_CONFIGURE_STREAMS	0x03
+#define GB_CAMERA_TYPE_CAPTURE			0x04
+#define GB_CAMERA_TYPE_FLUSH			0x05
+#define GB_CAMERA_TYPE_METADATA			0x06
+
+#define GB_CAMERA_MAX_STREAMS			4
+#define GB_CAMERA_MAX_SETTINGS_SIZE		8192
+
+/* Greybus Camera Configure Streams request payload */
+struct gb_camera_stream_config_request {
+	__le16 width;
+	__le16 height;
+	__le16 format;
+	__le16 padding;
+} __packed;
+
+struct gb_camera_configure_streams_request {
+	__u8 num_streams;
+	__u8 flags;
+#define GB_CAMERA_CONFIGURE_STREAMS_TEST_ONLY	0x01
+	__le16 padding;
+	struct gb_camera_stream_config_request config[0];
+} __packed;
+
+/* Greybus Camera Configure Streams response payload */
+struct gb_camera_stream_config_response {
+	__le16 width;
+	__le16 height;
+	__le16 format;
+	__u8 virtual_channel;
+	__u8 data_type[2];
+	__le16 max_pkt_size;
+	__u8 padding;
+	__le32 max_size;
+} __packed;
+
+struct gb_camera_configure_streams_response {
+	__u8 num_streams;
+#define GB_CAMERA_CONFIGURE_STREAMS_ADJUSTED	0x01
+	__u8 flags;
+	__u8 padding[2];
+	__le32 data_rate;
+	struct gb_camera_stream_config_response config[0];
+};
+
+/* Greybus Camera Capture request payload - response has no payload */
+struct gb_camera_capture_request {
+	__le32 request_id;
+	__u8 streams;
+	__u8 padding;
+	__le16 num_frames;
+	__u8 settings[0];
+} __packed;
+
+/* Greybus Camera Flush response payload - request has no payload */
+struct gb_camera_flush_response {
+	__le32 request_id;
+} __packed;
+
+/* Greybus Camera Metadata request payload - operation has no response */
+struct gb_camera_metadata_request {
+	__le32 request_id;
+	__le16 frame_number;
+	__u8 stream;
+	__u8 padding;
+	__u8 metadata[0];
+} __packed;
+
+/* Lights */
+
+/* Greybus Lights request types */
+#define GB_LIGHTS_TYPE_GET_LIGHTS		0x02
+#define GB_LIGHTS_TYPE_GET_LIGHT_CONFIG		0x03
+#define GB_LIGHTS_TYPE_GET_CHANNEL_CONFIG	0x04
+#define GB_LIGHTS_TYPE_GET_CHANNEL_FLASH_CONFIG	0x05
+#define GB_LIGHTS_TYPE_SET_BRIGHTNESS		0x06
+#define GB_LIGHTS_TYPE_SET_BLINK		0x07
+#define GB_LIGHTS_TYPE_SET_COLOR		0x08
+#define GB_LIGHTS_TYPE_SET_FADE			0x09
+#define GB_LIGHTS_TYPE_EVENT			0x0A
+#define GB_LIGHTS_TYPE_SET_FLASH_INTENSITY	0x0B
+#define GB_LIGHTS_TYPE_SET_FLASH_STROBE		0x0C
+#define GB_LIGHTS_TYPE_SET_FLASH_TIMEOUT	0x0D
+#define GB_LIGHTS_TYPE_GET_FLASH_FAULT		0x0E
+
+/* Greybus Light modes */
+
+/*
+ * if you add any specific mode below, update also the
+ * GB_CHANNEL_MODE_DEFINED_RANGE value accordingly
+ */
+#define GB_CHANNEL_MODE_NONE		0x00000000
+#define GB_CHANNEL_MODE_BATTERY		0x00000001
+#define GB_CHANNEL_MODE_POWER		0x00000002
+#define GB_CHANNEL_MODE_WIRELESS	0x00000004
+#define GB_CHANNEL_MODE_BLUETOOTH	0x00000008
+#define GB_CHANNEL_MODE_KEYBOARD	0x00000010
+#define GB_CHANNEL_MODE_BUTTONS		0x00000020
+#define GB_CHANNEL_MODE_NOTIFICATION	0x00000040
+#define GB_CHANNEL_MODE_ATTENTION	0x00000080
+#define GB_CHANNEL_MODE_FLASH		0x00000100
+#define GB_CHANNEL_MODE_TORCH		0x00000200
+#define GB_CHANNEL_MODE_INDICATOR	0x00000400
+
+/* Lights Mode valid bit values */
+#define GB_CHANNEL_MODE_DEFINED_RANGE	0x000004FF
+#define GB_CHANNEL_MODE_VENDOR_RANGE	0x00F00000
+
+/* Greybus Light Channels Flags */
+#define GB_LIGHT_CHANNEL_MULTICOLOR	0x00000001
+#define GB_LIGHT_CHANNEL_FADER		0x00000002
+#define GB_LIGHT_CHANNEL_BLINK		0x00000004
+
+/* get count of lights in module */
+struct gb_lights_get_lights_response {
+	__u8	lights_count;
+} __packed;
+
+/* light config request payload */
+struct gb_lights_get_light_config_request {
+	__u8	id;
+} __packed;
+
+/* light config response payload */
+struct gb_lights_get_light_config_response {
+	__u8	channel_count;
+	__u8	name[32];
+} __packed;
+
+/* channel config request payload */
+struct gb_lights_get_channel_config_request {
+	__u8	light_id;
+	__u8	channel_id;
+} __packed;
+
+/* channel flash config request payload */
+struct gb_lights_get_channel_flash_config_request {
+	__u8	light_id;
+	__u8	channel_id;
+} __packed;
+
+/* channel config response payload */
+struct gb_lights_get_channel_config_response {
+	__u8	max_brightness;
+	__le32	flags;
+	__le32	color;
+	__u8	color_name[32];
+	__le32	mode;
+	__u8	mode_name[32];
+} __packed;
+
+/* channel flash config response payload */
+struct gb_lights_get_channel_flash_config_response {
+	__le32	intensity_min_uA;
+	__le32	intensity_max_uA;
+	__le32	intensity_step_uA;
+	__le32	timeout_min_us;
+	__le32	timeout_max_us;
+	__le32	timeout_step_us;
+} __packed;
+
+/* blink request payload: response have no payload */
+struct gb_lights_blink_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__le16	time_on_ms;
+	__le16	time_off_ms;
+} __packed;
+
+/* set brightness request payload: response have no payload */
+struct gb_lights_set_brightness_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__u8	brightness;
+} __packed;
+
+/* set color request payload: response have no payload */
+struct gb_lights_set_color_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__le32	color;
+} __packed;
+
+/* set fade request payload: response have no payload */
+struct gb_lights_set_fade_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__u8	fade_in;
+	__u8	fade_out;
+} __packed;
+
+/* event request: generated by module */
+struct gb_lights_event_request {
+	__u8	light_id;
+	__u8	event;
+#define GB_LIGHTS_LIGHT_CONFIG		0x01
+} __packed;
+
+/* set flash intensity request payload: response have no payload */
+struct gb_lights_set_flash_intensity_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__le32	intensity_uA;
+} __packed;
+
+/* set flash strobe state request payload: response have no payload */
+struct gb_lights_set_flash_strobe_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__u8	state;
+} __packed;
+
+/* set flash timeout request payload: response have no payload */
+struct gb_lights_set_flash_timeout_request {
+	__u8	light_id;
+	__u8	channel_id;
+	__le32	timeout_us;
+} __packed;
+
+/* get flash fault request payload */
+struct gb_lights_get_flash_fault_request {
+	__u8	light_id;
+	__u8	channel_id;
+} __packed;
+
+/* get flash fault response payload */
+struct gb_lights_get_flash_fault_response {
+	__le32	fault;
+#define GB_LIGHTS_FLASH_FAULT_OVER_VOLTAGE		0x00000000
+#define GB_LIGHTS_FLASH_FAULT_TIMEOUT			0x00000001
+#define GB_LIGHTS_FLASH_FAULT_OVER_TEMPERATURE		0x00000002
+#define GB_LIGHTS_FLASH_FAULT_SHORT_CIRCUIT		0x00000004
+#define GB_LIGHTS_FLASH_FAULT_OVER_CURRENT		0x00000008
+#define GB_LIGHTS_FLASH_FAULT_INDICATOR			0x00000010
+#define GB_LIGHTS_FLASH_FAULT_UNDER_VOLTAGE		0x00000020
+#define GB_LIGHTS_FLASH_FAULT_INPUT_VOLTAGE		0x00000040
+#define GB_LIGHTS_FLASH_FAULT_LED_OVER_TEMPERATURE	0x00000080
+} __packed;
+
+/* Audio */
+
+#define GB_AUDIO_TYPE_GET_TOPOLOGY_SIZE		0x02
+#define GB_AUDIO_TYPE_GET_TOPOLOGY		0x03
+#define GB_AUDIO_TYPE_GET_CONTROL		0x04
+#define GB_AUDIO_TYPE_SET_CONTROL		0x05
+#define GB_AUDIO_TYPE_ENABLE_WIDGET		0x06
+#define GB_AUDIO_TYPE_DISABLE_WIDGET		0x07
+#define GB_AUDIO_TYPE_GET_PCM			0x08
+#define GB_AUDIO_TYPE_SET_PCM			0x09
+#define GB_AUDIO_TYPE_SET_TX_DATA_SIZE		0x0a
+						/* 0x0b unused */
+#define GB_AUDIO_TYPE_ACTIVATE_TX		0x0c
+#define GB_AUDIO_TYPE_DEACTIVATE_TX		0x0d
+#define GB_AUDIO_TYPE_SET_RX_DATA_SIZE		0x0e
+						/* 0x0f unused */
+#define GB_AUDIO_TYPE_ACTIVATE_RX		0x10
+#define GB_AUDIO_TYPE_DEACTIVATE_RX		0x11
+#define GB_AUDIO_TYPE_JACK_EVENT		0x12
+#define GB_AUDIO_TYPE_BUTTON_EVENT		0x13
+#define GB_AUDIO_TYPE_STREAMING_EVENT		0x14
+#define GB_AUDIO_TYPE_SEND_DATA			0x15
+
+/* Module must be able to buffer 10ms of audio data, minimum */
+#define GB_AUDIO_SAMPLE_BUFFER_MIN_US		10000
+
+#define GB_AUDIO_PCM_NAME_MAX			32
+#define AUDIO_DAI_NAME_MAX			32
+#define AUDIO_CONTROL_NAME_MAX			32
+#define AUDIO_CTL_ELEM_NAME_MAX			44
+#define AUDIO_ENUM_NAME_MAX			64
+#define AUDIO_WIDGET_NAME_MAX			32
+
+/* See SNDRV_PCM_FMTBIT_* in Linux source */
+#define GB_AUDIO_PCM_FMT_S8			BIT(0)
+#define GB_AUDIO_PCM_FMT_U8			BIT(1)
+#define GB_AUDIO_PCM_FMT_S16_LE			BIT(2)
+#define GB_AUDIO_PCM_FMT_S16_BE			BIT(3)
+#define GB_AUDIO_PCM_FMT_U16_LE			BIT(4)
+#define GB_AUDIO_PCM_FMT_U16_BE			BIT(5)
+#define GB_AUDIO_PCM_FMT_S24_LE			BIT(6)
+#define GB_AUDIO_PCM_FMT_S24_BE			BIT(7)
+#define GB_AUDIO_PCM_FMT_U24_LE			BIT(8)
+#define GB_AUDIO_PCM_FMT_U24_BE			BIT(9)
+#define GB_AUDIO_PCM_FMT_S32_LE			BIT(10)
+#define GB_AUDIO_PCM_FMT_S32_BE			BIT(11)
+#define GB_AUDIO_PCM_FMT_U32_LE			BIT(12)
+#define GB_AUDIO_PCM_FMT_U32_BE			BIT(13)
+
+/* See SNDRV_PCM_RATE_* in Linux source */
+#define GB_AUDIO_PCM_RATE_5512			BIT(0)
+#define GB_AUDIO_PCM_RATE_8000			BIT(1)
+#define GB_AUDIO_PCM_RATE_11025			BIT(2)
+#define GB_AUDIO_PCM_RATE_16000			BIT(3)
+#define GB_AUDIO_PCM_RATE_22050			BIT(4)
+#define GB_AUDIO_PCM_RATE_32000			BIT(5)
+#define GB_AUDIO_PCM_RATE_44100			BIT(6)
+#define GB_AUDIO_PCM_RATE_48000			BIT(7)
+#define GB_AUDIO_PCM_RATE_64000			BIT(8)
+#define GB_AUDIO_PCM_RATE_88200			BIT(9)
+#define GB_AUDIO_PCM_RATE_96000			BIT(10)
+#define GB_AUDIO_PCM_RATE_176400		BIT(11)
+#define GB_AUDIO_PCM_RATE_192000		BIT(12)
+
+#define GB_AUDIO_STREAM_TYPE_CAPTURE		0x1
+#define GB_AUDIO_STREAM_TYPE_PLAYBACK		0x2
+
+#define GB_AUDIO_CTL_ELEM_ACCESS_READ		BIT(0)
+#define GB_AUDIO_CTL_ELEM_ACCESS_WRITE		BIT(1)
+
+/* See SNDRV_CTL_ELEM_TYPE_* in Linux source */
+#define GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN		0x01
+#define GB_AUDIO_CTL_ELEM_TYPE_INTEGER		0x02
+#define GB_AUDIO_CTL_ELEM_TYPE_ENUMERATED	0x03
+#define GB_AUDIO_CTL_ELEM_TYPE_INTEGER64	0x06
+
+/* See SNDRV_CTL_ELEM_IFACE_* in Linux source */
+#define GB_AUDIO_CTL_ELEM_IFACE_CARD		0x00
+#define GB_AUDIO_CTL_ELEM_IFACE_HWDEP		0x01
+#define GB_AUDIO_CTL_ELEM_IFACE_MIXER		0x02
+#define GB_AUDIO_CTL_ELEM_IFACE_PCM		0x03
+#define GB_AUDIO_CTL_ELEM_IFACE_RAWMIDI		0x04
+#define GB_AUDIO_CTL_ELEM_IFACE_TIMER		0x05
+#define GB_AUDIO_CTL_ELEM_IFACE_SEQUENCER	0x06
+
+/* SNDRV_CTL_ELEM_ACCESS_* in Linux source */
+#define GB_AUDIO_ACCESS_READ			BIT(0)
+#define GB_AUDIO_ACCESS_WRITE			BIT(1)
+#define GB_AUDIO_ACCESS_VOLATILE		BIT(2)
+#define GB_AUDIO_ACCESS_TIMESTAMP		BIT(3)
+#define GB_AUDIO_ACCESS_TLV_READ		BIT(4)
+#define GB_AUDIO_ACCESS_TLV_WRITE		BIT(5)
+#define GB_AUDIO_ACCESS_TLV_COMMAND		BIT(6)
+#define GB_AUDIO_ACCESS_INACTIVE		BIT(7)
+#define GB_AUDIO_ACCESS_LOCK			BIT(8)
+#define GB_AUDIO_ACCESS_OWNER			BIT(9)
+
+/* enum snd_soc_dapm_type */
+#define GB_AUDIO_WIDGET_TYPE_INPUT		0x0
+#define GB_AUDIO_WIDGET_TYPE_OUTPUT		0x1
+#define GB_AUDIO_WIDGET_TYPE_MUX		0x2
+#define GB_AUDIO_WIDGET_TYPE_VIRT_MUX		0x3
+#define GB_AUDIO_WIDGET_TYPE_VALUE_MUX		0x4
+#define GB_AUDIO_WIDGET_TYPE_MIXER		0x5
+#define GB_AUDIO_WIDGET_TYPE_MIXER_NAMED_CTL	0x6
+#define GB_AUDIO_WIDGET_TYPE_PGA		0x7
+#define GB_AUDIO_WIDGET_TYPE_OUT_DRV		0x8
+#define GB_AUDIO_WIDGET_TYPE_ADC		0x9
+#define GB_AUDIO_WIDGET_TYPE_DAC		0xa
+#define GB_AUDIO_WIDGET_TYPE_MICBIAS		0xb
+#define GB_AUDIO_WIDGET_TYPE_MIC		0xc
+#define GB_AUDIO_WIDGET_TYPE_HP			0xd
+#define GB_AUDIO_WIDGET_TYPE_SPK		0xe
+#define GB_AUDIO_WIDGET_TYPE_LINE		0xf
+#define GB_AUDIO_WIDGET_TYPE_SWITCH		0x10
+#define GB_AUDIO_WIDGET_TYPE_VMID		0x11
+#define GB_AUDIO_WIDGET_TYPE_PRE		0x12
+#define GB_AUDIO_WIDGET_TYPE_POST		0x13
+#define GB_AUDIO_WIDGET_TYPE_SUPPLY		0x14
+#define GB_AUDIO_WIDGET_TYPE_REGULATOR_SUPPLY	0x15
+#define GB_AUDIO_WIDGET_TYPE_CLOCK_SUPPLY	0x16
+#define GB_AUDIO_WIDGET_TYPE_AIF_IN		0x17
+#define GB_AUDIO_WIDGET_TYPE_AIF_OUT		0x18
+#define GB_AUDIO_WIDGET_TYPE_SIGGEN		0x19
+#define GB_AUDIO_WIDGET_TYPE_DAI_IN		0x1a
+#define GB_AUDIO_WIDGET_TYPE_DAI_OUT		0x1b
+#define GB_AUDIO_WIDGET_TYPE_DAI_LINK		0x1c
+
+#define GB_AUDIO_WIDGET_STATE_DISABLED		0x01
+#define GB_AUDIO_WIDGET_STATE_ENAABLED		0x02
+
+#define GB_AUDIO_JACK_EVENT_INSERTION		0x1
+#define GB_AUDIO_JACK_EVENT_REMOVAL		0x2
+
+#define GB_AUDIO_BUTTON_EVENT_PRESS		0x1
+#define GB_AUDIO_BUTTON_EVENT_RELEASE		0x2
+
+#define GB_AUDIO_STREAMING_EVENT_UNSPECIFIED	0x1
+#define GB_AUDIO_STREAMING_EVENT_HALT		0x2
+#define GB_AUDIO_STREAMING_EVENT_INTERNAL_ERROR	0x3
+#define GB_AUDIO_STREAMING_EVENT_PROTOCOL_ERROR	0x4
+#define GB_AUDIO_STREAMING_EVENT_FAILURE	0x5
+#define GB_AUDIO_STREAMING_EVENT_UNDERRUN	0x6
+#define GB_AUDIO_STREAMING_EVENT_OVERRUN	0x7
+#define GB_AUDIO_STREAMING_EVENT_CLOCKING	0x8
+#define GB_AUDIO_STREAMING_EVENT_DATA_LEN	0x9
+
+#define GB_AUDIO_INVALID_INDEX			0xff
+
+/* enum snd_jack_types */
+#define GB_AUDIO_JACK_HEADPHONE			0x0000001
+#define GB_AUDIO_JACK_MICROPHONE		0x0000002
+#define GB_AUDIO_JACK_HEADSET			(GB_AUDIO_JACK_HEADPHONE | \
+						 GB_AUDIO_JACK_MICROPHONE)
+#define GB_AUDIO_JACK_LINEOUT			0x0000004
+#define GB_AUDIO_JACK_MECHANICAL		0x0000008
+#define GB_AUDIO_JACK_VIDEOOUT			0x0000010
+#define GB_AUDIO_JACK_AVOUT			(GB_AUDIO_JACK_LINEOUT | \
+						 GB_AUDIO_JACK_VIDEOOUT)
+#define GB_AUDIO_JACK_LINEIN			0x0000020
+#define GB_AUDIO_JACK_OC_HPHL			0x0000040
+#define GB_AUDIO_JACK_OC_HPHR			0x0000080
+#define GB_AUDIO_JACK_MICROPHONE2		0x0000200
+#define GB_AUDIO_JACK_ANC_HEADPHONE		(GB_AUDIO_JACK_HEADPHONE | \
+						 GB_AUDIO_JACK_MICROPHONE | \
+						 GB_AUDIO_JACK_MICROPHONE2)
+/* Kept separate from switches to facilitate implementation */
+#define GB_AUDIO_JACK_BTN_0			0x4000000
+#define GB_AUDIO_JACK_BTN_1			0x2000000
+#define GB_AUDIO_JACK_BTN_2			0x1000000
+#define GB_AUDIO_JACK_BTN_3			0x0800000
+
+struct gb_audio_pcm {
+	__u8	stream_name[GB_AUDIO_PCM_NAME_MAX];
+	__le32	formats;	/* GB_AUDIO_PCM_FMT_* */
+	__le32	rates;		/* GB_AUDIO_PCM_RATE_* */
+	__u8	chan_min;
+	__u8	chan_max;
+	__u8	sig_bits;	/* number of bits of content */
+} __packed;
+
+struct gb_audio_dai {
+	__u8			name[AUDIO_DAI_NAME_MAX];
+	__le16			data_cport;
+	struct gb_audio_pcm	capture;
+	struct gb_audio_pcm	playback;
+} __packed;
+
+struct gb_audio_integer {
+	__le32	min;
+	__le32	max;
+	__le32	step;
+} __packed;
+
+struct gb_audio_integer64 {
+	__le64	min;
+	__le64	max;
+	__le64	step;
+} __packed;
+
+struct gb_audio_enumerated {
+	__le32	items;
+	__le16	names_length;
+	__u8	names[0];
+} __packed;
+
+struct gb_audio_ctl_elem_info { /* See snd_ctl_elem_info in Linux source */
+	__u8		type;		/* GB_AUDIO_CTL_ELEM_TYPE_* */
+	__le16		dimen[4];
+	union {
+		struct gb_audio_integer		integer;
+		struct gb_audio_integer64	integer64;
+		struct gb_audio_enumerated	enumerated;
+	} value;
+} __packed;
+
+struct gb_audio_ctl_elem_value { /* See snd_ctl_elem_value in Linux source */
+	__le64				timestamp; /* XXX needed? */
+	union {
+		__le32	integer_value[2];	/* consider CTL_DOUBLE_xxx */
+		__le64	integer64_value[2];
+		__le32	enumerated_item[2];
+	} value;
+} __packed;
+
+struct gb_audio_control {
+	__u8	name[AUDIO_CONTROL_NAME_MAX];
+	__u8	id;		/* 0-63 */
+	__u8	iface;		/* GB_AUDIO_IFACE_* */
+	__le16	data_cport;
+	__le32	access;		/* GB_AUDIO_ACCESS_* */
+	__u8    count;		/* count of same elements */
+	__u8	count_values;	/* count of values, max=2 for CTL_DOUBLE_xxx */
+	struct gb_audio_ctl_elem_info	info;
+} __packed;
+
+struct gb_audio_widget {
+	__u8	name[AUDIO_WIDGET_NAME_MAX];
+	__u8	sname[AUDIO_WIDGET_NAME_MAX];
+	__u8	id;
+	__u8	type;		/* GB_AUDIO_WIDGET_TYPE_* */
+	__u8	state;		/* GB_AUDIO_WIDGET_STATE_* */
+	__u8	ncontrols;
+	struct gb_audio_control	ctl[0];	/* 'ncontrols' entries */
+} __packed;
+
+struct gb_audio_route {
+	__u8	source_id;	/* widget id */
+	__u8	destination_id;	/* widget id */
+	__u8	control_id;	/* 0-63 */
+	__u8	index;		/* Selection within the control */
+} __packed;
+
+struct gb_audio_topology {
+	__u8	num_dais;
+	__u8	num_controls;
+	__u8	num_widgets;
+	__u8	num_routes;
+	__le32	size_dais;
+	__le32	size_controls;
+	__le32	size_widgets;
+	__le32	size_routes;
+	__le32	jack_type;
+	/*
+	 * struct gb_audio_dai		dai[num_dais];
+	 * struct gb_audio_control	controls[num_controls];
+	 * struct gb_audio_widget	widgets[num_widgets];
+	 * struct gb_audio_route	routes[num_routes];
+	 */
+	__u8	data[0];
+} __packed;
+
+struct gb_audio_get_topology_size_response {
+	__le16	size;
+} __packed;
+
+struct gb_audio_get_topology_response {
+	struct gb_audio_topology	topology;
+} __packed;
+
+struct gb_audio_get_control_request {
+	__u8	control_id;
+	__u8	index;
+} __packed;
+
+struct gb_audio_get_control_response {
+	struct gb_audio_ctl_elem_value	value;
+} __packed;
+
+struct gb_audio_set_control_request {
+	__u8	control_id;
+	__u8	index;
+	struct gb_audio_ctl_elem_value	value;
+} __packed;
+
+struct gb_audio_enable_widget_request {
+	__u8	widget_id;
+} __packed;
+
+struct gb_audio_disable_widget_request {
+	__u8	widget_id;
+} __packed;
+
+struct gb_audio_get_pcm_request {
+	__le16	data_cport;
+} __packed;
+
+struct gb_audio_get_pcm_response {
+	__le32	format;
+	__le32	rate;
+	__u8	channels;
+	__u8	sig_bits;
+} __packed;
+
+struct gb_audio_set_pcm_request {
+	__le16	data_cport;
+	__le32	format;
+	__le32	rate;
+	__u8	channels;
+	__u8	sig_bits;
+} __packed;
+
+struct gb_audio_set_tx_data_size_request {
+	__le16	data_cport;
+	__le16	size;
+} __packed;
+
+struct gb_audio_activate_tx_request {
+	__le16	data_cport;
+} __packed;
+
+struct gb_audio_deactivate_tx_request {
+	__le16	data_cport;
+} __packed;
+
+struct gb_audio_set_rx_data_size_request {
+	__le16	data_cport;
+	__le16	size;
+} __packed;
+
+struct gb_audio_activate_rx_request {
+	__le16	data_cport;
+} __packed;
+
+struct gb_audio_deactivate_rx_request {
+	__le16	data_cport;
+} __packed;
+
+struct gb_audio_jack_event_request {
+	__u8	widget_id;
+	__u8	jack_attribute;
+	__u8	event;
+} __packed;
+
+struct gb_audio_button_event_request {
+	__u8	widget_id;
+	__u8	button_id;
+	__u8	event;
+} __packed;
+
+struct gb_audio_streaming_event_request {
+	__le16	data_cport;
+	__u8	event;
+} __packed;
+
+struct gb_audio_send_data_request {
+	__le64	timestamp;
+	__u8	data[0];
+} __packed;
+
+
+/* Log */
+
+/* operations */
+#define GB_LOG_TYPE_SEND_LOG	0x02
+
+/* length */
+#define GB_LOG_MAX_LEN		1024
+
+struct gb_log_send_log_request {
+	__le16	len;
+	__u8    msg[0];
+} __packed;
+
+#endif /* __GREYBUS_PROTOCOLS_H */
+
diff --git a/drivers/staging/greybus/greybus_trace.h b/drivers/staging/greybus/greybus_trace.h
new file mode 100644
index 000000000000..6f8692da9ec8
--- /dev/null
+++ b/drivers/staging/greybus/greybus_trace.h
@@ -0,0 +1,531 @@
+/*
+ * Greybus driver and device API
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM greybus
+
+#if !defined(_TRACE_GREYBUS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_GREYBUS_H
+
+#include <linux/tracepoint.h>
+
+struct gb_message;
+struct gb_operation;
+struct gb_connection;
+struct gb_bundle;
+struct gb_host_device;
+
+DECLARE_EVENT_CLASS(gb_message,
+
+	TP_PROTO(struct gb_message *message),
+
+	TP_ARGS(message),
+
+	TP_STRUCT__entry(
+		__field(u16, size)
+		__field(u16, operation_id)
+		__field(u8, type)
+		__field(u8, result)
+	),
+
+	TP_fast_assign(
+		__entry->size = le16_to_cpu(message->header->size);
+		__entry->operation_id =
+			le16_to_cpu(message->header->operation_id);
+		__entry->type = message->header->type;
+		__entry->result = message->header->result;
+	),
+
+	TP_printk("size=%hu operation_id=0x%04x type=0x%02x result=0x%02x",
+		  __entry->size, __entry->operation_id,
+		  __entry->type, __entry->result)
+);
+
+#define DEFINE_MESSAGE_EVENT(name)					\
+		DEFINE_EVENT(gb_message, name,				\
+				TP_PROTO(struct gb_message *message),	\
+				TP_ARGS(message))
+
+/*
+ * Occurs immediately before calling a host device's message_send()
+ * method.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_send);
+
+/*
+ * Occurs after an incoming request message has been received
+ */
+DEFINE_MESSAGE_EVENT(gb_message_recv_request);
+
+/*
+ * Occurs after an incoming response message has been received,
+ * after its matching request has been found.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_recv_response);
+
+/*
+ * Occurs after an operation has been canceled, possibly before the
+ * cancellation is complete.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_cancel_outgoing);
+
+/*
+ * Occurs when an incoming request is cancelled; if the response has
+ * been queued for sending, this occurs after it is sent.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_cancel_incoming);
+
+/*
+ * Occurs in the host driver message_send() function just prior to
+ * handing off the data to be processed by hardware.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_submit);
+
+#undef DEFINE_MESSAGE_EVENT
+
+DECLARE_EVENT_CLASS(gb_operation,
+
+	TP_PROTO(struct gb_operation *operation),
+
+	TP_ARGS(operation),
+
+	TP_STRUCT__entry(
+		__field(u16, cport_id)	/* CPort of HD side of connection */
+		__field(u16, id)	/* Operation ID */
+		__field(u8, type)
+		__field(unsigned long, flags)
+		__field(int, active)
+		__field(int, waiters)
+		__field(int, errno)
+	),
+
+	TP_fast_assign(
+		__entry->cport_id = operation->connection->hd_cport_id;
+		__entry->id = operation->id;
+		__entry->type = operation->type;
+		__entry->flags = operation->flags;
+		__entry->active = operation->active;
+		__entry->waiters = atomic_read(&operation->waiters);
+		__entry->errno = operation->errno;
+	),
+
+	TP_printk("id=%04x type=0x%02x cport_id=%04x flags=0x%lx active=%d waiters=%d errno=%d",
+		  __entry->id, __entry->cport_id, __entry->type, __entry->flags,
+		  __entry->active, __entry->waiters, __entry->errno)
+);
+
+#define DEFINE_OPERATION_EVENT(name)					\
+		DEFINE_EVENT(gb_operation, name,			\
+				TP_PROTO(struct gb_operation *operation), \
+				TP_ARGS(operation))
+
+/*
+ * Occurs after a new operation is created for an outgoing request
+ * has been successfully created.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_create);
+
+/*
+ * Occurs after a new core operation has been created.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_create_core);
+
+/*
+ * Occurs after a new operation has been created for an incoming
+ * request has been successfully created and initialized.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_create_incoming);
+
+/*
+ * Occurs when the last reference to an operation has been dropped,
+ * prior to freeing resources.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_destroy);
+
+/*
+ * Occurs when an operation has been marked active, after updating
+ * its active count.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_get_active);
+
+/*
+ * Occurs when an operation has been marked active, before updating
+ * its active count.
+ */
+DEFINE_OPERATION_EVENT(gb_operation_put_active);
+
+#undef DEFINE_OPERATION_EVENT
+
+DECLARE_EVENT_CLASS(gb_connection,
+
+	TP_PROTO(struct gb_connection *connection),
+
+	TP_ARGS(connection),
+
+	TP_STRUCT__entry(
+		__field(int, hd_bus_id)
+		__field(u8, bundle_id)
+		/* name contains "hd_cport_id/intf_id:cport_id" */
+		__dynamic_array(char, name, sizeof(connection->name))
+		__field(enum gb_connection_state, state)
+		__field(unsigned long, flags)
+	),
+
+	TP_fast_assign(
+		__entry->hd_bus_id = connection->hd->bus_id;
+		__entry->bundle_id = connection->bundle ?
+				connection->bundle->id : BUNDLE_ID_NONE;
+		memcpy(__get_str(name), connection->name,
+					sizeof(connection->name));
+		__entry->state = connection->state;
+		__entry->flags = connection->flags;
+	),
+
+	TP_printk("hd_bus_id=%d bundle_id=0x%02x name=\"%s\" state=%u flags=0x%lx",
+		  __entry->hd_bus_id, __entry->bundle_id, __get_str(name),
+		  (unsigned int)__entry->state, __entry->flags)
+);
+
+#define DEFINE_CONNECTION_EVENT(name)					\
+		DEFINE_EVENT(gb_connection, name,			\
+				TP_PROTO(struct gb_connection *connection), \
+				TP_ARGS(connection))
+
+/*
+ * Occurs after a new connection is successfully created.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_create);
+
+/*
+ * Occurs when the last reference to a connection has been dropped,
+ * before its resources are freed.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_release);
+
+/*
+ * Occurs when a new reference to connection is added, currently
+ * only when a message over the connection is received.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_get);
+
+/*
+ * Occurs when a new reference to connection is dropped, after a
+ * a received message is handled, or when the connection is
+ * destroyed.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_put);
+
+/*
+ * Occurs when a request to enable a connection is made, either for
+ * transmit only, or for both transmit and receive.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_enable);
+
+/*
+ * Occurs when a request to disable a connection is made, either for
+ * receive only, or for both transmit and receive.  Also occurs when
+ * a request to forcefully disable a connection is made.
+ */
+DEFINE_CONNECTION_EVENT(gb_connection_disable);
+
+#undef DEFINE_CONNECTION_EVENT
+
+DECLARE_EVENT_CLASS(gb_bundle,
+
+	TP_PROTO(struct gb_bundle *bundle),
+
+	TP_ARGS(bundle),
+
+	TP_STRUCT__entry(
+		__field(u8, intf_id)
+		__field(u8, id)
+		__field(u8, class)
+		__field(size_t, num_cports)
+	),
+
+	TP_fast_assign(
+		__entry->intf_id = bundle->intf->interface_id;
+		__entry->id = bundle->id;
+		__entry->class = bundle->class;
+		__entry->num_cports = bundle->num_cports;
+	),
+
+	TP_printk("intf_id=0x%02x id=%02x class=0x%02x num_cports=%zu",
+		  __entry->intf_id, __entry->id, __entry->class,
+		  __entry->num_cports)
+);
+
+#define DEFINE_BUNDLE_EVENT(name)					\
+		DEFINE_EVENT(gb_bundle, name,			\
+				TP_PROTO(struct gb_bundle *bundle), \
+				TP_ARGS(bundle))
+
+/*
+ * Occurs after a new bundle is successfully created.
+ */
+DEFINE_BUNDLE_EVENT(gb_bundle_create);
+
+/*
+ * Occurs when the last reference to a bundle has been dropped,
+ * before its resources are freed.
+ */
+DEFINE_BUNDLE_EVENT(gb_bundle_release);
+
+/*
+ * Occurs when a bundle is added to an interface when the interface
+ * is enabled.
+ */
+DEFINE_BUNDLE_EVENT(gb_bundle_add);
+
+/*
+ * Occurs when a registered bundle gets destroyed, normally at the
+ * time an interface is disabled.
+ */
+DEFINE_BUNDLE_EVENT(gb_bundle_destroy);
+
+#undef DEFINE_BUNDLE_EVENT
+
+DECLARE_EVENT_CLASS(gb_interface,
+
+	TP_PROTO(struct gb_interface *intf),
+
+	TP_ARGS(intf),
+
+	TP_STRUCT__entry(
+		__field(u8, module_id)
+		__field(u8, id)		/* Interface id */
+		__field(u8, device_id)
+		__field(int, disconnected)	/* bool */
+		__field(int, ejected)		/* bool */
+		__field(int, active)		/* bool */
+		__field(int, enabled)		/* bool */
+		__field(int, mode_switch)	/* bool */
+	),
+
+	TP_fast_assign(
+		__entry->module_id = intf->module->module_id;
+		__entry->id = intf->interface_id;
+		__entry->device_id = intf->device_id;
+		__entry->disconnected = intf->disconnected;
+		__entry->ejected = intf->ejected;
+		__entry->active = intf->active;
+		__entry->enabled = intf->enabled;
+		__entry->mode_switch = intf->mode_switch;
+	),
+
+	TP_printk("intf_id=%hhu device_id=%hhu module_id=%hhu D=%d J=%d A=%d E=%d M=%d",
+		__entry->id, __entry->device_id, __entry->module_id,
+		__entry->disconnected, __entry->ejected, __entry->active,
+		__entry->enabled, __entry->mode_switch)
+);
+
+#define DEFINE_INTERFACE_EVENT(name)					\
+		DEFINE_EVENT(gb_interface, name,			\
+				TP_PROTO(struct gb_interface *intf),	\
+				TP_ARGS(intf))
+
+/*
+ * Occurs after a new interface is successfully created.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_create);
+
+/*
+ * Occurs after the last reference to an interface has been dropped.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_release);
+
+/*
+ * Occurs after an interface been registerd.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_add);
+
+/*
+ * Occurs when a registered interface gets deregisterd.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_del);
+
+/*
+ * Occurs when a registered interface has been successfully
+ * activated.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_activate);
+
+/*
+ * Occurs when an activated interface is being deactivated.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_deactivate);
+
+/*
+ * Occurs when an interface has been successfully enabled.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_enable);
+
+/*
+ * Occurs when an enabled interface is being disabled.
+ */
+DEFINE_INTERFACE_EVENT(gb_interface_disable);
+
+#undef DEFINE_INTERFACE_EVENT
+
+DECLARE_EVENT_CLASS(gb_module,
+
+	TP_PROTO(struct gb_module *module),
+
+	TP_ARGS(module),
+
+	TP_STRUCT__entry(
+		__field(int, hd_bus_id)
+		__field(u8, module_id)
+		__field(size_t, num_interfaces)
+		__field(int, disconnected)	/* bool */
+	),
+
+	TP_fast_assign(
+		__entry->hd_bus_id = module->hd->bus_id;
+		__entry->module_id = module->module_id;
+		__entry->num_interfaces = module->num_interfaces;
+		__entry->disconnected = module->disconnected;
+	),
+
+	TP_printk("hd_bus_id=%d module_id=%hhu num_interfaces=%zu disconnected=%d",
+		__entry->hd_bus_id, __entry->module_id,
+		__entry->num_interfaces, __entry->disconnected)
+);
+
+#define DEFINE_MODULE_EVENT(name)					\
+		DEFINE_EVENT(gb_module, name,				\
+				TP_PROTO(struct gb_module *module),	\
+				TP_ARGS(module))
+
+/*
+ * Occurs after a new module is successfully created, before
+ * creating any of its interfaces.
+ */
+DEFINE_MODULE_EVENT(gb_module_create);
+
+/*
+ * Occurs after the last reference to a module has been dropped.
+ */
+DEFINE_MODULE_EVENT(gb_module_release);
+
+/*
+ * Occurs after a module is successfully created, before registering
+ * any of its interfaces.
+ */
+DEFINE_MODULE_EVENT(gb_module_add);
+
+/*
+ * Occurs when a module is deleted, before deregistering its
+ * interfaces.
+ */
+DEFINE_MODULE_EVENT(gb_module_del);
+
+#undef DEFINE_MODULE_EVENT
+
+DECLARE_EVENT_CLASS(gb_host_device,
+
+	TP_PROTO(struct gb_host_device *hd),
+
+	TP_ARGS(hd),
+
+	TP_STRUCT__entry(
+		__field(int, bus_id)
+		__field(size_t, num_cports)
+		__field(size_t, buffer_size_max)
+	),
+
+	TP_fast_assign(
+		__entry->bus_id = hd->bus_id;
+		__entry->num_cports = hd->num_cports;
+		__entry->buffer_size_max = hd->buffer_size_max;
+	),
+
+	TP_printk("bus_id=%d num_cports=%zu mtu=%zu",
+		__entry->bus_id, __entry->num_cports,
+		__entry->buffer_size_max)
+);
+
+#define DEFINE_HD_EVENT(name)						\
+		DEFINE_EVENT(gb_host_device, name,			\
+				TP_PROTO(struct gb_host_device *hd),	\
+				TP_ARGS(hd))
+
+/*
+ * Occurs after a new host device is successfully created, before
+ * its SVC has been set up.
+ */
+DEFINE_HD_EVENT(gb_hd_create);
+
+/*
+ * Occurs after the last reference to a host device has been
+ * dropped.
+ */
+DEFINE_HD_EVENT(gb_hd_release);
+
+/*
+ * Occurs after a new host device has been added, after the
+ * connection to its SVC has been enabled.
+ */
+DEFINE_HD_EVENT(gb_hd_add);
+
+/*
+ * Occurs when a host device is being disconnected from the AP USB
+ * host controller.
+ */
+DEFINE_HD_EVENT(gb_hd_del);
+
+/*
+ * Occurs when a host device has passed received data to the Greybus
+ * core, after it has been determined it is destined for a valid
+ * CPort.
+ */
+DEFINE_HD_EVENT(gb_hd_in);
+
+#undef DEFINE_HD_EVENT
+
+/*
+ * Occurs on a TimeSync synchronization event or a TimeSync ping event.
+ */
+TRACE_EVENT(gb_timesync_irq,
+
+	TP_PROTO(u8 ping, u8 strobe, u8 count, u64 frame_time),
+
+	TP_ARGS(ping, strobe, count, frame_time),
+
+	TP_STRUCT__entry(
+		__field(u8, ping)
+		__field(u8, strobe)
+		__field(u8, count)
+		__field(u64, frame_time)
+	),
+
+	TP_fast_assign(
+		__entry->ping = ping;
+		__entry->strobe = strobe;
+		__entry->count = count;
+		__entry->frame_time = frame_time;
+	),
+
+	TP_printk("%s %d/%d frame-time %llu\n",
+		  __entry->ping ? "ping" : "strobe", __entry->strobe,
+		  __entry->count, __entry->frame_time)
+);
+
+#endif /* _TRACE_GREYBUS_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+/*
+ * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal
+ */
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE greybus_trace
+#include <trace/define_trace.h>
+
diff --git a/drivers/staging/greybus/hd.c b/drivers/staging/greybus/hd.c
new file mode 100644
index 000000000000..185ae3fa10fd
--- /dev/null
+++ b/drivers/staging/greybus/hd.c
@@ -0,0 +1,257 @@
+/*
+ * Greybus Host Device
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_create);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_release);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_add);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_del);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_in);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_message_submit);
+
+static struct ida gb_hd_bus_id_map;
+
+int gb_hd_output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
+		 bool async)
+{
+	if (!hd || !hd->driver || !hd->driver->output)
+		return -EINVAL;
+	return hd->driver->output(hd, req, size, cmd, async);
+}
+EXPORT_SYMBOL_GPL(gb_hd_output);
+
+static ssize_t bus_id_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_host_device *hd = to_gb_host_device(dev);
+
+	return sprintf(buf, "%d\n", hd->bus_id);
+}
+static DEVICE_ATTR_RO(bus_id);
+
+static struct attribute *bus_attrs[] = {
+	&dev_attr_bus_id.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(bus);
+
+int gb_hd_cport_reserve(struct gb_host_device *hd, u16 cport_id)
+{
+	struct ida *id_map = &hd->cport_id_map;
+	int ret;
+
+	ret = ida_simple_get(id_map, cport_id, cport_id + 1, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&hd->dev, "failed to reserve cport %u\n", cport_id);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_hd_cport_reserve);
+
+void gb_hd_cport_release_reserved(struct gb_host_device *hd, u16 cport_id)
+{
+	struct ida *id_map = &hd->cport_id_map;
+
+	ida_simple_remove(id_map, cport_id);
+}
+EXPORT_SYMBOL_GPL(gb_hd_cport_release_reserved);
+
+/* Locking: Caller guarantees serialisation */
+int gb_hd_cport_allocate(struct gb_host_device *hd, int cport_id,
+				unsigned long flags)
+{
+	struct ida *id_map = &hd->cport_id_map;
+	int ida_start, ida_end;
+
+	if (hd->driver->cport_allocate)
+		return hd->driver->cport_allocate(hd, cport_id, flags);
+
+	if (cport_id < 0) {
+		ida_start = 0;
+		ida_end = hd->num_cports;
+	} else if (cport_id < hd->num_cports) {
+		ida_start = cport_id;
+		ida_end = cport_id + 1;
+	} else {
+		dev_err(&hd->dev, "cport %d not available\n", cport_id);
+		return -EINVAL;
+	}
+
+	return ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
+}
+
+/* Locking: Caller guarantees serialisation */
+void gb_hd_cport_release(struct gb_host_device *hd, u16 cport_id)
+{
+	if (hd->driver->cport_release) {
+		hd->driver->cport_release(hd, cport_id);
+		return;
+	}
+
+	ida_simple_remove(&hd->cport_id_map, cport_id);
+}
+
+static void gb_hd_release(struct device *dev)
+{
+	struct gb_host_device *hd = to_gb_host_device(dev);
+
+	trace_gb_hd_release(hd);
+
+	if (hd->svc)
+		gb_svc_put(hd->svc);
+	ida_simple_remove(&gb_hd_bus_id_map, hd->bus_id);
+	ida_destroy(&hd->cport_id_map);
+	kfree(hd);
+}
+
+struct device_type greybus_hd_type = {
+	.name		= "greybus_host_device",
+	.release	= gb_hd_release,
+};
+
+struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,
+					struct device *parent,
+					size_t buffer_size_max,
+					size_t num_cports)
+{
+	struct gb_host_device *hd;
+	int ret;
+
+	/*
+	 * Validate that the driver implements all of the callbacks
+	 * so that we don't have to every time we make them.
+	 */
+	if ((!driver->message_send) || (!driver->message_cancel)) {
+		dev_err(parent, "mandatory hd-callbacks missing\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
+		dev_err(parent, "greybus host-device buffers too small\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (num_cports == 0 || num_cports > CPORT_ID_MAX + 1) {
+		dev_err(parent, "Invalid number of CPorts: %zu\n", num_cports);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * Make sure to never allocate messages larger than what the Greybus
+	 * protocol supports.
+	 */
+	if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
+		dev_warn(parent, "limiting buffer size to %u\n",
+			 GB_OPERATION_MESSAGE_SIZE_MAX);
+		buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
+	}
+
+	hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
+	if (!hd)
+		return ERR_PTR(-ENOMEM);
+
+	ret = ida_simple_get(&gb_hd_bus_id_map, 1, 0, GFP_KERNEL);
+	if (ret < 0) {
+		kfree(hd);
+		return ERR_PTR(ret);
+	}
+	hd->bus_id = ret;
+
+	hd->driver = driver;
+	INIT_LIST_HEAD(&hd->modules);
+	INIT_LIST_HEAD(&hd->connections);
+	ida_init(&hd->cport_id_map);
+	hd->buffer_size_max = buffer_size_max;
+	hd->num_cports = num_cports;
+
+	hd->dev.parent = parent;
+	hd->dev.bus = &greybus_bus_type;
+	hd->dev.type = &greybus_hd_type;
+	hd->dev.groups = bus_groups;
+	hd->dev.dma_mask = hd->dev.parent->dma_mask;
+	device_initialize(&hd->dev);
+	dev_set_name(&hd->dev, "greybus%d", hd->bus_id);
+
+	trace_gb_hd_create(hd);
+
+	hd->svc = gb_svc_create(hd);
+	if (!hd->svc) {
+		dev_err(&hd->dev, "failed to create svc\n");
+		put_device(&hd->dev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return hd;
+}
+EXPORT_SYMBOL_GPL(gb_hd_create);
+
+int gb_hd_add(struct gb_host_device *hd)
+{
+	int ret;
+
+	ret = device_add(&hd->dev);
+	if (ret)
+		return ret;
+
+	ret = gb_svc_add(hd->svc);
+	if (ret) {
+		device_del(&hd->dev);
+		return ret;
+	}
+
+	trace_gb_hd_add(hd);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_hd_add);
+
+void gb_hd_del(struct gb_host_device *hd)
+{
+	trace_gb_hd_del(hd);
+
+	/*
+	 * Tear down the svc and flush any on-going hotplug processing before
+	 * removing the remaining interfaces.
+	 */
+	gb_svc_del(hd->svc);
+
+	device_del(&hd->dev);
+}
+EXPORT_SYMBOL_GPL(gb_hd_del);
+
+void gb_hd_shutdown(struct gb_host_device *hd)
+{
+	gb_svc_del(hd->svc);
+}
+EXPORT_SYMBOL_GPL(gb_hd_shutdown);
+
+void gb_hd_put(struct gb_host_device *hd)
+{
+	put_device(&hd->dev);
+}
+EXPORT_SYMBOL_GPL(gb_hd_put);
+
+int __init gb_hd_init(void)
+{
+	ida_init(&gb_hd_bus_id_map);
+
+	return 0;
+}
+
+void gb_hd_exit(void)
+{
+	ida_destroy(&gb_hd_bus_id_map);
+}
diff --git a/drivers/staging/greybus/hd.h b/drivers/staging/greybus/hd.h
new file mode 100644
index 000000000000..c4250cfe595f
--- /dev/null
+++ b/drivers/staging/greybus/hd.h
@@ -0,0 +1,90 @@
+/*
+ * Greybus Host Device
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __HD_H
+#define __HD_H
+
+struct gb_host_device;
+struct gb_message;
+
+struct gb_hd_driver {
+	size_t	hd_priv_size;
+
+	int (*cport_allocate)(struct gb_host_device *hd, int cport_id,
+				unsigned long flags);
+	void (*cport_release)(struct gb_host_device *hd, u16 cport_id);
+	int (*cport_enable)(struct gb_host_device *hd, u16 cport_id,
+				unsigned long flags);
+	int (*cport_disable)(struct gb_host_device *hd, u16 cport_id);
+	int (*cport_connected)(struct gb_host_device *hd, u16 cport_id);
+	int (*cport_flush)(struct gb_host_device *hd, u16 cport_id);
+	int (*cport_shutdown)(struct gb_host_device *hd, u16 cport_id,
+				u8 phase, unsigned int timeout);
+	int (*cport_quiesce)(struct gb_host_device *hd, u16 cport_id,
+				size_t peer_space, unsigned int timeout);
+	int (*cport_clear)(struct gb_host_device *hd, u16 cport_id);
+
+	int (*message_send)(struct gb_host_device *hd, u16 dest_cport_id,
+			struct gb_message *message, gfp_t gfp_mask);
+	void (*message_cancel)(struct gb_message *message);
+	int (*latency_tag_enable)(struct gb_host_device *hd, u16 cport_id);
+	int (*latency_tag_disable)(struct gb_host_device *hd, u16 cport_id);
+	int (*output)(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
+		      bool async);
+	int (*timesync_enable)(struct gb_host_device *hd, u8 count,
+			       u64 frame_time, u32 strobe_delay, u32 refclk);
+	int (*timesync_disable)(struct gb_host_device *hd);
+	int (*timesync_authoritative)(struct gb_host_device *hd,
+				      u64 *frame_time);
+	int (*timesync_get_last_event)(struct gb_host_device *hd,
+				       u64 *frame_time);
+};
+
+struct gb_host_device {
+	struct device dev;
+	int bus_id;
+	const struct gb_hd_driver *driver;
+
+	struct list_head modules;
+	struct list_head connections;
+	struct ida cport_id_map;
+
+	/* Number of CPorts supported by the UniPro IP */
+	size_t num_cports;
+
+	/* Host device buffer constraints */
+	size_t buffer_size_max;
+
+	struct gb_svc *svc;
+	/* Private data for the host driver */
+	unsigned long hd_priv[0] __aligned(sizeof(s64));
+};
+#define to_gb_host_device(d) container_of(d, struct gb_host_device, dev)
+
+int gb_hd_cport_reserve(struct gb_host_device *hd, u16 cport_id);
+void gb_hd_cport_release_reserved(struct gb_host_device *hd, u16 cport_id);
+int gb_hd_cport_allocate(struct gb_host_device *hd, int cport_id,
+					unsigned long flags);
+void gb_hd_cport_release(struct gb_host_device *hd, u16 cport_id);
+
+struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,
+					struct device *parent,
+					size_t buffer_size_max,
+					size_t num_cports);
+int gb_hd_add(struct gb_host_device *hd);
+void gb_hd_del(struct gb_host_device *hd);
+void gb_hd_shutdown(struct gb_host_device *hd);
+void gb_hd_put(struct gb_host_device *hd);
+int gb_hd_output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
+		 bool in_irq);
+
+int gb_hd_init(void);
+void gb_hd_exit(void);
+
+#endif	/* __HD_H */
diff --git a/drivers/staging/greybus/hid.c b/drivers/staging/greybus/hid.c
new file mode 100644
index 000000000000..730d746fc4c2
--- /dev/null
+++ b/drivers/staging/greybus/hid.c
@@ -0,0 +1,536 @@
+/*
+ * HID class driver for the Greybus.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/bitops.h>
+#include <linux/hid.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include "greybus.h"
+
+/* Greybus HID device's structure */
+struct gb_hid {
+	struct gb_bundle *bundle;
+	struct gb_connection		*connection;
+
+	struct hid_device		*hid;
+	struct gb_hid_desc_response	hdesc;
+
+	unsigned long			flags;
+#define GB_HID_STARTED			0x01
+#define GB_HID_READ_PENDING		0x04
+
+	unsigned int			bufsize;
+	char				*inbuf;
+};
+
+static DEFINE_MUTEX(gb_hid_open_mutex);
+
+/* Routines to get controller's information over greybus */
+
+/* Operations performed on greybus */
+static int gb_hid_get_desc(struct gb_hid *ghid)
+{
+	return gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_DESC, NULL,
+				 0, &ghid->hdesc, sizeof(ghid->hdesc));
+}
+
+static int gb_hid_get_report_desc(struct gb_hid *ghid, char *rdesc)
+{
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT_DESC,
+				 NULL, 0, rdesc,
+				 le16_to_cpu(ghid->hdesc.wReportDescLength));
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_set_power(struct gb_hid *ghid, int type)
+{
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(ghid->connection, type, NULL, 0, NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_get_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
+			     unsigned char *buf, int len)
+{
+	struct gb_hid_get_report_request request;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	request.report_type = report_type;
+	request.report_id = report_id;
+
+	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT,
+				 &request, sizeof(request), buf, len);
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_set_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
+			     unsigned char *buf, int len)
+{
+	struct gb_hid_set_report_request *request;
+	struct gb_operation *operation;
+	int ret, size = sizeof(*request) + len - 1;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	operation = gb_operation_create(ghid->connection,
+					GB_HID_TYPE_SET_REPORT, size, 0,
+					GFP_KERNEL);
+	if (!operation) {
+		gb_pm_runtime_put_autosuspend(ghid->bundle);
+		return -ENOMEM;
+	}
+
+	request = operation->request->payload;
+	request->report_type = report_type;
+	request->report_id = report_id;
+	memcpy(request->report, buf, len);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret) {
+		dev_err(&operation->connection->bundle->dev,
+			"failed to set report: %d\n", ret);
+	} else {
+		ret = len;
+	}
+
+	gb_operation_put(operation);
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_hid *ghid = gb_connection_get_data(connection);
+	struct gb_hid_input_report_request *request = op->request->payload;
+
+	if (op->type != GB_HID_TYPE_IRQ_EVENT) {
+		dev_err(&connection->bundle->dev,
+			"unsupported unsolicited request\n");
+		return -EINVAL;
+	}
+
+	if (test_bit(GB_HID_STARTED, &ghid->flags))
+		hid_input_report(ghid->hid, HID_INPUT_REPORT,
+				 request->report, op->request->payload_size, 1);
+
+	return 0;
+}
+
+static int gb_hid_report_len(struct hid_report *report)
+{
+	return ((report->size - 1) >> 3) + 1 +
+		report->device->report_enum[report->type].numbered;
+}
+
+static void gb_hid_find_max_report(struct hid_device *hid, unsigned int type,
+				   unsigned int *max)
+{
+	struct hid_report *report;
+	unsigned int size;
+
+	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
+		size = gb_hid_report_len(report);
+		if (*max < size)
+			*max = size;
+	}
+}
+
+static void gb_hid_free_buffers(struct gb_hid *ghid)
+{
+	kfree(ghid->inbuf);
+	ghid->inbuf = NULL;
+	ghid->bufsize = 0;
+}
+
+static int gb_hid_alloc_buffers(struct gb_hid *ghid, size_t bufsize)
+{
+	ghid->inbuf = kzalloc(bufsize, GFP_KERNEL);
+	if (!ghid->inbuf)
+		return -ENOMEM;
+
+	ghid->bufsize = bufsize;
+
+	return 0;
+}
+
+/* Routines dealing with reports */
+static void gb_hid_init_report(struct gb_hid *ghid, struct hid_report *report)
+{
+	unsigned int size;
+
+	size = gb_hid_report_len(report);
+	if (gb_hid_get_report(ghid, report->type, report->id, ghid->inbuf,
+			      size))
+		return;
+
+	/*
+	 * hid->driver_lock is held as we are in probe function,
+	 * we just need to setup the input fields, so using
+	 * hid_report_raw_event is safe.
+	 */
+	hid_report_raw_event(ghid->hid, report->type, ghid->inbuf, size, 1);
+}
+
+static void gb_hid_init_reports(struct gb_hid *ghid)
+{
+	struct hid_device *hid = ghid->hid;
+	struct hid_report *report;
+
+	list_for_each_entry(report,
+		&hid->report_enum[HID_INPUT_REPORT].report_list, list)
+		gb_hid_init_report(ghid, report);
+
+	list_for_each_entry(report,
+		&hid->report_enum[HID_FEATURE_REPORT].report_list, list)
+		gb_hid_init_report(ghid, report);
+}
+
+static int __gb_hid_get_raw_report(struct hid_device *hid,
+		unsigned char report_number, __u8 *buf, size_t count,
+		unsigned char report_type)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret;
+
+	if (report_type == HID_OUTPUT_REPORT)
+		return -EINVAL;
+
+	ret = gb_hid_get_report(ghid, report_type, report_number, buf, count);
+	if (!ret)
+		ret = count;
+
+	return ret;
+}
+
+static int __gb_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
+				      size_t len, unsigned char report_type)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int report_id = buf[0];
+	int ret;
+
+	if (report_type == HID_INPUT_REPORT)
+		return -EINVAL;
+
+	if (report_id) {
+		buf++;
+		len--;
+	}
+
+	ret = gb_hid_set_report(ghid, report_type, report_id, buf, len);
+	if (report_id && ret >= 0)
+		ret++; /* add report_id to the number of transfered bytes */
+
+	return 0;
+}
+
+static int gb_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
+			       __u8 *buf, size_t len, unsigned char rtype,
+			       int reqtype)
+{
+	switch (reqtype) {
+	case HID_REQ_GET_REPORT:
+		return __gb_hid_get_raw_report(hid, reportnum, buf, len, rtype);
+	case HID_REQ_SET_REPORT:
+		if (buf[0] != reportnum)
+			return -EINVAL;
+		return __gb_hid_output_raw_report(hid, buf, len, rtype);
+	default:
+		return -EIO;
+	}
+}
+
+/* HID Callbacks */
+static int gb_hid_parse(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	unsigned int rsize;
+	char *rdesc;
+	int ret;
+
+	rsize = le16_to_cpu(ghid->hdesc.wReportDescLength);
+	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
+		dbg_hid("weird size of report descriptor (%u)\n", rsize);
+		return -EINVAL;
+	}
+
+	rdesc = kzalloc(rsize, GFP_KERNEL);
+	if (!rdesc) {
+		dbg_hid("couldn't allocate rdesc memory\n");
+		return -ENOMEM;
+	}
+
+	ret = gb_hid_get_report_desc(ghid, rdesc);
+	if (ret) {
+		hid_err(hid, "reading report descriptor failed\n");
+		goto free_rdesc;
+	}
+
+	ret = hid_parse_report(hid, rdesc, rsize);
+	if (ret)
+		dbg_hid("parsing report descriptor failed\n");
+
+free_rdesc:
+	kfree(rdesc);
+
+	return ret;
+}
+
+static int gb_hid_start(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
+	int ret;
+
+	gb_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
+	gb_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
+	gb_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
+
+	if (bufsize > HID_MAX_BUFFER_SIZE)
+		bufsize = HID_MAX_BUFFER_SIZE;
+
+	ret = gb_hid_alloc_buffers(ghid, bufsize);
+	if (ret)
+		return ret;
+
+	if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
+		gb_hid_init_reports(ghid);
+
+	return 0;
+}
+
+static void gb_hid_stop(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+
+	gb_hid_free_buffers(ghid);
+}
+
+static int gb_hid_open(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret = 0;
+
+	mutex_lock(&gb_hid_open_mutex);
+	if (!hid->open++) {
+		ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
+		if (ret < 0)
+			hid->open--;
+		else
+			set_bit(GB_HID_STARTED, &ghid->flags);
+	}
+	mutex_unlock(&gb_hid_open_mutex);
+
+	return ret;
+}
+
+static void gb_hid_close(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret;
+
+	/*
+	 * Protecting hid->open to make sure we don't restart data acquistion
+	 * due to a resumption we no longer care about..
+	 */
+	mutex_lock(&gb_hid_open_mutex);
+	if (!--hid->open) {
+		clear_bit(GB_HID_STARTED, &ghid->flags);
+
+		/* Save some power */
+		ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
+		if (ret)
+			dev_err(&ghid->connection->bundle->dev,
+				"failed to power off (%d)\n", ret);
+	}
+	mutex_unlock(&gb_hid_open_mutex);
+}
+
+static int gb_hid_power(struct hid_device *hid, int lvl)
+{
+	struct gb_hid *ghid = hid->driver_data;
+
+	switch (lvl) {
+	case PM_HINT_FULLON:
+		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
+	case PM_HINT_NORMAL:
+		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
+	}
+
+	return 0;
+}
+
+/* HID structure to pass callbacks */
+static struct hid_ll_driver gb_hid_ll_driver = {
+	.parse = gb_hid_parse,
+	.start = gb_hid_start,
+	.stop = gb_hid_stop,
+	.open = gb_hid_open,
+	.close = gb_hid_close,
+	.power = gb_hid_power,
+	.raw_request = gb_hid_raw_request,
+};
+
+static int gb_hid_init(struct gb_hid *ghid)
+{
+	struct hid_device *hid = ghid->hid;
+	int ret;
+
+	ret = gb_hid_get_desc(ghid);
+	if (ret)
+		return ret;
+
+	hid->version = le16_to_cpu(ghid->hdesc.bcdHID);
+	hid->vendor = le16_to_cpu(ghid->hdesc.wVendorID);
+	hid->product = le16_to_cpu(ghid->hdesc.wProductID);
+	hid->country = ghid->hdesc.bCountryCode;
+
+	hid->driver_data = ghid;
+	hid->ll_driver = &gb_hid_ll_driver;
+	hid->dev.parent = &ghid->connection->bundle->dev;
+//	hid->bus = BUS_GREYBUS; /* Need a bustype for GREYBUS in <linux/input.h> */
+
+	/* Set HID device's name */
+	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
+		 dev_name(&ghid->connection->bundle->dev),
+		 hid->vendor, hid->product);
+
+	return 0;
+}
+
+static int gb_hid_probe(struct gb_bundle *bundle,
+			const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct hid_device *hid;
+	struct gb_hid *ghid;
+	int ret;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_HID)
+		return -ENODEV;
+
+	ghid = kzalloc(sizeof(*ghid), GFP_KERNEL);
+	if (!ghid)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+						gb_hid_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto err_free_ghid;
+	}
+
+	gb_connection_set_data(connection, ghid);
+	ghid->connection = connection;
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid)) {
+		ret = PTR_ERR(hid);
+		goto err_connection_destroy;
+	}
+
+	ghid->hid = hid;
+	ghid->bundle = bundle;
+
+	greybus_set_drvdata(bundle, ghid);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_destroy_hid;
+
+	ret = gb_hid_init(ghid);
+	if (ret)
+		goto err_connection_disable;
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		hid_err(hid, "can't add hid device: %d\n", ret);
+		goto err_connection_disable;
+	}
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+err_connection_disable:
+	gb_connection_disable(connection);
+err_destroy_hid:
+	hid_destroy_device(hid);
+err_connection_destroy:
+	gb_connection_destroy(connection);
+err_free_ghid:
+	kfree(ghid);
+
+	return ret;
+}
+
+static void gb_hid_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_hid *ghid = greybus_get_drvdata(bundle);
+
+	if (gb_pm_runtime_get_sync(bundle))
+		gb_pm_runtime_get_noresume(bundle);
+
+	hid_destroy_device(ghid->hid);
+	gb_connection_disable(ghid->connection);
+	gb_connection_destroy(ghid->connection);
+	kfree(ghid);
+}
+
+static const struct greybus_bundle_id gb_hid_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_HID) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_hid_id_table);
+
+static struct greybus_driver gb_hid_driver = {
+	.name		= "hid",
+	.probe		= gb_hid_probe,
+	.disconnect	= gb_hid_disconnect,
+	.id_table	= gb_hid_id_table,
+};
+module_greybus_driver(gb_hid_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/i2c.c b/drivers/staging/greybus/i2c.c
new file mode 100644
index 000000000000..c2a50087000c
--- /dev/null
+++ b/drivers/staging/greybus/i2c.c
@@ -0,0 +1,343 @@
+/*
+ * I2C bridge driver for the Greybus "generic" I2C module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+struct gb_i2c_device {
+	struct gb_connection	*connection;
+	struct gbphy_device	*gbphy_dev;
+
+	u32			functionality;
+
+	struct i2c_adapter	adapter;
+};
+
+/*
+ * Map Greybus i2c functionality bits into Linux ones
+ */
+static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
+{
+	return gb_i2c_functionality;	/* All bits the same for now */
+}
+
+static int gb_i2c_functionality_operation(struct gb_i2c_device *gb_i2c_dev)
+{
+	struct gb_i2c_functionality_response response;
+	u32 functionality;
+	int ret;
+
+	ret = gb_operation_sync(gb_i2c_dev->connection,
+				GB_I2C_TYPE_FUNCTIONALITY,
+				NULL, 0, &response, sizeof(response));
+	if (ret)
+		return ret;
+
+	functionality = le32_to_cpu(response.functionality);
+	gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
+
+	return 0;
+}
+
+/*
+ * Map Linux i2c_msg flags into Greybus i2c transfer op flags.
+ */
+static u16 gb_i2c_transfer_op_flags_map(u16 flags)
+{
+	return flags;	/* All flags the same for now */
+}
+
+static void
+gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
+{
+	u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
+
+	op->addr = cpu_to_le16(msg->addr);
+	op->flags = cpu_to_le16(flags);
+	op->size = cpu_to_le16(msg->len);
+}
+
+static struct gb_operation *
+gb_i2c_operation_create(struct gb_connection *connection,
+			struct i2c_msg *msgs, u32 msg_count)
+{
+	struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
+	struct gb_i2c_transfer_request *request;
+	struct gb_operation *operation;
+	struct gb_i2c_transfer_op *op;
+	struct i2c_msg *msg;
+	u32 data_out_size = 0;
+	u32 data_in_size = 0;
+	size_t request_size;
+	void *data;
+	u16 op_count;
+	u32 i;
+
+	if (msg_count > (u32)U16_MAX) {
+		dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
+			msg_count);
+		return NULL;
+	}
+	op_count = (u16)msg_count;
+
+	/*
+	 * In addition to space for all message descriptors we need
+	 * to have enough to hold all outbound message data.
+	 */
+	msg = msgs;
+	for (i = 0; i < msg_count; i++, msg++)
+		if (msg->flags & I2C_M_RD)
+			data_in_size += (u32)msg->len;
+		else
+			data_out_size += (u32)msg->len;
+
+	request_size = sizeof(*request);
+	request_size += msg_count * sizeof(*op);
+	request_size += data_out_size;
+
+	/* Response consists only of incoming data */
+	operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
+				request_size, data_in_size, GFP_KERNEL);
+	if (!operation)
+		return NULL;
+
+	request = operation->request->payload;
+	request->op_count = cpu_to_le16(op_count);
+	/* Fill in the ops array */
+	op = &request->ops[0];
+	msg = msgs;
+	for (i = 0; i < msg_count; i++)
+		gb_i2c_fill_transfer_op(op++, msg++);
+
+	if (!data_out_size)
+		return operation;
+
+	/* Copy over the outgoing data; it starts after the last op */
+	data = op;
+	msg = msgs;
+	for (i = 0; i < msg_count; i++) {
+		if (!(msg->flags & I2C_M_RD)) {
+			memcpy(data, msg->buf, msg->len);
+			data += msg->len;
+		}
+		msg++;
+	}
+
+	return operation;
+}
+
+static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
+				struct gb_i2c_transfer_response *response)
+{
+	struct i2c_msg *msg = msgs;
+	u8 *data;
+	u32 i;
+
+	if (!response)
+		return;
+	data = response->data;
+	for (i = 0; i < msg_count; i++) {
+		if (msg->flags & I2C_M_RD) {
+			memcpy(msg->buf, data, msg->len);
+			data += msg->len;
+		}
+		msg++;
+	}
+}
+
+/*
+ * Some i2c transfer operations return results that are expected.
+ */
+static bool gb_i2c_expected_transfer_error(int errno)
+{
+	return errno == -EAGAIN || errno == -ENODEV;
+}
+
+static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
+					struct i2c_msg *msgs, u32 msg_count)
+{
+	struct gb_connection *connection = gb_i2c_dev->connection;
+	struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_i2c_operation_create(connection, msgs, msg_count);
+	if (!operation)
+		return -ENOMEM;
+
+	ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
+	if (ret)
+		goto exit_operation_put;
+
+	ret = gb_operation_request_send_sync(operation);
+	if (!ret) {
+		struct gb_i2c_transfer_response *response;
+
+		response = operation->response->payload;
+		gb_i2c_decode_response(msgs, msg_count, response);
+		ret = msg_count;
+	} else if (!gb_i2c_expected_transfer_error(ret)) {
+		dev_err(dev, "transfer operation failed (%d)\n", ret);
+	}
+
+	gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);
+
+exit_operation_put:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+		int msg_count)
+{
+	struct gb_i2c_device *gb_i2c_dev;
+
+	gb_i2c_dev = i2c_get_adapdata(adap);
+
+	return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
+}
+
+#if 0
+/* Later */
+static int gb_i2c_smbus_xfer(struct i2c_adapter *adap,
+			u16 addr, unsigned short flags, char read_write,
+			u8 command, int size, union i2c_smbus_data *data)
+{
+	struct gb_i2c_device *gb_i2c_dev;
+
+	gb_i2c_dev = i2c_get_adapdata(adap);
+
+	return 0;
+}
+#endif
+
+static u32 gb_i2c_functionality(struct i2c_adapter *adap)
+{
+	struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
+
+	return gb_i2c_dev->functionality;
+}
+
+static const struct i2c_algorithm gb_i2c_algorithm = {
+	.master_xfer	= gb_i2c_master_xfer,
+	/* .smbus_xfer	= gb_i2c_smbus_xfer, */
+	.functionality	= gb_i2c_functionality,
+};
+
+/*
+ * Do initial setup of the i2c device.  This includes verifying we
+ * can support it (based on the protocol version it advertises).
+ * If that's OK, we get and cached its functionality bits.
+ *
+ * Note: gb_i2c_dev->connection is assumed to have been valid.
+ */
+static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
+{
+	/* Assume the functionality never changes, just get it once */
+	return gb_i2c_functionality_operation(gb_i2c_dev);
+}
+
+static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
+			 const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct gb_i2c_device *gb_i2c_dev;
+	struct i2c_adapter *adapter;
+	int ret;
+
+	gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
+	if (!gb_i2c_dev)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  NULL);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto exit_i2cdev_free;
+	}
+
+	gb_i2c_dev->connection = connection;
+	gb_connection_set_data(connection, gb_i2c_dev);
+	gb_i2c_dev->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	ret = gb_i2c_device_setup(gb_i2c_dev);
+	if (ret)
+		goto exit_connection_disable;
+
+	/* Looks good; up our i2c adapter */
+	adapter = &gb_i2c_dev->adapter;
+	adapter->owner = THIS_MODULE;
+	adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adapter->algo = &gb_i2c_algorithm;
+	/* adapter->algo_data = what? */
+
+	adapter->dev.parent = &gbphy_dev->dev;
+	snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
+	i2c_set_adapdata(adapter, gb_i2c_dev);
+
+	ret = i2c_add_adapter(adapter);
+	if (ret)
+		goto exit_connection_disable;
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_i2cdev_free:
+	kfree(gb_i2c_dev);
+
+	return ret;
+}
+
+static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = gb_i2c_dev->connection;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	i2c_del_adapter(&gb_i2c_dev->adapter);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	kfree(gb_i2c_dev);
+}
+
+static const struct gbphy_device_id gb_i2c_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
+
+static struct gbphy_driver i2c_driver = {
+	.name		= "i2c",
+	.probe		= gb_i2c_probe,
+	.remove		= gb_i2c_remove,
+	.id_table	= gb_i2c_id_table,
+};
+
+module_gbphy_driver(i2c_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/interface.c b/drivers/staging/greybus/interface.c
new file mode 100644
index 000000000000..546b090e2d51
--- /dev/null
+++ b/drivers/staging/greybus/interface.c
@@ -0,0 +1,1316 @@
+/*
+ * Greybus interface code
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/delay.h>
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+#define GB_INTERFACE_MODE_SWITCH_TIMEOUT	2000
+
+#define GB_INTERFACE_DEVICE_ID_BAD	0xff
+
+#define GB_INTERFACE_AUTOSUSPEND_MS			3000
+
+/* Time required for interface to enter standby before disabling REFCLK */
+#define GB_INTERFACE_SUSPEND_HIBERNATE_DELAY_MS			20
+
+/* Don't-care selector index */
+#define DME_SELECTOR_INDEX_NULL		0
+
+/* DME attributes */
+/* FIXME: remove ES2 support and DME_T_TST_SRC_INCREMENT */
+#define DME_T_TST_SRC_INCREMENT		0x4083
+
+#define DME_DDBL1_MANUFACTURERID	0x5003
+#define DME_DDBL1_PRODUCTID		0x5004
+
+#define DME_TOSHIBA_GMP_VID		0x6000
+#define DME_TOSHIBA_GMP_PID		0x6001
+#define DME_TOSHIBA_GMP_SN0		0x6002
+#define DME_TOSHIBA_GMP_SN1		0x6003
+#define DME_TOSHIBA_GMP_INIT_STATUS	0x6101
+
+/* DDBL1 Manufacturer and Product ids */
+#define TOSHIBA_DMID			0x0126
+#define TOSHIBA_ES2_BRIDGE_DPID		0x1000
+#define TOSHIBA_ES3_APBRIDGE_DPID	0x1001
+#define TOSHIBA_ES3_GBPHY_DPID	0x1002
+
+static int gb_interface_hibernate_link(struct gb_interface *intf);
+static int gb_interface_refclk_set(struct gb_interface *intf, bool enable);
+
+static int gb_interface_dme_attr_get(struct gb_interface *intf,
+							u16 attr, u32 *val)
+{
+	return gb_svc_dme_peer_get(intf->hd->svc, intf->interface_id,
+					attr, DME_SELECTOR_INDEX_NULL, val);
+}
+
+static int gb_interface_read_ara_dme(struct gb_interface *intf)
+{
+	u32 sn0, sn1;
+	int ret;
+
+	/*
+	 * Unless this is a Toshiba bridge, bail out until we have defined
+	 * standard GMP attributes.
+	 */
+	if (intf->ddbl1_manufacturer_id != TOSHIBA_DMID) {
+		dev_err(&intf->dev, "unknown manufacturer %08x\n",
+				intf->ddbl1_manufacturer_id);
+		return -ENODEV;
+	}
+
+	ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_VID,
+					&intf->vendor_id);
+	if (ret)
+		return ret;
+
+	ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_PID,
+					&intf->product_id);
+	if (ret)
+		return ret;
+
+	ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_SN0, &sn0);
+	if (ret)
+		return ret;
+
+	ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_SN1, &sn1);
+	if (ret)
+		return ret;
+
+	intf->serial_number = (u64)sn1 << 32 | sn0;
+
+	return 0;
+}
+
+static int gb_interface_read_dme(struct gb_interface *intf)
+{
+	int ret;
+
+	/* DME attributes have already been read */
+	if (intf->dme_read)
+		return 0;
+
+	ret = gb_interface_dme_attr_get(intf, DME_DDBL1_MANUFACTURERID,
+					&intf->ddbl1_manufacturer_id);
+	if (ret)
+		return ret;
+
+	ret = gb_interface_dme_attr_get(intf, DME_DDBL1_PRODUCTID,
+					&intf->ddbl1_product_id);
+	if (ret)
+		return ret;
+
+	if (intf->ddbl1_manufacturer_id == TOSHIBA_DMID &&
+			intf->ddbl1_product_id == TOSHIBA_ES2_BRIDGE_DPID) {
+		intf->quirks |= GB_INTERFACE_QUIRK_NO_GMP_IDS;
+		intf->quirks |= GB_INTERFACE_QUIRK_NO_INIT_STATUS;
+	}
+
+	ret = gb_interface_read_ara_dme(intf);
+	if (ret)
+		return ret;
+
+	intf->dme_read = true;
+
+	return 0;
+}
+
+static int gb_interface_route_create(struct gb_interface *intf)
+{
+	struct gb_svc *svc = intf->hd->svc;
+	u8 intf_id = intf->interface_id;
+	u8 device_id;
+	int ret;
+
+	/* Allocate an interface device id. */
+	ret = ida_simple_get(&svc->device_id_map,
+			     GB_SVC_DEVICE_ID_MIN, GB_SVC_DEVICE_ID_MAX + 1,
+			     GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&intf->dev, "failed to allocate device id: %d\n", ret);
+		return ret;
+	}
+	device_id = ret;
+
+	ret = gb_svc_intf_device_id(svc, intf_id, device_id);
+	if (ret) {
+		dev_err(&intf->dev, "failed to set device id %u: %d\n",
+				device_id, ret);
+		goto err_ida_remove;
+	}
+
+	/* FIXME: Hard-coded AP device id. */
+	ret = gb_svc_route_create(svc, svc->ap_intf_id, GB_SVC_DEVICE_ID_AP,
+				  intf_id, device_id);
+	if (ret) {
+		dev_err(&intf->dev, "failed to create route: %d\n", ret);
+		goto err_svc_id_free;
+	}
+
+	intf->device_id = device_id;
+
+	return 0;
+
+err_svc_id_free:
+	/*
+	 * XXX Should we tell SVC that this id doesn't belong to interface
+	 * XXX anymore.
+	 */
+err_ida_remove:
+	ida_simple_remove(&svc->device_id_map, device_id);
+
+	return ret;
+}
+
+static void gb_interface_route_destroy(struct gb_interface *intf)
+{
+	struct gb_svc *svc = intf->hd->svc;
+
+	if (intf->device_id == GB_INTERFACE_DEVICE_ID_BAD)
+		return;
+
+	gb_svc_route_destroy(svc, svc->ap_intf_id, intf->interface_id);
+	ida_simple_remove(&svc->device_id_map, intf->device_id);
+	intf->device_id = GB_INTERFACE_DEVICE_ID_BAD;
+}
+
+/* Locking: Caller holds the interface mutex. */
+static int gb_interface_legacy_mode_switch(struct gb_interface *intf)
+{
+	int ret;
+
+	dev_info(&intf->dev, "legacy mode switch detected\n");
+
+	/* Mark as disconnected to prevent I/O during disable. */
+	intf->disconnected = true;
+	gb_interface_disable(intf);
+	intf->disconnected = false;
+
+	ret = gb_interface_enable(intf);
+	if (ret) {
+		dev_err(&intf->dev, "failed to re-enable interface: %d\n", ret);
+		gb_interface_deactivate(intf);
+	}
+
+	return ret;
+}
+
+void gb_interface_mailbox_event(struct gb_interface *intf, u16 result,
+								u32 mailbox)
+{
+	mutex_lock(&intf->mutex);
+
+	if (result) {
+		dev_warn(&intf->dev,
+				"mailbox event with UniPro error: 0x%04x\n",
+				result);
+		goto err_disable;
+	}
+
+	if (mailbox != GB_SVC_INTF_MAILBOX_GREYBUS) {
+		dev_warn(&intf->dev,
+				"mailbox event with unexpected value: 0x%08x\n",
+				mailbox);
+		goto err_disable;
+	}
+
+	if (intf->quirks & GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH) {
+		gb_interface_legacy_mode_switch(intf);
+		goto out_unlock;
+	}
+
+	if (!intf->mode_switch) {
+		dev_warn(&intf->dev, "unexpected mailbox event: 0x%08x\n",
+				mailbox);
+		goto err_disable;
+	}
+
+	dev_info(&intf->dev, "mode switch detected\n");
+
+	complete(&intf->mode_switch_completion);
+
+out_unlock:
+	mutex_unlock(&intf->mutex);
+
+	return;
+
+err_disable:
+	gb_interface_disable(intf);
+	gb_interface_deactivate(intf);
+	mutex_unlock(&intf->mutex);
+}
+
+static void gb_interface_mode_switch_work(struct work_struct *work)
+{
+	struct gb_interface *intf;
+	struct gb_control *control;
+	unsigned long timeout;
+	int ret;
+
+	intf = container_of(work, struct gb_interface, mode_switch_work);
+
+	mutex_lock(&intf->mutex);
+	/* Make sure interface is still enabled. */
+	if (!intf->enabled) {
+		dev_dbg(&intf->dev, "mode switch aborted\n");
+		intf->mode_switch = false;
+		mutex_unlock(&intf->mutex);
+		goto out_interface_put;
+	}
+
+	/*
+	 * Prepare the control device for mode switch and make sure to get an
+	 * extra reference before it goes away during interface disable.
+	 */
+	control = gb_control_get(intf->control);
+	gb_control_mode_switch_prepare(control);
+	gb_interface_disable(intf);
+	mutex_unlock(&intf->mutex);
+
+	timeout = msecs_to_jiffies(GB_INTERFACE_MODE_SWITCH_TIMEOUT);
+	ret = wait_for_completion_interruptible_timeout(
+			&intf->mode_switch_completion, timeout);
+
+	/* Finalise control-connection mode switch. */
+	gb_control_mode_switch_complete(control);
+	gb_control_put(control);
+
+	if (ret < 0) {
+		dev_err(&intf->dev, "mode switch interrupted\n");
+		goto err_deactivate;
+	} else if (ret == 0) {
+		dev_err(&intf->dev, "mode switch timed out\n");
+		goto err_deactivate;
+	}
+
+	/* Re-enable (re-enumerate) interface if still active. */
+	mutex_lock(&intf->mutex);
+	intf->mode_switch = false;
+	if (intf->active) {
+		ret = gb_interface_enable(intf);
+		if (ret) {
+			dev_err(&intf->dev, "failed to re-enable interface: %d\n",
+					ret);
+			gb_interface_deactivate(intf);
+		}
+	}
+	mutex_unlock(&intf->mutex);
+
+out_interface_put:
+	gb_interface_put(intf);
+
+	return;
+
+err_deactivate:
+	mutex_lock(&intf->mutex);
+	intf->mode_switch = false;
+	gb_interface_deactivate(intf);
+	mutex_unlock(&intf->mutex);
+
+	gb_interface_put(intf);
+}
+
+int gb_interface_request_mode_switch(struct gb_interface *intf)
+{
+	int ret = 0;
+
+	mutex_lock(&intf->mutex);
+	if (intf->mode_switch) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	intf->mode_switch = true;
+	reinit_completion(&intf->mode_switch_completion);
+
+	/*
+	 * Get a reference to the interface device, which will be put once the
+	 * mode switch is complete.
+	 */
+	get_device(&intf->dev);
+
+	if (!queue_work(system_long_wq, &intf->mode_switch_work)) {
+		put_device(&intf->dev);
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&intf->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_interface_request_mode_switch);
+
+/*
+ * T_TstSrcIncrement is written by the module on ES2 as a stand-in for the
+ * init-status attribute DME_TOSHIBA_INIT_STATUS. The AP needs to read and
+ * clear it after reading a non-zero value from it.
+ *
+ * FIXME: This is module-hardware dependent and needs to be extended for every
+ * type of module we want to support.
+ */
+static int gb_interface_read_and_clear_init_status(struct gb_interface *intf)
+{
+	struct gb_host_device *hd = intf->hd;
+	unsigned long bootrom_quirks;
+	unsigned long s2l_quirks;
+	int ret;
+	u32 value;
+	u16 attr;
+	u8 init_status;
+
+	/*
+	 * ES2 bridges use T_TstSrcIncrement for the init status.
+	 *
+	 * FIXME: Remove ES2 support
+	 */
+	if (intf->quirks & GB_INTERFACE_QUIRK_NO_INIT_STATUS)
+		attr = DME_T_TST_SRC_INCREMENT;
+	else
+		attr = DME_TOSHIBA_GMP_INIT_STATUS;
+
+	ret = gb_svc_dme_peer_get(hd->svc, intf->interface_id, attr,
+				  DME_SELECTOR_INDEX_NULL, &value);
+	if (ret)
+		return ret;
+
+	/*
+	 * A nonzero init status indicates the module has finished
+	 * initializing.
+	 */
+	if (!value) {
+		dev_err(&intf->dev, "invalid init status\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Extract the init status.
+	 *
+	 * For ES2: We need to check lowest 8 bits of 'value'.
+	 * For ES3: We need to check highest 8 bits out of 32 of 'value'.
+	 *
+	 * FIXME: Remove ES2 support
+	 */
+	if (intf->quirks & GB_INTERFACE_QUIRK_NO_INIT_STATUS)
+		init_status = value & 0xff;
+	else
+		init_status = value >> 24;
+
+	/*
+	 * Check if the interface is executing the quirky ES3 bootrom that,
+	 * for example, requires E2EFC, CSD and CSV to be disabled.
+	 */
+	bootrom_quirks = GB_INTERFACE_QUIRK_NO_CPORT_FEATURES |
+				GB_INTERFACE_QUIRK_FORCED_DISABLE |
+				GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH |
+				GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE;
+
+	s2l_quirks = GB_INTERFACE_QUIRK_NO_PM;
+
+	switch (init_status) {
+	case GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED:
+	case GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED:
+		intf->quirks |= bootrom_quirks;
+		break;
+	case GB_INIT_S2_LOADER_BOOT_STARTED:
+		/* S2 Loader doesn't support runtime PM */
+		intf->quirks &= ~bootrom_quirks;
+		intf->quirks |= s2l_quirks;
+		break;
+	default:
+		intf->quirks &= ~bootrom_quirks;
+		intf->quirks &= ~s2l_quirks;
+	}
+
+	/* Clear the init status. */
+	return gb_svc_dme_peer_set(hd->svc, intf->interface_id, attr,
+				   DME_SELECTOR_INDEX_NULL, 0);
+}
+
+/* interface sysfs attributes */
+#define gb_interface_attr(field, type)					\
+static ssize_t field##_show(struct device *dev,				\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_interface *intf = to_gb_interface(dev);		\
+	return scnprintf(buf, PAGE_SIZE, type"\n", intf->field);	\
+}									\
+static DEVICE_ATTR_RO(field)
+
+gb_interface_attr(ddbl1_manufacturer_id, "0x%08x");
+gb_interface_attr(ddbl1_product_id, "0x%08x");
+gb_interface_attr(interface_id, "%u");
+gb_interface_attr(vendor_id, "0x%08x");
+gb_interface_attr(product_id, "0x%08x");
+gb_interface_attr(serial_number, "0x%016llx");
+
+static ssize_t voltage_now_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	int ret;
+	u32 measurement;
+
+	ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
+					    GB_SVC_PWRMON_TYPE_VOL,
+					    &measurement);
+	if (ret) {
+		dev_err(&intf->dev, "failed to get voltage sample (%d)\n", ret);
+		return ret;
+	}
+
+	return sprintf(buf, "%u\n", measurement);
+}
+static DEVICE_ATTR_RO(voltage_now);
+
+static ssize_t current_now_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	int ret;
+	u32 measurement;
+
+	ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
+					    GB_SVC_PWRMON_TYPE_CURR,
+					    &measurement);
+	if (ret) {
+		dev_err(&intf->dev, "failed to get current sample (%d)\n", ret);
+		return ret;
+	}
+
+	return sprintf(buf, "%u\n", measurement);
+}
+static DEVICE_ATTR_RO(current_now);
+
+static ssize_t power_now_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	int ret;
+	u32 measurement;
+
+	ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
+					    GB_SVC_PWRMON_TYPE_PWR,
+					    &measurement);
+	if (ret) {
+		dev_err(&intf->dev, "failed to get power sample (%d)\n", ret);
+		return ret;
+	}
+
+	return sprintf(buf, "%u\n", measurement);
+}
+static DEVICE_ATTR_RO(power_now);
+
+static ssize_t power_state_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	if (intf->active)
+		return scnprintf(buf, PAGE_SIZE, "on\n");
+	else
+		return scnprintf(buf, PAGE_SIZE, "off\n");
+}
+
+static ssize_t power_state_store(struct device *dev,
+				 struct device_attribute *attr, const char *buf,
+				 size_t len)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	bool activate;
+	int ret = 0;
+
+	if (kstrtobool(buf, &activate))
+		return -EINVAL;
+
+	mutex_lock(&intf->mutex);
+
+	if (activate == intf->active)
+		goto unlock;
+
+	if (activate) {
+		ret = gb_interface_activate(intf);
+		if (ret) {
+			dev_err(&intf->dev,
+				"failed to activate interface: %d\n", ret);
+			goto unlock;
+		}
+
+		ret = gb_interface_enable(intf);
+		if (ret) {
+			dev_err(&intf->dev,
+				"failed to enable interface: %d\n", ret);
+			gb_interface_deactivate(intf);
+			goto unlock;
+		}
+	} else {
+		gb_interface_disable(intf);
+		gb_interface_deactivate(intf);
+	}
+
+unlock:
+	mutex_unlock(&intf->mutex);
+
+	if (ret)
+		return ret;
+
+	return len;
+}
+static DEVICE_ATTR_RW(power_state);
+
+static const char *gb_interface_type_string(struct gb_interface *intf)
+{
+	static const char * const types[] = {
+		[GB_INTERFACE_TYPE_INVALID] = "invalid",
+		[GB_INTERFACE_TYPE_UNKNOWN] = "unknown",
+		[GB_INTERFACE_TYPE_DUMMY] = "dummy",
+		[GB_INTERFACE_TYPE_UNIPRO] = "unipro",
+		[GB_INTERFACE_TYPE_GREYBUS] = "greybus",
+	};
+
+	return types[intf->type];
+}
+
+static ssize_t interface_type_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	return sprintf(buf, "%s\n", gb_interface_type_string(intf));
+}
+static DEVICE_ATTR_RO(interface_type);
+
+static struct attribute *interface_unipro_attrs[] = {
+	&dev_attr_ddbl1_manufacturer_id.attr,
+	&dev_attr_ddbl1_product_id.attr,
+	NULL
+};
+
+static struct attribute *interface_greybus_attrs[] = {
+	&dev_attr_vendor_id.attr,
+	&dev_attr_product_id.attr,
+	&dev_attr_serial_number.attr,
+	NULL
+};
+
+static struct attribute *interface_power_attrs[] = {
+	&dev_attr_voltage_now.attr,
+	&dev_attr_current_now.attr,
+	&dev_attr_power_now.attr,
+	&dev_attr_power_state.attr,
+	NULL
+};
+
+static struct attribute *interface_common_attrs[] = {
+	&dev_attr_interface_id.attr,
+	&dev_attr_interface_type.attr,
+	NULL
+};
+
+static umode_t interface_unipro_is_visible(struct kobject *kobj,
+						struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	switch (intf->type) {
+	case GB_INTERFACE_TYPE_UNIPRO:
+	case GB_INTERFACE_TYPE_GREYBUS:
+		return attr->mode;
+	default:
+		return 0;
+	}
+}
+
+static umode_t interface_greybus_is_visible(struct kobject *kobj,
+						struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	switch (intf->type) {
+	case GB_INTERFACE_TYPE_GREYBUS:
+		return attr->mode;
+	default:
+		return 0;
+	}
+}
+
+static umode_t interface_power_is_visible(struct kobject *kobj,
+						struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	switch (intf->type) {
+	case GB_INTERFACE_TYPE_UNIPRO:
+	case GB_INTERFACE_TYPE_GREYBUS:
+		return attr->mode;
+	default:
+		return 0;
+	}
+}
+
+static const struct attribute_group interface_unipro_group = {
+	.is_visible	= interface_unipro_is_visible,
+	.attrs		= interface_unipro_attrs,
+};
+
+static const struct attribute_group interface_greybus_group = {
+	.is_visible	= interface_greybus_is_visible,
+	.attrs		= interface_greybus_attrs,
+};
+
+static const struct attribute_group interface_power_group = {
+	.is_visible	= interface_power_is_visible,
+	.attrs		= interface_power_attrs,
+};
+
+static const struct attribute_group interface_common_group = {
+	.attrs		= interface_common_attrs,
+};
+
+static const struct attribute_group *interface_groups[] = {
+	&interface_unipro_group,
+	&interface_greybus_group,
+	&interface_power_group,
+	&interface_common_group,
+	NULL
+};
+
+static void gb_interface_release(struct device *dev)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+
+	trace_gb_interface_release(intf);
+
+	kfree(intf);
+}
+
+#ifdef CONFIG_PM
+static int gb_interface_suspend(struct device *dev)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	int ret, timesync_ret;
+
+	ret = gb_control_interface_suspend_prepare(intf->control);
+	if (ret)
+		return ret;
+
+	gb_timesync_interface_remove(intf);
+
+	ret = gb_control_suspend(intf->control);
+	if (ret)
+		goto err_hibernate_abort;
+
+	ret = gb_interface_hibernate_link(intf);
+	if (ret)
+		return ret;
+
+	/* Delay to allow interface to enter standby before disabling refclk */
+	msleep(GB_INTERFACE_SUSPEND_HIBERNATE_DELAY_MS);
+
+	ret = gb_interface_refclk_set(intf, false);
+	if (ret)
+		return ret;
+
+	return 0;
+
+err_hibernate_abort:
+	gb_control_interface_hibernate_abort(intf->control);
+
+	timesync_ret = gb_timesync_interface_add(intf);
+	if (timesync_ret) {
+		dev_err(dev, "failed to add to timesync: %d\n", timesync_ret);
+		return timesync_ret;
+	}
+
+	return ret;
+}
+
+static int gb_interface_resume(struct device *dev)
+{
+	struct gb_interface *intf = to_gb_interface(dev);
+	struct gb_svc *svc = intf->hd->svc;
+	int ret;
+
+	ret = gb_interface_refclk_set(intf, true);
+	if (ret)
+		return ret;
+
+	ret = gb_svc_intf_resume(svc, intf->interface_id);
+	if (ret)
+		return ret;
+
+	ret = gb_control_resume(intf->control);
+	if (ret)
+		return ret;
+
+	ret = gb_timesync_interface_add(intf);
+	if (ret) {
+		dev_err(dev, "failed to add to timesync: %d\n", ret);
+		return ret;
+	}
+
+	ret = gb_timesync_schedule_synchronous(intf);
+	if (ret) {
+		dev_err(dev, "failed to synchronize FrameTime: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_interface_runtime_idle(struct device *dev)
+{
+	pm_runtime_mark_last_busy(dev);
+	pm_request_autosuspend(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_interface_pm_ops = {
+	SET_RUNTIME_PM_OPS(gb_interface_suspend, gb_interface_resume,
+			   gb_interface_runtime_idle)
+};
+
+struct device_type greybus_interface_type = {
+	.name =		"greybus_interface",
+	.release =	gb_interface_release,
+	.pm =		&gb_interface_pm_ops,
+};
+
+/*
+ * A Greybus module represents a user-replaceable component on a GMP
+ * phone.  An interface is the physical connection on that module.  A
+ * module may have more than one interface.
+ *
+ * Create a gb_interface structure to represent a discovered interface.
+ * The position of interface within the Endo is encoded in "interface_id"
+ * argument.
+ *
+ * Returns a pointer to the new interfce or a null pointer if a
+ * failure occurs due to memory exhaustion.
+ */
+struct gb_interface *gb_interface_create(struct gb_module *module,
+					 u8 interface_id)
+{
+	struct gb_host_device *hd = module->hd;
+	struct gb_interface *intf;
+
+	intf = kzalloc(sizeof(*intf), GFP_KERNEL);
+	if (!intf)
+		return NULL;
+
+	intf->hd = hd;		/* XXX refcount? */
+	intf->module = module;
+	intf->interface_id = interface_id;
+	INIT_LIST_HEAD(&intf->bundles);
+	INIT_LIST_HEAD(&intf->manifest_descs);
+	mutex_init(&intf->mutex);
+	INIT_WORK(&intf->mode_switch_work, gb_interface_mode_switch_work);
+	init_completion(&intf->mode_switch_completion);
+
+	/* Invalid device id to start with */
+	intf->device_id = GB_INTERFACE_DEVICE_ID_BAD;
+
+	intf->dev.parent = &module->dev;
+	intf->dev.bus = &greybus_bus_type;
+	intf->dev.type = &greybus_interface_type;
+	intf->dev.groups = interface_groups;
+	intf->dev.dma_mask = module->dev.dma_mask;
+	device_initialize(&intf->dev);
+	dev_set_name(&intf->dev, "%s.%u", dev_name(&module->dev),
+			interface_id);
+
+	pm_runtime_set_autosuspend_delay(&intf->dev,
+					 GB_INTERFACE_AUTOSUSPEND_MS);
+
+	trace_gb_interface_create(intf);
+
+	return intf;
+}
+
+static int gb_interface_vsys_set(struct gb_interface *intf, bool enable)
+{
+	struct gb_svc *svc = intf->hd->svc;
+	int ret;
+
+	dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);
+
+	ret = gb_svc_intf_vsys_set(svc, intf->interface_id, enable);
+	if (ret) {
+		dev_err(&intf->dev, "failed to set v_sys: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_interface_refclk_set(struct gb_interface *intf, bool enable)
+{
+	struct gb_svc *svc = intf->hd->svc;
+	int ret;
+
+	dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);
+
+	ret = gb_svc_intf_refclk_set(svc, intf->interface_id, enable);
+	if (ret) {
+		dev_err(&intf->dev, "failed to set refclk: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_interface_unipro_set(struct gb_interface *intf, bool enable)
+{
+	struct gb_svc *svc = intf->hd->svc;
+	int ret;
+
+	dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);
+
+	ret = gb_svc_intf_unipro_set(svc, intf->interface_id, enable);
+	if (ret) {
+		dev_err(&intf->dev, "failed to set UniPro: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_interface_activate_operation(struct gb_interface *intf,
+					   enum gb_interface_type *intf_type)
+{
+	struct gb_svc *svc = intf->hd->svc;
+	u8 type;
+	int ret;
+
+	dev_dbg(&intf->dev, "%s\n", __func__);
+
+	ret = gb_svc_intf_activate(svc, intf->interface_id, &type);
+	if (ret) {
+		dev_err(&intf->dev, "failed to activate: %d\n", ret);
+		return ret;
+	}
+
+	switch (type) {
+	case GB_SVC_INTF_TYPE_DUMMY:
+		*intf_type = GB_INTERFACE_TYPE_DUMMY;
+		/* FIXME: handle as an error for now */
+		return -ENODEV;
+	case GB_SVC_INTF_TYPE_UNIPRO:
+		*intf_type = GB_INTERFACE_TYPE_UNIPRO;
+		dev_err(&intf->dev, "interface type UniPro not supported\n");
+		/* FIXME: handle as an error for now */
+		return -ENODEV;
+	case GB_SVC_INTF_TYPE_GREYBUS:
+		*intf_type = GB_INTERFACE_TYPE_GREYBUS;
+		break;
+	default:
+		dev_err(&intf->dev, "unknown interface type: %u\n", type);
+		*intf_type = GB_INTERFACE_TYPE_UNKNOWN;
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int gb_interface_hibernate_link(struct gb_interface *intf)
+{
+	struct gb_svc *svc = intf->hd->svc;
+
+	return gb_svc_intf_set_power_mode_hibernate(svc, intf->interface_id);
+}
+
+static int _gb_interface_activate(struct gb_interface *intf,
+				  enum gb_interface_type *type)
+{
+	int ret;
+
+	*type = GB_INTERFACE_TYPE_UNKNOWN;
+
+	if (intf->ejected || intf->removed)
+		return -ENODEV;
+
+	ret = gb_interface_vsys_set(intf, true);
+	if (ret)
+		return ret;
+
+	ret = gb_interface_refclk_set(intf, true);
+	if (ret)
+		goto err_vsys_disable;
+
+	ret = gb_interface_unipro_set(intf, true);
+	if (ret)
+		goto err_refclk_disable;
+
+	ret = gb_interface_activate_operation(intf, type);
+	if (ret) {
+		switch (*type) {
+		case GB_INTERFACE_TYPE_UNIPRO:
+		case GB_INTERFACE_TYPE_GREYBUS:
+			goto err_hibernate_link;
+		default:
+			goto err_unipro_disable;
+		}
+	}
+
+	ret = gb_interface_read_dme(intf);
+	if (ret)
+		goto err_hibernate_link;
+
+	ret = gb_interface_route_create(intf);
+	if (ret)
+		goto err_hibernate_link;
+
+	intf->active = true;
+
+	trace_gb_interface_activate(intf);
+
+	return 0;
+
+err_hibernate_link:
+	gb_interface_hibernate_link(intf);
+err_unipro_disable:
+	gb_interface_unipro_set(intf, false);
+err_refclk_disable:
+	gb_interface_refclk_set(intf, false);
+err_vsys_disable:
+	gb_interface_vsys_set(intf, false);
+
+	return ret;
+}
+
+/*
+ * At present, we assume a UniPro-only module to be a Greybus module that
+ * failed to send its mailbox poke. There is some reason to believe that this
+ * is because of a bug in the ES3 bootrom.
+ *
+ * FIXME: Check if this is a Toshiba bridge before retrying?
+ */
+static int _gb_interface_activate_es3_hack(struct gb_interface *intf,
+					   enum gb_interface_type *type)
+{
+	int retries = 3;
+	int ret;
+
+	while (retries--) {
+		ret = _gb_interface_activate(intf, type);
+		if (ret == -ENODEV && *type == GB_INTERFACE_TYPE_UNIPRO)
+			continue;
+
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * Activate an interface.
+ *
+ * Locking: Caller holds the interface mutex.
+ */
+int gb_interface_activate(struct gb_interface *intf)
+{
+	enum gb_interface_type type;
+	int ret;
+
+	switch (intf->type) {
+	case GB_INTERFACE_TYPE_INVALID:
+	case GB_INTERFACE_TYPE_GREYBUS:
+		ret = _gb_interface_activate_es3_hack(intf, &type);
+		break;
+	default:
+		ret = _gb_interface_activate(intf, &type);
+	}
+
+	/* Make sure type is detected correctly during reactivation. */
+	if (intf->type != GB_INTERFACE_TYPE_INVALID) {
+		if (type != intf->type) {
+			dev_err(&intf->dev, "failed to detect interface type\n");
+
+			if (!ret)
+				gb_interface_deactivate(intf);
+
+			return -EIO;
+		}
+	} else {
+		intf->type = type;
+	}
+
+	return ret;
+}
+
+/*
+ * Deactivate an interface.
+ *
+ * Locking: Caller holds the interface mutex.
+ */
+void gb_interface_deactivate(struct gb_interface *intf)
+{
+	if (!intf->active)
+		return;
+
+	trace_gb_interface_deactivate(intf);
+
+	/* Abort any ongoing mode switch. */
+	if (intf->mode_switch)
+		complete(&intf->mode_switch_completion);
+
+	gb_interface_route_destroy(intf);
+	gb_interface_hibernate_link(intf);
+	gb_interface_unipro_set(intf, false);
+	gb_interface_refclk_set(intf, false);
+	gb_interface_vsys_set(intf, false);
+
+	intf->active = false;
+}
+
+/*
+ * Enable an interface by enabling its control connection, fetching the
+ * manifest and other information over it, and finally registering its child
+ * devices.
+ *
+ * Locking: Caller holds the interface mutex.
+ */
+int gb_interface_enable(struct gb_interface *intf)
+{
+	struct gb_control *control;
+	struct gb_bundle *bundle, *tmp;
+	int ret, size;
+	void *manifest;
+
+	ret = gb_interface_read_and_clear_init_status(intf);
+	if (ret) {
+		dev_err(&intf->dev, "failed to clear init status: %d\n", ret);
+		return ret;
+	}
+
+	/* Establish control connection */
+	control = gb_control_create(intf);
+	if (IS_ERR(control)) {
+		dev_err(&intf->dev, "failed to create control device: %ld\n",
+				PTR_ERR(control));
+		return PTR_ERR(control);
+	}
+	intf->control = control;
+
+	ret = gb_control_enable(intf->control);
+	if (ret)
+		goto err_put_control;
+
+	/* Get manifest size using control protocol on CPort */
+	size = gb_control_get_manifest_size_operation(intf);
+	if (size <= 0) {
+		dev_err(&intf->dev, "failed to get manifest size: %d\n", size);
+
+		if (size)
+			ret = size;
+		else
+			ret =  -EINVAL;
+
+		goto err_disable_control;
+	}
+
+	manifest = kmalloc(size, GFP_KERNEL);
+	if (!manifest) {
+		ret = -ENOMEM;
+		goto err_disable_control;
+	}
+
+	/* Get manifest using control protocol on CPort */
+	ret = gb_control_get_manifest_operation(intf, manifest, size);
+	if (ret) {
+		dev_err(&intf->dev, "failed to get manifest: %d\n", ret);
+		goto err_free_manifest;
+	}
+
+	/*
+	 * Parse the manifest and build up our data structures representing
+	 * what's in it.
+	 */
+	if (!gb_manifest_parse(intf, manifest, size)) {
+		dev_err(&intf->dev, "failed to parse manifest\n");
+		ret = -EINVAL;
+		goto err_destroy_bundles;
+	}
+
+	ret = gb_control_get_bundle_versions(intf->control);
+	if (ret)
+		goto err_destroy_bundles;
+
+	ret = gb_timesync_interface_add(intf);
+	if (ret) {
+		dev_err(&intf->dev, "failed to add to timesync: %d\n", ret);
+		goto err_destroy_bundles;
+	}
+
+	/* Register the control device and any bundles */
+	ret = gb_control_add(intf->control);
+	if (ret)
+		goto err_remove_timesync;
+
+	pm_runtime_use_autosuspend(&intf->dev);
+	pm_runtime_get_noresume(&intf->dev);
+	pm_runtime_set_active(&intf->dev);
+	pm_runtime_enable(&intf->dev);
+
+	list_for_each_entry_safe_reverse(bundle, tmp, &intf->bundles, links) {
+		ret = gb_bundle_add(bundle);
+		if (ret) {
+			gb_bundle_destroy(bundle);
+			continue;
+		}
+	}
+
+	kfree(manifest);
+
+	intf->enabled = true;
+
+	pm_runtime_put(&intf->dev);
+
+	trace_gb_interface_enable(intf);
+
+	return 0;
+
+err_remove_timesync:
+	gb_timesync_interface_remove(intf);
+err_destroy_bundles:
+	list_for_each_entry_safe(bundle, tmp, &intf->bundles, links)
+		gb_bundle_destroy(bundle);
+err_free_manifest:
+	kfree(manifest);
+err_disable_control:
+	gb_control_disable(intf->control);
+err_put_control:
+	gb_control_put(intf->control);
+	intf->control = NULL;
+
+	return ret;
+}
+
+/*
+ * Disable an interface and destroy its bundles.
+ *
+ * Locking: Caller holds the interface mutex.
+ */
+void gb_interface_disable(struct gb_interface *intf)
+{
+	struct gb_bundle *bundle;
+	struct gb_bundle *next;
+
+	if (!intf->enabled)
+		return;
+
+	trace_gb_interface_disable(intf);
+
+	pm_runtime_get_sync(&intf->dev);
+
+	/* Set disconnected flag to avoid I/O during connection tear down. */
+	if (intf->quirks & GB_INTERFACE_QUIRK_FORCED_DISABLE)
+		intf->disconnected = true;
+
+	list_for_each_entry_safe(bundle, next, &intf->bundles, links)
+		gb_bundle_destroy(bundle);
+
+	if (!intf->mode_switch && !intf->disconnected)
+		gb_control_interface_deactivate_prepare(intf->control);
+
+	gb_control_del(intf->control);
+	gb_timesync_interface_remove(intf);
+	gb_control_disable(intf->control);
+	gb_control_put(intf->control);
+	intf->control = NULL;
+
+	intf->enabled = false;
+
+	pm_runtime_disable(&intf->dev);
+	pm_runtime_set_suspended(&intf->dev);
+	pm_runtime_dont_use_autosuspend(&intf->dev);
+	pm_runtime_put_noidle(&intf->dev);
+}
+
+/* Enable TimeSync on an Interface control connection. */
+int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,
+				 u64 frame_time, u32 strobe_delay, u32 refclk)
+{
+	return gb_control_timesync_enable(intf->control, count,
+					  frame_time, strobe_delay,
+					  refclk);
+}
+
+/* Disable TimeSync on an Interface control connection. */
+int gb_interface_timesync_disable(struct gb_interface *intf)
+{
+	return gb_control_timesync_disable(intf->control);
+}
+
+/* Transmit the Authoritative FrameTime via an Interface control connection. */
+int gb_interface_timesync_authoritative(struct gb_interface *intf,
+					u64 *frame_time)
+{
+	return gb_control_timesync_authoritative(intf->control,
+						frame_time);
+}
+
+/* Register an interface. */
+int gb_interface_add(struct gb_interface *intf)
+{
+	int ret;
+
+	ret = device_add(&intf->dev);
+	if (ret) {
+		dev_err(&intf->dev, "failed to register interface: %d\n", ret);
+		return ret;
+	}
+
+	trace_gb_interface_add(intf);
+
+	dev_info(&intf->dev, "Interface added (%s)\n",
+			gb_interface_type_string(intf));
+
+	switch (intf->type) {
+	case GB_INTERFACE_TYPE_GREYBUS:
+		dev_info(&intf->dev, "GMP VID=0x%08x, PID=0x%08x\n",
+				intf->vendor_id, intf->product_id);
+		/* fall-through */
+	case GB_INTERFACE_TYPE_UNIPRO:
+		dev_info(&intf->dev, "DDBL1 Manufacturer=0x%08x, Product=0x%08x\n",
+				intf->ddbl1_manufacturer_id,
+				intf->ddbl1_product_id);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Deregister an interface. */
+void gb_interface_del(struct gb_interface *intf)
+{
+	if (device_is_registered(&intf->dev)) {
+		trace_gb_interface_del(intf);
+
+		device_del(&intf->dev);
+		dev_info(&intf->dev, "Interface removed\n");
+	}
+}
+
+void gb_interface_put(struct gb_interface *intf)
+{
+	put_device(&intf->dev);
+}
diff --git a/drivers/staging/greybus/interface.h b/drivers/staging/greybus/interface.h
new file mode 100644
index 000000000000..03299d2a8be5
--- /dev/null
+++ b/drivers/staging/greybus/interface.h
@@ -0,0 +1,88 @@
+/*
+ * Greybus Interface Block code
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __INTERFACE_H
+#define __INTERFACE_H
+
+enum gb_interface_type {
+	GB_INTERFACE_TYPE_INVALID = 0,
+	GB_INTERFACE_TYPE_UNKNOWN,
+	GB_INTERFACE_TYPE_DUMMY,
+	GB_INTERFACE_TYPE_UNIPRO,
+	GB_INTERFACE_TYPE_GREYBUS,
+};
+
+#define GB_INTERFACE_QUIRK_NO_CPORT_FEATURES		BIT(0)
+#define GB_INTERFACE_QUIRK_NO_INIT_STATUS		BIT(1)
+#define GB_INTERFACE_QUIRK_NO_GMP_IDS			BIT(2)
+#define GB_INTERFACE_QUIRK_FORCED_DISABLE		BIT(3)
+#define GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH		BIT(4)
+#define GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE		BIT(5)
+#define GB_INTERFACE_QUIRK_NO_PM			BIT(6)
+
+struct gb_interface {
+	struct device dev;
+	struct gb_control *control;
+
+	struct list_head bundles;
+	struct list_head module_node;
+	struct list_head manifest_descs;
+	u8 interface_id;	/* Physical location within the Endo */
+	u8 device_id;
+	u8 features;		/* Feature flags set in the manifest */
+
+	enum gb_interface_type type;
+
+	u32 ddbl1_manufacturer_id;
+	u32 ddbl1_product_id;
+	u32 vendor_id;
+	u32 product_id;
+	u64 serial_number;
+
+	struct gb_host_device *hd;
+	struct gb_module *module;
+
+	unsigned long quirks;
+
+	struct mutex mutex;
+
+	bool disconnected;
+
+	bool ejected;
+	bool removed;
+	bool active;
+	bool enabled;
+	bool mode_switch;
+	bool dme_read;
+
+	struct work_struct mode_switch_work;
+	struct completion mode_switch_completion;
+};
+#define to_gb_interface(d) container_of(d, struct gb_interface, dev)
+
+struct gb_interface *gb_interface_create(struct gb_module *module,
+					 u8 interface_id);
+int gb_interface_activate(struct gb_interface *intf);
+void gb_interface_deactivate(struct gb_interface *intf);
+int gb_interface_enable(struct gb_interface *intf);
+void gb_interface_disable(struct gb_interface *intf);
+int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,
+				 u64 frame_time, u32 strobe_delay, u32 refclk);
+int gb_interface_timesync_authoritative(struct gb_interface *intf,
+					u64 *frame_time);
+int gb_interface_timesync_disable(struct gb_interface *intf);
+int gb_interface_add(struct gb_interface *intf);
+void gb_interface_del(struct gb_interface *intf);
+void gb_interface_put(struct gb_interface *intf);
+void gb_interface_mailbox_event(struct gb_interface *intf, u16 result,
+								u32 mailbox);
+
+int gb_interface_request_mode_switch(struct gb_interface *intf);
+
+#endif /* __INTERFACE_H */
diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
new file mode 100644
index 000000000000..b2847feb7e86
--- /dev/null
+++ b/drivers/staging/greybus/light.c
@@ -0,0 +1,1359 @@
+/*
+ * Greybus Lights protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/led-class-flash.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/version.h>
+#include <media/v4l2-flash-led-class.h>
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+
+#define NAMES_MAX	32
+
+struct gb_channel {
+	u8				id;
+	u32				flags;
+	u32				color;
+	char				*color_name;
+	u8				fade_in;
+	u8				fade_out;
+	u32				mode;
+	char				*mode_name;
+	struct attribute		**attrs;
+	struct attribute_group		*attr_group;
+	const struct attribute_group	**attr_groups;
+	struct led_classdev		*led;
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
+	struct led_classdev_flash	fled;
+	struct led_flash_setting	intensity_uA;
+	struct led_flash_setting	timeout_us;
+#else
+	struct led_classdev		cled;
+#endif
+	struct gb_light			*light;
+	bool				is_registered;
+	bool				releasing;
+	bool				strobe_state;
+	bool				active;
+	struct mutex			lock;
+};
+
+struct gb_light {
+	u8			id;
+	char			*name;
+	struct gb_lights	*glights;
+	u32			flags;
+	u8			channels_count;
+	struct gb_channel	*channels;
+	bool			has_flash;
+	bool			ready;
+#if IS_REACHABLE(CONFIG_V4L2_FLASH_LED_CLASS)
+	struct v4l2_flash	*v4l2_flash;
+#endif
+};
+
+struct gb_lights {
+	struct gb_connection	*connection;
+	u8			lights_count;
+	struct gb_light		*lights;
+	struct mutex		lights_lock;
+};
+
+static void gb_lights_channel_free(struct gb_channel *channel);
+
+static struct gb_connection *get_conn_from_channel(struct gb_channel *channel)
+{
+	return channel->light->glights->connection;
+}
+
+static struct gb_connection *get_conn_from_light(struct gb_light *light)
+{
+	return light->glights->connection;
+}
+
+static bool is_channel_flash(struct gb_channel *channel)
+{
+	return !!(channel->mode & (GB_CHANNEL_MODE_FLASH | GB_CHANNEL_MODE_TORCH
+				   | GB_CHANNEL_MODE_INDICATOR));
+}
+
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
+static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
+{
+	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(cdev);
+
+	return container_of(fled_cdev, struct gb_channel, fled);
+}
+
+static struct led_classdev *get_channel_cdev(struct gb_channel *channel)
+{
+	return &channel->fled.led_cdev;
+}
+
+static struct gb_channel *get_channel_from_mode(struct gb_light *light,
+						u32 mode)
+{
+	struct gb_channel *channel = NULL;
+	int i;
+
+	for (i = 0; i < light->channels_count; i++) {
+		channel = &light->channels[i];
+		if (channel && channel->mode == mode)
+			break;
+	}
+	return channel;
+}
+
+static int __gb_lights_flash_intensity_set(struct gb_channel *channel,
+					   u32 intensity)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_set_flash_intensity_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.intensity_uA = cpu_to_le32(intensity);
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_INTENSITY,
+				&req, sizeof(req), NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
+{
+	u32 intensity;
+
+	/* If the channel is flash we need to get the attached torch channel */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH)
+		channel = get_channel_from_mode(channel->light,
+						GB_CHANNEL_MODE_TORCH);
+
+	/* For not flash we need to convert brightness to intensity */
+	intensity = channel->intensity_uA.min +
+			(channel->intensity_uA.step * channel->led->brightness);
+
+	return __gb_lights_flash_intensity_set(channel, intensity);
+}
+#else
+static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct gb_channel, cled);
+}
+
+static struct led_classdev *get_channel_cdev(struct gb_channel *channel)
+{
+	return &channel->cled;
+}
+
+static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
+{
+	return 0;
+}
+#endif
+
+static int gb_lights_color_set(struct gb_channel *channel, u32 color);
+static int gb_lights_fade_set(struct gb_channel *channel);
+
+static void led_lock(struct led_classdev *cdev)
+{
+	mutex_lock(&cdev->led_access);
+}
+
+static void led_unlock(struct led_classdev *cdev)
+{
+	mutex_unlock(&cdev->led_access);
+}
+
+#define gb_lights_fade_attr(__dir)					\
+static ssize_t fade_##__dir##_show(struct device *dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+{									\
+	struct led_classdev *cdev = dev_get_drvdata(dev);		\
+	struct gb_channel *channel = get_channel_from_cdev(cdev);	\
+									\
+	return sprintf(buf, "%u\n", channel->fade_##__dir);		\
+}									\
+									\
+static ssize_t fade_##__dir##_store(struct device *dev,			\
+				    struct device_attribute *attr,	\
+				    const char *buf, size_t size)	\
+{									\
+	struct led_classdev *cdev = dev_get_drvdata(dev);		\
+	struct gb_channel *channel = get_channel_from_cdev(cdev);	\
+	u8 fade;							\
+	int ret;							\
+									\
+	led_lock(cdev);							\
+	if (led_sysfs_is_disabled(cdev)) {				\
+		ret = -EBUSY;						\
+		goto unlock;						\
+	}								\
+									\
+	ret = kstrtou8(buf, 0, &fade);					\
+	if (ret < 0) {							\
+		dev_err(dev, "could not parse fade value %d\n", ret);	\
+		goto unlock;						\
+	}								\
+	if (channel->fade_##__dir == fade)				\
+		goto unlock;						\
+	channel->fade_##__dir = fade;					\
+									\
+	ret = gb_lights_fade_set(channel);				\
+	if (ret < 0)							\
+		goto unlock;						\
+									\
+	ret = size;							\
+unlock:									\
+	led_unlock(cdev);						\
+	return ret;							\
+}									\
+static DEVICE_ATTR_RW(fade_##__dir)
+
+gb_lights_fade_attr(in);
+gb_lights_fade_attr(out);
+
+static ssize_t color_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct led_classdev *cdev = dev_get_drvdata(dev);
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	return sprintf(buf, "0x%08x\n", channel->color);
+}
+
+static ssize_t color_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t size)
+{
+	struct led_classdev *cdev = dev_get_drvdata(dev);
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+	u32 color;
+	int ret;
+
+	led_lock(cdev);
+	if (led_sysfs_is_disabled(cdev)) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+	ret = kstrtou32(buf, 0, &color);
+	if (ret < 0) {
+		dev_err(dev, "could not parse color value %d\n", ret);
+		goto unlock;
+	}
+
+	ret = gb_lights_color_set(channel, color);
+	if (ret < 0)
+		goto unlock;
+
+	channel->color = color;
+	ret = size;
+unlock:
+	led_unlock(cdev);
+	return ret;
+}
+static DEVICE_ATTR_RW(color);
+
+static int channel_attr_groups_set(struct gb_channel *channel,
+				   struct led_classdev *cdev)
+{
+	int attr = 0;
+	int size = 0;
+
+	if (channel->flags & GB_LIGHT_CHANNEL_MULTICOLOR)
+		size++;
+	if (channel->flags & GB_LIGHT_CHANNEL_FADER)
+		size += 2;
+
+	if (!size)
+		return 0;
+
+	/* Set attributes based in the channel flags */
+	channel->attrs = kcalloc(size + 1, sizeof(**channel->attrs),
+				 GFP_KERNEL);
+	if (!channel->attrs)
+		return -ENOMEM;
+	channel->attr_group = kcalloc(1, sizeof(*channel->attr_group),
+				      GFP_KERNEL);
+	if (!channel->attr_group)
+		return -ENOMEM;
+	channel->attr_groups = kcalloc(2, sizeof(*channel->attr_groups),
+				       GFP_KERNEL);
+	if (!channel->attr_groups)
+		return -ENOMEM;
+
+	if (channel->flags & GB_LIGHT_CHANNEL_MULTICOLOR)
+		channel->attrs[attr++] = &dev_attr_color.attr;
+	if (channel->flags & GB_LIGHT_CHANNEL_FADER) {
+		channel->attrs[attr++] = &dev_attr_fade_in.attr;
+		channel->attrs[attr++] = &dev_attr_fade_out.attr;
+	}
+
+	channel->attr_group->attrs = channel->attrs;
+
+	channel->attr_groups[0] = channel->attr_group;
+
+	cdev->groups = channel->attr_groups;
+
+	return 0;
+}
+
+static int gb_lights_fade_set(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_set_fade_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.fade_in = channel->fade_in;
+	req.fade_out = channel->fade_out;
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FADE,
+				&req, sizeof(req), NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int gb_lights_color_set(struct gb_channel *channel, u32 color)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_set_color_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.color = cpu_to_le32(color);
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_COLOR,
+				&req, sizeof(req), NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int __gb_lights_led_brightness_set(struct gb_channel *channel)
+{
+	struct gb_lights_set_brightness_request req;
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	bool old_active;
+	int ret;
+
+	mutex_lock(&channel->lock);
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		goto out_unlock;
+
+	old_active = channel->active;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.brightness = (u8)channel->led->brightness;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_BRIGHTNESS,
+				&req, sizeof(req), NULL, 0);
+	if (ret < 0)
+		goto out_pm_put;
+
+	if (channel->led->brightness)
+		channel->active = true;
+	else
+		channel->active = false;
+
+	/* we need to keep module alive when turning to active state */
+	if (!old_active && channel->active)
+		goto out_unlock;
+
+	/*
+	 * on the other hand if going to inactive we still hold a reference and
+	 * need to put it, so we could go to suspend.
+	 */
+	if (old_active && !channel->active)
+		gb_pm_runtime_put_autosuspend(bundle);
+
+out_pm_put:
+	gb_pm_runtime_put_autosuspend(bundle);
+out_unlock:
+	mutex_unlock(&channel->lock);
+
+	return ret;
+}
+
+static int __gb_lights_brightness_set(struct gb_channel *channel)
+{
+	int ret;
+
+	if (channel->releasing)
+		return 0;
+
+	if (is_channel_flash(channel))
+		ret = __gb_lights_flash_brightness_set(channel);
+	else
+		ret = __gb_lights_led_brightness_set(channel);
+
+	return ret;
+}
+
+static int gb_brightness_set(struct led_classdev *cdev,
+			     enum led_brightness value)
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	channel->led->brightness = value;
+
+	return __gb_lights_brightness_set(channel);
+}
+
+static enum led_brightness gb_brightness_get(struct led_classdev *cdev)
+
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	return channel->led->brightness;
+}
+
+static int gb_blink_set(struct led_classdev *cdev, unsigned long *delay_on,
+			unsigned long *delay_off)
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_blink_request req;
+	bool old_active;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	mutex_lock(&channel->lock);
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		goto out_unlock;
+
+	old_active = channel->active;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.time_on_ms = cpu_to_le16(*delay_on);
+	req.time_off_ms = cpu_to_le16(*delay_off);
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_BLINK, &req,
+				sizeof(req), NULL, 0);
+	if (ret < 0)
+		goto out_pm_put;
+
+	if (delay_on)
+		channel->active = true;
+	else
+		channel->active = false;
+
+	/* we need to keep module alive when turning to active state */
+	if (!old_active && channel->active)
+		goto out_unlock;
+
+	/*
+	 * on the other hand if going to inactive we still hold a reference and
+	 * need to put it, so we could go to suspend.
+	 */
+	if (old_active && !channel->active)
+		gb_pm_runtime_put_autosuspend(bundle);
+
+out_pm_put:
+	gb_pm_runtime_put_autosuspend(bundle);
+out_unlock:
+	mutex_unlock(&channel->lock);
+
+	return ret;
+}
+
+static void gb_lights_led_operations_set(struct gb_channel *channel,
+					 struct led_classdev *cdev)
+{
+	cdev->brightness_get = gb_brightness_get;
+	cdev->brightness_set_blocking = gb_brightness_set;
+
+	if (channel->flags & GB_LIGHT_CHANNEL_BLINK)
+		cdev->blink_set = gb_blink_set;
+}
+
+#if IS_REACHABLE(CONFIG_V4L2_FLASH_LED_CLASS)
+/* V4L2 specific helpers */
+static const struct v4l2_flash_ops v4l2_flash_ops;
+
+static void __gb_lights_channel_v4l2_config(struct led_flash_setting *channel_s,
+					    struct led_flash_setting *v4l2_s)
+{
+	v4l2_s->min = channel_s->min;
+	v4l2_s->max = channel_s->max;
+	v4l2_s->step = channel_s->step;
+	/* For v4l2 val is the default value */
+	v4l2_s->val = channel_s->max;
+}
+
+static int gb_lights_light_v4l2_register(struct gb_light *light)
+{
+	struct gb_connection *connection = get_conn_from_light(light);
+	struct device *dev = &connection->bundle->dev;
+	struct v4l2_flash_config *sd_cfg;
+	struct led_classdev_flash *fled;
+	struct led_classdev_flash *iled = NULL;
+	struct gb_channel *channel_torch, *channel_ind, *channel_flash;
+	int ret = 0;
+
+	sd_cfg = kcalloc(1, sizeof(*sd_cfg), GFP_KERNEL);
+	if (!sd_cfg)
+		return -ENOMEM;
+
+	channel_torch = get_channel_from_mode(light, GB_CHANNEL_MODE_TORCH);
+	if (channel_torch)
+		__gb_lights_channel_v4l2_config(&channel_torch->intensity_uA,
+						&sd_cfg->torch_intensity);
+
+	channel_ind = get_channel_from_mode(light, GB_CHANNEL_MODE_INDICATOR);
+	if (channel_ind) {
+		__gb_lights_channel_v4l2_config(&channel_ind->intensity_uA,
+						&sd_cfg->indicator_intensity);
+		iled = &channel_ind->fled;
+	}
+
+	channel_flash = get_channel_from_mode(light, GB_CHANNEL_MODE_FLASH);
+	WARN_ON(!channel_flash);
+
+	fled = &channel_flash->fled;
+
+	snprintf(sd_cfg->dev_name, sizeof(sd_cfg->dev_name), "%s", light->name);
+
+	/* Set the possible values to faults, in our case all faults */
+	sd_cfg->flash_faults = LED_FAULT_OVER_VOLTAGE | LED_FAULT_TIMEOUT |
+		LED_FAULT_OVER_TEMPERATURE | LED_FAULT_SHORT_CIRCUIT |
+		LED_FAULT_OVER_CURRENT | LED_FAULT_INDICATOR |
+		LED_FAULT_UNDER_VOLTAGE | LED_FAULT_INPUT_VOLTAGE |
+		LED_FAULT_LED_OVER_TEMPERATURE;
+
+	light->v4l2_flash = v4l2_flash_init(dev, NULL, fled, iled,
+					    &v4l2_flash_ops, sd_cfg);
+	if (IS_ERR_OR_NULL(light->v4l2_flash)) {
+		ret = PTR_ERR(light->v4l2_flash);
+		goto out_free;
+	}
+
+	return ret;
+
+out_free:
+	kfree(sd_cfg);
+	return ret;
+}
+
+static void gb_lights_light_v4l2_unregister(struct gb_light *light)
+{
+	v4l2_flash_release(light->v4l2_flash);
+}
+#else
+static int gb_lights_light_v4l2_register(struct gb_light *light)
+{
+	struct gb_connection *connection = get_conn_from_light(light);
+
+	dev_err(&connection->bundle->dev, "no support for v4l2 subdevices\n");
+	return 0;
+}
+
+static void gb_lights_light_v4l2_unregister(struct gb_light *light)
+{
+}
+#endif
+
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
+/* Flash specific operations */
+static int gb_lights_flash_intensity_set(struct led_classdev_flash *fcdev,
+					 u32 brightness)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	int ret;
+
+	ret = __gb_lights_flash_intensity_set(channel, brightness);
+	if (ret < 0)
+		return ret;
+
+	fcdev->brightness.val = brightness;
+
+	return 0;
+}
+
+static int gb_lights_flash_intensity_get(struct led_classdev_flash *fcdev,
+					 u32 *brightness)
+{
+	*brightness = fcdev->brightness.val;
+
+	return 0;
+}
+
+static int gb_lights_flash_strobe_set(struct led_classdev_flash *fcdev,
+				      bool state)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_set_flash_strobe_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.state = state ? 1 : 0;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_STROBE,
+				&req, sizeof(req), NULL, 0);
+	if (!ret)
+		channel->strobe_state = state;
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int gb_lights_flash_strobe_get(struct led_classdev_flash *fcdev,
+				      bool *state)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+
+	*state = channel->strobe_state;
+	return 0;
+}
+
+static int gb_lights_flash_timeout_set(struct led_classdev_flash *fcdev,
+				       u32 timeout)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_set_flash_timeout_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.timeout_us = cpu_to_le32(timeout);
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_TIMEOUT,
+				&req, sizeof(req), NULL, 0);
+	if (!ret)
+		fcdev->timeout.val = timeout;
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int gb_lights_flash_fault_get(struct led_classdev_flash *fcdev,
+				     u32 *fault)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_bundle *bundle = connection->bundle;
+	struct gb_lights_get_flash_fault_request req;
+	struct gb_lights_get_flash_fault_response resp;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret < 0)
+		return ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_GET_FLASH_FAULT,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (!ret)
+		*fault = le32_to_cpu(resp.fault);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static const struct led_flash_ops gb_lights_flash_ops = {
+	.flash_brightness_set	= gb_lights_flash_intensity_set,
+	.flash_brightness_get	= gb_lights_flash_intensity_get,
+	.strobe_set		= gb_lights_flash_strobe_set,
+	.strobe_get		= gb_lights_flash_strobe_get,
+	.timeout_set		= gb_lights_flash_timeout_set,
+	.fault_get		= gb_lights_flash_fault_get,
+};
+
+static int __gb_lights_channel_torch_attach(struct gb_channel *channel,
+					    struct gb_channel *channel_torch)
+{
+	char *name;
+
+	/* we can only attach torch to a flash channel */
+	if (!(channel->mode & GB_CHANNEL_MODE_FLASH))
+		return 0;
+
+	/* Move torch brightness to the destination */
+	channel->led->max_brightness = channel_torch->led->max_brightness;
+
+	/* append mode name to flash name */
+	name = kasprintf(GFP_KERNEL, "%s_%s", channel->led->name,
+			 channel_torch->mode_name);
+	if (!name)
+		return -ENOMEM;
+	kfree(channel->led->name);
+	channel->led->name = name;
+
+	channel_torch->led = channel->led;
+
+	return 0;
+}
+
+static int __gb_lights_flash_led_register(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct led_classdev_flash *fled = &channel->fled;
+	struct led_flash_setting *fset;
+	struct gb_channel *channel_torch;
+	int ret;
+
+	fled->ops = &gb_lights_flash_ops;
+
+	fled->led_cdev.flags |= LED_DEV_CAP_FLASH;
+
+	fset = &fled->brightness;
+	fset->min = channel->intensity_uA.min;
+	fset->max = channel->intensity_uA.max;
+	fset->step = channel->intensity_uA.step;
+	fset->val = channel->intensity_uA.max;
+
+	/* Only the flash mode have the timeout constraints settings */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH) {
+		fset = &fled->timeout;
+		fset->min = channel->timeout_us.min;
+		fset->max = channel->timeout_us.max;
+		fset->step = channel->timeout_us.step;
+		fset->val = channel->timeout_us.max;
+	}
+
+	/*
+	 * If light have torch mode channel, this channel will be the led
+	 * classdev of the registered above flash classdev
+	 */
+	channel_torch = get_channel_from_mode(channel->light,
+					      GB_CHANNEL_MODE_TORCH);
+	if (channel_torch) {
+		ret = __gb_lights_channel_torch_attach(channel, channel_torch);
+		if (ret < 0)
+			goto fail;
+	}
+
+	ret = led_classdev_flash_register(&connection->bundle->dev, fled);
+	if (ret < 0)
+		goto fail;
+
+	channel->is_registered = true;
+	return 0;
+fail:
+	channel->led = NULL;
+	return ret;
+}
+
+static void __gb_lights_flash_led_unregister(struct gb_channel *channel)
+{
+	if (!channel->is_registered)
+		return;
+
+	led_classdev_flash_unregister(&channel->fled);
+}
+
+static int gb_lights_channel_flash_config(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_get_channel_flash_config_request req;
+	struct gb_lights_get_channel_flash_config_response conf;
+	struct led_flash_setting *fset;
+	int ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection,
+				GB_LIGHTS_TYPE_GET_CHANNEL_FLASH_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Intensity constraints for flash related modes: flash, torch,
+	 * indicator.  They will be needed for v4l2 registration.
+	 */
+	fset = &channel->intensity_uA;
+	fset->min = le32_to_cpu(conf.intensity_min_uA);
+	fset->max = le32_to_cpu(conf.intensity_max_uA);
+	fset->step = le32_to_cpu(conf.intensity_step_uA);
+
+	/*
+	 * On flash type, max brightness is set as the number of intensity steps
+	 * available.
+	 */
+	channel->led->max_brightness = (fset->max - fset->min) / fset->step;
+
+	/* Only the flash mode have the timeout constraints settings */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH) {
+		fset = &channel->timeout_us;
+		fset->min = le32_to_cpu(conf.timeout_min_us);
+		fset->max = le32_to_cpu(conf.timeout_max_us);
+		fset->step = le32_to_cpu(conf.timeout_step_us);
+	}
+
+	return 0;
+}
+#else
+static int gb_lights_channel_flash_config(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+
+	dev_err(&connection->bundle->dev, "no support for flash devices\n");
+	return 0;
+}
+
+static int __gb_lights_flash_led_register(struct gb_channel *channel)
+{
+	return 0;
+}
+
+static void __gb_lights_flash_led_unregister(struct gb_channel *channel)
+{
+}
+
+#endif
+
+static int __gb_lights_led_register(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct led_classdev *cdev = get_channel_cdev(channel);
+	int ret;
+
+	ret = led_classdev_register(&connection->bundle->dev, cdev);
+	if (ret < 0)
+		channel->led = NULL;
+	else
+		channel->is_registered = true;
+	return ret;
+}
+
+static int gb_lights_channel_register(struct gb_channel *channel)
+{
+	/* Normal LED channel, just register in led classdev and we are done */
+	if (!is_channel_flash(channel))
+		return __gb_lights_led_register(channel);
+
+	/*
+	 * Flash Type need more work, register flash classdev, indicator as
+	 * flash classdev, torch will be led classdev of the flash classdev.
+	 */
+	if (!(channel->mode & GB_CHANNEL_MODE_TORCH))
+		return __gb_lights_flash_led_register(channel);
+
+	return 0;
+}
+
+static void __gb_lights_led_unregister(struct gb_channel *channel)
+{
+	struct led_classdev *cdev = get_channel_cdev(channel);
+
+	if (!channel->is_registered)
+		return;
+
+	led_classdev_unregister(cdev);
+	channel->led = NULL;
+}
+
+static void gb_lights_channel_unregister(struct gb_channel *channel)
+{
+	/* The same as register, handle channels differently */
+	if (!is_channel_flash(channel)) {
+		__gb_lights_led_unregister(channel);
+		return;
+	}
+
+	if (channel->mode & GB_CHANNEL_MODE_TORCH)
+		__gb_lights_led_unregister(channel);
+	else
+		__gb_lights_flash_led_unregister(channel);
+}
+
+static int gb_lights_channel_config(struct gb_light *light,
+				    struct gb_channel *channel)
+{
+	struct gb_lights_get_channel_config_response conf;
+	struct gb_lights_get_channel_config_request req;
+	struct gb_connection *connection = get_conn_from_light(light);
+	struct led_classdev *cdev = get_channel_cdev(channel);
+	char *name;
+	int ret;
+
+	req.light_id = light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_GET_CHANNEL_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	channel->light = light;
+	channel->mode = le32_to_cpu(conf.mode);
+	channel->flags = le32_to_cpu(conf.flags);
+	channel->color = le32_to_cpu(conf.color);
+	channel->color_name = kstrndup(conf.color_name, NAMES_MAX, GFP_KERNEL);
+	if (!channel->color_name)
+		return -ENOMEM;
+	channel->mode_name = kstrndup(conf.mode_name, NAMES_MAX, GFP_KERNEL);
+	if (!channel->mode_name)
+		return -ENOMEM;
+
+	channel->led = cdev;
+
+	name = kasprintf(GFP_KERNEL, "%s:%s:%s", light->name,
+			 channel->color_name, channel->mode_name);
+	if (!name)
+		return -ENOMEM;
+
+	cdev->name = name;
+
+	cdev->max_brightness = conf.max_brightness;
+
+	ret = channel_attr_groups_set(channel, cdev);
+	if (ret < 0)
+		return ret;
+
+	gb_lights_led_operations_set(channel, cdev);
+
+	/*
+	 * If it is not a flash related channel (flash, torch or indicator) we
+	 * are done here. If not, continue and fetch flash related
+	 * configurations.
+	 */
+	if (!is_channel_flash(channel))
+		return ret;
+
+	light->has_flash = true;
+
+	ret = gb_lights_channel_flash_config(channel);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+static int gb_lights_light_config(struct gb_lights *glights, u8 id)
+{
+	struct gb_light *light = &glights->lights[id];
+	struct gb_lights_get_light_config_request req;
+	struct gb_lights_get_light_config_response conf;
+	int ret;
+	int i;
+
+	light->glights = glights;
+	light->id = id;
+
+	req.id = id;
+
+	ret = gb_operation_sync(glights->connection,
+				GB_LIGHTS_TYPE_GET_LIGHT_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	if (!conf.channel_count)
+		return -EINVAL;
+	if (!strlen(conf.name))
+		return -EINVAL;
+
+	light->channels_count = conf.channel_count;
+	light->name = kstrndup(conf.name, NAMES_MAX, GFP_KERNEL);
+
+	light->channels = kzalloc(light->channels_count *
+				  sizeof(struct gb_channel), GFP_KERNEL);
+	if (!light->channels)
+		return -ENOMEM;
+
+	/* First we collect all the configurations for all channels */
+	for (i = 0; i < light->channels_count; i++) {
+		light->channels[i].id = i;
+		ret = gb_lights_channel_config(light, &light->channels[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int gb_lights_light_register(struct gb_light *light)
+{
+	int ret;
+	int i;
+
+	/*
+	 * Then, if everything went ok in getting configurations, we register
+	 * the classdev, flash classdev and v4l2 subsystem, if a flash device is
+	 * found.
+	 */
+	for (i = 0; i < light->channels_count; i++) {
+		ret = gb_lights_channel_register(&light->channels[i]);
+		if (ret < 0)
+			return ret;
+
+		mutex_init(&light->channels[i].lock);
+	}
+
+	light->ready = true;
+
+	if (light->has_flash) {
+		ret = gb_lights_light_v4l2_register(light);
+		if (ret < 0) {
+			light->has_flash = false;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void gb_lights_channel_free(struct gb_channel *channel)
+{
+	kfree(channel->attrs);
+	kfree(channel->attr_group);
+	kfree(channel->attr_groups);
+	kfree(channel->color_name);
+	kfree(channel->mode_name);
+	mutex_destroy(&channel->lock);
+}
+
+static void gb_lights_channel_release(struct gb_channel *channel)
+{
+	channel->releasing = true;
+
+	gb_lights_channel_unregister(channel);
+
+	gb_lights_channel_free(channel);
+}
+
+static void gb_lights_light_release(struct gb_light *light)
+{
+	int i;
+	int count;
+
+	light->ready = false;
+
+	count = light->channels_count;
+
+	if (light->has_flash)
+		gb_lights_light_v4l2_unregister(light);
+
+	for (i = 0; i < count; i++) {
+		gb_lights_channel_release(&light->channels[i]);
+		light->channels_count--;
+	}
+	kfree(light->channels);
+	kfree(light->name);
+}
+
+static void gb_lights_release(struct gb_lights *glights)
+{
+	int i;
+
+	if (!glights)
+		return;
+
+	mutex_lock(&glights->lights_lock);
+	if (!glights->lights)
+		goto free_glights;
+
+	for (i = 0; i < glights->lights_count; i++)
+		gb_lights_light_release(&glights->lights[i]);
+
+	kfree(glights->lights);
+
+free_glights:
+	mutex_unlock(&glights->lights_lock);
+	mutex_destroy(&glights->lights_lock);
+	kfree(glights);
+}
+
+static int gb_lights_get_count(struct gb_lights *glights)
+{
+	struct gb_lights_get_lights_response resp;
+	int ret;
+
+	ret = gb_operation_sync(glights->connection, GB_LIGHTS_TYPE_GET_LIGHTS,
+				NULL, 0, &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	if (!resp.lights_count)
+		return -EINVAL;
+
+	glights->lights_count = resp.lights_count;
+
+	return 0;
+}
+
+static int gb_lights_create_all(struct gb_lights *glights)
+{
+	struct gb_connection *connection = glights->connection;
+	int ret;
+	int i;
+
+	mutex_lock(&glights->lights_lock);
+	ret = gb_lights_get_count(glights);
+	if (ret < 0)
+		goto out;
+
+	glights->lights = kzalloc(glights->lights_count *
+				  sizeof(struct gb_light), GFP_KERNEL);
+	if (!glights->lights) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < glights->lights_count; i++) {
+		ret = gb_lights_light_config(glights, i);
+		if (ret < 0) {
+			dev_err(&connection->bundle->dev,
+				"Fail to configure lights device\n");
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&glights->lights_lock);
+	return ret;
+}
+
+static int gb_lights_register_all(struct gb_lights *glights)
+{
+	struct gb_connection *connection = glights->connection;
+	int ret = 0;
+	int i;
+
+	mutex_lock(&glights->lights_lock);
+	for (i = 0; i < glights->lights_count; i++) {
+		ret = gb_lights_light_register(&glights->lights[i]);
+		if (ret < 0) {
+			dev_err(&connection->bundle->dev,
+				"Fail to enable lights device\n");
+			break;
+		}
+	}
+
+	mutex_unlock(&glights->lights_lock);
+	return ret;
+}
+
+static int gb_lights_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct device *dev = &connection->bundle->dev;
+	struct gb_lights *glights = gb_connection_get_data(connection);
+	struct gb_light *light;
+	struct gb_message *request;
+	struct gb_lights_event_request *payload;
+	int ret =  0;
+	u8 light_id;
+	u8 event;
+
+	if (op->type != GB_LIGHTS_TYPE_EVENT) {
+		dev_err(dev, "Unsupported unsolicited event: %u\n", op->type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*payload)) {
+		dev_err(dev, "Wrong event size received (%zu < %zu)\n",
+			request->payload_size, sizeof(*payload));
+		return -EINVAL;
+	}
+
+	payload = request->payload;
+	light_id = payload->light_id;
+
+	if (light_id >= glights->lights_count ||
+	    !glights->lights[light_id].ready) {
+		dev_err(dev, "Event received for unconfigured light id: %d\n",
+			light_id);
+		return -EINVAL;
+	}
+
+	event = payload->event;
+
+	if (event & GB_LIGHTS_LIGHT_CONFIG) {
+		light = &glights->lights[light_id];
+
+		mutex_lock(&glights->lights_lock);
+		gb_lights_light_release(light);
+		ret = gb_lights_light_config(glights, light_id);
+		if (!ret)
+			ret = gb_lights_light_register(light);
+		if (ret < 0)
+			gb_lights_light_release(light);
+		mutex_unlock(&glights->lights_lock);
+	}
+
+	return ret;
+}
+
+static int gb_lights_probe(struct gb_bundle *bundle,
+			   const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_lights *glights;
+	int ret;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LIGHTS)
+		return -ENODEV;
+
+	glights = kzalloc(sizeof(*glights), GFP_KERNEL);
+	if (!glights)
+		return -ENOMEM;
+
+	mutex_init(&glights->lights_lock);
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+					  gb_lights_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto out;
+	}
+
+	glights->connection = connection;
+	gb_connection_set_data(connection, glights);
+
+	greybus_set_drvdata(bundle, glights);
+
+	/* We aren't ready to receive an incoming request yet */
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto error_connection_destroy;
+
+	/*
+	 * Setup all the lights devices over this connection, if anything goes
+	 * wrong tear down all lights
+	 */
+	ret = gb_lights_create_all(glights);
+	if (ret < 0)
+		goto error_connection_disable;
+
+	/* We are ready to receive an incoming request now, enable RX as well */
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto error_connection_disable;
+
+	/* Enable & register lights */
+	ret = gb_lights_register_all(glights);
+	if (ret < 0)
+		goto error_connection_disable;
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+error_connection_disable:
+	gb_connection_disable(connection);
+error_connection_destroy:
+	gb_connection_destroy(connection);
+out:
+	gb_lights_release(glights);
+	return ret;
+}
+
+static void gb_lights_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_lights *glights = greybus_get_drvdata(bundle);
+
+	if (gb_pm_runtime_get_sync(bundle))
+		gb_pm_runtime_get_noresume(bundle);
+
+	gb_connection_disable(glights->connection);
+	gb_connection_destroy(glights->connection);
+
+	gb_lights_release(glights);
+}
+
+static const struct greybus_bundle_id gb_lights_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LIGHTS) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_lights_id_table);
+
+static struct greybus_driver gb_lights_driver = {
+	.name		= "lights",
+	.probe		= gb_lights_probe,
+	.disconnect	= gb_lights_disconnect,
+	.id_table	= gb_lights_id_table,
+};
+module_greybus_driver(gb_lights_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/log.c b/drivers/staging/greybus/log.c
new file mode 100644
index 000000000000..70dd9e5a1cf2
--- /dev/null
+++ b/drivers/staging/greybus/log.c
@@ -0,0 +1,132 @@
+/*
+ * Greybus driver for the log protocol
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sizes.h>
+#include <linux/uaccess.h>
+
+#include "greybus.h"
+
+struct gb_log {
+	struct gb_connection *connection;
+};
+
+static int gb_log_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct device *dev = &connection->bundle->dev;
+	struct gb_log_send_log_request *receive;
+	u16 len;
+
+	if (op->type != GB_LOG_TYPE_SEND_LOG) {
+		dev_err(dev, "unknown request type 0x%02x\n", op->type);
+		return -EINVAL;
+	}
+
+	/* Verify size of payload */
+	if (op->request->payload_size < sizeof(*receive)) {
+		dev_err(dev, "log request too small (%zu < %zu)\n",
+				op->request->payload_size, sizeof(*receive));
+		return -EINVAL;
+	}
+	receive = op->request->payload;
+	len = le16_to_cpu(receive->len);
+	if (len != (int)(op->request->payload_size - sizeof(*receive))) {
+		dev_err(dev, "log request wrong size %d vs %d\n", len,
+				(int)(op->request->payload_size - sizeof(*receive)));
+		return -EINVAL;
+	}
+	if (len == 0) {
+		dev_err(dev, "log request of 0 bytes?\n");
+		return -EINVAL;
+	}
+
+	if (len > GB_LOG_MAX_LEN) {
+		dev_err(dev, "log request too big: %d\n", len);
+		return -EINVAL;
+	}
+
+	/* Ensure the buffer is 0 terminated */
+	receive->msg[len - 1] = '\0';
+
+	/* Print with dev_dbg() so that it can be easily turned off using
+	 * dynamic debugging (and prevent any DoS) */
+	dev_dbg(dev, "%s", receive->msg);
+
+	return 0;
+}
+
+static int gb_log_probe(struct gb_bundle *bundle,
+			const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_log *log;
+	int retval;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LOG)
+		return -ENODEV;
+
+	log = kzalloc(sizeof(*log), GFP_KERNEL);
+	if (!log)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+			gb_log_request_handler);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto error_free;
+	}
+
+	log->connection = connection;
+	greybus_set_drvdata(bundle, log);
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto error_connection_destroy;
+
+	return 0;
+
+error_connection_destroy:
+	gb_connection_destroy(connection);
+error_free:
+	kfree(log);
+	return retval;
+}
+
+static void gb_log_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_log *log = greybus_get_drvdata(bundle);
+	struct gb_connection *connection = log->connection;
+
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+
+	kfree(log);
+}
+
+static const struct greybus_bundle_id gb_log_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LOG) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_log_id_table);
+
+static struct greybus_driver gb_log_driver = {
+	.name           = "log",
+	.probe          = gb_log_probe,
+	.disconnect     = gb_log_disconnect,
+	.id_table       = gb_log_id_table,
+};
+module_greybus_driver(gb_log_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
new file mode 100644
index 000000000000..8b0d0dc2ed8b
--- /dev/null
+++ b/drivers/staging/greybus/loopback.c
@@ -0,0 +1,1365 @@
+/*
+ * Loopback bridge driver for the Greybus loopback module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/random.h>
+#include <linux/sizes.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/kfifo.h>
+#include <linux/debugfs.h>
+#include <linux/list_sort.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/atomic.h>
+#include <linux/pm_runtime.h>
+
+#include <asm/div64.h>
+
+#include "greybus.h"
+#include "connection.h"
+
+#define NSEC_PER_DAY 86400000000000ULL
+
+struct gb_loopback_stats {
+	u32 min;
+	u32 max;
+	u64 sum;
+	u32 count;
+};
+
+struct gb_loopback_device {
+	struct dentry *root;
+	u32 count;
+	size_t size_max;
+
+	/* We need to take a lock in atomic context */
+	spinlock_t lock;
+	struct list_head list;
+	struct list_head list_op_async;
+	wait_queue_head_t wq;
+};
+
+static struct gb_loopback_device gb_dev;
+
+struct gb_loopback_async_operation {
+	struct gb_loopback *gb;
+	struct gb_operation *operation;
+	struct timeval ts;
+	struct timer_list timer;
+	struct list_head entry;
+	struct work_struct work;
+	struct kref kref;
+	bool pending;
+	int (*completion)(struct gb_loopback_async_operation *op_async);
+};
+
+struct gb_loopback {
+	struct gb_connection *connection;
+
+	struct dentry *file;
+	struct kfifo kfifo_lat;
+	struct kfifo kfifo_ts;
+	struct mutex mutex;
+	struct task_struct *task;
+	struct list_head entry;
+	struct device *dev;
+	wait_queue_head_t wq;
+	wait_queue_head_t wq_completion;
+	atomic_t outstanding_operations;
+
+	/* Per connection stats */
+	struct timeval ts;
+	struct gb_loopback_stats latency;
+	struct gb_loopback_stats throughput;
+	struct gb_loopback_stats requests_per_second;
+	struct gb_loopback_stats apbridge_unipro_latency;
+	struct gb_loopback_stats gbphy_firmware_latency;
+
+	int type;
+	int async;
+	int id;
+	u32 size;
+	u32 iteration_max;
+	u32 iteration_count;
+	int us_wait;
+	u32 error;
+	u32 requests_completed;
+	u32 requests_timedout;
+	u32 timeout;
+	u32 jiffy_timeout;
+	u32 timeout_min;
+	u32 timeout_max;
+	u32 outstanding_operations_max;
+	u32 lbid;
+	u64 elapsed_nsecs;
+	u32 apbridge_latency_ts;
+	u32 gbphy_latency_ts;
+
+	u32 send_count;
+};
+
+static struct class loopback_class = {
+	.name		= "gb_loopback",
+	.owner		= THIS_MODULE,
+};
+static DEFINE_IDA(loopback_ida);
+
+/* Min/max values in jiffies */
+#define GB_LOOPBACK_TIMEOUT_MIN				1
+#define GB_LOOPBACK_TIMEOUT_MAX				10000
+
+#define GB_LOOPBACK_FIFO_DEFAULT			8192
+
+static unsigned kfifo_depth = GB_LOOPBACK_FIFO_DEFAULT;
+module_param(kfifo_depth, uint, 0444);
+
+/* Maximum size of any one send data buffer we support */
+#define MAX_PACKET_SIZE (PAGE_SIZE * 2)
+
+#define GB_LOOPBACK_US_WAIT_MAX				1000000
+
+/* interface sysfs attributes */
+#define gb_loopback_ro_attr(field)				\
+static ssize_t field##_show(struct device *dev,			\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	return sprintf(buf, "%u\n", gb->field);			\
+}									\
+static DEVICE_ATTR_RO(field)
+
+#define gb_loopback_ro_stats_attr(name, field, type)		\
+static ssize_t name##_##field##_show(struct device *dev,	\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	/* Report 0 for min and max if no transfer successed */		\
+	if (!gb->requests_completed)					\
+		return sprintf(buf, "0\n");				\
+	return sprintf(buf, "%"#type"\n", gb->name.field);	\
+}									\
+static DEVICE_ATTR_RO(name##_##field)
+
+#define gb_loopback_ro_avg_attr(name)			\
+static ssize_t name##_avg_show(struct device *dev,		\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback_stats *stats;				\
+	struct gb_loopback *gb;						\
+	u64 avg, rem;							\
+	u32 count;							\
+	gb = dev_get_drvdata(dev);			\
+	stats = &gb->name;					\
+	count = stats->count ? stats->count : 1;			\
+	avg = stats->sum + count / 2000000; /* round closest */		\
+	rem = do_div(avg, count);					\
+	rem *= 1000000;							\
+	do_div(rem, count);						\
+	return sprintf(buf, "%llu.%06u\n", avg, (u32)rem);		\
+}									\
+static DEVICE_ATTR_RO(name##_avg)
+
+#define gb_loopback_stats_attrs(field)				\
+	gb_loopback_ro_stats_attr(field, min, u);		\
+	gb_loopback_ro_stats_attr(field, max, u);		\
+	gb_loopback_ro_avg_attr(field)
+
+#define gb_loopback_attr(field, type)					\
+static ssize_t field##_show(struct device *dev,				\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	return sprintf(buf, "%"#type"\n", gb->field);			\
+}									\
+static ssize_t field##_store(struct device *dev,			\
+			    struct device_attribute *attr,		\
+			    const char *buf,				\
+			    size_t len)					\
+{									\
+	int ret;							\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	mutex_lock(&gb->mutex);						\
+	ret = sscanf(buf, "%"#type, &gb->field);			\
+	if (ret != 1)							\
+		len = -EINVAL;						\
+	else								\
+		gb_loopback_check_attr(gb, bundle);			\
+	mutex_unlock(&gb->mutex);					\
+	return len;							\
+}									\
+static DEVICE_ATTR_RW(field)
+
+#define gb_dev_loopback_ro_attr(field, conn)				\
+static ssize_t field##_show(struct device *dev,		\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	return sprintf(buf, "%u\n", gb->field);				\
+}									\
+static DEVICE_ATTR_RO(field)
+
+#define gb_dev_loopback_rw_attr(field, type)				\
+static ssize_t field##_show(struct device *dev,				\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	return sprintf(buf, "%"#type"\n", gb->field);			\
+}									\
+static ssize_t field##_store(struct device *dev,			\
+			    struct device_attribute *attr,		\
+			    const char *buf,				\
+			    size_t len)					\
+{									\
+	int ret;							\
+	struct gb_loopback *gb = dev_get_drvdata(dev);			\
+	mutex_lock(&gb->mutex);						\
+	ret = sscanf(buf, "%"#type, &gb->field);			\
+	if (ret != 1)							\
+		len = -EINVAL;						\
+	else								\
+		gb_loopback_check_attr(gb);		\
+	mutex_unlock(&gb->mutex);					\
+	return len;							\
+}									\
+static DEVICE_ATTR_RW(field)
+
+static void gb_loopback_reset_stats(struct gb_loopback *gb);
+static void gb_loopback_check_attr(struct gb_loopback *gb)
+{
+	if (gb->us_wait > GB_LOOPBACK_US_WAIT_MAX)
+		gb->us_wait = GB_LOOPBACK_US_WAIT_MAX;
+	if (gb->size > gb_dev.size_max)
+		gb->size = gb_dev.size_max;
+	gb->requests_timedout = 0;
+	gb->requests_completed = 0;
+	gb->iteration_count = 0;
+	gb->send_count = 0;
+	gb->error = 0;
+
+	if (kfifo_depth < gb->iteration_max) {
+		dev_warn(gb->dev,
+			 "cannot log bytes %u kfifo_depth %u\n",
+			 gb->iteration_max, kfifo_depth);
+	}
+	kfifo_reset_out(&gb->kfifo_lat);
+	kfifo_reset_out(&gb->kfifo_ts);
+
+	switch (gb->type) {
+	case GB_LOOPBACK_TYPE_PING:
+	case GB_LOOPBACK_TYPE_TRANSFER:
+	case GB_LOOPBACK_TYPE_SINK:
+		gb->jiffy_timeout = usecs_to_jiffies(gb->timeout);
+		if (!gb->jiffy_timeout)
+			gb->jiffy_timeout = GB_LOOPBACK_TIMEOUT_MIN;
+		else if (gb->jiffy_timeout > GB_LOOPBACK_TIMEOUT_MAX)
+			gb->jiffy_timeout = GB_LOOPBACK_TIMEOUT_MAX;
+		gb_loopback_reset_stats(gb);
+		wake_up(&gb->wq);
+		break;
+	default:
+		gb->type = 0;
+		break;
+	}
+}
+
+/* Time to send and receive one message */
+gb_loopback_stats_attrs(latency);
+/* Number of requests sent per second on this cport */
+gb_loopback_stats_attrs(requests_per_second);
+/* Quantity of data sent and received on this cport */
+gb_loopback_stats_attrs(throughput);
+/* Latency across the UniPro link from APBridge's perspective */
+gb_loopback_stats_attrs(apbridge_unipro_latency);
+/* Firmware induced overhead in the GPBridge */
+gb_loopback_stats_attrs(gbphy_firmware_latency);
+
+/* Number of errors encountered during loop */
+gb_loopback_ro_attr(error);
+/* Number of requests successfully completed async */
+gb_loopback_ro_attr(requests_completed);
+/* Number of requests timed out async */
+gb_loopback_ro_attr(requests_timedout);
+/* Timeout minimum in useconds */
+gb_loopback_ro_attr(timeout_min);
+/* Timeout minimum in useconds */
+gb_loopback_ro_attr(timeout_max);
+
+/*
+ * Type of loopback message to send based on protocol type definitions
+ * 0 => Don't send message
+ * 2 => Send ping message continuously (message without payload)
+ * 3 => Send transfer message continuously (message with payload,
+ *					   payload returned in response)
+ * 4 => Send a sink message (message with payload, no payload in response)
+ */
+gb_dev_loopback_rw_attr(type, d);
+/* Size of transfer message payload: 0-4096 bytes */
+gb_dev_loopback_rw_attr(size, u);
+/* Time to wait between two messages: 0-1000 ms */
+gb_dev_loopback_rw_attr(us_wait, d);
+/* Maximum iterations for a given operation: 1-(2^32-1), 0 implies infinite */
+gb_dev_loopback_rw_attr(iteration_max, u);
+/* The current index of the for (i = 0; i < iteration_max; i++) loop */
+gb_dev_loopback_ro_attr(iteration_count, false);
+/* A flag to indicate synchronous or asynchronous operations */
+gb_dev_loopback_rw_attr(async, u);
+/* Timeout of an individual asynchronous request */
+gb_dev_loopback_rw_attr(timeout, u);
+/* Maximum number of in-flight operations before back-off */
+gb_dev_loopback_rw_attr(outstanding_operations_max, u);
+
+static struct attribute *loopback_attrs[] = {
+	&dev_attr_latency_min.attr,
+	&dev_attr_latency_max.attr,
+	&dev_attr_latency_avg.attr,
+	&dev_attr_requests_per_second_min.attr,
+	&dev_attr_requests_per_second_max.attr,
+	&dev_attr_requests_per_second_avg.attr,
+	&dev_attr_throughput_min.attr,
+	&dev_attr_throughput_max.attr,
+	&dev_attr_throughput_avg.attr,
+	&dev_attr_apbridge_unipro_latency_min.attr,
+	&dev_attr_apbridge_unipro_latency_max.attr,
+	&dev_attr_apbridge_unipro_latency_avg.attr,
+	&dev_attr_gbphy_firmware_latency_min.attr,
+	&dev_attr_gbphy_firmware_latency_max.attr,
+	&dev_attr_gbphy_firmware_latency_avg.attr,
+	&dev_attr_type.attr,
+	&dev_attr_size.attr,
+	&dev_attr_us_wait.attr,
+	&dev_attr_iteration_count.attr,
+	&dev_attr_iteration_max.attr,
+	&dev_attr_async.attr,
+	&dev_attr_error.attr,
+	&dev_attr_requests_completed.attr,
+	&dev_attr_requests_timedout.attr,
+	&dev_attr_timeout.attr,
+	&dev_attr_outstanding_operations_max.attr,
+	&dev_attr_timeout_min.attr,
+	&dev_attr_timeout_max.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(loopback);
+
+static void gb_loopback_calculate_stats(struct gb_loopback *gb, bool error);
+
+static u32 gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)
+{
+	u32 lat;
+
+	do_div(elapsed_nsecs, NSEC_PER_USEC);
+	lat = elapsed_nsecs;
+	return lat;
+}
+
+static u64 __gb_loopback_calc_latency(u64 t1, u64 t2)
+{
+	if (t2 > t1)
+		return t2 - t1;
+	else
+		return NSEC_PER_DAY - t2 + t1;
+}
+
+static u64 gb_loopback_calc_latency(struct timeval *ts, struct timeval *te)
+{
+	u64 t1, t2;
+
+	t1 = timeval_to_ns(ts);
+	t2 = timeval_to_ns(te);
+
+	return __gb_loopback_calc_latency(t1, t2);
+}
+
+static void gb_loopback_push_latency_ts(struct gb_loopback *gb,
+					struct timeval *ts, struct timeval *te)
+{
+	kfifo_in(&gb->kfifo_ts, (unsigned char *)ts, sizeof(*ts));
+	kfifo_in(&gb->kfifo_ts, (unsigned char *)te, sizeof(*te));
+}
+
+static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
+				      void *request, int request_size,
+				      void *response, int response_size)
+{
+	struct gb_operation *operation;
+	struct timeval ts, te;
+	int ret;
+
+	do_gettimeofday(&ts);
+	operation = gb_operation_create(gb->connection, type, request_size,
+					response_size, GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	if (request_size)
+		memcpy(operation->request->payload, request, request_size);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret) {
+		dev_err(&gb->connection->bundle->dev,
+			"synchronous operation failed: %d\n", ret);
+		goto out_put_operation;
+	} else {
+		if (response_size == operation->response->payload_size) {
+			memcpy(response, operation->response->payload,
+			       response_size);
+		} else {
+			dev_err(&gb->connection->bundle->dev,
+				"response size %zu expected %d\n",
+				operation->response->payload_size,
+				response_size);
+			ret = -EINVAL;
+			goto out_put_operation;
+		}
+	}
+
+	do_gettimeofday(&te);
+
+	/* Calculate the total time the message took */
+	gb_loopback_push_latency_ts(gb, &ts, &te);
+	gb->elapsed_nsecs = gb_loopback_calc_latency(&ts, &te);
+
+out_put_operation:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static void __gb_loopback_async_operation_destroy(struct kref *kref)
+{
+	struct gb_loopback_async_operation *op_async;
+
+	op_async = container_of(kref, struct gb_loopback_async_operation, kref);
+
+	list_del(&op_async->entry);
+	if (op_async->operation)
+		gb_operation_put(op_async->operation);
+	atomic_dec(&op_async->gb->outstanding_operations);
+	wake_up(&op_async->gb->wq_completion);
+	kfree(op_async);
+}
+
+static void gb_loopback_async_operation_get(struct gb_loopback_async_operation
+					    *op_async)
+{
+	kref_get(&op_async->kref);
+}
+
+static void gb_loopback_async_operation_put(struct gb_loopback_async_operation
+					    *op_async)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&gb_dev.lock, flags);
+	kref_put(&op_async->kref, __gb_loopback_async_operation_destroy);
+	spin_unlock_irqrestore(&gb_dev.lock, flags);
+}
+
+static struct gb_loopback_async_operation *
+	gb_loopback_operation_find(u16 id)
+{
+	struct gb_loopback_async_operation *op_async;
+	bool found = false;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gb_dev.lock, flags);
+	list_for_each_entry(op_async, &gb_dev.list_op_async, entry) {
+		if (op_async->operation->id == id) {
+			gb_loopback_async_operation_get(op_async);
+			found = true;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&gb_dev.lock, flags);
+
+	return found ? op_async : NULL;
+}
+
+static void gb_loopback_async_wait_all(struct gb_loopback *gb)
+{
+	wait_event(gb->wq_completion,
+		   !atomic_read(&gb->outstanding_operations));
+}
+
+static void gb_loopback_async_operation_callback(struct gb_operation *operation)
+{
+	struct gb_loopback_async_operation *op_async;
+	struct gb_loopback *gb;
+	struct timeval te;
+	bool err = false;
+
+	do_gettimeofday(&te);
+	op_async = gb_loopback_operation_find(operation->id);
+	if (!op_async)
+		return;
+
+	gb = op_async->gb;
+	mutex_lock(&gb->mutex);
+
+	if (!op_async->pending || gb_operation_result(operation)) {
+		err = true;
+	} else {
+		if (op_async->completion)
+			if (op_async->completion(op_async))
+				err = true;
+	}
+
+	if (!err) {
+		gb_loopback_push_latency_ts(gb, &op_async->ts, &te);
+		gb->elapsed_nsecs = gb_loopback_calc_latency(&op_async->ts,
+							     &te);
+	}
+
+	if (op_async->pending) {
+		if (err)
+			gb->error++;
+		gb->iteration_count++;
+		op_async->pending = false;
+		del_timer_sync(&op_async->timer);
+		gb_loopback_async_operation_put(op_async);
+		gb_loopback_calculate_stats(gb, err);
+	}
+	mutex_unlock(&gb->mutex);
+
+	dev_dbg(&gb->connection->bundle->dev, "complete operation %d\n",
+		operation->id);
+
+	gb_loopback_async_operation_put(op_async);
+}
+
+static void gb_loopback_async_operation_work(struct work_struct *work)
+{
+	struct gb_loopback *gb;
+	struct gb_operation *operation;
+	struct gb_loopback_async_operation *op_async;
+
+	op_async = container_of(work, struct gb_loopback_async_operation, work);
+	gb = op_async->gb;
+	operation = op_async->operation;
+
+	mutex_lock(&gb->mutex);
+	if (op_async->pending) {
+		gb->requests_timedout++;
+		gb->error++;
+		gb->iteration_count++;
+		op_async->pending = false;
+		gb_loopback_async_operation_put(op_async);
+		gb_loopback_calculate_stats(gb, true);
+	}
+	mutex_unlock(&gb->mutex);
+
+	dev_dbg(&gb->connection->bundle->dev, "timeout operation %d\n",
+		operation->id);
+
+	gb_operation_cancel(operation, -ETIMEDOUT);
+	gb_loopback_async_operation_put(op_async);
+}
+
+static void gb_loopback_async_operation_timeout(unsigned long data)
+{
+	struct gb_loopback_async_operation *op_async;
+	u16 id = data;
+
+	op_async = gb_loopback_operation_find(id);
+	if (!op_async) {
+		pr_err("operation %d not found - time out ?\n", id);
+		return;
+	}
+	schedule_work(&op_async->work);
+}
+
+static int gb_loopback_async_operation(struct gb_loopback *gb, int type,
+				       void *request, int request_size,
+				       int response_size,
+				       void *completion)
+{
+	struct gb_loopback_async_operation *op_async;
+	struct gb_operation *operation;
+	int ret;
+	unsigned long flags;
+
+	op_async = kzalloc(sizeof(*op_async), GFP_KERNEL);
+	if (!op_async)
+		return -ENOMEM;
+
+	INIT_WORK(&op_async->work, gb_loopback_async_operation_work);
+	init_timer(&op_async->timer);
+	kref_init(&op_async->kref);
+
+	operation = gb_operation_create(gb->connection, type, request_size,
+					response_size, GFP_KERNEL);
+	if (!operation) {
+		kfree(op_async);
+		return -ENOMEM;
+	}
+
+	if (request_size)
+		memcpy(operation->request->payload, request, request_size);
+
+	op_async->gb = gb;
+	op_async->operation = operation;
+	op_async->completion = completion;
+
+	spin_lock_irqsave(&gb_dev.lock, flags);
+	list_add_tail(&op_async->entry, &gb_dev.list_op_async);
+	spin_unlock_irqrestore(&gb_dev.lock, flags);
+
+	do_gettimeofday(&op_async->ts);
+	op_async->pending = true;
+	atomic_inc(&gb->outstanding_operations);
+	mutex_lock(&gb->mutex);
+	ret = gb_operation_request_send(operation,
+					gb_loopback_async_operation_callback,
+					GFP_KERNEL);
+	if (ret)
+		goto error;
+
+	op_async->timer.function = gb_loopback_async_operation_timeout;
+	op_async->timer.expires = jiffies + gb->jiffy_timeout;
+	op_async->timer.data = (unsigned long)operation->id;
+	add_timer(&op_async->timer);
+
+	goto done;
+error:
+	gb_loopback_async_operation_put(op_async);
+done:
+	mutex_unlock(&gb->mutex);
+	return ret;
+}
+
+static int gb_loopback_sync_sink(struct gb_loopback *gb, u32 len)
+{
+	struct gb_loopback_transfer_request *request;
+	int retval;
+
+	request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->len = cpu_to_le32(len);
+	retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_SINK,
+					    request, len + sizeof(*request),
+					    NULL, 0);
+	kfree(request);
+	return retval;
+}
+
+static int gb_loopback_sync_transfer(struct gb_loopback *gb, u32 len)
+{
+	struct gb_loopback_transfer_request *request;
+	struct gb_loopback_transfer_response *response;
+	int retval;
+
+	gb->apbridge_latency_ts = 0;
+	gb->gbphy_latency_ts = 0;
+
+	request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+	response = kmalloc(len + sizeof(*response), GFP_KERNEL);
+	if (!response) {
+		kfree(request);
+		return -ENOMEM;
+	}
+
+	memset(request->data, 0x5A, len);
+
+	request->len = cpu_to_le32(len);
+	retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_TRANSFER,
+					    request, len + sizeof(*request),
+					    response, len + sizeof(*response));
+	if (retval)
+		goto gb_error;
+
+	if (memcmp(request->data, response->data, len)) {
+		dev_err(&gb->connection->bundle->dev,
+			"Loopback Data doesn't match\n");
+		retval = -EREMOTEIO;
+	}
+	gb->apbridge_latency_ts = (u32)__le32_to_cpu(response->reserved0);
+	gb->gbphy_latency_ts = (u32)__le32_to_cpu(response->reserved1);
+
+gb_error:
+	kfree(request);
+	kfree(response);
+
+	return retval;
+}
+
+static int gb_loopback_sync_ping(struct gb_loopback *gb)
+{
+	return gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_PING,
+					  NULL, 0, NULL, 0);
+}
+
+static int gb_loopback_async_sink(struct gb_loopback *gb, u32 len)
+{
+	struct gb_loopback_transfer_request *request;
+	int retval;
+
+	request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->len = cpu_to_le32(len);
+	retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_SINK,
+					     request, len + sizeof(*request),
+					     0, NULL);
+	kfree(request);
+	return retval;
+}
+
+static int gb_loopback_async_transfer_complete(
+				struct gb_loopback_async_operation *op_async)
+{
+	struct gb_loopback *gb;
+	struct gb_operation *operation;
+	struct gb_loopback_transfer_request *request;
+	struct gb_loopback_transfer_response *response;
+	size_t len;
+	int retval = 0;
+
+	gb = op_async->gb;
+	operation = op_async->operation;
+	request = operation->request->payload;
+	response = operation->response->payload;
+	len = le32_to_cpu(request->len);
+
+	if (memcmp(request->data, response->data, len)) {
+		dev_err(&gb->connection->bundle->dev,
+			"Loopback Data doesn't match operation id %d\n",
+			operation->id);
+		retval = -EREMOTEIO;
+	} else {
+		gb->apbridge_latency_ts =
+			(u32)__le32_to_cpu(response->reserved0);
+		gb->gbphy_latency_ts =
+			(u32)__le32_to_cpu(response->reserved1);
+	}
+
+	return retval;
+}
+
+static int gb_loopback_async_transfer(struct gb_loopback *gb, u32 len)
+{
+	struct gb_loopback_transfer_request *request;
+	int retval, response_len;
+
+	request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	memset(request->data, 0x5A, len);
+
+	request->len = cpu_to_le32(len);
+	response_len = sizeof(struct gb_loopback_transfer_response);
+	retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_TRANSFER,
+					     request, len + sizeof(*request),
+					     len + response_len,
+					     gb_loopback_async_transfer_complete);
+	if (retval)
+		goto gb_error;
+
+gb_error:
+	kfree(request);
+	return retval;
+}
+
+static int gb_loopback_async_ping(struct gb_loopback *gb)
+{
+	return gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_PING,
+					   NULL, 0, 0, NULL);
+}
+
+static int gb_loopback_request_handler(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	struct gb_loopback_transfer_request *request;
+	struct gb_loopback_transfer_response *response;
+	struct device *dev = &connection->bundle->dev;
+	size_t len;
+
+	/* By convention, the AP initiates the version operation */
+	switch (operation->type) {
+	case GB_LOOPBACK_TYPE_PING:
+	case GB_LOOPBACK_TYPE_SINK:
+		return 0;
+	case GB_LOOPBACK_TYPE_TRANSFER:
+		if (operation->request->payload_size < sizeof(*request)) {
+			dev_err(dev, "transfer request too small (%zu < %zu)\n",
+				operation->request->payload_size,
+				sizeof(*request));
+			return -EINVAL;	/* -EMSGSIZE */
+		}
+		request = operation->request->payload;
+		len = le32_to_cpu(request->len);
+		if (len > gb_dev.size_max) {
+			dev_err(dev, "transfer request too large (%zu > %zu)\n",
+				len, gb_dev.size_max);
+			return -EINVAL;
+		}
+
+		if (!gb_operation_response_alloc(operation,
+				len + sizeof(*response), GFP_KERNEL)) {
+			dev_err(dev, "error allocating response\n");
+			return -ENOMEM;
+		}
+		response = operation->response->payload;
+		response->len = cpu_to_le32(len);
+		if (len)
+			memcpy(response->data, request->data, len);
+
+		return 0;
+	default:
+		dev_err(dev, "unsupported request: %u\n", operation->type);
+		return -EINVAL;
+	}
+}
+
+static void gb_loopback_reset_stats(struct gb_loopback *gb)
+{
+	struct gb_loopback_stats reset = {
+		.min = U32_MAX,
+	};
+
+	/* Reset per-connection stats */
+	memcpy(&gb->latency, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->throughput, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->requests_per_second, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->apbridge_unipro_latency, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->gbphy_firmware_latency, &reset,
+	       sizeof(struct gb_loopback_stats));
+
+	/* Should be initialized at least once per transaction set */
+	gb->apbridge_latency_ts = 0;
+	gb->gbphy_latency_ts = 0;
+	memset(&gb->ts, 0, sizeof(struct timeval));
+}
+
+static void gb_loopback_update_stats(struct gb_loopback_stats *stats, u32 val)
+{
+	if (stats->min > val)
+		stats->min = val;
+	if (stats->max < val)
+		stats->max = val;
+	stats->sum += val;
+	stats->count++;
+}
+
+static void gb_loopback_update_stats_window(struct gb_loopback_stats *stats,
+					    u64 val, u32 count)
+{
+	stats->sum += val;
+	stats->count += count;
+
+	do_div(val, count);
+	if (stats->min > val)
+		stats->min = val;
+	if (stats->max < val)
+		stats->max = val;
+}
+
+static void gb_loopback_requests_update(struct gb_loopback *gb, u32 latency)
+{
+	u64 req = gb->requests_completed * USEC_PER_SEC;
+
+	gb_loopback_update_stats_window(&gb->requests_per_second, req, latency);
+}
+
+static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
+{
+	u64 aggregate_size = sizeof(struct gb_operation_msg_hdr) * 2;
+
+	switch (gb->type) {
+	case GB_LOOPBACK_TYPE_PING:
+		break;
+	case GB_LOOPBACK_TYPE_SINK:
+		aggregate_size += sizeof(struct gb_loopback_transfer_request) +
+				  gb->size;
+		break;
+	case GB_LOOPBACK_TYPE_TRANSFER:
+		aggregate_size += sizeof(struct gb_loopback_transfer_request) +
+				  sizeof(struct gb_loopback_transfer_response) +
+				  gb->size * 2;
+		break;
+	default:
+		return;
+	}
+
+	aggregate_size *= gb->requests_completed;
+	aggregate_size *= USEC_PER_SEC;
+	gb_loopback_update_stats_window(&gb->throughput, aggregate_size,
+					latency);
+}
+
+static void gb_loopback_calculate_latency_stats(struct gb_loopback *gb)
+{
+	u32 lat;
+
+	/* Express latency in terms of microseconds */
+	lat = gb_loopback_nsec_to_usec_latency(gb->elapsed_nsecs);
+
+	/* Log latency stastic */
+	gb_loopback_update_stats(&gb->latency, lat);
+
+	/* Raw latency log on a per thread basis */
+	kfifo_in(&gb->kfifo_lat, (unsigned char *)&lat, sizeof(lat));
+
+	/* Log the firmware supplied latency values */
+	gb_loopback_update_stats(&gb->apbridge_unipro_latency,
+				 gb->apbridge_latency_ts);
+	gb_loopback_update_stats(&gb->gbphy_firmware_latency,
+				 gb->gbphy_latency_ts);
+}
+
+static void gb_loopback_calculate_stats(struct gb_loopback *gb, bool error)
+{
+	u64 nlat;
+	u32 lat;
+	struct timeval te;
+
+	if (!error) {
+		gb->requests_completed++;
+		gb_loopback_calculate_latency_stats(gb);
+	}
+
+	do_gettimeofday(&te);
+	nlat = gb_loopback_calc_latency(&gb->ts, &te);
+	if (nlat >= NSEC_PER_SEC || gb->iteration_count == gb->iteration_max) {
+		lat = gb_loopback_nsec_to_usec_latency(nlat);
+
+		gb_loopback_throughput_update(gb, lat);
+		gb_loopback_requests_update(gb, lat);
+
+		if (gb->iteration_count != gb->iteration_max) {
+			gb->ts = te;
+			gb->requests_completed = 0;
+		}
+	}
+}
+
+static void gb_loopback_async_wait_to_send(struct gb_loopback *gb)
+{
+	if (!(gb->async && gb->outstanding_operations_max))
+		return;
+	wait_event_interruptible(gb->wq_completion,
+				 (atomic_read(&gb->outstanding_operations) <
+				  gb->outstanding_operations_max) ||
+				  kthread_should_stop());
+}
+
+static int gb_loopback_fn(void *data)
+{
+	int error = 0;
+	int us_wait = 0;
+	int type;
+	int ret;
+	u32 size;
+
+	struct gb_loopback *gb = data;
+	struct gb_bundle *bundle = gb->connection->bundle;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	while (1) {
+		if (!gb->type) {
+			gb_pm_runtime_put_autosuspend(bundle);
+			wait_event_interruptible(gb->wq, gb->type ||
+						 kthread_should_stop());
+			ret = gb_pm_runtime_get_sync(bundle);
+			if (ret)
+				return ret;
+		}
+
+		if (kthread_should_stop())
+			break;
+
+		/* Limit the maximum number of in-flight async operations */
+		gb_loopback_async_wait_to_send(gb);
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&gb->mutex);
+
+		/* Optionally terminate */
+		if (gb->send_count == gb->iteration_max) {
+			if (gb->iteration_count == gb->iteration_max) {
+				gb->type = 0;
+				gb->send_count = 0;
+				sysfs_notify(&gb->dev->kobj,  NULL,
+						"iteration_count");
+			}
+			mutex_unlock(&gb->mutex);
+			continue;
+		}
+		size = gb->size;
+		us_wait = gb->us_wait;
+		type = gb->type;
+		if (gb->ts.tv_usec == 0 && gb->ts.tv_sec == 0)
+			do_gettimeofday(&gb->ts);
+		mutex_unlock(&gb->mutex);
+
+		/* Else operations to perform */
+		if (gb->async) {
+			if (type == GB_LOOPBACK_TYPE_PING) {
+				error = gb_loopback_async_ping(gb);
+			} else if (type == GB_LOOPBACK_TYPE_TRANSFER) {
+				error = gb_loopback_async_transfer(gb, size);
+			} else if (type == GB_LOOPBACK_TYPE_SINK) {
+				error = gb_loopback_async_sink(gb, size);
+			}
+
+			if (error)
+				gb->error++;
+		} else {
+			/* We are effectively single threaded here */
+			if (type == GB_LOOPBACK_TYPE_PING)
+				error = gb_loopback_sync_ping(gb);
+			else if (type == GB_LOOPBACK_TYPE_TRANSFER)
+				error = gb_loopback_sync_transfer(gb, size);
+			else if (type == GB_LOOPBACK_TYPE_SINK)
+				error = gb_loopback_sync_sink(gb, size);
+
+			if (error)
+				gb->error++;
+			gb->iteration_count++;
+			gb_loopback_calculate_stats(gb, !!error);
+		}
+		gb->send_count++;
+		if (us_wait)
+			udelay(us_wait);
+	}
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+}
+
+static int gb_loopback_dbgfs_latency_show_common(struct seq_file *s,
+						 struct kfifo *kfifo,
+						 struct mutex *mutex)
+{
+	u32 latency;
+	int retval;
+
+	if (kfifo_len(kfifo) == 0) {
+		retval = -EAGAIN;
+		goto done;
+	}
+
+	mutex_lock(mutex);
+	retval = kfifo_out(kfifo, &latency, sizeof(latency));
+	if (retval > 0) {
+		seq_printf(s, "%u", latency);
+		retval = 0;
+	}
+	mutex_unlock(mutex);
+done:
+	return retval;
+}
+
+static int gb_loopback_dbgfs_latency_show(struct seq_file *s, void *unused)
+{
+	struct gb_loopback *gb = s->private;
+
+	return gb_loopback_dbgfs_latency_show_common(s, &gb->kfifo_lat,
+						     &gb->mutex);
+}
+
+static int gb_loopback_latency_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, gb_loopback_dbgfs_latency_show,
+			   inode->i_private);
+}
+
+static const struct file_operations gb_loopback_debugfs_latency_ops = {
+	.open		= gb_loopback_latency_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int gb_loopback_bus_id_compare(void *priv, struct list_head *lha,
+				      struct list_head *lhb)
+{
+	struct gb_loopback *a = list_entry(lha, struct gb_loopback, entry);
+	struct gb_loopback *b = list_entry(lhb, struct gb_loopback, entry);
+	struct gb_connection *ca = a->connection;
+	struct gb_connection *cb = b->connection;
+
+	if (ca->bundle->intf->interface_id < cb->bundle->intf->interface_id)
+		return -1;
+	if (cb->bundle->intf->interface_id < ca->bundle->intf->interface_id)
+		return 1;
+	if (ca->bundle->id < cb->bundle->id)
+		return -1;
+	if (cb->bundle->id < ca->bundle->id)
+		return 1;
+	if (ca->intf_cport_id < cb->intf_cport_id)
+		return -1;
+	else if (cb->intf_cport_id < ca->intf_cport_id)
+		return 1;
+
+	return 0;
+}
+
+static void gb_loopback_insert_id(struct gb_loopback *gb)
+{
+	struct gb_loopback *gb_list;
+	u32 new_lbid = 0;
+
+	/* perform an insertion sort */
+	list_add_tail(&gb->entry, &gb_dev.list);
+	list_sort(NULL, &gb_dev.list, gb_loopback_bus_id_compare);
+	list_for_each_entry(gb_list, &gb_dev.list, entry) {
+		gb_list->lbid = 1 << new_lbid;
+		new_lbid++;
+	}
+}
+
+#define DEBUGFS_NAMELEN 32
+
+static int gb_loopback_probe(struct gb_bundle *bundle,
+			     const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_loopback *gb;
+	struct device *dev;
+	int retval;
+	char name[DEBUGFS_NAMELEN];
+	unsigned long flags;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LOOPBACK)
+		return -ENODEV;
+
+	gb = kzalloc(sizeof(*gb), GFP_KERNEL);
+	if (!gb)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+					  gb_loopback_request_handler);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto out_kzalloc;
+	}
+
+	gb->connection = connection;
+	greybus_set_drvdata(bundle, gb);
+
+	init_waitqueue_head(&gb->wq);
+	init_waitqueue_head(&gb->wq_completion);
+	atomic_set(&gb->outstanding_operations, 0);
+	gb_loopback_reset_stats(gb);
+
+	/* Reported values to user-space for min/max timeouts */
+	gb->timeout_min = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MIN);
+	gb->timeout_max = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MAX);
+
+	if (!gb_dev.count) {
+		/* Calculate maximum payload */
+		gb_dev.size_max = gb_operation_get_payload_size_max(connection);
+		if (gb_dev.size_max <=
+			sizeof(struct gb_loopback_transfer_request)) {
+			retval = -EINVAL;
+			goto out_connection_destroy;
+		}
+		gb_dev.size_max -= sizeof(struct gb_loopback_transfer_request);
+	}
+
+	/* Create per-connection sysfs and debugfs data-points */
+	snprintf(name, sizeof(name), "raw_latency_%s",
+		 dev_name(&connection->bundle->dev));
+	gb->file = debugfs_create_file(name, S_IFREG | S_IRUGO, gb_dev.root, gb,
+				       &gb_loopback_debugfs_latency_ops);
+
+	gb->id = ida_simple_get(&loopback_ida, 0, 0, GFP_KERNEL);
+	if (gb->id < 0) {
+		retval = gb->id;
+		goto out_debugfs_remove;
+	}
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto out_ida_remove;
+
+	dev = device_create_with_groups(&loopback_class,
+					&connection->bundle->dev,
+					MKDEV(0, 0), gb, loopback_groups,
+					"gb_loopback%d", gb->id);
+	if (IS_ERR(dev)) {
+		retval = PTR_ERR(dev);
+		goto out_connection_disable;
+	}
+	gb->dev = dev;
+
+	/* Allocate kfifo */
+	if (kfifo_alloc(&gb->kfifo_lat, kfifo_depth * sizeof(u32),
+			  GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_conn;
+	}
+	if (kfifo_alloc(&gb->kfifo_ts, kfifo_depth * sizeof(struct timeval) * 2,
+			  GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_kfifo0;
+	}
+
+	/* Fork worker thread */
+	mutex_init(&gb->mutex);
+	gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
+	if (IS_ERR(gb->task)) {
+		retval = PTR_ERR(gb->task);
+		goto out_kfifo1;
+	}
+
+	spin_lock_irqsave(&gb_dev.lock, flags);
+	gb_loopback_insert_id(gb);
+	gb_dev.count++;
+	spin_unlock_irqrestore(&gb_dev.lock, flags);
+
+	gb_connection_latency_tag_enable(connection);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+out_kfifo1:
+	kfifo_free(&gb->kfifo_ts);
+out_kfifo0:
+	kfifo_free(&gb->kfifo_lat);
+out_conn:
+	device_unregister(dev);
+out_connection_disable:
+	gb_connection_disable(connection);
+out_ida_remove:
+	ida_simple_remove(&loopback_ida, gb->id);
+out_debugfs_remove:
+	debugfs_remove(gb->file);
+out_connection_destroy:
+	gb_connection_destroy(connection);
+out_kzalloc:
+	kfree(gb);
+
+	return retval;
+}
+
+static void gb_loopback_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_loopback *gb = greybus_get_drvdata(bundle);
+	unsigned long flags;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		gb_pm_runtime_get_noresume(bundle);
+
+	gb_connection_disable(gb->connection);
+
+	if (!IS_ERR_OR_NULL(gb->task))
+		kthread_stop(gb->task);
+
+	kfifo_free(&gb->kfifo_lat);
+	kfifo_free(&gb->kfifo_ts);
+	gb_connection_latency_tag_disable(gb->connection);
+	debugfs_remove(gb->file);
+
+	/*
+	 * FIXME: gb_loopback_async_wait_all() is redundant now, as connection
+	 * is disabled at the beginning and so we can't have any more
+	 * incoming/outgoing requests.
+	 */
+	gb_loopback_async_wait_all(gb);
+
+	spin_lock_irqsave(&gb_dev.lock, flags);
+	gb_dev.count--;
+	list_del(&gb->entry);
+	spin_unlock_irqrestore(&gb_dev.lock, flags);
+
+	device_unregister(gb->dev);
+	ida_simple_remove(&loopback_ida, gb->id);
+
+	gb_connection_destroy(gb->connection);
+	kfree(gb);
+}
+
+static const struct greybus_bundle_id gb_loopback_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LOOPBACK) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_loopback_id_table);
+
+static struct greybus_driver gb_loopback_driver = {
+	.name		= "loopback",
+	.probe		= gb_loopback_probe,
+	.disconnect	= gb_loopback_disconnect,
+	.id_table	= gb_loopback_id_table,
+};
+
+static int loopback_init(void)
+{
+	int retval;
+
+	INIT_LIST_HEAD(&gb_dev.list);
+	INIT_LIST_HEAD(&gb_dev.list_op_async);
+	spin_lock_init(&gb_dev.lock);
+	gb_dev.root = debugfs_create_dir("gb_loopback", NULL);
+
+	retval = class_register(&loopback_class);
+	if (retval)
+		goto err;
+
+	retval = greybus_register(&gb_loopback_driver);
+	if (retval)
+		goto err_unregister;
+
+	return 0;
+
+err_unregister:
+	class_unregister(&loopback_class);
+err:
+	debugfs_remove_recursive(gb_dev.root);
+	return retval;
+}
+module_init(loopback_init);
+
+static void __exit loopback_exit(void)
+{
+	debugfs_remove_recursive(gb_dev.root);
+	greybus_deregister(&gb_loopback_driver);
+	class_unregister(&loopback_class);
+	ida_destroy(&loopback_ida);
+}
+module_exit(loopback_exit);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/manifest.c b/drivers/staging/greybus/manifest.c
new file mode 100644
index 000000000000..3d1592fc94ea
--- /dev/null
+++ b/drivers/staging/greybus/manifest.c
@@ -0,0 +1,535 @@
+/*
+ * Greybus manifest parsing
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+
+static const char *get_descriptor_type_string(u8 type)
+{
+	switch(type) {
+	case GREYBUS_TYPE_INVALID:
+		return "invalid";
+	case GREYBUS_TYPE_STRING:
+		return "string";
+	case GREYBUS_TYPE_INTERFACE:
+		return "interface";
+	case GREYBUS_TYPE_CPORT:
+		return "cport";
+	case GREYBUS_TYPE_BUNDLE:
+		return "bundle";
+	default:
+		WARN_ON(1);
+		return "unknown";
+	}
+}
+
+/*
+ * We scan the manifest once to identify where all the descriptors
+ * are.  The result is a list of these manifest_desc structures.  We
+ * then pick through them for what we're looking for (starting with
+ * the interface descriptor).  As each is processed we remove it from
+ * the list.  When we're done the list should (probably) be empty.
+ */
+struct manifest_desc {
+	struct list_head		links;
+
+	size_t				size;
+	void				*data;
+	enum greybus_descriptor_type	type;
+};
+
+static void release_manifest_descriptor(struct manifest_desc *descriptor)
+{
+	list_del(&descriptor->links);
+	kfree(descriptor);
+}
+
+static void release_manifest_descriptors(struct gb_interface *intf)
+{
+	struct manifest_desc *descriptor;
+	struct manifest_desc *next;
+
+	list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links)
+		release_manifest_descriptor(descriptor);
+}
+
+static void release_cport_descriptors(struct list_head *head, u8 bundle_id)
+{
+	struct manifest_desc *desc, *tmp;
+	struct greybus_descriptor_cport *desc_cport;
+
+	list_for_each_entry_safe(desc, tmp, head, links) {
+		desc_cport = desc->data;
+
+		if (desc->type != GREYBUS_TYPE_CPORT)
+			continue;
+
+		if (desc_cport->bundle == bundle_id)
+			release_manifest_descriptor(desc);
+	}
+}
+
+static struct manifest_desc *get_next_bundle_desc(struct gb_interface *intf)
+{
+	struct manifest_desc *descriptor;
+	struct manifest_desc *next;
+
+	list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links)
+		if (descriptor->type == GREYBUS_TYPE_BUNDLE)
+			return descriptor;
+
+	return NULL;
+}
+
+/*
+ * Validate the given descriptor.  Its reported size must fit within
+ * the number of bytes remaining, and it must have a recognized
+ * type.  Check that the reported size is at least as big as what
+ * we expect to see.  (It could be bigger, perhaps for a new version
+ * of the format.)
+ *
+ * Returns the (non-zero) number of bytes consumed by the descriptor,
+ * or a negative errno.
+ */
+static int identify_descriptor(struct gb_interface *intf,
+			       struct greybus_descriptor *desc, size_t size)
+{
+	struct greybus_descriptor_header *desc_header = &desc->header;
+	struct manifest_desc *descriptor;
+	size_t desc_size;
+	size_t expected_size;
+
+	if (size < sizeof(*desc_header)) {
+		dev_err(&intf->dev, "manifest too small (%zu < %zu)\n",
+				size, sizeof(*desc_header));
+		return -EINVAL;		/* Must at least have header */
+	}
+
+	desc_size = le16_to_cpu(desc_header->size);
+	if (desc_size > size) {
+		dev_err(&intf->dev, "descriptor too big (%zu > %zu)\n",
+				desc_size, size);
+		return -EINVAL;
+	}
+
+	/* Descriptor needs to at least have a header */
+	expected_size = sizeof(*desc_header);
+
+	switch (desc_header->type) {
+	case GREYBUS_TYPE_STRING:
+		expected_size += sizeof(struct greybus_descriptor_string);
+		expected_size += desc->string.length;
+
+		/* String descriptors are padded to 4 byte boundaries */
+		expected_size = ALIGN(expected_size, 4);
+		break;
+	case GREYBUS_TYPE_INTERFACE:
+		expected_size += sizeof(struct greybus_descriptor_interface);
+		break;
+	case GREYBUS_TYPE_BUNDLE:
+		expected_size += sizeof(struct greybus_descriptor_bundle);
+		break;
+	case GREYBUS_TYPE_CPORT:
+		expected_size += sizeof(struct greybus_descriptor_cport);
+		break;
+	case GREYBUS_TYPE_INVALID:
+	default:
+		dev_err(&intf->dev, "invalid descriptor type (%u)\n",
+				desc_header->type);
+		return -EINVAL;
+	}
+
+	if (desc_size < expected_size) {
+		dev_err(&intf->dev, "%s descriptor too small (%zu < %zu)\n",
+				get_descriptor_type_string(desc_header->type),
+				desc_size, expected_size);
+		return -EINVAL;
+	}
+
+	/* Descriptor bigger than what we expect */
+	if (desc_size > expected_size) {
+		dev_warn(&intf->dev, "%s descriptor size mismatch (want %zu got %zu)\n",
+				get_descriptor_type_string(desc_header->type),
+				expected_size, desc_size);
+	}
+
+	descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL);
+	if (!descriptor)
+		return -ENOMEM;
+
+	descriptor->size = desc_size;
+	descriptor->data = (char *)desc + sizeof(*desc_header);
+	descriptor->type = desc_header->type;
+	list_add_tail(&descriptor->links, &intf->manifest_descs);
+
+	/* desc_size is positive and is known to fit in a signed int */
+
+	return desc_size;
+}
+
+/*
+ * Find the string descriptor having the given id, validate it, and
+ * allocate a duplicate copy of it.  The duplicate has an extra byte
+ * which guarantees the returned string is NUL-terminated.
+ *
+ * String index 0 is valid (it represents "no string"), and for
+ * that a null pointer is returned.
+ *
+ * Otherwise returns a pointer to a newly-allocated copy of the
+ * descriptor string, or an error-coded pointer on failure.
+ */
+static char *gb_string_get(struct gb_interface *intf, u8 string_id)
+{
+	struct greybus_descriptor_string *desc_string;
+	struct manifest_desc *descriptor;
+	bool found = false;
+	char *string;
+
+	/* A zero string id means no string (but no error) */
+	if (!string_id)
+		return NULL;
+
+	list_for_each_entry(descriptor, &intf->manifest_descs, links) {
+		if (descriptor->type != GREYBUS_TYPE_STRING)
+			continue;
+
+		desc_string = descriptor->data;
+		if (desc_string->id == string_id) {
+			found = true;
+			break;
+		}
+	}
+	if (!found)
+		return ERR_PTR(-ENOENT);
+
+	/* Allocate an extra byte so we can guarantee it's NUL-terminated */
+	string = kmemdup(&desc_string->string, desc_string->length + 1,
+				GFP_KERNEL);
+	if (!string)
+		return ERR_PTR(-ENOMEM);
+	string[desc_string->length] = '\0';
+
+	/* Ok we've used this string, so we're done with it */
+	release_manifest_descriptor(descriptor);
+
+	return string;
+}
+
+/*
+ * Find cport descriptors in the manifest associated with the given
+ * bundle, and set up data structures for the functions that use
+ * them.  Returns the number of cports set up for the bundle, or 0
+ * if there is an error.
+ */
+static u32 gb_manifest_parse_cports(struct gb_bundle *bundle)
+{
+	struct gb_interface *intf = bundle->intf;
+	struct greybus_descriptor_cport *desc_cport;
+	struct manifest_desc *desc, *next, *tmp;
+	LIST_HEAD(list);
+	u8 bundle_id = bundle->id;
+	u16 cport_id;
+	u32 count = 0;
+	int i;
+
+	/* Set up all cport descriptors associated with this bundle */
+	list_for_each_entry_safe(desc, next, &intf->manifest_descs, links) {
+		if (desc->type != GREYBUS_TYPE_CPORT)
+			continue;
+
+		desc_cport = desc->data;
+		if (desc_cport->bundle != bundle_id)
+			continue;
+
+		cport_id = le16_to_cpu(desc_cport->id);
+		if (cport_id > CPORT_ID_MAX)
+			goto exit;
+
+		/* Nothing else should have its cport_id as control cport id */
+		if (cport_id == GB_CONTROL_CPORT_ID) {
+			dev_err(&bundle->dev, "invalid cport id found (%02u)\n",
+				cport_id);
+			goto exit;
+		}
+
+		/*
+		 * Found one, move it to our temporary list after checking for
+		 * duplicates.
+		 */
+		list_for_each_entry(tmp, &list, links) {
+			desc_cport = tmp->data;
+			if (cport_id == le16_to_cpu(desc_cport->id)) {
+				dev_err(&bundle->dev,
+						"duplicate CPort %u found\n",
+						cport_id);
+				goto exit;
+			}
+		}
+		list_move_tail(&desc->links, &list);
+		count++;
+	}
+
+	if (!count)
+		return 0;
+
+	bundle->cport_desc = kcalloc(count, sizeof(*bundle->cport_desc),
+					GFP_KERNEL);
+	if (!bundle->cport_desc)
+		goto exit;
+
+	bundle->num_cports = count;
+
+	i = 0;
+	list_for_each_entry_safe(desc, next, &list, links) {
+		desc_cport = desc->data;
+		memcpy(&bundle->cport_desc[i++], desc_cport,
+				sizeof(*desc_cport));
+
+		/* Release the cport descriptor */
+		release_manifest_descriptor(desc);
+	}
+
+	return count;
+exit:
+	release_cport_descriptors(&list, bundle_id);
+	/*
+	 * Free all cports for this bundle to avoid 'excess descriptors'
+	 * warnings.
+	 */
+	release_cport_descriptors(&intf->manifest_descs, bundle_id);
+
+	return 0;	/* Error; count should also be 0 */
+}
+
+/*
+ * Find bundle descriptors in the manifest and set up their data
+ * structures.  Returns the number of bundles set up for the
+ * given interface.
+ */
+static u32 gb_manifest_parse_bundles(struct gb_interface *intf)
+{
+	struct manifest_desc *desc;
+	struct gb_bundle *bundle;
+	struct gb_bundle *bundle_next;
+	u32 count = 0;
+	u8 bundle_id;
+	u8 class;
+
+	while ((desc = get_next_bundle_desc(intf))) {
+		struct greybus_descriptor_bundle *desc_bundle;
+
+		/* Found one.  Set up its bundle structure*/
+		desc_bundle = desc->data;
+		bundle_id = desc_bundle->id;
+		class = desc_bundle->class;
+
+		/* Done with this bundle descriptor */
+		release_manifest_descriptor(desc);
+
+		/* Ignore any legacy control bundles */
+		if (bundle_id == GB_CONTROL_BUNDLE_ID) {
+			dev_dbg(&intf->dev, "%s - ignoring control bundle\n",
+					__func__);
+			release_cport_descriptors(&intf->manifest_descs,
+								bundle_id);
+			continue;
+		}
+
+		/* Nothing else should have its class set to control class */
+		if (class == GREYBUS_CLASS_CONTROL) {
+			dev_err(&intf->dev,
+				"bundle %u cannot use control class\n",
+				bundle_id);
+			goto cleanup;
+		}
+
+		bundle = gb_bundle_create(intf, bundle_id, class);
+		if (!bundle)
+			goto cleanup;
+
+		/*
+		 * Now go set up this bundle's functions and cports.
+		 *
+		 * A 'bundle' represents a device in greybus. It may require
+		 * multiple cports for its functioning. If we fail to setup any
+		 * cport of a bundle, we better reject the complete bundle as
+		 * the device may not be able to function properly then.
+		 *
+		 * But, failing to setup a cport of bundle X doesn't mean that
+		 * the device corresponding to bundle Y will not work properly.
+		 * Bundles should be treated as separate independent devices.
+		 *
+		 * While parsing manifest for an interface, treat bundles as
+		 * separate entities and don't reject entire interface and its
+		 * bundles on failing to initialize a cport. But make sure the
+		 * bundle which needs the cport, gets destroyed properly.
+		 */
+		if (!gb_manifest_parse_cports(bundle)) {
+			gb_bundle_destroy(bundle);
+			continue;
+		}
+
+		count++;
+	}
+
+	return count;
+cleanup:
+	/* An error occurred; undo any changes we've made */
+	list_for_each_entry_safe(bundle, bundle_next, &intf->bundles, links) {
+		gb_bundle_destroy(bundle);
+		count--;
+	}
+	return 0;	/* Error; count should also be 0 */
+}
+
+static bool gb_manifest_parse_interface(struct gb_interface *intf,
+					struct manifest_desc *interface_desc)
+{
+	struct greybus_descriptor_interface *desc_intf = interface_desc->data;
+	struct gb_control *control = intf->control;
+	char *str;
+
+	/* Handle the strings first--they can fail */
+	str = gb_string_get(intf, desc_intf->vendor_stringid);
+	if (IS_ERR(str))
+		return false;
+	control->vendor_string = str;
+
+	str = gb_string_get(intf, desc_intf->product_stringid);
+	if (IS_ERR(str))
+		goto out_free_vendor_string;
+	control->product_string = str;
+
+	/* Assign feature flags communicated via manifest */
+	intf->features = desc_intf->features;
+
+	/* Release the interface descriptor, now that we're done with it */
+	release_manifest_descriptor(interface_desc);
+
+	/* An interface must have at least one bundle descriptor */
+	if (!gb_manifest_parse_bundles(intf)) {
+		dev_err(&intf->dev, "manifest bundle descriptors not valid\n");
+		goto out_err;
+	}
+
+	return true;
+out_err:
+	kfree(control->product_string);
+	control->product_string = NULL;
+out_free_vendor_string:
+	kfree(control->vendor_string);
+	control->vendor_string = NULL;
+
+	return false;
+}
+
+/*
+ * Parse a buffer containing an interface manifest.
+ *
+ * If we find anything wrong with the content/format of the buffer
+ * we reject it.
+ *
+ * The first requirement is that the manifest's version is
+ * one we can parse.
+ *
+ * We make an initial pass through the buffer and identify all of
+ * the descriptors it contains, keeping track for each its type
+ * and the location size of its data in the buffer.
+ *
+ * Next we scan the descriptors, looking for an interface descriptor;
+ * there must be exactly one of those.  When found, we record the
+ * information it contains, and then remove that descriptor (and any
+ * string descriptors it refers to) from further consideration.
+ *
+ * After that we look for the interface's bundles--there must be at
+ * least one of those.
+ *
+ * Returns true if parsing was successful, false otherwise.
+ */
+bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size)
+{
+	struct greybus_manifest *manifest;
+	struct greybus_manifest_header *header;
+	struct greybus_descriptor *desc;
+	struct manifest_desc *descriptor;
+	struct manifest_desc *interface_desc = NULL;
+	u16 manifest_size;
+	u32 found = 0;
+	bool result;
+
+	/* Manifest descriptor list should be empty here */
+	if (WARN_ON(!list_empty(&intf->manifest_descs)))
+		return false;
+
+	/* we have to have at _least_ the manifest header */
+	if (size < sizeof(*header)) {
+		dev_err(&intf->dev, "short manifest (%zu < %zu)\n",
+				size, sizeof(*header));
+		return false;
+	}
+
+	/* Make sure the size is right */
+	manifest = data;
+	header = &manifest->header;
+	manifest_size = le16_to_cpu(header->size);
+	if (manifest_size != size) {
+		dev_err(&intf->dev, "manifest size mismatch (%zu != %u)\n",
+				size, manifest_size);
+		return false;
+	}
+
+	/* Validate major/minor number */
+	if (header->version_major > GREYBUS_VERSION_MAJOR) {
+		dev_err(&intf->dev, "manifest version too new (%u.%u > %u.%u)\n",
+				header->version_major, header->version_minor,
+				GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR);
+		return false;
+	}
+
+	/* OK, find all the descriptors */
+	desc = manifest->descriptors;
+	size -= sizeof(*header);
+	while (size) {
+		int desc_size;
+
+		desc_size = identify_descriptor(intf, desc, size);
+		if (desc_size < 0) {
+			result = false;
+			goto out;
+		}
+		desc = (struct greybus_descriptor *)((char *)desc + desc_size);
+		size -= desc_size;
+	}
+
+	/* There must be a single interface descriptor */
+	list_for_each_entry(descriptor, &intf->manifest_descs, links) {
+		if (descriptor->type == GREYBUS_TYPE_INTERFACE)
+			if (!found++)
+				interface_desc = descriptor;
+	}
+	if (found != 1) {
+		dev_err(&intf->dev, "manifest must have 1 interface descriptor (%u found)\n",
+				found);
+		result = false;
+		goto out;
+	}
+
+	/* Parse the manifest, starting with the interface descriptor */
+	result = gb_manifest_parse_interface(intf, interface_desc);
+
+	/*
+	 * We really should have no remaining descriptors, but we
+	 * don't know what newer format manifests might leave.
+	 */
+	if (result && !list_empty(&intf->manifest_descs))
+		dev_info(&intf->dev, "excess descriptors in interface manifest\n");
+out:
+	release_manifest_descriptors(intf);
+
+	return result;
+}
diff --git a/drivers/staging/greybus/manifest.h b/drivers/staging/greybus/manifest.h
new file mode 100644
index 000000000000..d96428407cd7
--- /dev/null
+++ b/drivers/staging/greybus/manifest.h
@@ -0,0 +1,16 @@
+/*
+ * Greybus manifest parsing
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __MANIFEST_H
+#define __MANIFEST_H
+
+struct gb_interface;
+bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size);
+
+#endif /* __MANIFEST_H */
diff --git a/drivers/staging/greybus/module.c b/drivers/staging/greybus/module.c
new file mode 100644
index 000000000000..69f67ddbd4a3
--- /dev/null
+++ b/drivers/staging/greybus/module.c
@@ -0,0 +1,238 @@
+/*
+ * Greybus Module code
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+
+static ssize_t eject_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t len)
+{
+	struct gb_module *module = to_gb_module(dev);
+	struct gb_interface *intf;
+	size_t i;
+	long val;
+	int ret;
+
+	ret = kstrtol(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (!val)
+		return len;
+
+	for (i = 0; i < module->num_interfaces; ++i) {
+		intf = module->interfaces[i];
+
+		mutex_lock(&intf->mutex);
+		/* Set flag to prevent concurrent activation. */
+		intf->ejected = true;
+		gb_interface_disable(intf);
+		gb_interface_deactivate(intf);
+		mutex_unlock(&intf->mutex);
+	}
+
+	/* Tell the SVC to eject the primary interface. */
+	ret = gb_svc_intf_eject(module->hd->svc, module->module_id);
+	if (ret)
+		return ret;
+
+	return len;
+}
+static DEVICE_ATTR_WO(eject);
+
+static ssize_t module_id_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_module *module = to_gb_module(dev);
+
+	return sprintf(buf, "%u\n", module->module_id);
+}
+static DEVICE_ATTR_RO(module_id);
+
+static ssize_t num_interfaces_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gb_module *module = to_gb_module(dev);
+
+	return sprintf(buf, "%zu\n", module->num_interfaces);
+}
+static DEVICE_ATTR_RO(num_interfaces);
+
+static struct attribute *module_attrs[] = {
+	&dev_attr_eject.attr,
+	&dev_attr_module_id.attr,
+	&dev_attr_num_interfaces.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(module);
+
+static void gb_module_release(struct device *dev)
+{
+	struct gb_module *module = to_gb_module(dev);
+
+	trace_gb_module_release(module);
+
+	kfree(module);
+}
+
+struct device_type greybus_module_type = {
+	.name		= "greybus_module",
+	.release	= gb_module_release,
+};
+
+struct gb_module *gb_module_create(struct gb_host_device *hd, u8 module_id,
+					size_t num_interfaces)
+{
+	struct gb_interface *intf;
+	struct gb_module *module;
+	int i;
+
+	module = kzalloc(sizeof(*module) + num_interfaces * sizeof(intf),
+				GFP_KERNEL);
+	if (!module)
+		return NULL;
+
+	module->hd = hd;
+	module->module_id = module_id;
+	module->num_interfaces = num_interfaces;
+
+	module->dev.parent = &hd->dev;
+	module->dev.bus = &greybus_bus_type;
+	module->dev.type = &greybus_module_type;
+	module->dev.groups = module_groups;
+	module->dev.dma_mask = hd->dev.dma_mask;
+	device_initialize(&module->dev);
+	dev_set_name(&module->dev, "%d-%u", hd->bus_id, module_id);
+
+	trace_gb_module_create(module);
+
+	for (i = 0; i < num_interfaces; ++i) {
+		intf = gb_interface_create(module, module_id + i);
+		if (!intf) {
+			dev_err(&module->dev, "failed to create interface %u\n",
+					module_id + i);
+			goto err_put_interfaces;
+		}
+		module->interfaces[i] = intf;
+	}
+
+	return module;
+
+err_put_interfaces:
+	for (--i; i > 0; --i)
+		gb_interface_put(module->interfaces[i]);
+
+	put_device(&module->dev);
+
+	return NULL;
+}
+
+/*
+ * Register and enable an interface after first attempting to activate it.
+ */
+static void gb_module_register_interface(struct gb_interface *intf)
+{
+	struct gb_module *module = intf->module;
+	u8 intf_id = intf->interface_id;
+	int ret;
+
+	mutex_lock(&intf->mutex);
+
+	ret = gb_interface_activate(intf);
+	if (ret) {
+		if (intf->type != GB_INTERFACE_TYPE_DUMMY) {
+			dev_err(&module->dev,
+					"failed to activate interface %u: %d\n",
+					intf_id, ret);
+		}
+
+		gb_interface_add(intf);
+		goto err_unlock;
+	}
+
+	ret = gb_interface_add(intf);
+	if (ret)
+		goto err_interface_deactivate;
+
+	ret = gb_interface_enable(intf);
+	if (ret) {
+		dev_err(&module->dev, "failed to enable interface %u: %d\n",
+				intf_id, ret);
+		goto err_interface_deactivate;
+	}
+
+	mutex_unlock(&intf->mutex);
+
+	return;
+
+err_interface_deactivate:
+	gb_interface_deactivate(intf);
+err_unlock:
+	mutex_unlock(&intf->mutex);
+}
+
+static void gb_module_deregister_interface(struct gb_interface *intf)
+{
+	/* Mark as disconnected to prevent I/O during disable. */
+	if (intf->module->disconnected)
+		intf->disconnected = true;
+
+	mutex_lock(&intf->mutex);
+	intf->removed = true;
+	gb_interface_disable(intf);
+	gb_interface_deactivate(intf);
+	mutex_unlock(&intf->mutex);
+
+	gb_interface_del(intf);
+}
+
+/* Register a module and its interfaces. */
+int gb_module_add(struct gb_module *module)
+{
+	size_t i;
+	int ret;
+
+	ret = device_add(&module->dev);
+	if (ret) {
+		dev_err(&module->dev, "failed to register module: %d\n", ret);
+		return ret;
+	}
+
+	trace_gb_module_add(module);
+
+	for (i = 0; i < module->num_interfaces; ++i)
+		gb_module_register_interface(module->interfaces[i]);
+
+	return 0;
+}
+
+/* Deregister a module and its interfaces. */
+void gb_module_del(struct gb_module *module)
+{
+	size_t i;
+
+	for (i = 0; i < module->num_interfaces; ++i)
+		gb_module_deregister_interface(module->interfaces[i]);
+
+	trace_gb_module_del(module);
+
+	device_del(&module->dev);
+}
+
+void gb_module_put(struct gb_module *module)
+{
+	size_t i;
+
+	for (i = 0; i < module->num_interfaces; ++i)
+		gb_interface_put(module->interfaces[i]);
+
+	put_device(&module->dev);
+}
diff --git a/drivers/staging/greybus/module.h b/drivers/staging/greybus/module.h
new file mode 100644
index 000000000000..88a97ce04243
--- /dev/null
+++ b/drivers/staging/greybus/module.h
@@ -0,0 +1,34 @@
+/*
+ * Greybus Module code
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __MODULE_H
+#define __MODULE_H
+
+struct gb_module {
+	struct device dev;
+	struct gb_host_device *hd;
+
+	struct list_head hd_node;
+
+	u8 module_id;
+	size_t num_interfaces;
+
+	bool disconnected;
+
+	struct gb_interface *interfaces[0];
+};
+#define to_gb_module(d) container_of(d, struct gb_module, dev)
+
+struct gb_module *gb_module_create(struct gb_host_device *hd, u8 module_id,
+				   size_t num_interfaces);
+int gb_module_add(struct gb_module *module);
+void gb_module_del(struct gb_module *module);
+void gb_module_put(struct gb_module *module);
+
+#endif /* __MODULE_H */
diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
new file mode 100644
index 000000000000..0123109a1070
--- /dev/null
+++ b/drivers/staging/greybus/operation.c
@@ -0,0 +1,1239 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+
+#include "greybus.h"
+#include "greybus_trace.h"
+
+static struct kmem_cache *gb_operation_cache;
+static struct kmem_cache *gb_message_cache;
+
+/* Workqueue to handle Greybus operation completions. */
+static struct workqueue_struct *gb_operation_completion_wq;
+
+/* Wait queue for synchronous cancellations. */
+static DECLARE_WAIT_QUEUE_HEAD(gb_operation_cancellation_queue);
+
+/*
+ * Protects updates to operation->errno.
+ */
+static DEFINE_SPINLOCK(gb_operations_lock);
+
+static int gb_operation_response_send(struct gb_operation *operation,
+					int errno);
+
+/*
+ * Increment operation active count and add to connection list unless the
+ * connection is going away.
+ *
+ * Caller holds operation reference.
+ */
+static int gb_operation_get_active(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	unsigned long flags;
+
+	spin_lock_irqsave(&connection->lock, flags);
+	switch (connection->state) {
+	case GB_CONNECTION_STATE_ENABLED:
+		break;
+	case GB_CONNECTION_STATE_ENABLED_TX:
+		if (gb_operation_is_incoming(operation))
+			goto err_unlock;
+		break;
+	case GB_CONNECTION_STATE_DISCONNECTING:
+		if (!gb_operation_is_core(operation))
+			goto err_unlock;
+		break;
+	default:
+		goto err_unlock;
+	}
+
+	if (operation->active++ == 0)
+		list_add_tail(&operation->links, &connection->operations);
+
+	trace_gb_operation_get_active(operation);
+
+	spin_unlock_irqrestore(&connection->lock, flags);
+
+	return 0;
+
+err_unlock:
+	spin_unlock_irqrestore(&connection->lock, flags);
+
+	return -ENOTCONN;
+}
+
+/* Caller holds operation reference. */
+static void gb_operation_put_active(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	unsigned long flags;
+
+	spin_lock_irqsave(&connection->lock, flags);
+
+	trace_gb_operation_put_active(operation);
+
+	if (--operation->active == 0) {
+		list_del(&operation->links);
+		if (atomic_read(&operation->waiters))
+			wake_up(&gb_operation_cancellation_queue);
+	}
+	spin_unlock_irqrestore(&connection->lock, flags);
+}
+
+static bool gb_operation_is_active(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	unsigned long flags;
+	bool ret;
+
+	spin_lock_irqsave(&connection->lock, flags);
+	ret = operation->active;
+	spin_unlock_irqrestore(&connection->lock, flags);
+
+	return ret;
+}
+
+/*
+ * Set an operation's result.
+ *
+ * Initially an outgoing operation's errno value is -EBADR.
+ * If no error occurs before sending the request message the only
+ * valid value operation->errno can be set to is -EINPROGRESS,
+ * indicating the request has been (or rather is about to be) sent.
+ * At that point nobody should be looking at the result until the
+ * response arrives.
+ *
+ * The first time the result gets set after the request has been
+ * sent, that result "sticks."  That is, if two concurrent threads
+ * race to set the result, the first one wins.  The return value
+ * tells the caller whether its result was recorded; if not the
+ * caller has nothing more to do.
+ *
+ * The result value -EILSEQ is reserved to signal an implementation
+ * error; if it's ever observed, the code performing the request has
+ * done something fundamentally wrong.  It is an error to try to set
+ * the result to -EBADR, and attempts to do so result in a warning,
+ * and -EILSEQ is used instead.  Similarly, the only valid result
+ * value to set for an operation in initial state is -EINPROGRESS.
+ * Attempts to do otherwise will also record a (successful) -EILSEQ
+ * operation result.
+ */
+static bool gb_operation_result_set(struct gb_operation *operation, int result)
+{
+	unsigned long flags;
+	int prev;
+
+	if (result == -EINPROGRESS) {
+		/*
+		 * -EINPROGRESS is used to indicate the request is
+		 * in flight.  It should be the first result value
+		 * set after the initial -EBADR.  Issue a warning
+		 * and record an implementation error if it's
+		 * set at any other time.
+		 */
+		spin_lock_irqsave(&gb_operations_lock, flags);
+		prev = operation->errno;
+		if (prev == -EBADR)
+			operation->errno = result;
+		else
+			operation->errno = -EILSEQ;
+		spin_unlock_irqrestore(&gb_operations_lock, flags);
+		WARN_ON(prev != -EBADR);
+
+		return true;
+	}
+
+	/*
+	 * The first result value set after a request has been sent
+	 * will be the final result of the operation.  Subsequent
+	 * attempts to set the result are ignored.
+	 *
+	 * Note that -EBADR is a reserved "initial state" result
+	 * value.  Attempts to set this value result in a warning,
+	 * and the result code is set to -EILSEQ instead.
+	 */
+	if (WARN_ON(result == -EBADR))
+		result = -EILSEQ; /* Nobody should be setting -EBADR */
+
+	spin_lock_irqsave(&gb_operations_lock, flags);
+	prev = operation->errno;
+	if (prev == -EINPROGRESS)
+		operation->errno = result;	/* First and final result */
+	spin_unlock_irqrestore(&gb_operations_lock, flags);
+
+	return prev == -EINPROGRESS;
+}
+
+int gb_operation_result(struct gb_operation *operation)
+{
+	int result = operation->errno;
+
+	WARN_ON(result == -EBADR);
+	WARN_ON(result == -EINPROGRESS);
+
+	return result;
+}
+EXPORT_SYMBOL_GPL(gb_operation_result);
+
+/*
+ * Looks up an outgoing operation on a connection and returns a refcounted
+ * pointer if found, or NULL otherwise.
+ */
+static struct gb_operation *
+gb_operation_find_outgoing(struct gb_connection *connection, u16 operation_id)
+{
+	struct gb_operation *operation;
+	unsigned long flags;
+	bool found = false;
+
+	spin_lock_irqsave(&connection->lock, flags);
+	list_for_each_entry(operation, &connection->operations, links)
+		if (operation->id == operation_id &&
+				!gb_operation_is_incoming(operation)) {
+			gb_operation_get(operation);
+			found = true;
+			break;
+		}
+	spin_unlock_irqrestore(&connection->lock, flags);
+
+	return found ? operation : NULL;
+}
+
+static int gb_message_send(struct gb_message *message, gfp_t gfp)
+{
+	struct gb_connection *connection = message->operation->connection;
+
+	trace_gb_message_send(message);
+	return connection->hd->driver->message_send(connection->hd,
+					connection->hd_cport_id,
+					message,
+					gfp);
+}
+
+/*
+ * Cancel a message we have passed to the host device layer to be sent.
+ */
+static void gb_message_cancel(struct gb_message *message)
+{
+	struct gb_host_device *hd = message->operation->connection->hd;
+
+	hd->driver->message_cancel(message);
+}
+
+static void gb_operation_request_handle(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	int status;
+	int ret;
+
+	if (connection->handler) {
+		status = connection->handler(operation);
+	} else {
+		dev_err(&connection->hd->dev,
+			"%s: unexpected incoming request of type 0x%02x\n",
+			connection->name, operation->type);
+
+		status = -EPROTONOSUPPORT;
+	}
+
+	ret = gb_operation_response_send(operation, status);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to send response %d for type 0x%02x: %d\n",
+			connection->name, status, operation->type, ret);
+		return;
+	}
+}
+
+/*
+ * Process operation work.
+ *
+ * For incoming requests, call the protocol request handler. The operation
+ * result should be -EINPROGRESS at this point.
+ *
+ * For outgoing requests, the operation result value should have
+ * been set before queueing this.  The operation callback function
+ * allows the original requester to know the request has completed
+ * and its result is available.
+ */
+static void gb_operation_work(struct work_struct *work)
+{
+	struct gb_operation *operation;
+
+	operation = container_of(work, struct gb_operation, work);
+
+	if (gb_operation_is_incoming(operation))
+		gb_operation_request_handle(operation);
+	else
+		operation->callback(operation);
+
+	gb_operation_put_active(operation);
+	gb_operation_put(operation);
+}
+
+static void gb_operation_message_init(struct gb_host_device *hd,
+				struct gb_message *message, u16 operation_id,
+				size_t payload_size, u8 type)
+{
+	struct gb_operation_msg_hdr *header;
+
+	header = message->buffer;
+
+	message->header = header;
+	message->payload = payload_size ? header + 1 : NULL;
+	message->payload_size = payload_size;
+
+	/*
+	 * The type supplied for incoming message buffers will be
+	 * GB_REQUEST_TYPE_INVALID. Such buffers will be overwritten by
+	 * arriving data so there's no need to initialize the message header.
+	 */
+	if (type != GB_REQUEST_TYPE_INVALID) {
+		u16 message_size = (u16)(sizeof(*header) + payload_size);
+
+		/*
+		 * For a request, the operation id gets filled in
+		 * when the message is sent.  For a response, it
+		 * will be copied from the request by the caller.
+		 *
+		 * The result field in a request message must be
+		 * zero.  It will be set just prior to sending for
+		 * a response.
+		 */
+		header->size = cpu_to_le16(message_size);
+		header->operation_id = 0;
+		header->type = type;
+		header->result = 0;
+	}
+}
+
+/*
+ * Allocate a message to be used for an operation request or response.
+ * Both types of message contain a common header.  The request message
+ * for an outgoing operation is outbound, as is the response message
+ * for an incoming operation.  The message header for an outbound
+ * message is partially initialized here.
+ *
+ * The headers for inbound messages don't need to be initialized;
+ * they'll be filled in by arriving data.
+ *
+ * Our message buffers have the following layout:
+ *	message header  \_ these combined are
+ *	message payload /  the message size
+ */
+static struct gb_message *
+gb_operation_message_alloc(struct gb_host_device *hd, u8 type,
+				size_t payload_size, gfp_t gfp_flags)
+{
+	struct gb_message *message;
+	struct gb_operation_msg_hdr *header;
+	size_t message_size = payload_size + sizeof(*header);
+
+	if (message_size > hd->buffer_size_max) {
+		dev_warn(&hd->dev, "requested message size too big (%zu > %zu)\n",
+				message_size, hd->buffer_size_max);
+		return NULL;
+	}
+
+	/* Allocate the message structure and buffer. */
+	message = kmem_cache_zalloc(gb_message_cache, gfp_flags);
+	if (!message)
+		return NULL;
+
+	message->buffer = kzalloc(message_size, gfp_flags);
+	if (!message->buffer)
+		goto err_free_message;
+
+	/* Initialize the message.  Operation id is filled in later. */
+	gb_operation_message_init(hd, message, 0, payload_size, type);
+
+	return message;
+
+err_free_message:
+	kmem_cache_free(gb_message_cache, message);
+
+	return NULL;
+}
+
+static void gb_operation_message_free(struct gb_message *message)
+{
+	kfree(message->buffer);
+	kmem_cache_free(gb_message_cache, message);
+}
+
+/*
+ * Map an enum gb_operation_status value (which is represented in a
+ * message as a single byte) to an appropriate Linux negative errno.
+ */
+static int gb_operation_status_map(u8 status)
+{
+	switch (status) {
+	case GB_OP_SUCCESS:
+		return 0;
+	case GB_OP_INTERRUPTED:
+		return -EINTR;
+	case GB_OP_TIMEOUT:
+		return -ETIMEDOUT;
+	case GB_OP_NO_MEMORY:
+		return -ENOMEM;
+	case GB_OP_PROTOCOL_BAD:
+		return -EPROTONOSUPPORT;
+	case GB_OP_OVERFLOW:
+		return -EMSGSIZE;
+	case GB_OP_INVALID:
+		return -EINVAL;
+	case GB_OP_RETRY:
+		return -EAGAIN;
+	case GB_OP_NONEXISTENT:
+		return -ENODEV;
+	case GB_OP_MALFUNCTION:
+		return -EILSEQ;
+	case GB_OP_UNKNOWN_ERROR:
+	default:
+		return -EIO;
+	}
+}
+
+/*
+ * Map a Linux errno value (from operation->errno) into the value
+ * that should represent it in a response message status sent
+ * over the wire.  Returns an enum gb_operation_status value (which
+ * is represented in a message as a single byte).
+ */
+static u8 gb_operation_errno_map(int errno)
+{
+	switch (errno) {
+	case 0:
+		return GB_OP_SUCCESS;
+	case -EINTR:
+		return GB_OP_INTERRUPTED;
+	case -ETIMEDOUT:
+		return GB_OP_TIMEOUT;
+	case -ENOMEM:
+		return GB_OP_NO_MEMORY;
+	case -EPROTONOSUPPORT:
+		return GB_OP_PROTOCOL_BAD;
+	case -EMSGSIZE:
+		return GB_OP_OVERFLOW;	/* Could be underflow too */
+	case -EINVAL:
+		return GB_OP_INVALID;
+	case -EAGAIN:
+		return GB_OP_RETRY;
+	case -EILSEQ:
+		return GB_OP_MALFUNCTION;
+	case -ENODEV:
+		return GB_OP_NONEXISTENT;
+	case -EIO:
+	default:
+		return GB_OP_UNKNOWN_ERROR;
+	}
+}
+
+bool gb_operation_response_alloc(struct gb_operation *operation,
+					size_t response_size, gfp_t gfp)
+{
+	struct gb_host_device *hd = operation->connection->hd;
+	struct gb_operation_msg_hdr *request_header;
+	struct gb_message *response;
+	u8 type;
+
+	type = operation->type | GB_MESSAGE_TYPE_RESPONSE;
+	response = gb_operation_message_alloc(hd, type, response_size, gfp);
+	if (!response)
+		return false;
+	response->operation = operation;
+
+	/*
+	 * Size and type get initialized when the message is
+	 * allocated.  The errno will be set before sending.  All
+	 * that's left is the operation id, which we copy from the
+	 * request message header (as-is, in little-endian order).
+	 */
+	request_header = operation->request->header;
+	response->header->operation_id = request_header->operation_id;
+	operation->response = response;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(gb_operation_response_alloc);
+
+/*
+ * Create a Greybus operation to be sent over the given connection.
+ * The request buffer will be big enough for a payload of the given
+ * size.
+ *
+ * For outgoing requests, the request message's header will be
+ * initialized with the type of the request and the message size.
+ * Outgoing operations must also specify the response buffer size,
+ * which must be sufficient to hold all expected response data.  The
+ * response message header will eventually be overwritten, so there's
+ * no need to initialize it here.
+ *
+ * Request messages for incoming operations can arrive in interrupt
+ * context, so they must be allocated with GFP_ATOMIC.  In this case
+ * the request buffer will be immediately overwritten, so there is
+ * no need to initialize the message header.  Responsibility for
+ * allocating a response buffer lies with the incoming request
+ * handler for a protocol.  So we don't allocate that here.
+ *
+ * Returns a pointer to the new operation or a null pointer if an
+ * error occurs.
+ */
+static struct gb_operation *
+gb_operation_create_common(struct gb_connection *connection, u8 type,
+				size_t request_size, size_t response_size,
+				unsigned long op_flags, gfp_t gfp_flags)
+{
+	struct gb_host_device *hd = connection->hd;
+	struct gb_operation *operation;
+
+	operation = kmem_cache_zalloc(gb_operation_cache, gfp_flags);
+	if (!operation)
+		return NULL;
+	operation->connection = connection;
+
+	operation->request = gb_operation_message_alloc(hd, type, request_size,
+							gfp_flags);
+	if (!operation->request)
+		goto err_cache;
+	operation->request->operation = operation;
+
+	/* Allocate the response buffer for outgoing operations */
+	if (!(op_flags & GB_OPERATION_FLAG_INCOMING)) {
+		if (!gb_operation_response_alloc(operation, response_size,
+						 gfp_flags)) {
+			goto err_request;
+		}
+	}
+
+	operation->flags = op_flags;
+	operation->type = type;
+	operation->errno = -EBADR;  /* Initial value--means "never set" */
+
+	INIT_WORK(&operation->work, gb_operation_work);
+	init_completion(&operation->completion);
+	kref_init(&operation->kref);
+	atomic_set(&operation->waiters, 0);
+
+	return operation;
+
+err_request:
+	gb_operation_message_free(operation->request);
+err_cache:
+	kmem_cache_free(gb_operation_cache, operation);
+
+	return NULL;
+}
+
+/*
+ * Create a new operation associated with the given connection.  The
+ * request and response sizes provided are the number of bytes
+ * required to hold the request/response payload only.  Both of
+ * these are allowed to be 0.  Note that 0x00 is reserved as an
+ * invalid operation type for all protocols, and this is enforced
+ * here.
+ */
+struct gb_operation *
+gb_operation_create_flags(struct gb_connection *connection,
+				u8 type, size_t request_size,
+				size_t response_size, unsigned long flags,
+				gfp_t gfp)
+{
+	struct gb_operation *operation;
+
+	if (WARN_ON_ONCE(type == GB_REQUEST_TYPE_INVALID))
+		return NULL;
+	if (WARN_ON_ONCE(type & GB_MESSAGE_TYPE_RESPONSE))
+		type &= ~GB_MESSAGE_TYPE_RESPONSE;
+
+	if (WARN_ON_ONCE(flags & ~GB_OPERATION_FLAG_USER_MASK))
+		flags &= GB_OPERATION_FLAG_USER_MASK;
+
+	operation = gb_operation_create_common(connection, type,
+						request_size, response_size,
+						flags, gfp);
+	if (operation)
+		trace_gb_operation_create(operation);
+
+	return operation;
+}
+EXPORT_SYMBOL_GPL(gb_operation_create_flags);
+
+struct gb_operation *
+gb_operation_create_core(struct gb_connection *connection,
+				u8 type, size_t request_size,
+				size_t response_size, unsigned long flags,
+				gfp_t gfp)
+{
+	struct gb_operation *operation;
+
+	flags |= GB_OPERATION_FLAG_CORE;
+
+	operation = gb_operation_create_common(connection, type,
+						request_size, response_size,
+						flags, gfp);
+	if (operation)
+		trace_gb_operation_create_core(operation);
+
+	return operation;
+}
+/* Do not export this function. */
+
+size_t gb_operation_get_payload_size_max(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+
+	return hd->buffer_size_max - sizeof(struct gb_operation_msg_hdr);
+}
+EXPORT_SYMBOL_GPL(gb_operation_get_payload_size_max);
+
+static struct gb_operation *
+gb_operation_create_incoming(struct gb_connection *connection, u16 id,
+				u8 type, void *data, size_t size)
+{
+	struct gb_operation *operation;
+	size_t request_size;
+	unsigned long flags = GB_OPERATION_FLAG_INCOMING;
+
+	/* Caller has made sure we at least have a message header. */
+	request_size = size - sizeof(struct gb_operation_msg_hdr);
+
+	if (!id)
+		flags |= GB_OPERATION_FLAG_UNIDIRECTIONAL;
+
+	operation = gb_operation_create_common(connection, type,
+						request_size,
+						GB_REQUEST_TYPE_INVALID,
+						flags, GFP_ATOMIC);
+	if (!operation)
+		return NULL;
+
+	operation->id = id;
+	memcpy(operation->request->header, data, size);
+	trace_gb_operation_create_incoming(operation);
+
+	return operation;
+}
+
+/*
+ * Get an additional reference on an operation.
+ */
+void gb_operation_get(struct gb_operation *operation)
+{
+	kref_get(&operation->kref);
+}
+EXPORT_SYMBOL_GPL(gb_operation_get);
+
+/*
+ * Destroy a previously created operation.
+ */
+static void _gb_operation_destroy(struct kref *kref)
+{
+	struct gb_operation *operation;
+
+	operation = container_of(kref, struct gb_operation, kref);
+
+	trace_gb_operation_destroy(operation);
+
+	if (operation->response)
+		gb_operation_message_free(operation->response);
+	gb_operation_message_free(operation->request);
+
+	kmem_cache_free(gb_operation_cache, operation);
+}
+
+/*
+ * Drop a reference on an operation, and destroy it when the last
+ * one is gone.
+ */
+void gb_operation_put(struct gb_operation *operation)
+{
+	if (WARN_ON(!operation))
+		return;
+
+	kref_put(&operation->kref, _gb_operation_destroy);
+}
+EXPORT_SYMBOL_GPL(gb_operation_put);
+
+/* Tell the requester we're done */
+static void gb_operation_sync_callback(struct gb_operation *operation)
+{
+	complete(&operation->completion);
+}
+
+/**
+ * gb_operation_request_send() - send an operation request message
+ * @operation:	the operation to initiate
+ * @callback:	the operation completion callback
+ * @gfp:	the memory flags to use for any allocations
+ *
+ * The caller has filled in any payload so the request message is ready to go.
+ * The callback function supplied will be called when the response message has
+ * arrived, a unidirectional request has been sent, or the operation is
+ * cancelled, indicating that the operation is complete. The callback function
+ * can fetch the result of the operation using gb_operation_result() if
+ * desired.
+ *
+ * Return: 0 if the request was successfully queued in the host-driver queues,
+ * or a negative errno.
+ */
+int gb_operation_request_send(struct gb_operation *operation,
+				gb_operation_callback callback,
+				gfp_t gfp)
+{
+	struct gb_connection *connection = operation->connection;
+	struct gb_operation_msg_hdr *header;
+	unsigned int cycle;
+	int ret;
+
+	if (gb_connection_is_offloaded(connection))
+		return -EBUSY;
+
+	if (!callback)
+		return -EINVAL;
+
+	/*
+	 * Record the callback function, which is executed in
+	 * non-atomic (workqueue) context when the final result
+	 * of an operation has been set.
+	 */
+	operation->callback = callback;
+
+	/*
+	 * Assign the operation's id, and store it in the request header.
+	 * Zero is a reserved operation id for unidirectional operations.
+	 */
+	if (gb_operation_is_unidirectional(operation)) {
+		operation->id = 0;
+	} else {
+		cycle = (unsigned int)atomic_inc_return(&connection->op_cycle);
+		operation->id = (u16)(cycle % U16_MAX + 1);
+	}
+
+	header = operation->request->header;
+	header->operation_id = cpu_to_le16(operation->id);
+
+	gb_operation_result_set(operation, -EINPROGRESS);
+
+	/*
+	 * Get an extra reference on the operation. It'll be dropped when the
+	 * operation completes.
+	 */
+	gb_operation_get(operation);
+	ret = gb_operation_get_active(operation);
+	if (ret)
+		goto err_put;
+
+	ret = gb_message_send(operation->request, gfp);
+	if (ret)
+		goto err_put_active;
+
+	return 0;
+
+err_put_active:
+	gb_operation_put_active(operation);
+err_put:
+	gb_operation_put(operation);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_operation_request_send);
+
+/*
+ * Send a synchronous operation.  This function is expected to
+ * block, returning only when the response has arrived, (or when an
+ * error is detected.  The return value is the result of the
+ * operation.
+ */
+int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
+						unsigned int timeout)
+{
+	int ret;
+	unsigned long timeout_jiffies;
+
+	ret = gb_operation_request_send(operation, gb_operation_sync_callback,
+					GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	if (timeout)
+		timeout_jiffies = msecs_to_jiffies(timeout);
+	else
+		timeout_jiffies = MAX_SCHEDULE_TIMEOUT;
+
+	ret = wait_for_completion_interruptible_timeout(&operation->completion,
+							timeout_jiffies);
+	if (ret < 0) {
+		/* Cancel the operation if interrupted */
+		gb_operation_cancel(operation, -ECANCELED);
+	} else if (ret == 0) {
+		/* Cancel the operation if op timed out */
+		gb_operation_cancel(operation, -ETIMEDOUT);
+	}
+
+	return gb_operation_result(operation);
+}
+EXPORT_SYMBOL_GPL(gb_operation_request_send_sync_timeout);
+
+/*
+ * Send a response for an incoming operation request.  A non-zero
+ * errno indicates a failed operation.
+ *
+ * If there is any response payload, the incoming request handler is
+ * responsible for allocating the response message.  Otherwise the
+ * it can simply supply the result errno; this function will
+ * allocate the response message if necessary.
+ */
+static int gb_operation_response_send(struct gb_operation *operation,
+					int errno)
+{
+	struct gb_connection *connection = operation->connection;
+	int ret;
+
+	if (!operation->response &&
+			!gb_operation_is_unidirectional(operation)) {
+		if (!gb_operation_response_alloc(operation, 0, GFP_KERNEL))
+			return -ENOMEM;
+	}
+
+	/* Record the result */
+	if (!gb_operation_result_set(operation, errno)) {
+		dev_err(&connection->hd->dev, "request result already set\n");
+		return -EIO;	/* Shouldn't happen */
+	}
+
+	/* Sender of request does not care about response. */
+	if (gb_operation_is_unidirectional(operation))
+		return 0;
+
+	/* Reference will be dropped when message has been sent. */
+	gb_operation_get(operation);
+	ret = gb_operation_get_active(operation);
+	if (ret)
+		goto err_put;
+
+	/* Fill in the response header and send it */
+	operation->response->header->result = gb_operation_errno_map(errno);
+
+	ret = gb_message_send(operation->response, GFP_KERNEL);
+	if (ret)
+		goto err_put_active;
+
+	return 0;
+
+err_put_active:
+	gb_operation_put_active(operation);
+err_put:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+/*
+ * This function is called when a message send request has completed.
+ */
+void greybus_message_sent(struct gb_host_device *hd,
+					struct gb_message *message, int status)
+{
+	struct gb_operation *operation = message->operation;
+	struct gb_connection *connection = operation->connection;
+
+	/*
+	 * If the message was a response, we just need to drop our
+	 * reference to the operation.  If an error occurred, report
+	 * it.
+	 *
+	 * For requests, if there's no error and the operation in not
+	 * unidirectional, there's nothing more to do until the response
+	 * arrives. If an error occurred attempting to send it, or if the
+	 * operation is unidrectional, record the result of the operation and
+	 * schedule its completion.
+	 */
+	if (message == operation->response) {
+		if (status) {
+			dev_err(&connection->hd->dev,
+				"%s: error sending response 0x%02x: %d\n",
+				connection->name, operation->type, status);
+		}
+
+		gb_operation_put_active(operation);
+		gb_operation_put(operation);
+	} else if (status || gb_operation_is_unidirectional(operation)) {
+		if (gb_operation_result_set(operation, status)) {
+			queue_work(gb_operation_completion_wq,
+					&operation->work);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(greybus_message_sent);
+
+/*
+ * We've received data on a connection, and it doesn't look like a
+ * response, so we assume it's a request.
+ *
+ * This is called in interrupt context, so just copy the incoming
+ * data into the request buffer and handle the rest via workqueue.
+ */
+static void gb_connection_recv_request(struct gb_connection *connection,
+				const struct gb_operation_msg_hdr *header,
+				void *data, size_t size)
+{
+	struct gb_operation *operation;
+	u16 operation_id;
+	u8 type;
+	int ret;
+
+	operation_id = le16_to_cpu(header->operation_id);
+	type = header->type;
+
+	operation = gb_operation_create_incoming(connection, operation_id,
+						type, data, size);
+	if (!operation) {
+		dev_err(&connection->hd->dev,
+			"%s: can't create incoming operation\n",
+			connection->name);
+		return;
+	}
+
+	ret = gb_operation_get_active(operation);
+	if (ret) {
+		gb_operation_put(operation);
+		return;
+	}
+	trace_gb_message_recv_request(operation->request);
+
+	/*
+	 * The initial reference to the operation will be dropped when the
+	 * request handler returns.
+	 */
+	if (gb_operation_result_set(operation, -EINPROGRESS))
+		queue_work(connection->wq, &operation->work);
+}
+
+/*
+ * We've received data that appears to be an operation response
+ * message.  Look up the operation, and record that we've received
+ * its response.
+ *
+ * This is called in interrupt context, so just copy the incoming
+ * data into the response buffer and handle the rest via workqueue.
+ */
+static void gb_connection_recv_response(struct gb_connection *connection,
+				const struct gb_operation_msg_hdr *header,
+				void *data, size_t size)
+{
+	struct gb_operation *operation;
+	struct gb_message *message;
+	size_t message_size;
+	u16 operation_id;
+	int errno;
+
+	operation_id = le16_to_cpu(header->operation_id);
+
+	if (!operation_id) {
+		dev_err_ratelimited(&connection->hd->dev,
+				"%s: invalid response id 0 received\n",
+				connection->name);
+		return;
+	}
+
+	operation = gb_operation_find_outgoing(connection, operation_id);
+	if (!operation) {
+		dev_err_ratelimited(&connection->hd->dev,
+				"%s: unexpected response id 0x%04x received\n",
+				connection->name, operation_id);
+		return;
+	}
+
+	errno = gb_operation_status_map(header->result);
+	message = operation->response;
+	message_size = sizeof(*header) + message->payload_size;
+	if (!errno && size > message_size) {
+		dev_err_ratelimited(&connection->hd->dev,
+				"%s: malformed response 0x%02x received (%zu > %zu)\n",
+				connection->name, header->type,
+				size, message_size);
+		errno = -EMSGSIZE;
+	} else if (!errno && size < message_size) {
+		if (gb_operation_short_response_allowed(operation)) {
+			message->payload_size = size - sizeof(*header);
+		} else {
+			dev_err_ratelimited(&connection->hd->dev,
+					"%s: short response 0x%02x received (%zu < %zu)\n",
+					connection->name, header->type,
+					size, message_size);
+			errno = -EMSGSIZE;
+		}
+	}
+
+	/* We must ignore the payload if a bad status is returned */
+	if (errno)
+		size = sizeof(*header);
+
+	/* The rest will be handled in work queue context */
+	if (gb_operation_result_set(operation, errno)) {
+		memcpy(message->buffer, data, size);
+
+		trace_gb_message_recv_response(message);
+
+		queue_work(gb_operation_completion_wq, &operation->work);
+	}
+
+	gb_operation_put(operation);
+}
+
+/*
+ * Handle data arriving on a connection.  As soon as we return the
+ * supplied data buffer will be reused (so unless we do something
+ * with, it's effectively dropped).
+ */
+void gb_connection_recv(struct gb_connection *connection,
+				void *data, size_t size)
+{
+	struct gb_operation_msg_hdr header;
+	struct device *dev = &connection->hd->dev;
+	size_t msg_size;
+
+	if (connection->state == GB_CONNECTION_STATE_DISABLED ||
+			gb_connection_is_offloaded(connection)) {
+		dev_warn_ratelimited(dev, "%s: dropping %zu received bytes\n",
+				connection->name, size);
+		return;
+	}
+
+	if (size < sizeof(header)) {
+		dev_err_ratelimited(dev, "%s: short message received\n",
+				connection->name);
+		return;
+	}
+
+	/* Use memcpy as data may be unaligned */
+	memcpy(&header, data, sizeof(header));
+	msg_size = le16_to_cpu(header.size);
+	if (size < msg_size) {
+		dev_err_ratelimited(dev,
+				"%s: incomplete message 0x%04x of type 0x%02x received (%zu < %zu)\n",
+				connection->name,
+				le16_to_cpu(header.operation_id),
+				header.type, size, msg_size);
+		return;		/* XXX Should still complete operation */
+	}
+
+	if (header.type & GB_MESSAGE_TYPE_RESPONSE) {
+		gb_connection_recv_response(connection,	&header, data,
+						msg_size);
+	} else {
+		gb_connection_recv_request(connection, &header, data,
+						msg_size);
+	}
+}
+
+/*
+ * Cancel an outgoing operation synchronously, and record the given error to
+ * indicate why.
+ */
+void gb_operation_cancel(struct gb_operation *operation, int errno)
+{
+	if (WARN_ON(gb_operation_is_incoming(operation)))
+		return;
+
+	if (gb_operation_result_set(operation, errno)) {
+		gb_message_cancel(operation->request);
+		queue_work(gb_operation_completion_wq, &operation->work);
+	}
+	trace_gb_message_cancel_outgoing(operation->request);
+
+	atomic_inc(&operation->waiters);
+	wait_event(gb_operation_cancellation_queue,
+			!gb_operation_is_active(operation));
+	atomic_dec(&operation->waiters);
+}
+EXPORT_SYMBOL_GPL(gb_operation_cancel);
+
+/*
+ * Cancel an incoming operation synchronously. Called during connection tear
+ * down.
+ */
+void gb_operation_cancel_incoming(struct gb_operation *operation, int errno)
+{
+	if (WARN_ON(!gb_operation_is_incoming(operation)))
+		return;
+
+	if (!gb_operation_is_unidirectional(operation)) {
+		/*
+		 * Make sure the request handler has submitted the response
+		 * before cancelling it.
+		 */
+		flush_work(&operation->work);
+		if (!gb_operation_result_set(operation, errno))
+			gb_message_cancel(operation->response);
+	}
+	trace_gb_message_cancel_incoming(operation->response);
+
+	atomic_inc(&operation->waiters);
+	wait_event(gb_operation_cancellation_queue,
+			!gb_operation_is_active(operation));
+	atomic_dec(&operation->waiters);
+}
+
+/**
+ * gb_operation_sync_timeout() - implement a "simple" synchronous operation
+ * @connection: the Greybus connection to send this to
+ * @type: the type of operation to send
+ * @request: pointer to a memory buffer to copy the request from
+ * @request_size: size of @request
+ * @response: pointer to a memory buffer to copy the response to
+ * @response_size: the size of @response.
+ * @timeout: operation timeout in milliseconds
+ *
+ * This function implements a simple synchronous Greybus operation.  It sends
+ * the provided operation request and waits (sleeps) until the corresponding
+ * operation response message has been successfully received, or an error
+ * occurs.  @request and @response are buffers to hold the request and response
+ * data respectively, and if they are not NULL, their size must be specified in
+ * @request_size and @response_size.
+ *
+ * If a response payload is to come back, and @response is not NULL,
+ * @response_size number of bytes will be copied into @response if the operation
+ * is successful.
+ *
+ * If there is an error, the response buffer is left alone.
+ */
+int gb_operation_sync_timeout(struct gb_connection *connection, int type,
+				void *request, int request_size,
+				void *response, int response_size,
+				unsigned int timeout)
+{
+	struct gb_operation *operation;
+	int ret;
+
+	if ((response_size && !response) ||
+	    (request_size && !request))
+		return -EINVAL;
+
+	operation = gb_operation_create(connection, type,
+					request_size, response_size,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	if (request_size)
+		memcpy(operation->request->payload, request, request_size);
+
+	ret = gb_operation_request_send_sync_timeout(operation, timeout);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: synchronous operation id 0x%04x of type 0x%02x failed: %d\n",
+			connection->name, operation->id, type, ret);
+	} else {
+		if (response_size) {
+			memcpy(response, operation->response->payload,
+			       response_size);
+		}
+	}
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_operation_sync_timeout);
+
+/**
+ * gb_operation_unidirectional_timeout() - initiate a unidirectional operation
+ * @connection:		connection to use
+ * @type:		type of operation to send
+ * @request:		memory buffer to copy the request from
+ * @request_size:	size of @request
+ * @timeout:		send timeout in milliseconds
+ *
+ * Initiate a unidirectional operation by sending a request message and
+ * waiting for it to be acknowledged as sent by the host device.
+ *
+ * Note that successful send of a unidirectional operation does not imply that
+ * the request as actually reached the remote end of the connection.
+ */
+int gb_operation_unidirectional_timeout(struct gb_connection *connection,
+				int type, void *request, int request_size,
+				unsigned int timeout)
+{
+	struct gb_operation *operation;
+	int ret;
+
+	if (request_size && !request)
+		return -EINVAL;
+
+	operation = gb_operation_create_flags(connection, type,
+					request_size, 0,
+					GB_OPERATION_FLAG_UNIDIRECTIONAL,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	if (request_size)
+		memcpy(operation->request->payload, request, request_size);
+
+	ret = gb_operation_request_send_sync_timeout(operation, timeout);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: unidirectional operation of type 0x%02x failed: %d\n",
+			connection->name, type, ret);
+	}
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_operation_unidirectional_timeout);
+
+int __init gb_operation_init(void)
+{
+	gb_message_cache = kmem_cache_create("gb_message_cache",
+				sizeof(struct gb_message), 0, 0, NULL);
+	if (!gb_message_cache)
+		return -ENOMEM;
+
+	gb_operation_cache = kmem_cache_create("gb_operation_cache",
+				sizeof(struct gb_operation), 0, 0, NULL);
+	if (!gb_operation_cache)
+		goto err_destroy_message_cache;
+
+	gb_operation_completion_wq = alloc_workqueue("greybus_completion",
+				0, 0);
+	if (!gb_operation_completion_wq)
+		goto err_destroy_operation_cache;
+
+	return 0;
+
+err_destroy_operation_cache:
+	kmem_cache_destroy(gb_operation_cache);
+	gb_operation_cache = NULL;
+err_destroy_message_cache:
+	kmem_cache_destroy(gb_message_cache);
+	gb_message_cache = NULL;
+
+	return -ENOMEM;
+}
+
+void gb_operation_exit(void)
+{
+	destroy_workqueue(gb_operation_completion_wq);
+	gb_operation_completion_wq = NULL;
+	kmem_cache_destroy(gb_operation_cache);
+	gb_operation_cache = NULL;
+	kmem_cache_destroy(gb_message_cache);
+	gb_message_cache = NULL;
+}
diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
new file mode 100644
index 000000000000..de09a2c7de54
--- /dev/null
+++ b/drivers/staging/greybus/operation.h
@@ -0,0 +1,210 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __OPERATION_H
+#define __OPERATION_H
+
+#include <linux/completion.h>
+
+struct gb_operation;
+
+/* The default amount of time a request is given to complete */
+#define GB_OPERATION_TIMEOUT_DEFAULT	1000	/* milliseconds */
+
+/*
+ * The top bit of the type in an operation message header indicates
+ * whether the message is a request (bit clear) or response (bit set)
+ */
+#define GB_MESSAGE_TYPE_RESPONSE	((u8)0x80)
+
+enum gb_operation_result {
+	GB_OP_SUCCESS		= 0x00,
+	GB_OP_INTERRUPTED	= 0x01,
+	GB_OP_TIMEOUT		= 0x02,
+	GB_OP_NO_MEMORY		= 0x03,
+	GB_OP_PROTOCOL_BAD	= 0x04,
+	GB_OP_OVERFLOW		= 0x05,
+	GB_OP_INVALID		= 0x06,
+	GB_OP_RETRY		= 0x07,
+	GB_OP_NONEXISTENT	= 0x08,
+	GB_OP_UNKNOWN_ERROR	= 0xfe,
+	GB_OP_MALFUNCTION	= 0xff,
+};
+
+#define GB_OPERATION_MESSAGE_SIZE_MIN	sizeof(struct gb_operation_msg_hdr)
+#define GB_OPERATION_MESSAGE_SIZE_MAX	U16_MAX
+
+/*
+ * Protocol code should only examine the payload and payload_size fields, and
+ * host-controller drivers may use the hcpriv field. All other fields are
+ * intended to be private to the operations core code.
+ */
+struct gb_message {
+	struct gb_operation		*operation;
+	struct gb_operation_msg_hdr	*header;
+
+	void				*payload;
+	size_t				payload_size;
+
+	void				*buffer;
+
+	void				*hcpriv;
+};
+
+#define GB_OPERATION_FLAG_INCOMING		BIT(0)
+#define GB_OPERATION_FLAG_UNIDIRECTIONAL	BIT(1)
+#define GB_OPERATION_FLAG_SHORT_RESPONSE	BIT(2)
+#define GB_OPERATION_FLAG_CORE			BIT(3)
+
+#define GB_OPERATION_FLAG_USER_MASK	(GB_OPERATION_FLAG_SHORT_RESPONSE | \
+					 GB_OPERATION_FLAG_UNIDIRECTIONAL)
+
+/*
+ * A Greybus operation is a remote procedure call performed over a
+ * connection between two UniPro interfaces.
+ *
+ * Every operation consists of a request message sent to the other
+ * end of the connection coupled with a reply message returned to
+ * the sender.  Every operation has a type, whose interpretation is
+ * dependent on the protocol associated with the connection.
+ *
+ * Only four things in an operation structure are intended to be
+ * directly usable by protocol handlers:  the operation's connection
+ * pointer; the operation type; the request message payload (and
+ * size); and the response message payload (and size).  Note that a
+ * message with a 0-byte payload has a null message payload pointer.
+ *
+ * In addition, every operation has a result, which is an errno
+ * value.  Protocol handlers access the operation result using
+ * gb_operation_result().
+ */
+typedef void (*gb_operation_callback)(struct gb_operation *);
+struct gb_operation {
+	struct gb_connection	*connection;
+	struct gb_message	*request;
+	struct gb_message	*response;
+
+	unsigned long		flags;
+	u8			type;
+	u16			id;
+	int			errno;		/* Operation result */
+
+	struct work_struct	work;
+	gb_operation_callback	callback;
+	struct completion	completion;
+
+	struct kref		kref;
+	atomic_t		waiters;
+
+	int			active;
+	struct list_head	links;		/* connection->operations */
+};
+
+static inline bool
+gb_operation_is_incoming(struct gb_operation *operation)
+{
+	return operation->flags & GB_OPERATION_FLAG_INCOMING;
+}
+
+static inline bool
+gb_operation_is_unidirectional(struct gb_operation *operation)
+{
+	return operation->flags & GB_OPERATION_FLAG_UNIDIRECTIONAL;
+}
+
+static inline bool
+gb_operation_short_response_allowed(struct gb_operation *operation)
+{
+	return operation->flags & GB_OPERATION_FLAG_SHORT_RESPONSE;
+}
+
+static inline bool gb_operation_is_core(struct gb_operation *operation)
+{
+	return operation->flags & GB_OPERATION_FLAG_CORE;
+}
+
+void gb_connection_recv(struct gb_connection *connection,
+					void *data, size_t size);
+
+int gb_operation_result(struct gb_operation *operation);
+
+size_t gb_operation_get_payload_size_max(struct gb_connection *connection);
+struct gb_operation *
+gb_operation_create_flags(struct gb_connection *connection,
+				u8 type, size_t request_size,
+				size_t response_size, unsigned long flags,
+				gfp_t gfp);
+
+static inline struct gb_operation *
+gb_operation_create(struct gb_connection *connection,
+				u8 type, size_t request_size,
+				size_t response_size, gfp_t gfp)
+{
+	return gb_operation_create_flags(connection, type, request_size,
+						response_size, 0, gfp);
+}
+
+struct gb_operation *
+gb_operation_create_core(struct gb_connection *connection,
+				u8 type, size_t request_size,
+				size_t response_size, unsigned long flags,
+				gfp_t gfp);
+
+void gb_operation_get(struct gb_operation *operation);
+void gb_operation_put(struct gb_operation *operation);
+
+bool gb_operation_response_alloc(struct gb_operation *operation,
+					size_t response_size, gfp_t gfp);
+
+int gb_operation_request_send(struct gb_operation *operation,
+				gb_operation_callback callback,
+				gfp_t gfp);
+int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
+						unsigned int timeout);
+static inline int
+gb_operation_request_send_sync(struct gb_operation *operation)
+{
+	return gb_operation_request_send_sync_timeout(operation,
+			GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+void gb_operation_cancel(struct gb_operation *operation, int errno);
+void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);
+
+void greybus_message_sent(struct gb_host_device *hd,
+				struct gb_message *message, int status);
+
+int gb_operation_sync_timeout(struct gb_connection *connection, int type,
+				void *request, int request_size,
+				void *response, int response_size,
+				unsigned int timeout);
+int gb_operation_unidirectional_timeout(struct gb_connection *connection,
+				int type, void *request, int request_size,
+				unsigned int timeout);
+
+static inline int gb_operation_sync(struct gb_connection *connection, int type,
+		      void *request, int request_size,
+		      void *response, int response_size)
+{
+	return gb_operation_sync_timeout(connection, type,
+			request, request_size, response, response_size,
+			GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+static inline int gb_operation_unidirectional(struct gb_connection *connection,
+				int type, void *request, int request_size)
+{
+	return gb_operation_unidirectional_timeout(connection, type,
+			request, request_size, GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+int gb_operation_init(void);
+void gb_operation_exit(void);
+
+#endif /* !__OPERATION_H */
diff --git a/drivers/staging/greybus/power_supply.c b/drivers/staging/greybus/power_supply.c
new file mode 100644
index 000000000000..e85c988b7034
--- /dev/null
+++ b/drivers/staging/greybus/power_supply.c
@@ -0,0 +1,1141 @@
+/*
+ * Power Supply driver for a Greybus module.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+
+#include "greybus.h"
+
+#define PROP_MAX 32
+
+struct gb_power_supply_prop {
+	enum power_supply_property	prop;
+	u8				gb_prop;
+	int				val;
+	int				previous_val;
+	bool				is_writeable;
+};
+
+struct gb_power_supply {
+	u8				id;
+	bool				registered;
+	struct power_supply		*psy;
+	struct power_supply_desc	desc;
+	char				name[64];
+	struct gb_power_supplies	*supplies;
+	struct delayed_work		work;
+	char				*manufacturer;
+	char				*model_name;
+	char				*serial_number;
+	u8				type;
+	u8				properties_count;
+	u8				properties_count_str;
+	unsigned long			last_update;
+	u8				cache_invalid;
+	unsigned int			update_interval;
+	bool				changed;
+	struct gb_power_supply_prop	*props;
+	enum power_supply_property	*props_raw;
+	bool				pm_acquired;
+	struct mutex			supply_lock;
+};
+
+struct gb_power_supplies {
+	struct gb_connection	*connection;
+	u8			supplies_count;
+	struct gb_power_supply	*supply;
+	struct mutex		supplies_lock;
+};
+
+#define to_gb_power_supply(x) power_supply_get_drvdata(x)
+
+/*
+ * General power supply properties that could be absent from various reasons,
+ * like kernel versions or vendor specific versions
+ */
+#ifndef POWER_SUPPLY_PROP_VOLTAGE_BOOT
+	#define POWER_SUPPLY_PROP_VOLTAGE_BOOT	-1
+#endif
+#ifndef POWER_SUPPLY_PROP_CURRENT_BOOT
+	#define POWER_SUPPLY_PROP_CURRENT_BOOT	-1
+#endif
+#ifndef POWER_SUPPLY_PROP_CALIBRATE
+	#define POWER_SUPPLY_PROP_CALIBRATE	-1
+#endif
+
+/* cache time in milliseconds, if cache_time is set to 0 cache is disable */
+static unsigned int cache_time = 1000;
+/*
+ * update interval initial and maximum value, between the two will
+ * back-off exponential
+ */
+static unsigned int update_interval_init = 1 * HZ;
+static unsigned int update_interval_max = 30 * HZ;
+
+struct gb_power_supply_changes {
+	enum power_supply_property	prop;
+	u32				tolerance_change;
+	void (*prop_changed)(struct gb_power_supply *gbpsy,
+			     struct gb_power_supply_prop *prop);
+};
+
+static void gb_power_supply_state_change(struct gb_power_supply *gbpsy,
+					 struct gb_power_supply_prop *prop);
+
+static const struct gb_power_supply_changes psy_props_changes[] = {
+	{	.prop			= GB_POWER_SUPPLY_PROP_STATUS,
+		.tolerance_change	= 0,
+		.prop_changed		= gb_power_supply_state_change,
+	},
+	{	.prop			= GB_POWER_SUPPLY_PROP_TEMP,
+		.tolerance_change	= 500,
+		.prop_changed		= NULL,
+	},
+	{	.prop			= GB_POWER_SUPPLY_PROP_ONLINE,
+		.tolerance_change	= 0,
+		.prop_changed		= NULL,
+	},
+};
+
+static int get_psp_from_gb_prop(int gb_prop, enum power_supply_property *psp)
+{
+	int prop;
+
+	switch (gb_prop) {
+	case GB_POWER_SUPPLY_PROP_STATUS:
+		prop = POWER_SUPPLY_PROP_STATUS;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_TYPE:
+		prop = POWER_SUPPLY_PROP_CHARGE_TYPE;
+		break;
+	case GB_POWER_SUPPLY_PROP_HEALTH:
+		prop = POWER_SUPPLY_PROP_HEALTH;
+		break;
+	case GB_POWER_SUPPLY_PROP_PRESENT:
+		prop = POWER_SUPPLY_PROP_PRESENT;
+		break;
+	case GB_POWER_SUPPLY_PROP_ONLINE:
+		prop = POWER_SUPPLY_PROP_ONLINE;
+		break;
+	case GB_POWER_SUPPLY_PROP_AUTHENTIC:
+		prop = POWER_SUPPLY_PROP_AUTHENTIC;
+		break;
+	case GB_POWER_SUPPLY_PROP_TECHNOLOGY:
+		prop = POWER_SUPPLY_PROP_TECHNOLOGY;
+		break;
+	case GB_POWER_SUPPLY_PROP_CYCLE_COUNT:
+		prop = POWER_SUPPLY_PROP_CYCLE_COUNT;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_MAX:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_MIN:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_MIN;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_AVG:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_OCV:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_OCV;
+		break;
+	case GB_POWER_SUPPLY_PROP_VOLTAGE_BOOT:
+		prop = POWER_SUPPLY_PROP_VOLTAGE_BOOT;
+		break;
+	case GB_POWER_SUPPLY_PROP_CURRENT_MAX:
+		prop = POWER_SUPPLY_PROP_CURRENT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_CURRENT_NOW:
+		prop = POWER_SUPPLY_PROP_CURRENT_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_CURRENT_AVG:
+		prop = POWER_SUPPLY_PROP_CURRENT_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_CURRENT_BOOT:
+		prop = POWER_SUPPLY_PROP_CURRENT_BOOT;
+		break;
+	case GB_POWER_SUPPLY_PROP_POWER_NOW:
+		prop = POWER_SUPPLY_PROP_POWER_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_POWER_AVG:
+		prop = POWER_SUPPLY_PROP_POWER_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		prop = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN:
+		prop = POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_FULL:
+		prop = POWER_SUPPLY_PROP_CHARGE_FULL;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_EMPTY:
+		prop = POWER_SUPPLY_PROP_CHARGE_EMPTY;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_NOW:
+		prop = POWER_SUPPLY_PROP_CHARGE_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_AVG:
+		prop = POWER_SUPPLY_PROP_CHARGE_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_COUNTER:
+		prop = POWER_SUPPLY_PROP_CHARGE_COUNTER;
+		break;
+	case GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		prop = POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT;
+		break;
+	case GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		prop = POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		prop = POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE;
+		break;
+	case GB_POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		prop = POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		prop = POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX:
+		prop = POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		prop = POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+		prop = POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN:
+		prop = POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_FULL:
+		prop = POWER_SUPPLY_PROP_ENERGY_FULL;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_EMPTY:
+		prop = POWER_SUPPLY_PROP_ENERGY_EMPTY;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_NOW:
+		prop = POWER_SUPPLY_PROP_ENERGY_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_ENERGY_AVG:
+		prop = POWER_SUPPLY_PROP_ENERGY_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_CAPACITY:
+		prop = POWER_SUPPLY_PROP_CAPACITY;
+		break;
+	case GB_POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
+		prop = POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN;
+		break;
+	case GB_POWER_SUPPLY_PROP_CAPACITY_ALERT_MAX:
+		prop = POWER_SUPPLY_PROP_CAPACITY_ALERT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_CAPACITY_LEVEL:
+		prop = POWER_SUPPLY_PROP_CAPACITY_LEVEL;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP:
+		prop = POWER_SUPPLY_PROP_TEMP;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_MAX:
+		prop = POWER_SUPPLY_PROP_TEMP_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_MIN:
+		prop = POWER_SUPPLY_PROP_TEMP_MIN;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		prop = POWER_SUPPLY_PROP_TEMP_ALERT_MIN;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		prop = POWER_SUPPLY_PROP_TEMP_ALERT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_AMBIENT:
+		prop = POWER_SUPPLY_PROP_TEMP_AMBIENT;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN:
+		prop = POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN;
+		break;
+	case GB_POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX:
+		prop = POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX;
+		break;
+	case GB_POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+		prop = POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
+		prop = POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
+		prop = POWER_SUPPLY_PROP_TIME_TO_FULL_NOW;
+		break;
+	case GB_POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
+		prop = POWER_SUPPLY_PROP_TIME_TO_FULL_AVG;
+		break;
+	case GB_POWER_SUPPLY_PROP_TYPE:
+		prop = POWER_SUPPLY_PROP_TYPE;
+		break;
+	case GB_POWER_SUPPLY_PROP_SCOPE:
+		prop = POWER_SUPPLY_PROP_SCOPE;
+		break;
+	case GB_POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		prop = POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT;
+		break;
+	case GB_POWER_SUPPLY_PROP_CALIBRATE:
+		prop = POWER_SUPPLY_PROP_CALIBRATE;
+		break;
+	default:
+		prop = -1;
+		break;
+	}
+
+	if (prop < 0)
+		return prop;
+
+	*psp = (enum power_supply_property)prop;
+
+	return 0;
+}
+
+static struct gb_connection *get_conn_from_psy(struct gb_power_supply *gbpsy)
+{
+	return gbpsy->supplies->connection;
+}
+
+static struct gb_power_supply_prop *get_psy_prop(struct gb_power_supply *gbpsy,
+						 enum power_supply_property psp)
+{
+	int i;
+
+	for (i = 0; i < gbpsy->properties_count; i++)
+		if (gbpsy->props[i].prop == psp)
+			return &gbpsy->props[i];
+	return NULL;
+}
+
+static int is_psy_prop_writeable(struct gb_power_supply *gbpsy,
+				     enum power_supply_property psp)
+{
+	struct gb_power_supply_prop *prop;
+
+	prop = get_psy_prop(gbpsy, psp);
+	if (!prop)
+		return -ENOENT;
+	return prop->is_writeable ? 1 : 0;
+}
+
+static int is_prop_valint(enum power_supply_property psp)
+{
+	return ((psp < POWER_SUPPLY_PROP_MODEL_NAME) ? 1 : 0);
+}
+
+static void next_interval(struct gb_power_supply *gbpsy)
+{
+	if (gbpsy->update_interval == update_interval_max)
+		return;
+
+	/* do some exponential back-off in the update interval */
+	gbpsy->update_interval *= 2;
+	if (gbpsy->update_interval > update_interval_max)
+		gbpsy->update_interval = update_interval_max;
+}
+
+static void __gb_power_supply_changed(struct gb_power_supply *gbpsy)
+{
+	power_supply_changed(gbpsy->psy);
+}
+
+static void gb_power_supply_state_change(struct gb_power_supply *gbpsy,
+					 struct gb_power_supply_prop *prop)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	int ret;
+
+	/*
+	 * Check gbpsy->pm_acquired to make sure only one pair of 'get_sync'
+	 * and 'put_autosuspend' runtime pm call for state property change.
+	 */
+	mutex_lock(&gbpsy->supply_lock);
+
+	if ((prop->val == GB_POWER_SUPPLY_STATUS_CHARGING) &&
+	    !gbpsy->pm_acquired) {
+		ret = gb_pm_runtime_get_sync(connection->bundle);
+		if (ret)
+			dev_err(&connection->bundle->dev,
+				"Fail to set wake lock for charging state\n");
+		else
+			gbpsy->pm_acquired = true;
+	} else {
+		if (gbpsy->pm_acquired) {
+			ret = gb_pm_runtime_put_autosuspend(connection->bundle);
+			if (ret)
+				dev_err(&connection->bundle->dev,
+					"Fail to set wake unlock for none charging\n");
+			else
+				gbpsy->pm_acquired = false;
+		}
+	}
+
+	mutex_unlock(&gbpsy->supply_lock);
+}
+
+static void check_changed(struct gb_power_supply *gbpsy,
+			  struct gb_power_supply_prop *prop)
+{
+	const struct gb_power_supply_changes *psyc;
+	int val = prop->val;
+	int prev_val = prop->previous_val;
+	bool changed = false;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(psy_props_changes); i++) {
+		psyc = &psy_props_changes[i];
+		if (prop->prop == psyc->prop) {
+			if (!psyc->tolerance_change)
+				changed = true;
+			else if (val < prev_val &&
+				 prev_val - val > psyc->tolerance_change)
+				changed = true;
+			else if (val > prev_val &&
+				 val - prev_val > psyc->tolerance_change)
+				changed = true;
+
+			if (changed && psyc->prop_changed)
+				psyc->prop_changed(gbpsy, prop);
+
+			if (changed)
+				gbpsy->changed = true;
+			break;
+		}
+	}
+}
+
+static int total_props(struct gb_power_supply *gbpsy)
+{
+	/* this return the intval plus the strval properties */
+	return (gbpsy->properties_count + gbpsy->properties_count_str);
+}
+
+static void prop_append(struct gb_power_supply *gbpsy,
+			enum power_supply_property prop)
+{
+	enum power_supply_property *new_props_raw;
+
+	gbpsy->properties_count_str++;
+	new_props_raw = krealloc(gbpsy->props_raw, total_props(gbpsy) *
+				 sizeof(enum power_supply_property),
+				 GFP_KERNEL);
+	if (!new_props_raw)
+		return;
+	gbpsy->props_raw = new_props_raw;
+	gbpsy->props_raw[total_props(gbpsy) - 1] = prop;
+}
+
+static int __gb_power_supply_set_name(char *init_name, char *name, size_t len)
+{
+	unsigned int i = 0;
+	int ret = 0;
+	struct power_supply *psy;
+
+	if (!strlen(init_name))
+		init_name = "gb_power_supply";
+	strlcpy(name, init_name, len);
+
+	while ((ret < len) && (psy = power_supply_get_by_name(name))) {
+		power_supply_put(psy);
+
+		ret = snprintf(name, len, "%s_%u", init_name, ++i);
+	}
+	if (ret >= len)
+		return -ENOMEM;
+	return i;
+}
+
+static void _gb_power_supply_append_props(struct gb_power_supply *gbpsy)
+{
+	if (strlen(gbpsy->manufacturer))
+		prop_append(gbpsy, POWER_SUPPLY_PROP_MANUFACTURER);
+	if (strlen(gbpsy->model_name))
+		prop_append(gbpsy, POWER_SUPPLY_PROP_MODEL_NAME);
+	if (strlen(gbpsy->serial_number))
+		prop_append(gbpsy, POWER_SUPPLY_PROP_SERIAL_NUMBER);
+}
+
+static int gb_power_supply_description_get(struct gb_power_supply *gbpsy)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	struct gb_power_supply_get_description_request req;
+	struct gb_power_supply_get_description_response resp;
+	int ret;
+
+	req.psy_id = gbpsy->id;
+
+	ret = gb_operation_sync(connection,
+				GB_POWER_SUPPLY_TYPE_GET_DESCRIPTION,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	gbpsy->manufacturer = kstrndup(resp.manufacturer, PROP_MAX, GFP_KERNEL);
+	if (!gbpsy->manufacturer)
+		return -ENOMEM;
+	gbpsy->model_name = kstrndup(resp.model, PROP_MAX, GFP_KERNEL);
+	if (!gbpsy->model_name)
+		return -ENOMEM;
+	gbpsy->serial_number = kstrndup(resp.serial_number, PROP_MAX,
+				       GFP_KERNEL);
+	if (!gbpsy->serial_number)
+		return -ENOMEM;
+
+	gbpsy->type = le16_to_cpu(resp.type);
+	gbpsy->properties_count = resp.properties_count;
+
+	return 0;
+}
+
+static int gb_power_supply_prop_descriptors_get(struct gb_power_supply *gbpsy)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	struct gb_power_supply_get_property_descriptors_request *req;
+	struct gb_power_supply_get_property_descriptors_response *resp;
+	struct gb_operation *op;
+	u8 props_count = gbpsy->properties_count;
+	enum power_supply_property psp;
+	int ret;
+	int i, r = 0;
+
+	if (props_count == 0)
+		return 0;
+
+	op = gb_operation_create(connection,
+				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
+				 sizeof(req), sizeof(*resp) + props_count *
+				 sizeof(struct gb_power_supply_props_desc),
+				 GFP_KERNEL);
+	if (!op)
+		return -ENOMEM;
+
+	req = op->request->payload;
+	req->psy_id = gbpsy->id;
+
+	ret = gb_operation_request_send_sync(op);
+	if (ret < 0)
+		goto out_put_operation;
+
+	resp = op->response->payload;
+
+	/* validate received properties */
+	for (i = 0; i < props_count; i++) {
+		ret = get_psp_from_gb_prop(resp->props[i].property, &psp);
+		if (ret < 0) {
+			dev_warn(&connection->bundle->dev,
+				 "greybus property %u it is not supported by this kernel, dropped\n",
+				 resp->props[i].property);
+			gbpsy->properties_count--;
+		}
+	}
+
+	gbpsy->props = kcalloc(gbpsy->properties_count, sizeof(*gbpsy->props),
+			      GFP_KERNEL);
+	if (!gbpsy->props) {
+		ret = -ENOMEM;
+		goto out_put_operation;
+	}
+
+	gbpsy->props_raw = kcalloc(gbpsy->properties_count,
+				   sizeof(*gbpsy->props_raw), GFP_KERNEL);
+	if (!gbpsy->props_raw) {
+		ret = -ENOMEM;
+		goto out_put_operation;
+	}
+
+	/* Store available properties, skip the ones we do not support */
+	for (i = 0; i < props_count; i++) {
+		ret = get_psp_from_gb_prop(resp->props[i].property, &psp);
+		if (ret < 0) {
+			r++;
+			continue;
+		}
+		gbpsy->props[i - r].prop = psp;
+		gbpsy->props[i - r].gb_prop = resp->props[i].property;
+		gbpsy->props_raw[i - r] = psp;
+		if (resp->props[i].is_writeable)
+			gbpsy->props[i - r].is_writeable = true;
+	}
+
+	/*
+	 * now append the properties that we already got information in the
+	 * get_description operation. (char * ones)
+	 */
+	_gb_power_supply_append_props(gbpsy);
+
+	ret = 0;
+out_put_operation:
+	gb_operation_put(op);
+
+	return ret;
+}
+
+static int __gb_power_supply_property_update(struct gb_power_supply *gbpsy,
+					     enum power_supply_property psp)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	struct gb_power_supply_prop *prop;
+	struct gb_power_supply_get_property_request req;
+	struct gb_power_supply_get_property_response resp;
+	int val;
+	int ret;
+
+	prop = get_psy_prop(gbpsy, psp);
+	if (!prop)
+		return -EINVAL;
+	req.psy_id = gbpsy->id;
+	req.property = prop->gb_prop;
+
+	ret = gb_operation_sync(connection, GB_POWER_SUPPLY_TYPE_GET_PROPERTY,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	val = le32_to_cpu(resp.prop_val);
+	if (val == prop->val)
+		return 0;
+
+	prop->previous_val = prop->val;
+	prop->val = val;
+
+	check_changed(gbpsy, prop);
+
+	return 0;
+}
+
+static int __gb_power_supply_property_get(struct gb_power_supply *gbpsy,
+					  enum power_supply_property psp,
+					  union power_supply_propval *val)
+{
+	struct gb_power_supply_prop *prop;
+
+	prop = get_psy_prop(gbpsy, psp);
+	if (!prop)
+		return -EINVAL;
+
+	val->intval = prop->val;
+	return 0;
+}
+
+static int __gb_power_supply_property_strval_get(struct gb_power_supply *gbpsy,
+						enum power_supply_property psp,
+						union power_supply_propval *val)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = gbpsy->model_name;
+		break;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = gbpsy->manufacturer;
+		break;
+	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+		val->strval = gbpsy->serial_number;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int _gb_power_supply_property_get(struct gb_power_supply *gbpsy,
+					 enum power_supply_property psp,
+					 union power_supply_propval *val)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	int ret;
+
+	/*
+	 * Properties of type const char *, were already fetched on
+	 * get_description operation and should be cached in gb
+	 */
+	if (is_prop_valint(psp))
+		ret = __gb_power_supply_property_get(gbpsy, psp, val);
+	else
+		ret = __gb_power_supply_property_strval_get(gbpsy, psp, val);
+
+	if (ret < 0)
+		dev_err(&connection->bundle->dev, "get property %u\n", psp);
+
+	return 0;
+}
+
+static int is_cache_valid(struct gb_power_supply *gbpsy)
+{
+	/* check if cache is good enough or it has expired */
+	if (gbpsy->cache_invalid) {
+		gbpsy->cache_invalid = 0;
+		return 0;
+	}
+
+	if (gbpsy->last_update &&
+	    time_is_after_jiffies(gbpsy->last_update +
+				  msecs_to_jiffies(cache_time)))
+		return 1;
+
+	return 0;
+}
+
+static int gb_power_supply_status_get(struct gb_power_supply *gbpsy)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	int ret = 0;
+	int i;
+
+	if (is_cache_valid(gbpsy))
+		return 0;
+
+	ret = gb_pm_runtime_get_sync(connection->bundle);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < gbpsy->properties_count; i++) {
+		ret = __gb_power_supply_property_update(gbpsy,
+							gbpsy->props[i].prop);
+		if (ret < 0)
+			break;
+	}
+
+	if (ret == 0)
+		gbpsy->last_update = jiffies;
+
+	gb_pm_runtime_put_autosuspend(connection->bundle);
+	return ret;
+}
+
+static void gb_power_supply_status_update(struct gb_power_supply *gbpsy)
+{
+	/* check if there a change that need to be reported */
+	gb_power_supply_status_get(gbpsy);
+
+	if (!gbpsy->changed)
+		return;
+
+	gbpsy->update_interval = update_interval_init;
+	__gb_power_supply_changed(gbpsy);
+	gbpsy->changed = false;
+}
+
+static void gb_power_supply_work(struct work_struct *work)
+{
+	struct gb_power_supply *gbpsy = container_of(work,
+						     struct gb_power_supply,
+						     work.work);
+
+	/*
+	 * if the poll interval is not set, disable polling, this is helpful
+	 * specially at unregister time.
+	 */
+	if (!gbpsy->update_interval)
+		return;
+
+	gb_power_supply_status_update(gbpsy);
+	next_interval(gbpsy);
+	schedule_delayed_work(&gbpsy->work, gbpsy->update_interval);
+}
+
+static int get_property(struct power_supply *b,
+			enum power_supply_property psp,
+			union power_supply_propval *val)
+{
+	struct gb_power_supply *gbpsy = to_gb_power_supply(b);
+
+	gb_power_supply_status_get(gbpsy);
+
+	return _gb_power_supply_property_get(gbpsy, psp, val);
+}
+
+static int gb_power_supply_property_set(struct gb_power_supply *gbpsy,
+					enum power_supply_property psp,
+					int val)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	struct gb_power_supply_prop *prop;
+	struct gb_power_supply_set_property_request req;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(connection->bundle);
+	if (ret)
+		return ret;
+
+	prop = get_psy_prop(gbpsy, psp);
+	if (!prop) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	req.psy_id = gbpsy->id;
+	req.property = prop->gb_prop;
+	req.prop_val = cpu_to_le32((s32)val);
+
+	ret = gb_operation_sync(connection, GB_POWER_SUPPLY_TYPE_SET_PROPERTY,
+				&req, sizeof(req), NULL, 0);
+	if (ret < 0)
+		goto out;
+
+	/* cache immediately the new value */
+	prop->val = val;
+
+out:
+	gb_pm_runtime_put_autosuspend(connection->bundle);
+	return ret;
+}
+
+static int set_property(struct power_supply *b,
+			enum power_supply_property psp,
+			const union power_supply_propval *val)
+{
+	struct gb_power_supply *gbpsy = to_gb_power_supply(b);
+
+	return gb_power_supply_property_set(gbpsy, psp, val->intval);
+}
+
+static int property_is_writeable(struct power_supply *b,
+				 enum power_supply_property psp)
+{
+	struct gb_power_supply *gbpsy = to_gb_power_supply(b);
+
+	return is_psy_prop_writeable(gbpsy, psp);
+}
+
+static int gb_power_supply_register(struct gb_power_supply *gbpsy)
+{
+	struct gb_connection *connection = get_conn_from_psy(gbpsy);
+	struct power_supply_config cfg = {};
+
+	cfg.drv_data = gbpsy;
+
+	gbpsy->desc.name		= gbpsy->name;
+	gbpsy->desc.type		= gbpsy->type;
+	gbpsy->desc.properties		= gbpsy->props_raw;
+	gbpsy->desc.num_properties	= total_props(gbpsy);
+	gbpsy->desc.get_property	= get_property;
+	gbpsy->desc.set_property	= set_property;
+	gbpsy->desc.property_is_writeable = property_is_writeable;
+
+	gbpsy->psy = power_supply_register(&connection->bundle->dev,
+					   &gbpsy->desc, &cfg);
+	return PTR_ERR_OR_ZERO(gbpsy->psy);
+}
+
+static void _gb_power_supply_free(struct gb_power_supply *gbpsy)
+{
+	kfree(gbpsy->serial_number);
+	kfree(gbpsy->model_name);
+	kfree(gbpsy->manufacturer);
+	kfree(gbpsy->props_raw);
+	kfree(gbpsy->props);
+}
+
+static void _gb_power_supply_release(struct gb_power_supply *gbpsy)
+{
+	gbpsy->update_interval = 0;
+
+	cancel_delayed_work_sync(&gbpsy->work);
+
+	if (gbpsy->registered)
+		power_supply_unregister(gbpsy->psy);
+
+	_gb_power_supply_free(gbpsy);
+}
+
+static void _gb_power_supplies_release(struct gb_power_supplies *supplies)
+{
+	int i;
+
+	if (!supplies->supply)
+		return;
+
+	mutex_lock(&supplies->supplies_lock);
+	for (i = 0; i < supplies->supplies_count; i++)
+		_gb_power_supply_release(&supplies->supply[i]);
+	kfree(supplies->supply);
+	mutex_unlock(&supplies->supplies_lock);
+	kfree(supplies);
+}
+
+static int gb_power_supplies_get_count(struct gb_power_supplies *supplies)
+{
+	struct gb_power_supply_get_supplies_response resp;
+	int ret;
+
+	ret = gb_operation_sync(supplies->connection,
+				GB_POWER_SUPPLY_TYPE_GET_SUPPLIES,
+				NULL, 0, &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	if  (!resp.supplies_count)
+		return -EINVAL;
+
+	supplies->supplies_count = resp.supplies_count;
+
+	return ret;
+}
+
+static int gb_power_supply_config(struct gb_power_supplies *supplies, int id)
+{
+	struct gb_power_supply *gbpsy = &supplies->supply[id];
+	int ret;
+
+	gbpsy->supplies = supplies;
+	gbpsy->id = id;
+
+	ret = gb_power_supply_description_get(gbpsy);
+	if (ret < 0)
+		return ret;
+
+	return gb_power_supply_prop_descriptors_get(gbpsy);
+}
+
+static int gb_power_supply_enable(struct gb_power_supply *gbpsy)
+{
+	int ret;
+
+	/* guarantee that we have an unique name, before register */
+	ret =  __gb_power_supply_set_name(gbpsy->model_name, gbpsy->name,
+					  sizeof(gbpsy->name));
+	if (ret < 0)
+		return ret;
+
+	mutex_init(&gbpsy->supply_lock);
+
+	ret = gb_power_supply_register(gbpsy);
+	if (ret < 0)
+		return ret;
+
+	gbpsy->update_interval = update_interval_init;
+	INIT_DELAYED_WORK(&gbpsy->work, gb_power_supply_work);
+	schedule_delayed_work(&gbpsy->work, 0);
+
+	/* everything went fine, mark it for release code to know */
+	gbpsy->registered = true;
+
+	return 0;
+}
+
+static int gb_power_supplies_setup(struct gb_power_supplies *supplies)
+{
+	struct gb_connection *connection = supplies->connection;
+	int ret;
+	int i;
+
+	mutex_lock(&supplies->supplies_lock);
+
+	ret = gb_power_supplies_get_count(supplies);
+	if (ret < 0)
+		goto out;
+
+	supplies->supply = kzalloc(supplies->supplies_count *
+				     sizeof(struct gb_power_supply),
+				     GFP_KERNEL);
+
+	if (!supplies->supply) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < supplies->supplies_count; i++) {
+		ret = gb_power_supply_config(supplies, i);
+		if (ret < 0) {
+			dev_err(&connection->bundle->dev,
+				"Fail to configure supplies devices\n");
+			goto out;
+		}
+	}
+out:
+	mutex_unlock(&supplies->supplies_lock);
+	return ret;
+}
+
+static int gb_power_supplies_register(struct gb_power_supplies *supplies)
+{
+	struct gb_connection *connection = supplies->connection;
+	int ret = 0;
+	int i;
+
+	mutex_lock(&supplies->supplies_lock);
+
+	for (i = 0; i < supplies->supplies_count; i++) {
+		ret = gb_power_supply_enable(&supplies->supply[i]);
+		if (ret < 0) {
+			dev_err(&connection->bundle->dev,
+				"Fail to enable supplies devices\n");
+			break;
+		}
+	}
+
+	mutex_unlock(&supplies->supplies_lock);
+	return ret;
+}
+
+static int gb_supplies_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_power_supplies *supplies = gb_connection_get_data(connection);
+	struct gb_power_supply *gbpsy;
+	struct gb_message *request;
+	struct gb_power_supply_event_request *payload;
+	u8 psy_id;
+	u8 event;
+	int ret = 0;
+
+	if (op->type != GB_POWER_SUPPLY_TYPE_EVENT) {
+		dev_err(&connection->bundle->dev,
+			"Unsupported unsolicited event: %u\n", op->type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*payload)) {
+		dev_err(&connection->bundle->dev,
+			"Wrong event size received (%zu < %zu)\n",
+			request->payload_size, sizeof(*payload));
+		return -EINVAL;
+	}
+
+	payload = request->payload;
+	psy_id = payload->psy_id;
+	mutex_lock(&supplies->supplies_lock);
+	if (psy_id >= supplies->supplies_count ||
+	    !supplies->supply[psy_id].registered) {
+		dev_err(&connection->bundle->dev,
+			"Event received for unconfigured power_supply id: %d\n",
+			psy_id);
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	event = payload->event;
+	/*
+	 * we will only handle events after setup is done and before release is
+	 * running. For that just check update_interval.
+	 */
+	gbpsy = &supplies->supply[psy_id];
+	if (!gbpsy->update_interval) {
+		ret = -ESHUTDOWN;
+		goto out_unlock;
+	}
+
+	if (event & GB_POWER_SUPPLY_UPDATE) {
+		/*
+		 * we need to make sure we invalidate cache, if not no new
+		 * values for the properties will be fetch and the all propose
+		 * of this event is missed
+		 */
+		gbpsy->cache_invalid = 1;
+		gb_power_supply_status_update(gbpsy);
+	}
+
+out_unlock:
+	mutex_unlock(&supplies->supplies_lock);
+	return ret;
+}
+
+static int gb_power_supply_probe(struct gb_bundle *bundle,
+				 const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_power_supplies *supplies;
+	int ret;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_POWER_SUPPLY)
+		return -ENODEV;
+
+	supplies = kzalloc(sizeof(*supplies), GFP_KERNEL);
+	if (!supplies)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+					  gb_supplies_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto out;
+	}
+
+	supplies->connection = connection;
+	gb_connection_set_data(connection, supplies);
+
+	mutex_init(&supplies->supplies_lock);
+
+	greybus_set_drvdata(bundle, supplies);
+
+	/* We aren't ready to receive an incoming request yet */
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto error_connection_destroy;
+
+	ret = gb_power_supplies_setup(supplies);
+	if (ret < 0)
+		goto error_connection_disable;
+
+	/* We are ready to receive an incoming request now, enable RX as well */
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto error_connection_disable;
+
+	ret = gb_power_supplies_register(supplies);
+	if (ret < 0)
+		goto error_connection_disable;
+
+	gb_pm_runtime_put_autosuspend(bundle);
+	return 0;
+
+error_connection_disable:
+	gb_connection_disable(connection);
+error_connection_destroy:
+	gb_connection_destroy(connection);
+out:
+	_gb_power_supplies_release(supplies);
+	return ret;
+}
+
+static void gb_power_supply_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_power_supplies *supplies = greybus_get_drvdata(bundle);
+
+	gb_connection_disable(supplies->connection);
+	gb_connection_destroy(supplies->connection);
+
+	_gb_power_supplies_release(supplies);
+}
+
+static const struct greybus_bundle_id gb_power_supply_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_POWER_SUPPLY) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_power_supply_id_table);
+
+static struct greybus_driver gb_power_supply_driver = {
+	.name		= "power_supply",
+	.probe		= gb_power_supply_probe,
+	.disconnect	= gb_power_supply_disconnect,
+	.id_table	= gb_power_supply_id_table,
+};
+module_greybus_driver(gb_power_supply_driver);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
new file mode 100644
index 000000000000..c4bf3298ba07
--- /dev/null
+++ b/drivers/staging/greybus/pwm.c
@@ -0,0 +1,338 @@
+/*
+ * PWM Greybus driver.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pwm.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+struct gb_pwm_chip {
+	struct gb_connection	*connection;
+	u8			pwm_max;	/* max pwm number */
+
+	struct pwm_chip		chip;
+	struct pwm_chip		*pwm;
+};
+#define pwm_chip_to_gb_pwm_chip(chip) \
+	container_of(chip, struct gb_pwm_chip, chip)
+
+
+static int gb_pwm_count_operation(struct gb_pwm_chip *pwmc)
+{
+	struct gb_pwm_count_response response;
+	int ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_PWM_COUNT,
+				NULL, 0, &response, sizeof(response));
+	if (ret)
+		return ret;
+	pwmc->pwm_max = response.count;
+	return 0;
+}
+
+static int gb_pwm_activate_operation(struct gb_pwm_chip *pwmc,
+				     u8 which)
+{
+	struct gb_pwm_activate_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ACTIVATE,
+				&request, sizeof(request), NULL, 0);
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_deactivate_operation(struct gb_pwm_chip *pwmc,
+				       u8 which)
+{
+	struct gb_pwm_deactivate_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DEACTIVATE,
+				&request, sizeof(request), NULL, 0);
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_config_operation(struct gb_pwm_chip *pwmc,
+				   u8 which, u32 duty, u32 period)
+{
+	struct gb_pwm_config_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+	request.duty = cpu_to_le32(duty);
+	request.period = cpu_to_le32(period);
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_CONFIG,
+				&request, sizeof(request), NULL, 0);
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_set_polarity_operation(struct gb_pwm_chip *pwmc,
+					 u8 which, u8 polarity)
+{
+	struct gb_pwm_polarity_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+	request.polarity = polarity;
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_POLARITY,
+				&request, sizeof(request), NULL, 0);
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_enable_operation(struct gb_pwm_chip *pwmc,
+				   u8 which)
+{
+	struct gb_pwm_enable_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ENABLE,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_disable_operation(struct gb_pwm_chip *pwmc,
+				    u8 which)
+{
+	struct gb_pwm_disable_request request;
+	struct gbphy_device *gbphy_dev;
+	int ret;
+
+	if (which > pwmc->pwm_max)
+		return -EINVAL;
+
+	request.which = which;
+
+	ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DISABLE,
+				&request, sizeof(request), NULL, 0);
+
+	gbphy_dev = to_gbphy_dev(pwmc->chip.dev);
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+}
+
+static int gb_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	return gb_pwm_activate_operation(pwmc, pwm->hwpwm);
+};
+
+static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	if (pwm_is_enabled(pwm))
+		dev_warn(chip->dev, "freeing PWM device without disabling\n");
+
+	gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
+}
+
+static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			 int duty_ns, int period_ns)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
+};
+
+static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+			       enum pwm_polarity polarity)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
+};
+
+static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
+};
+
+static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+
+	gb_pwm_disable_operation(pwmc, pwm->hwpwm);
+};
+
+static const struct pwm_ops gb_pwm_ops = {
+	.request = gb_pwm_request,
+	.free = gb_pwm_free,
+	.config = gb_pwm_config,
+	.set_polarity = gb_pwm_set_polarity,
+	.enable = gb_pwm_enable,
+	.disable = gb_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int gb_pwm_probe(struct gbphy_device *gbphy_dev,
+			const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct gb_pwm_chip *pwmc;
+	struct pwm_chip *pwm;
+	int ret;
+
+	pwmc = kzalloc(sizeof(*pwmc), GFP_KERNEL);
+	if (!pwmc)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  NULL);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto exit_pwmc_free;
+	}
+
+	pwmc->connection = connection;
+	gb_connection_set_data(connection, pwmc);
+	gb_gbphy_set_data(gbphy_dev, pwmc);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	/* Query number of pwms present */
+	ret = gb_pwm_count_operation(pwmc);
+	if (ret)
+		goto exit_connection_disable;
+
+	pwm = &pwmc->chip;
+
+	pwm->dev = &gbphy_dev->dev;
+	pwm->ops = &gb_pwm_ops;
+	pwm->base = -1;			/* Allocate base dynamically */
+	pwm->npwm = pwmc->pwm_max + 1;
+	pwm->can_sleep = true;		/* FIXME */
+
+	ret = pwmchip_add(pwm);
+	if (ret) {
+		dev_err(&gbphy_dev->dev,
+			"failed to register PWM: %d\n", ret);
+		goto exit_connection_disable;
+	}
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_pwmc_free:
+	kfree(pwmc);
+	return ret;
+}
+
+static void gb_pwm_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_pwm_chip *pwmc = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = pwmc->connection;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	pwmchip_remove(&pwmc->chip);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	kfree(pwmc);
+}
+
+static const struct gbphy_device_id gb_pwm_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_PWM) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_pwm_id_table);
+
+static struct gbphy_driver pwm_driver = {
+	.name		= "pwm",
+	.probe		= gb_pwm_probe,
+	.remove		= gb_pwm_remove,
+	.id_table	= gb_pwm_id_table,
+};
+
+module_gbphy_driver(pwm_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c
new file mode 100644
index 000000000000..729d25811568
--- /dev/null
+++ b/drivers/staging/greybus/raw.c
@@ -0,0 +1,381 @@
+/*
+ * Greybus driver for the Raw protocol
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sizes.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/uaccess.h>
+
+#include "greybus.h"
+
+struct gb_raw {
+	struct gb_connection *connection;
+
+	struct list_head list;
+	int list_data;
+	struct mutex list_lock;
+	dev_t dev;
+	struct cdev cdev;
+	struct device *device;
+};
+
+struct raw_data {
+	struct list_head entry;
+	u32 len;
+	u8 data[0];
+};
+
+static struct class *raw_class;
+static int raw_major;
+static const struct file_operations raw_fops;
+static DEFINE_IDA(minors);
+
+/* Number of minor devices this driver supports */
+#define NUM_MINORS	256
+
+/* Maximum size of any one send data buffer we support */
+#define MAX_PACKET_SIZE	(PAGE_SIZE * 2)
+
+/*
+ * Maximum size of the data in the receive buffer we allow before we start to
+ * drop messages on the floor
+ */
+#define MAX_DATA_SIZE	(MAX_PACKET_SIZE * 8)
+
+/*
+ * Add the raw data message to the list of received messages.
+ */
+static int receive_data(struct gb_raw *raw, u32 len, u8 *data)
+{
+	struct raw_data *raw_data;
+	struct device *dev = &raw->connection->bundle->dev;
+	int retval = 0;
+
+	if (len > MAX_PACKET_SIZE) {
+		dev_err(dev, "Too big of a data packet, rejected\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&raw->list_lock);
+	if ((raw->list_data + len) > MAX_DATA_SIZE) {
+		dev_err(dev, "Too much data in receive buffer, now dropping packets\n");
+		retval = -EINVAL;
+		goto exit;
+	}
+
+	raw_data = kmalloc(sizeof(*raw_data) + len, GFP_KERNEL);
+	if (!raw_data) {
+		retval = -ENOMEM;
+		goto exit;
+	}
+
+	raw->list_data += len;
+	raw_data->len = len;
+	memcpy(&raw_data->data[0], data, len);
+
+	list_add_tail(&raw_data->entry, &raw->list);
+exit:
+	mutex_unlock(&raw->list_lock);
+	return retval;
+}
+
+static int gb_raw_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct device *dev = &connection->bundle->dev;
+	struct gb_raw *raw = greybus_get_drvdata(connection->bundle);
+	struct gb_raw_send_request *receive;
+	u32 len;
+
+	if (op->type != GB_RAW_TYPE_SEND) {
+		dev_err(dev, "unknown request type 0x%02x\n", op->type);
+		return -EINVAL;
+	}
+
+	/* Verify size of payload */
+	if (op->request->payload_size < sizeof(*receive)) {
+		dev_err(dev, "raw receive request too small (%zu < %zu)\n",
+			op->request->payload_size, sizeof(*receive));
+		return -EINVAL;
+	}
+	receive = op->request->payload;
+	len = le32_to_cpu(receive->len);
+	if (len != (int)(op->request->payload_size - sizeof(__le32))) {
+		dev_err(dev, "raw receive request wrong size %d vs %d\n", len,
+			(int)(op->request->payload_size - sizeof(__le32)));
+		return -EINVAL;
+	}
+	if (len == 0) {
+		dev_err(dev, "raw receive request of 0 bytes?\n");
+		return -EINVAL;
+	}
+
+	return receive_data(raw, len, receive->data);
+}
+
+static int gb_raw_send(struct gb_raw *raw, u32 len, const char __user *data)
+{
+	struct gb_connection *connection = raw->connection;
+	struct gb_raw_send_request *request;
+	int retval;
+
+	request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	if (copy_from_user(&request->data[0], data, len)) {
+		kfree(request);
+		return -EFAULT;
+	}
+
+	request->len = cpu_to_le32(len);
+
+	retval = gb_operation_sync(connection, GB_RAW_TYPE_SEND,
+				   request, len + sizeof(*request),
+				   NULL, 0);
+
+	kfree(request);
+	return retval;
+}
+
+static int gb_raw_probe(struct gb_bundle *bundle,
+			const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_raw *raw;
+	int retval;
+	int minor;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_RAW)
+		return -ENODEV;
+
+	raw = kzalloc(sizeof(*raw), GFP_KERNEL);
+	if (!raw)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+					  gb_raw_request_handler);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto error_free;
+	}
+
+	INIT_LIST_HEAD(&raw->list);
+	mutex_init(&raw->list_lock);
+
+	raw->connection = connection;
+	greybus_set_drvdata(bundle, raw);
+
+	minor = ida_simple_get(&minors, 0, 0, GFP_KERNEL);
+	if (minor < 0) {
+		retval = minor;
+		goto error_connection_destroy;
+	}
+
+	raw->dev = MKDEV(raw_major, minor);
+	cdev_init(&raw->cdev, &raw_fops);
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto error_remove_ida;
+
+	retval = cdev_add(&raw->cdev, raw->dev, 1);
+	if (retval)
+		goto error_connection_disable;
+
+	raw->device = device_create(raw_class, &connection->bundle->dev,
+				    raw->dev, raw, "gb!raw%d", minor);
+	if (IS_ERR(raw->device)) {
+		retval = PTR_ERR(raw->device);
+		goto error_del_cdev;
+	}
+
+	return 0;
+
+error_del_cdev:
+	cdev_del(&raw->cdev);
+
+error_connection_disable:
+	gb_connection_disable(connection);
+
+error_remove_ida:
+	ida_simple_remove(&minors, minor);
+
+error_connection_destroy:
+	gb_connection_destroy(connection);
+
+error_free:
+	kfree(raw);
+	return retval;
+}
+
+static void gb_raw_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_raw *raw = greybus_get_drvdata(bundle);
+	struct gb_connection *connection = raw->connection;
+	struct raw_data *raw_data;
+	struct raw_data *temp;
+
+	// FIXME - handle removing a connection when the char device node is open.
+	device_destroy(raw_class, raw->dev);
+	cdev_del(&raw->cdev);
+	gb_connection_disable(connection);
+	ida_simple_remove(&minors, MINOR(raw->dev));
+	gb_connection_destroy(connection);
+
+	mutex_lock(&raw->list_lock);
+	list_for_each_entry_safe(raw_data, temp, &raw->list, entry) {
+		list_del(&raw_data->entry);
+		kfree(raw_data);
+	}
+	mutex_unlock(&raw->list_lock);
+
+	kfree(raw);
+}
+
+/*
+ * Character device node interfaces.
+ *
+ * Note, we are using read/write to only allow a single read/write per message.
+ * This means for read(), you have to provide a big enough buffer for the full
+ * message to be copied into.  If the buffer isn't big enough, the read() will
+ * fail with -ENOSPC.
+ */
+
+static int raw_open(struct inode *inode, struct file *file)
+{
+	struct cdev *cdev = inode->i_cdev;
+	struct gb_raw *raw = container_of(cdev, struct gb_raw, cdev);
+
+	file->private_data = raw;
+	return 0;
+}
+
+static ssize_t raw_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	struct gb_raw *raw = file->private_data;
+	int retval;
+
+	if (!count)
+		return 0;
+
+	if (count > MAX_PACKET_SIZE)
+		return -E2BIG;
+
+	retval = gb_raw_send(raw, count, buf);
+	if (retval)
+		return retval;
+
+	return count;
+}
+
+static ssize_t raw_read(struct file *file, char __user *buf, size_t count,
+			loff_t *ppos)
+{
+	struct gb_raw *raw = file->private_data;
+	int retval = 0;
+	struct raw_data *raw_data;
+
+	mutex_lock(&raw->list_lock);
+	if (list_empty(&raw->list))
+		goto exit;
+
+	raw_data = list_first_entry(&raw->list, struct raw_data, entry);
+	if (raw_data->len > count) {
+		retval = -ENOSPC;
+		goto exit;
+	}
+
+	if (copy_to_user(buf, &raw_data->data[0], raw_data->len)) {
+		retval = -EFAULT;
+		goto exit;
+	}
+
+	list_del(&raw_data->entry);
+	raw->list_data -= raw_data->len;
+	retval = raw_data->len;
+	kfree(raw_data);
+
+exit:
+	mutex_unlock(&raw->list_lock);
+	return retval;
+}
+
+static const struct file_operations raw_fops = {
+	.owner		= THIS_MODULE,
+	.write		= raw_write,
+	.read		= raw_read,
+	.open		= raw_open,
+	.llseek		= noop_llseek,
+};
+
+static const struct greybus_bundle_id gb_raw_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_RAW) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_raw_id_table);
+
+static struct greybus_driver gb_raw_driver = {
+	.name		= "raw",
+	.probe		= gb_raw_probe,
+	.disconnect	= gb_raw_disconnect,
+	.id_table	= gb_raw_id_table,
+};
+
+static int raw_init(void)
+{
+	dev_t dev;
+	int retval;
+
+	raw_class = class_create(THIS_MODULE, "gb_raw");
+	if (IS_ERR(raw_class)) {
+		retval = PTR_ERR(raw_class);
+		goto error_class;
+	}
+
+	retval = alloc_chrdev_region(&dev, 0, NUM_MINORS, "gb_raw");
+	if (retval < 0)
+		goto error_chrdev;
+
+	raw_major = MAJOR(dev);
+
+	retval = greybus_register(&gb_raw_driver);
+	if (retval)
+		goto error_gb;
+
+	return 0;
+
+error_gb:
+	unregister_chrdev_region(dev, NUM_MINORS);
+error_chrdev:
+	class_destroy(raw_class);
+error_class:
+	return retval;
+}
+module_init(raw_init);
+
+static void __exit raw_exit(void)
+{
+	greybus_deregister(&gb_raw_driver);
+	unregister_chrdev_region(MKDEV(raw_major, 0), NUM_MINORS);
+	class_destroy(raw_class);
+	ida_destroy(&minors);
+}
+module_exit(raw_exit);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/sdio.c b/drivers/staging/greybus/sdio.c
new file mode 100644
index 000000000000..c7133b1c7fd8
--- /dev/null
+++ b/drivers/staging/greybus/sdio.c
@@ -0,0 +1,884 @@
+/*
+ * SD/MMC Greybus driver.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mmc/core.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/scatterlist.h>
+#include <linux/workqueue.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+struct gb_sdio_host {
+	struct gb_connection	*connection;
+	struct gbphy_device	*gbphy_dev;
+	struct mmc_host		*mmc;
+	struct mmc_request	*mrq;
+	struct mutex		lock;	/* lock for this host */
+	size_t			data_max;
+	spinlock_t		xfer;	/* lock to cancel ongoing transfer */
+	bool			xfer_stop;
+	struct workqueue_struct	*mrq_workqueue;
+	struct work_struct	mrqwork;
+	u8			queued_events;
+	bool			removed;
+	bool			card_present;
+	bool			read_only;
+};
+
+
+#define GB_SDIO_RSP_R1_R5_R6_R7	(GB_SDIO_RSP_PRESENT | GB_SDIO_RSP_CRC | \
+				 GB_SDIO_RSP_OPCODE)
+#define GB_SDIO_RSP_R3_R4	(GB_SDIO_RSP_PRESENT)
+#define GB_SDIO_RSP_R2		(GB_SDIO_RSP_PRESENT | GB_SDIO_RSP_CRC | \
+				 GB_SDIO_RSP_136)
+#define GB_SDIO_RSP_R1B		(GB_SDIO_RSP_PRESENT | GB_SDIO_RSP_CRC | \
+				 GB_SDIO_RSP_OPCODE | GB_SDIO_RSP_BUSY)
+
+/* kernel vdd starts at 0x80 and we need to translate to greybus ones 0x01 */
+#define GB_SDIO_VDD_SHIFT	8
+
+#ifndef MMC_CAP2_CORE_RUNTIME_PM
+#define MMC_CAP2_CORE_RUNTIME_PM	0
+#endif
+
+static inline bool single_op(struct mmc_command *cmd)
+{
+	uint32_t opcode = cmd->opcode;
+
+	return opcode == MMC_WRITE_BLOCK ||
+	       opcode == MMC_READ_SINGLE_BLOCK;
+}
+
+static void _gb_sdio_set_host_caps(struct gb_sdio_host *host, u32 r)
+{
+	u32 caps = 0;
+	u32 caps2 = 0;
+
+	caps = ((r & GB_SDIO_CAP_NONREMOVABLE) ? MMC_CAP_NONREMOVABLE : 0) |
+		((r & GB_SDIO_CAP_4_BIT_DATA) ? MMC_CAP_4_BIT_DATA : 0) |
+		((r & GB_SDIO_CAP_8_BIT_DATA) ? MMC_CAP_8_BIT_DATA : 0) |
+		((r & GB_SDIO_CAP_MMC_HS) ? MMC_CAP_MMC_HIGHSPEED : 0) |
+		((r & GB_SDIO_CAP_SD_HS) ? MMC_CAP_SD_HIGHSPEED : 0) |
+		((r & GB_SDIO_CAP_ERASE) ? MMC_CAP_ERASE : 0) |
+		((r & GB_SDIO_CAP_1_2V_DDR) ? MMC_CAP_1_2V_DDR : 0) |
+		((r & GB_SDIO_CAP_1_8V_DDR) ? MMC_CAP_1_8V_DDR : 0) |
+		((r & GB_SDIO_CAP_POWER_OFF_CARD) ? MMC_CAP_POWER_OFF_CARD : 0) |
+		((r & GB_SDIO_CAP_UHS_SDR12) ? MMC_CAP_UHS_SDR12 : 0) |
+		((r & GB_SDIO_CAP_UHS_SDR25) ? MMC_CAP_UHS_SDR25 : 0) |
+		((r & GB_SDIO_CAP_UHS_SDR50) ? MMC_CAP_UHS_SDR50 : 0) |
+		((r & GB_SDIO_CAP_UHS_SDR104) ? MMC_CAP_UHS_SDR104 : 0) |
+		((r & GB_SDIO_CAP_UHS_DDR50) ? MMC_CAP_UHS_DDR50 : 0) |
+		((r & GB_SDIO_CAP_DRIVER_TYPE_A) ? MMC_CAP_DRIVER_TYPE_A : 0) |
+		((r & GB_SDIO_CAP_DRIVER_TYPE_C) ? MMC_CAP_DRIVER_TYPE_C : 0) |
+		((r & GB_SDIO_CAP_DRIVER_TYPE_D) ? MMC_CAP_DRIVER_TYPE_D : 0);
+
+	caps2 = ((r & GB_SDIO_CAP_HS200_1_2V) ? MMC_CAP2_HS200_1_2V_SDR : 0) |
+		((r & GB_SDIO_CAP_HS400_1_2V) ? MMC_CAP2_HS400_1_2V : 0) |
+		((r & GB_SDIO_CAP_HS400_1_8V) ? MMC_CAP2_HS400_1_8V : 0) |
+		((r & GB_SDIO_CAP_HS200_1_8V) ? MMC_CAP2_HS200_1_8V_SDR : 0);
+
+	host->mmc->caps = caps;
+	host->mmc->caps2 = caps2 | MMC_CAP2_CORE_RUNTIME_PM;
+
+	if (caps & MMC_CAP_NONREMOVABLE)
+		host->card_present = true;
+}
+
+static u32 _gb_sdio_get_host_ocr(u32 ocr)
+{
+	return (((ocr & GB_SDIO_VDD_165_195) ? MMC_VDD_165_195 : 0) |
+		((ocr & GB_SDIO_VDD_20_21) ? MMC_VDD_20_21 : 0) |
+		((ocr & GB_SDIO_VDD_21_22) ? MMC_VDD_21_22 : 0) |
+		((ocr & GB_SDIO_VDD_22_23) ? MMC_VDD_22_23 : 0) |
+		((ocr & GB_SDIO_VDD_23_24) ? MMC_VDD_23_24 : 0) |
+		((ocr & GB_SDIO_VDD_24_25) ? MMC_VDD_24_25 : 0) |
+		((ocr & GB_SDIO_VDD_25_26) ? MMC_VDD_25_26 : 0) |
+		((ocr & GB_SDIO_VDD_26_27) ? MMC_VDD_26_27 : 0) |
+		((ocr & GB_SDIO_VDD_27_28) ? MMC_VDD_27_28 : 0) |
+		((ocr & GB_SDIO_VDD_28_29) ? MMC_VDD_28_29 : 0) |
+		((ocr & GB_SDIO_VDD_29_30) ? MMC_VDD_29_30 : 0) |
+		((ocr & GB_SDIO_VDD_30_31) ? MMC_VDD_30_31 : 0) |
+		((ocr & GB_SDIO_VDD_31_32) ? MMC_VDD_31_32 : 0) |
+		((ocr & GB_SDIO_VDD_32_33) ? MMC_VDD_32_33 : 0) |
+		((ocr & GB_SDIO_VDD_33_34) ? MMC_VDD_33_34 : 0) |
+		((ocr & GB_SDIO_VDD_34_35) ? MMC_VDD_34_35 : 0) |
+		((ocr & GB_SDIO_VDD_35_36) ? MMC_VDD_35_36 : 0)
+		);
+}
+
+static int gb_sdio_get_caps(struct gb_sdio_host *host)
+{
+	struct gb_sdio_get_caps_response response;
+	struct mmc_host *mmc = host->mmc;
+	u16 data_max;
+	u32 blksz;
+	u32 ocr;
+	u32 r;
+	int ret;
+
+	ret = gb_operation_sync(host->connection, GB_SDIO_TYPE_GET_CAPABILITIES,
+				NULL, 0, &response, sizeof(response));
+	if (ret < 0)
+		return ret;
+	r = le32_to_cpu(response.caps);
+
+	_gb_sdio_set_host_caps(host, r);
+
+	/* get the max block size that could fit our payload */
+	data_max = gb_operation_get_payload_size_max(host->connection);
+	data_max = min(data_max - sizeof(struct gb_sdio_transfer_request),
+		       data_max - sizeof(struct gb_sdio_transfer_response));
+
+	blksz = min_t(u16, le16_to_cpu(response.max_blk_size), data_max);
+	blksz = max_t(u32, 512, blksz);
+
+	mmc->max_blk_size = rounddown_pow_of_two(blksz);
+	mmc->max_blk_count = le16_to_cpu(response.max_blk_count);
+	host->data_max = data_max;
+
+	/* get ocr supported values */
+	ocr = _gb_sdio_get_host_ocr(le32_to_cpu(response.ocr));
+	mmc->ocr_avail = ocr;
+	mmc->ocr_avail_sdio = mmc->ocr_avail;
+	mmc->ocr_avail_sd = mmc->ocr_avail;
+	mmc->ocr_avail_mmc = mmc->ocr_avail;
+
+	/* get frequency range values */
+	mmc->f_min = le32_to_cpu(response.f_min);
+	mmc->f_max = le32_to_cpu(response.f_max);
+
+	return 0;
+}
+
+static void _gb_queue_event(struct gb_sdio_host *host, u8 event)
+{
+	if (event & GB_SDIO_CARD_INSERTED)
+		host->queued_events &= ~GB_SDIO_CARD_REMOVED;
+	else if (event & GB_SDIO_CARD_REMOVED)
+		host->queued_events &= ~GB_SDIO_CARD_INSERTED;
+
+	host->queued_events |= event;
+}
+
+static int _gb_sdio_process_events(struct gb_sdio_host *host, u8 event)
+{
+	u8 state_changed = 0;
+
+	if (event & GB_SDIO_CARD_INSERTED) {
+		if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+			return 0;
+		if (host->card_present)
+			return 0;
+		host->card_present = true;
+		state_changed = 1;
+	}
+
+	if (event & GB_SDIO_CARD_REMOVED) {
+		if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+			return 0;
+		if (!(host->card_present))
+			return 0;
+		host->card_present = false;
+		state_changed = 1;
+	}
+
+	if (event & GB_SDIO_WP) {
+		host->read_only = true;
+	}
+
+	if (state_changed) {
+		dev_info(mmc_dev(host->mmc), "card %s now event\n",
+			 (host->card_present ?  "inserted" : "removed"));
+		mmc_detect_change(host->mmc, 0);
+	}
+
+	return 0;
+}
+
+static int gb_sdio_request_handler(struct gb_operation *op)
+{
+	struct gb_sdio_host *host = gb_connection_get_data(op->connection);
+	struct gb_message *request;
+	struct gb_sdio_event_request *payload;
+	u8 type = op->type;
+	int ret =  0;
+	u8 event;
+
+	if (type != GB_SDIO_TYPE_EVENT) {
+		dev_err(mmc_dev(host->mmc),
+			"unsupported unsolicited event: %u\n", type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*payload)) {
+		dev_err(mmc_dev(host->mmc), "wrong event size received (%zu < %zu)\n",
+			request->payload_size, sizeof(*payload));
+		return -EINVAL;
+	}
+
+	payload = request->payload;
+	event = payload->event;
+
+	if (host->removed)
+		_gb_queue_event(host, event);
+	else
+		ret = _gb_sdio_process_events(host, event);
+
+	return ret;
+}
+
+static int gb_sdio_set_ios(struct gb_sdio_host *host,
+			   struct gb_sdio_set_ios_request *request)
+{
+	int ret;
+
+	ret = gbphy_runtime_get_sync(host->gbphy_dev);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(host->connection, GB_SDIO_TYPE_SET_IOS, request,
+				sizeof(*request), NULL, 0);
+
+	gbphy_runtime_put_autosuspend(host->gbphy_dev);
+
+	return ret;
+}
+
+static int _gb_sdio_send(struct gb_sdio_host *host, struct mmc_data *data,
+			 size_t len, u16 nblocks, off_t skip)
+{
+	struct gb_sdio_transfer_request *request;
+	struct gb_sdio_transfer_response *response;
+	struct gb_operation *operation;
+	struct scatterlist *sg = data->sg;
+	unsigned int sg_len = data->sg_len;
+	size_t copied;
+	u16 send_blksz;
+	u16 send_blocks;
+	int ret;
+
+	WARN_ON(len > host->data_max);
+
+	operation = gb_operation_create(host->connection, GB_SDIO_TYPE_TRANSFER,
+					len + sizeof(*request),
+					sizeof(*response), GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	request = operation->request->payload;
+	request->data_flags = (data->flags >> 8);
+	request->data_blocks = cpu_to_le16(nblocks);
+	request->data_blksz = cpu_to_le16(data->blksz);
+
+	copied = sg_pcopy_to_buffer(sg, sg_len, &request->data[0], len, skip);
+
+	if (copied != len) {
+		ret = -EINVAL;
+		goto err_put_operation;
+	}
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret < 0)
+		goto err_put_operation;
+
+	response = operation->response->payload;
+
+	send_blocks = le16_to_cpu(response->data_blocks);
+	send_blksz = le16_to_cpu(response->data_blksz);
+
+	if (len != send_blksz * send_blocks) {
+		dev_err(mmc_dev(host->mmc), "send: size received: %zu != %d\n",
+			len, send_blksz * send_blocks);
+		ret = -EINVAL;
+	}
+
+err_put_operation:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int _gb_sdio_recv(struct gb_sdio_host *host, struct mmc_data *data,
+			 size_t len, u16 nblocks, off_t skip)
+{
+	struct gb_sdio_transfer_request *request;
+	struct gb_sdio_transfer_response *response;
+	struct gb_operation *operation;
+	struct scatterlist *sg = data->sg;
+	unsigned int sg_len = data->sg_len;
+	size_t copied;
+	u16 recv_blksz;
+	u16 recv_blocks;
+	int ret;
+
+	WARN_ON(len > host->data_max);
+
+	operation = gb_operation_create(host->connection, GB_SDIO_TYPE_TRANSFER,
+					sizeof(*request),
+					len + sizeof(*response), GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	request = operation->request->payload;
+	request->data_flags = (data->flags >> 8);
+	request->data_blocks = cpu_to_le16(nblocks);
+	request->data_blksz = cpu_to_le16(data->blksz);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret < 0)
+		goto err_put_operation;
+
+	response = operation->response->payload;
+	recv_blocks = le16_to_cpu(response->data_blocks);
+	recv_blksz = le16_to_cpu(response->data_blksz);
+
+	if (len != recv_blksz * recv_blocks) {
+		dev_err(mmc_dev(host->mmc), "recv: size received: %d != %zu\n",
+			recv_blksz * recv_blocks, len);
+		ret = -EINVAL;
+		goto err_put_operation;
+	}
+
+	copied = sg_pcopy_from_buffer(sg, sg_len, &response->data[0], len,
+				      skip);
+	if (copied != len)
+		ret = -EINVAL;
+
+err_put_operation:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int gb_sdio_transfer(struct gb_sdio_host *host, struct mmc_data *data)
+{
+	size_t left, len;
+	off_t skip = 0;
+	int ret = 0;
+	u16 nblocks;
+
+	if (single_op(data->mrq->cmd) && data->blocks > 1) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	left = data->blksz * data->blocks;
+
+	while (left) {
+		/* check is a stop transmission is pending */
+		spin_lock(&host->xfer);
+		if (host->xfer_stop) {
+			host->xfer_stop = false;
+			spin_unlock(&host->xfer);
+			ret = -EINTR;
+			goto out;
+		}
+		spin_unlock(&host->xfer);
+		len = min(left, host->data_max);
+		nblocks = len / data->blksz;
+		len = nblocks * data->blksz;
+
+		if (data->flags & MMC_DATA_READ) {
+			ret = _gb_sdio_recv(host, data, len, nblocks, skip);
+			if (ret < 0)
+				goto out;
+		} else {
+			ret = _gb_sdio_send(host, data, len, nblocks, skip);
+			if (ret < 0)
+				goto out;
+		}
+		data->bytes_xfered += len;
+		left -= len;
+		skip += len;
+	}
+
+out:
+	data->error = ret;
+	return ret;
+}
+
+static int gb_sdio_command(struct gb_sdio_host *host, struct mmc_command *cmd)
+{
+	struct gb_sdio_command_request request = {0};
+	struct gb_sdio_command_response response;
+	struct mmc_data *data = host->mrq->data;
+	u8 cmd_flags;
+	u8 cmd_type;
+	int i;
+	int ret;
+
+	switch (mmc_resp_type(cmd)) {
+	case MMC_RSP_NONE:
+		cmd_flags = GB_SDIO_RSP_NONE;
+		break;
+	case MMC_RSP_R1:
+		cmd_flags = GB_SDIO_RSP_R1_R5_R6_R7;
+		break;
+	case MMC_RSP_R1B:
+		cmd_flags = GB_SDIO_RSP_R1B;
+		break;
+	case MMC_RSP_R2:
+		cmd_flags = GB_SDIO_RSP_R2;
+		break;
+	case MMC_RSP_R3:
+		cmd_flags = GB_SDIO_RSP_R3_R4;
+		break;
+	default:
+		dev_err(mmc_dev(host->mmc), "cmd flag invalid 0x%04x\n",
+			mmc_resp_type(cmd));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	switch (mmc_cmd_type(cmd)) {
+	case MMC_CMD_BC:
+		cmd_type = GB_SDIO_CMD_BC;
+		break;
+	case MMC_CMD_BCR:
+		cmd_type = GB_SDIO_CMD_BCR;
+		break;
+	case MMC_CMD_AC:
+		cmd_type = GB_SDIO_CMD_AC;
+		break;
+	case MMC_CMD_ADTC:
+		cmd_type = GB_SDIO_CMD_ADTC;
+		break;
+	default:
+		dev_err(mmc_dev(host->mmc), "cmd type invalid 0x%04x\n",
+			mmc_cmd_type(cmd));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	request.cmd = cmd->opcode;
+	request.cmd_flags = cmd_flags;
+	request.cmd_type = cmd_type;
+	request.cmd_arg = cpu_to_le32(cmd->arg);
+	/* some controllers need to know at command time data details */
+	if (data) {
+		request.data_blocks = cpu_to_le16(data->blocks);
+		request.data_blksz = cpu_to_le16(data->blksz);
+	}
+
+	ret = gb_operation_sync(host->connection, GB_SDIO_TYPE_COMMAND,
+				&request, sizeof(request), &response,
+				sizeof(response));
+	if (ret < 0)
+		goto out;
+
+	/* no response expected */
+	if (cmd_flags & GB_SDIO_RSP_NONE)
+		goto out;
+
+	/* long response expected */
+	if (cmd_flags & GB_SDIO_RSP_R2)
+		for (i = 0; i < 4; i++)
+			cmd->resp[i] = le32_to_cpu(response.resp[i]);
+	else
+		cmd->resp[0] = le32_to_cpu(response.resp[0]);
+
+out:
+	cmd->error = ret;
+	return ret;
+}
+
+static void gb_sdio_mrq_work(struct work_struct *work)
+{
+	struct gb_sdio_host *host;
+	struct mmc_request *mrq;
+	int ret;
+
+	host = container_of(work, struct gb_sdio_host, mrqwork);
+
+	ret = gbphy_runtime_get_sync(host->gbphy_dev);
+	if (ret)
+		return;
+
+	mutex_lock(&host->lock);
+	mrq = host->mrq;
+	if (!mrq) {
+		mutex_unlock(&host->lock);
+		gbphy_runtime_put_autosuspend(host->gbphy_dev);
+		dev_err(mmc_dev(host->mmc), "mmc request is NULL");
+		return;
+	}
+
+	if (host->removed) {
+		mrq->cmd->error = -ESHUTDOWN;
+		goto done;
+	}
+
+	if (mrq->sbc) {
+		ret = gb_sdio_command(host, mrq->sbc);
+		if (ret < 0)
+			goto done;
+	}
+
+	ret = gb_sdio_command(host, mrq->cmd);
+	if (ret < 0)
+		goto done;
+
+	if (mrq->data) {
+		ret = gb_sdio_transfer(host, mrq->data);
+		if (ret < 0)
+			goto done;
+	}
+
+	if (mrq->stop) {
+		ret = gb_sdio_command(host, mrq->stop);
+		if (ret < 0)
+			goto done;
+	}
+
+done:
+	host->mrq = NULL;
+	mutex_unlock(&host->lock);
+	mmc_request_done(host->mmc, mrq);
+	gbphy_runtime_put_autosuspend(host->gbphy_dev);
+}
+
+static void gb_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct gb_sdio_host *host = mmc_priv(mmc);
+	struct mmc_command *cmd = mrq->cmd;
+
+	/* Check if it is a cancel to ongoing transfer */
+	if (cmd->opcode == MMC_STOP_TRANSMISSION) {
+		spin_lock(&host->xfer);
+		host->xfer_stop = true;
+		spin_unlock(&host->xfer);
+	}
+
+	mutex_lock(&host->lock);
+
+	WARN_ON(host->mrq);
+	host->mrq = mrq;
+
+	if (host->removed) {
+		mrq->cmd->error = -ESHUTDOWN;
+		goto out;
+	}
+	if (!host->card_present) {
+		mrq->cmd->error = -ENOMEDIUM;
+		goto out;
+	}
+
+	queue_work(host->mrq_workqueue, &host->mrqwork);
+
+	mutex_unlock(&host->lock);
+	return;
+
+out:
+	host->mrq = NULL;
+	mutex_unlock(&host->lock);
+	mmc_request_done(mmc, mrq);
+}
+
+static void gb_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct gb_sdio_host *host = mmc_priv(mmc);
+	struct gb_sdio_set_ios_request request;
+	int ret;
+	u8 power_mode;
+	u8 bus_width;
+	u8 timing;
+	u8 signal_voltage;
+	u8 drv_type;
+	u32 vdd = 0;
+
+	mutex_lock(&host->lock);
+	request.clock = cpu_to_le32(ios->clock);
+
+	if (ios->vdd)
+		vdd = 1 << (ios->vdd - GB_SDIO_VDD_SHIFT);
+	request.vdd = cpu_to_le32(vdd);
+
+	request.bus_mode = (ios->bus_mode == MMC_BUSMODE_OPENDRAIN ?
+			    GB_SDIO_BUSMODE_OPENDRAIN :
+			    GB_SDIO_BUSMODE_PUSHPULL);
+
+	switch (ios->power_mode) {
+	case MMC_POWER_OFF:
+	default:
+		power_mode = GB_SDIO_POWER_OFF;
+		break;
+	case MMC_POWER_UP:
+		power_mode = GB_SDIO_POWER_UP;
+		break;
+	case MMC_POWER_ON:
+		power_mode = GB_SDIO_POWER_ON;
+		break;
+	case MMC_POWER_UNDEFINED:
+		power_mode = GB_SDIO_POWER_UNDEFINED;
+		break;
+	}
+	request.power_mode = power_mode;
+
+	switch (ios->bus_width) {
+	case MMC_BUS_WIDTH_1:
+		bus_width = GB_SDIO_BUS_WIDTH_1;
+		break;
+	case MMC_BUS_WIDTH_4:
+	default:
+		bus_width = GB_SDIO_BUS_WIDTH_4;
+		break;
+	case MMC_BUS_WIDTH_8:
+		bus_width = GB_SDIO_BUS_WIDTH_8;
+		break;
+	}
+	request.bus_width = bus_width;
+
+	switch (ios->timing) {
+	case MMC_TIMING_LEGACY:
+	default:
+		timing = GB_SDIO_TIMING_LEGACY;
+		break;
+	case MMC_TIMING_MMC_HS:
+		timing = GB_SDIO_TIMING_MMC_HS;
+		break;
+	case MMC_TIMING_SD_HS:
+		timing = GB_SDIO_TIMING_SD_HS;
+		break;
+	case MMC_TIMING_UHS_SDR12:
+		timing = GB_SDIO_TIMING_UHS_SDR12;
+		break;
+	case MMC_TIMING_UHS_SDR25:
+		timing = GB_SDIO_TIMING_UHS_SDR25;
+		break;
+	case MMC_TIMING_UHS_SDR50:
+		timing = GB_SDIO_TIMING_UHS_SDR50;
+		break;
+	case MMC_TIMING_UHS_SDR104:
+		timing = GB_SDIO_TIMING_UHS_SDR104;
+		break;
+	case MMC_TIMING_UHS_DDR50:
+		timing = GB_SDIO_TIMING_UHS_DDR50;
+		break;
+	case MMC_TIMING_MMC_DDR52:
+		timing = GB_SDIO_TIMING_MMC_DDR52;
+		break;
+	case MMC_TIMING_MMC_HS200:
+		timing = GB_SDIO_TIMING_MMC_HS200;
+		break;
+	case MMC_TIMING_MMC_HS400:
+		timing = GB_SDIO_TIMING_MMC_HS400;
+		break;
+	}
+	request.timing = timing;
+
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_330:
+		signal_voltage = GB_SDIO_SIGNAL_VOLTAGE_330;
+		break;
+	case MMC_SIGNAL_VOLTAGE_180:
+	default:
+		signal_voltage = GB_SDIO_SIGNAL_VOLTAGE_180;
+		break;
+	case MMC_SIGNAL_VOLTAGE_120:
+		signal_voltage = GB_SDIO_SIGNAL_VOLTAGE_120;
+		break;
+	}
+	request.signal_voltage = signal_voltage;
+
+	switch (ios->drv_type) {
+	case MMC_SET_DRIVER_TYPE_A:
+		drv_type = GB_SDIO_SET_DRIVER_TYPE_A;
+		break;
+	case MMC_SET_DRIVER_TYPE_C:
+		drv_type = GB_SDIO_SET_DRIVER_TYPE_C;
+		break;
+	case MMC_SET_DRIVER_TYPE_D:
+		drv_type = GB_SDIO_SET_DRIVER_TYPE_D;
+		break;
+	case MMC_SET_DRIVER_TYPE_B:
+	default:
+		drv_type = GB_SDIO_SET_DRIVER_TYPE_B;
+		break;
+	}
+	request.drv_type = drv_type;
+
+	ret = gb_sdio_set_ios(host, &request);
+	if (ret < 0)
+		goto out;
+
+	memcpy(&mmc->ios, ios, sizeof(mmc->ios));
+
+out:
+	mutex_unlock(&host->lock);
+}
+
+static int gb_mmc_get_ro(struct mmc_host *mmc)
+{
+	struct gb_sdio_host *host = mmc_priv(mmc);
+
+	mutex_lock(&host->lock);
+	if (host->removed) {
+		mutex_unlock(&host->lock);
+		return -ESHUTDOWN;
+	}
+	mutex_unlock(&host->lock);
+
+	return host->read_only;
+}
+
+static int gb_mmc_get_cd(struct mmc_host *mmc)
+{
+	struct gb_sdio_host *host = mmc_priv(mmc);
+
+	mutex_lock(&host->lock);
+	if (host->removed) {
+		mutex_unlock(&host->lock);
+		return -ESHUTDOWN;
+	}
+	mutex_unlock(&host->lock);
+
+	return host->card_present;
+}
+
+static int gb_mmc_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	return 0;
+}
+
+static const struct mmc_host_ops gb_sdio_ops = {
+	.request	= gb_mmc_request,
+	.set_ios	= gb_mmc_set_ios,
+	.get_ro		= gb_mmc_get_ro,
+	.get_cd		= gb_mmc_get_cd,
+	.start_signal_voltage_switch	= gb_mmc_switch_voltage,
+};
+
+static int gb_sdio_probe(struct gbphy_device *gbphy_dev,
+			 const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct mmc_host *mmc;
+	struct gb_sdio_host *host;
+	int ret = 0;
+
+	mmc = mmc_alloc_host(sizeof(*host), &gbphy_dev->dev);
+	if (!mmc)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  gb_sdio_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto exit_mmc_free;
+	}
+
+	host = mmc_priv(mmc);
+	host->mmc = mmc;
+	host->removed = true;
+
+	host->connection = connection;
+	gb_connection_set_data(connection, host);
+	host->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, host);
+
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	ret = gb_sdio_get_caps(host);
+	if (ret < 0)
+		goto exit_connection_disable;
+
+	mmc->ops = &gb_sdio_ops;
+
+	mmc->max_segs = host->mmc->max_blk_count;
+
+	/* for now we make a map 1:1 between max request and segment size */
+	mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
+	mmc->max_seg_size = mmc->max_req_size;
+
+	mutex_init(&host->lock);
+	spin_lock_init(&host->xfer);
+	host->mrq_workqueue = alloc_workqueue("mmc-%s", 0, 1,
+					      dev_name(&gbphy_dev->dev));
+	if (!host->mrq_workqueue) {
+		ret = -ENOMEM;
+		goto exit_connection_disable;
+	}
+	INIT_WORK(&host->mrqwork, gb_sdio_mrq_work);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_wq_destroy;
+
+	ret = mmc_add_host(mmc);
+	if (ret < 0)
+		goto exit_wq_destroy;
+	host->removed = false;
+	ret = _gb_sdio_process_events(host, host->queued_events);
+	host->queued_events = 0;
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+
+	return ret;
+
+exit_wq_destroy:
+	destroy_workqueue(host->mrq_workqueue);
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_mmc_free:
+	mmc_free_host(mmc);
+
+	return ret;
+}
+
+static void gb_sdio_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_sdio_host *host = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = host->connection;
+	struct mmc_host *mmc;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	mutex_lock(&host->lock);
+	host->removed = true;
+	mmc = host->mmc;
+	gb_connection_set_data(connection, NULL);
+	mutex_unlock(&host->lock);
+
+	flush_workqueue(host->mrq_workqueue);
+	destroy_workqueue(host->mrq_workqueue);
+	gb_connection_disable_rx(connection);
+	mmc_remove_host(mmc);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	mmc_free_host(mmc);
+}
+
+static const struct gbphy_device_id gb_sdio_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_SDIO) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_sdio_id_table);
+
+static struct gbphy_driver sdio_driver = {
+	.name		= "sdio",
+	.probe		= gb_sdio_probe,
+	.remove		= gb_sdio_remove,
+	.id_table	= gb_sdio_id_table,
+};
+
+module_gbphy_driver(sdio_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/spi.c b/drivers/staging/greybus/spi.c
new file mode 100644
index 000000000000..c893552b5c0b
--- /dev/null
+++ b/drivers/staging/greybus/spi.c
@@ -0,0 +1,79 @@
+/*
+ * SPI bridge PHY driver.
+ *
+ * Copyright 2014-2016 Google Inc.
+ * Copyright 2014-2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/module.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+#include "spilib.h"
+
+static struct spilib_ops *spilib_ops;
+
+static int gb_spi_probe(struct gbphy_device *gbphy_dev,
+			const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	int ret;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  NULL);
+	if (IS_ERR(connection))
+		return PTR_ERR(connection);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	ret = gb_spilib_master_init(connection, &gbphy_dev->dev, spilib_ops);
+	if (ret)
+		goto exit_connection_disable;
+
+	gb_gbphy_set_data(gbphy_dev, connection);
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+
+	return ret;
+}
+
+static void gb_spi_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_connection *connection = gb_gbphy_get_data(gbphy_dev);
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	gb_spilib_master_exit(connection);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+}
+
+static const struct gbphy_device_id gb_spi_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_SPI) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_spi_id_table);
+
+static struct gbphy_driver spi_driver = {
+	.name		= "spi",
+	.probe		= gb_spi_probe,
+	.remove		= gb_spi_remove,
+	.id_table	= gb_spi_id_table,
+};
+
+module_gbphy_driver(spi_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/spilib.c b/drivers/staging/greybus/spilib.c
new file mode 100644
index 000000000000..e97b19148497
--- /dev/null
+++ b/drivers/staging/greybus/spilib.c
@@ -0,0 +1,565 @@
+/*
+ * Greybus SPI library
+ *
+ * Copyright 2014-2016 Google Inc.
+ * Copyright 2014-2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "greybus.h"
+#include "spilib.h"
+
+struct gb_spilib {
+	struct gb_connection	*connection;
+	struct device		*parent;
+	struct spi_transfer	*first_xfer;
+	struct spi_transfer	*last_xfer;
+	struct spilib_ops	*ops;
+	u32			rx_xfer_offset;
+	u32			tx_xfer_offset;
+	u32			last_xfer_size;
+	unsigned int		op_timeout;
+	u16			mode;
+	u16			flags;
+	u32			bits_per_word_mask;
+	u8			num_chipselect;
+	u32			min_speed_hz;
+	u32			max_speed_hz;
+};
+
+#define GB_SPI_STATE_MSG_DONE		((void *)0)
+#define GB_SPI_STATE_MSG_IDLE		((void *)1)
+#define GB_SPI_STATE_MSG_RUNNING	((void *)2)
+#define GB_SPI_STATE_OP_READY		((void *)3)
+#define GB_SPI_STATE_OP_DONE		((void *)4)
+#define GB_SPI_STATE_MSG_ERROR		((void *)-1)
+
+#define XFER_TIMEOUT_TOLERANCE		200
+
+static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
+{
+	return gb_connection_get_data(spi->connection);
+}
+
+static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
+{
+	size_t headers_size;
+
+	data_max -= sizeof(struct gb_spi_transfer_request);
+	headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
+
+	return tx_size + headers_size > data_max ? 0 : 1;
+}
+
+static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
+				size_t data_max)
+{
+	size_t rx_xfer_size;
+
+	data_max -= sizeof(struct gb_spi_transfer_response);
+
+	if (rx_size + len > data_max)
+		rx_xfer_size = data_max - rx_size;
+	else
+		rx_xfer_size = len;
+
+	/* if this is a write_read, for symmetry read the same as write */
+	if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
+		rx_xfer_size = *tx_xfer_size;
+	if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
+		*tx_xfer_size = rx_xfer_size;
+
+	return rx_xfer_size;
+}
+
+static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
+				size_t data_max)
+{
+	size_t headers_size;
+
+	data_max -= sizeof(struct gb_spi_transfer_request);
+	headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
+
+	if (tx_size + headers_size + len > data_max)
+		return data_max - (tx_size + sizeof(struct gb_spi_transfer));
+
+	return len;
+}
+
+static void clean_xfer_state(struct gb_spilib *spi)
+{
+	spi->first_xfer = NULL;
+	spi->last_xfer = NULL;
+	spi->rx_xfer_offset = 0;
+	spi->tx_xfer_offset = 0;
+	spi->last_xfer_size = 0;
+	spi->op_timeout = 0;
+}
+
+static bool is_last_xfer_done(struct gb_spilib *spi)
+{
+	struct spi_transfer *last_xfer = spi->last_xfer;
+
+	if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
+	    (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
+		return true;
+
+	return false;
+}
+
+static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
+{
+	struct spi_transfer *last_xfer = spi->last_xfer;
+
+	if (msg->state != GB_SPI_STATE_OP_DONE)
+		return 0;
+
+	/*
+	 * if we transferred all content of the last transfer, reset values and
+	 * check if this was the last transfer in the message
+	 */
+	if (is_last_xfer_done(spi)) {
+		spi->tx_xfer_offset = 0;
+		spi->rx_xfer_offset = 0;
+		spi->op_timeout = 0;
+		if (last_xfer == list_last_entry(&msg->transfers,
+						 struct spi_transfer,
+						 transfer_list))
+			msg->state = GB_SPI_STATE_MSG_DONE;
+		else
+			spi->first_xfer = list_next_entry(last_xfer,
+							  transfer_list);
+		return 0;
+	}
+
+	spi->first_xfer = last_xfer;
+	if (last_xfer->tx_buf)
+		spi->tx_xfer_offset += spi->last_xfer_size;
+
+	if (last_xfer->rx_buf)
+		spi->rx_xfer_offset += spi->last_xfer_size;
+
+	return 0;
+}
+
+static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
+					  struct spi_message *msg)
+{
+	if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
+				    transfer_list))
+		return NULL;
+
+	return list_next_entry(xfer, transfer_list);
+}
+
+/* Routines to transfer data */
+static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
+		struct gb_connection *connection, struct spi_message *msg)
+{
+	struct gb_spi_transfer_request *request;
+	struct spi_device *dev = msg->spi;
+	struct spi_transfer *xfer;
+	struct gb_spi_transfer *gb_xfer;
+	struct gb_operation *operation;
+	u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
+	u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
+	u32 total_len = 0;
+	unsigned int xfer_timeout;
+	size_t data_max;
+	void *tx_data;
+
+	data_max = gb_operation_get_payload_size_max(connection);
+	xfer = spi->first_xfer;
+
+	/* Find number of transfers queued and tx/rx length in the message */
+
+	while (msg->state != GB_SPI_STATE_OP_READY) {
+		msg->state = GB_SPI_STATE_MSG_RUNNING;
+		spi->last_xfer = xfer;
+
+		if (!xfer->tx_buf && !xfer->rx_buf) {
+			dev_err(spi->parent,
+				"bufferless transfer, length %u\n", xfer->len);
+			msg->state = GB_SPI_STATE_MSG_ERROR;
+			return NULL;
+		}
+
+		tx_xfer_size = 0;
+		rx_xfer_size = 0;
+
+		if (xfer->tx_buf) {
+			len = xfer->len - spi->tx_xfer_offset;
+			if (!tx_header_fit_operation(tx_size, count, data_max))
+				break;
+			tx_xfer_size = calc_tx_xfer_size(tx_size, count,
+							 len, data_max);
+			spi->last_xfer_size = tx_xfer_size;
+		}
+
+		if (xfer->rx_buf) {
+			len = xfer->len - spi->rx_xfer_offset;
+			rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
+							 len, data_max);
+			spi->last_xfer_size = rx_xfer_size;
+		}
+
+		tx_size += tx_xfer_size;
+		rx_size += rx_xfer_size;
+
+		total_len += spi->last_xfer_size;
+		count++;
+
+		xfer = get_next_xfer(xfer, msg);
+		if (!xfer || total_len >= data_max)
+			msg->state = GB_SPI_STATE_OP_READY;
+	}
+
+	/*
+	 * In addition to space for all message descriptors we need
+	 * to have enough to hold all tx data.
+	 */
+	request_size = sizeof(*request);
+	request_size += count * sizeof(*gb_xfer);
+	request_size += tx_size;
+
+	/* Response consists only of incoming data */
+	operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
+					request_size, rx_size, GFP_KERNEL);
+	if (!operation)
+		return NULL;
+
+	request = operation->request->payload;
+	request->count = cpu_to_le16(count);
+	request->mode = dev->mode;
+	request->chip_select = dev->chip_select;
+
+	gb_xfer = &request->transfers[0];
+	tx_data = gb_xfer + count;	/* place tx data after last gb_xfer */
+
+	/* Fill in the transfers array */
+	xfer = spi->first_xfer;
+	while (msg->state != GB_SPI_STATE_OP_DONE) {
+		if (xfer == spi->last_xfer)
+			xfer_len = spi->last_xfer_size;
+		else
+			xfer_len = xfer->len;
+
+		/* make sure we do not timeout in a slow transfer */
+		xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
+		xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
+
+		if (xfer_timeout > spi->op_timeout)
+			spi->op_timeout = xfer_timeout;
+
+		gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
+		gb_xfer->len = cpu_to_le32(xfer_len);
+		gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
+		gb_xfer->cs_change = xfer->cs_change;
+		gb_xfer->bits_per_word = xfer->bits_per_word;
+
+		/* Copy tx data */
+		if (xfer->tx_buf) {
+			gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
+			memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
+			       xfer_len);
+			tx_data += xfer_len;
+		}
+
+		if (xfer->rx_buf)
+			gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
+
+		if (xfer == spi->last_xfer) {
+			if (!is_last_xfer_done(spi))
+				gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
+			msg->state = GB_SPI_STATE_OP_DONE;
+			continue;
+		}
+
+		gb_xfer++;
+		xfer = get_next_xfer(xfer, msg);
+	}
+
+	msg->actual_length += total_len;
+
+	return operation;
+}
+
+static void gb_spi_decode_response(struct gb_spilib *spi,
+				   struct spi_message *msg,
+				   struct gb_spi_transfer_response *response)
+{
+	struct spi_transfer *xfer = spi->first_xfer;
+	void *rx_data = response->data;
+	u32 xfer_len;
+
+	while (xfer) {
+		/* Copy rx data */
+		if (xfer->rx_buf) {
+			if (xfer == spi->first_xfer)
+				xfer_len = xfer->len - spi->rx_xfer_offset;
+			else if (xfer == spi->last_xfer)
+				xfer_len = spi->last_xfer_size;
+			else
+				xfer_len = xfer->len;
+
+			memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
+			       xfer_len);
+			rx_data += xfer_len;
+		}
+
+		if (xfer == spi->last_xfer)
+			break;
+
+		xfer = list_next_entry(xfer, transfer_list);
+	}
+}
+
+static int gb_spi_transfer_one_message(struct spi_master *master,
+				       struct spi_message *msg)
+{
+	struct gb_spilib *spi = spi_master_get_devdata(master);
+	struct gb_connection *connection = spi->connection;
+	struct gb_spi_transfer_response *response;
+	struct gb_operation *operation;
+	int ret = 0;
+
+	spi->first_xfer = list_first_entry_or_null(&msg->transfers,
+						   struct spi_transfer,
+						   transfer_list);
+	if (!spi->first_xfer) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	msg->state = GB_SPI_STATE_MSG_IDLE;
+
+	while (msg->state != GB_SPI_STATE_MSG_DONE &&
+	       msg->state != GB_SPI_STATE_MSG_ERROR) {
+		operation = gb_spi_operation_create(spi, connection, msg);
+		if (!operation) {
+			msg->state = GB_SPI_STATE_MSG_ERROR;
+			ret = -EINVAL;
+			continue;
+		}
+
+		ret = gb_operation_request_send_sync_timeout(operation,
+							     spi->op_timeout);
+		if (!ret) {
+			response = operation->response->payload;
+			if (response)
+				gb_spi_decode_response(spi, msg, response);
+		} else {
+			dev_err(spi->parent,
+				"transfer operation failed: %d\n", ret);
+			msg->state = GB_SPI_STATE_MSG_ERROR;
+		}
+
+		gb_operation_put(operation);
+		setup_next_xfer(spi, msg);
+	}
+
+out:
+	msg->status = ret;
+	clean_xfer_state(spi);
+	spi_finalize_current_message(master);
+
+	return ret;
+}
+
+static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
+{
+	struct gb_spilib *spi = spi_master_get_devdata(master);
+
+	return spi->ops->prepare_transfer_hardware(spi->parent);
+}
+
+static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
+{
+	struct gb_spilib *spi = spi_master_get_devdata(master);
+
+	spi->ops->unprepare_transfer_hardware(spi->parent);
+
+	return 0;
+}
+
+static int gb_spi_setup(struct spi_device *spi)
+{
+	/* Nothing to do for now */
+	return 0;
+}
+
+static void gb_spi_cleanup(struct spi_device *spi)
+{
+	/* Nothing to do for now */
+}
+
+/* Routines to get controller information */
+
+/*
+ * Map Greybus spi mode bits/flags/bpw into Linux ones.
+ * All bits are same for now and so these macro's return same values.
+ */
+#define gb_spi_mode_map(mode) mode
+#define gb_spi_flags_map(flags) flags
+
+static int gb_spi_get_master_config(struct gb_spilib *spi)
+{
+	struct gb_spi_master_config_response response;
+	u16 mode, flags;
+	int ret;
+
+	ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
+				NULL, 0, &response, sizeof(response));
+	if (ret < 0)
+		return ret;
+
+	mode = le16_to_cpu(response.mode);
+	spi->mode = gb_spi_mode_map(mode);
+
+	flags = le16_to_cpu(response.flags);
+	spi->flags = gb_spi_flags_map(flags);
+
+	spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
+	spi->num_chipselect = response.num_chipselect;
+
+	spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
+	spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
+
+	return 0;
+}
+
+static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
+{
+	struct spi_master *master = get_master_from_spi(spi);
+	struct gb_spi_device_config_request request;
+	struct gb_spi_device_config_response response;
+	struct spi_board_info spi_board = { {0} };
+	struct spi_device *spidev;
+	int ret;
+	u8 dev_type;
+
+	request.chip_select = cs;
+
+	ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+
+	dev_type = response.device_type;
+
+	if (dev_type == GB_SPI_SPI_DEV)
+		strlcpy(spi_board.modalias, "spidev",
+			sizeof(spi_board.modalias));
+	else if (dev_type == GB_SPI_SPI_NOR)
+		strlcpy(spi_board.modalias, "spi-nor",
+			sizeof(spi_board.modalias));
+	else if (dev_type == GB_SPI_SPI_MODALIAS)
+		memcpy(spi_board.modalias, response.name,
+		       sizeof(spi_board.modalias));
+	else
+		return -EINVAL;
+
+	spi_board.mode		= le16_to_cpu(response.mode);
+	spi_board.bus_num	= master->bus_num;
+	spi_board.chip_select	= cs;
+	spi_board.max_speed_hz	= le32_to_cpu(response.max_speed_hz);
+
+	spidev = spi_new_device(master, &spi_board);
+	if (!spidev)
+		return -EINVAL;
+
+	return 0;
+}
+
+int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
+			  struct spilib_ops *ops)
+{
+	struct gb_spilib *spi;
+	struct spi_master *master;
+	int ret;
+	u8 i;
+
+	/* Allocate master with space for data */
+	master = spi_alloc_master(dev, sizeof(*spi));
+	if (!master) {
+		dev_err(dev, "cannot alloc SPI master\n");
+		return -ENOMEM;
+	}
+
+	spi = spi_master_get_devdata(master);
+	spi->connection = connection;
+	gb_connection_set_data(connection, master);
+	spi->parent = dev;
+	spi->ops = ops;
+
+	/* get master configuration */
+	ret = gb_spi_get_master_config(spi);
+	if (ret)
+		goto exit_spi_put;
+
+	master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
+	master->num_chipselect = spi->num_chipselect;
+	master->mode_bits = spi->mode;
+	master->flags = spi->flags;
+	master->bits_per_word_mask = spi->bits_per_word_mask;
+
+	/* Attach methods */
+	master->cleanup = gb_spi_cleanup;
+	master->setup = gb_spi_setup;
+	master->transfer_one_message = gb_spi_transfer_one_message;
+
+	if (ops && ops->prepare_transfer_hardware) {
+		master->prepare_transfer_hardware =
+			gb_spi_prepare_transfer_hardware;
+	}
+
+	if (ops && ops->unprepare_transfer_hardware) {
+		master->unprepare_transfer_hardware =
+			gb_spi_unprepare_transfer_hardware;
+	}
+
+	master->auto_runtime_pm = true;
+
+	ret = spi_register_master(master);
+	if (ret < 0)
+		goto exit_spi_put;
+
+	/* now, fetch the devices configuration */
+	for (i = 0; i < spi->num_chipselect; i++) {
+		ret = gb_spi_setup_device(spi, i);
+		if (ret < 0) {
+			dev_err(dev, "failed to allocate spi device %d: %d\n",
+				i, ret);
+			goto exit_spi_unregister;
+		}
+	}
+
+	return 0;
+
+exit_spi_unregister:
+	spi_unregister_master(master);
+exit_spi_put:
+	spi_master_put(master);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_spilib_master_init);
+
+void gb_spilib_master_exit(struct gb_connection *connection)
+{
+	struct spi_master *master = gb_connection_get_data(connection);
+
+	spi_unregister_master(master);
+	spi_master_put(master);
+}
+EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/spilib.h b/drivers/staging/greybus/spilib.h
new file mode 100644
index 000000000000..566d0dde7f79
--- /dev/null
+++ b/drivers/staging/greybus/spilib.h
@@ -0,0 +1,24 @@
+/*
+ * Greybus SPI library header
+ *
+ * copyright 2016 google inc.
+ * copyright 2016 linaro ltd.
+ *
+ * released under the gplv2 only.
+ */
+
+#ifndef __SPILIB_H
+#define __SPILIB_H
+
+struct device;
+struct gb_connection;
+
+struct spilib_ops {
+	int (*prepare_transfer_hardware)(struct device *dev);
+	void (*unprepare_transfer_hardware)(struct device *dev);
+};
+
+int gb_spilib_master_init(struct gb_connection *connection, struct device *dev, struct spilib_ops *ops);
+void gb_spilib_master_exit(struct gb_connection *connection);
+
+#endif /* __SPILIB_H */
diff --git a/drivers/staging/greybus/svc.c b/drivers/staging/greybus/svc.c
new file mode 100644
index 000000000000..550055ec27a5
--- /dev/null
+++ b/drivers/staging/greybus/svc.c
@@ -0,0 +1,1486 @@
+/*
+ * SVC Greybus driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/workqueue.h>
+
+#include "greybus.h"
+
+#define SVC_INTF_EJECT_TIMEOUT		9000
+#define SVC_INTF_ACTIVATE_TIMEOUT	6000
+#define SVC_INTF_RESUME_TIMEOUT		3000
+
+struct gb_svc_deferred_request {
+	struct work_struct work;
+	struct gb_operation *operation;
+};
+
+
+static int gb_svc_queue_deferred_request(struct gb_operation *operation);
+
+static ssize_t endo_id_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	return sprintf(buf, "0x%04x\n", svc->endo_id);
+}
+static DEVICE_ATTR_RO(endo_id);
+
+static ssize_t ap_intf_id_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	return sprintf(buf, "%u\n", svc->ap_intf_id);
+}
+static DEVICE_ATTR_RO(ap_intf_id);
+
+// FIXME
+// This is a hack, we need to do this "right" and clean the interface up
+// properly, not just forcibly yank the thing out of the system and hope for the
+// best.  But for now, people want their modules to come out without having to
+// throw the thing to the ground or get out a screwdriver.
+static ssize_t intf_eject_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t len)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+	unsigned short intf_id;
+	int ret;
+
+	ret = kstrtou16(buf, 10, &intf_id);
+	if (ret < 0)
+		return ret;
+
+	dev_warn(dev, "Forcibly trying to eject interface %d\n", intf_id);
+
+	ret = gb_svc_intf_eject(svc, intf_id);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+static DEVICE_ATTR_WO(intf_eject);
+
+static ssize_t watchdog_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	return sprintf(buf, "%s\n",
+		       gb_svc_watchdog_enabled(svc) ? "enabled" : "disabled");
+}
+
+static ssize_t watchdog_store(struct device *dev,
+			      struct device_attribute *attr, const char *buf,
+			      size_t len)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+	int retval;
+	bool user_request;
+
+	retval = strtobool(buf, &user_request);
+	if (retval)
+		return retval;
+
+	if (user_request)
+		retval = gb_svc_watchdog_enable(svc);
+	else
+		retval = gb_svc_watchdog_disable(svc);
+	if (retval)
+		return retval;
+	return len;
+}
+static DEVICE_ATTR_RW(watchdog);
+
+static ssize_t watchdog_action_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL)
+		return sprintf(buf, "panic\n");
+	else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO)
+		return sprintf(buf, "reset\n");
+
+	return -EINVAL;
+}
+
+static ssize_t watchdog_action_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	if (sysfs_streq(buf, "panic"))
+		svc->action = GB_SVC_WATCHDOG_BITE_PANIC_KERNEL;
+	else if (sysfs_streq(buf, "reset"))
+		svc->action = GB_SVC_WATCHDOG_BITE_RESET_UNIPRO;
+	else
+		return -EINVAL;
+
+	return len;
+}
+static DEVICE_ATTR_RW(watchdog_action);
+
+static int gb_svc_pwrmon_rail_count_get(struct gb_svc *svc, u8 *value)
+{
+	struct gb_svc_pwrmon_rail_count_get_response response;
+	int ret;
+
+	ret = gb_operation_sync(svc->connection,
+				GB_SVC_TYPE_PWRMON_RAIL_COUNT_GET, NULL, 0,
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->dev, "failed to get rail count: %d\n", ret);
+		return ret;
+	}
+
+	*value = response.rail_count;
+
+	return 0;
+}
+
+static int gb_svc_pwrmon_rail_names_get(struct gb_svc *svc,
+		struct gb_svc_pwrmon_rail_names_get_response *response,
+		size_t bufsize)
+{
+	int ret;
+
+	ret = gb_operation_sync(svc->connection,
+				GB_SVC_TYPE_PWRMON_RAIL_NAMES_GET, NULL, 0,
+				response, bufsize);
+	if (ret) {
+		dev_err(&svc->dev, "failed to get rail names: %d\n", ret);
+		return ret;
+	}
+
+	if (response->status != GB_SVC_OP_SUCCESS) {
+		dev_err(&svc->dev,
+			"SVC error while getting rail names: %u\n",
+			response->status);
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+static int gb_svc_pwrmon_sample_get(struct gb_svc *svc, u8 rail_id,
+				    u8 measurement_type, u32 *value)
+{
+	struct gb_svc_pwrmon_sample_get_request request;
+	struct gb_svc_pwrmon_sample_get_response response;
+	int ret;
+
+	request.rail_id = rail_id;
+	request.measurement_type = measurement_type;
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_PWRMON_SAMPLE_GET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->dev, "failed to get rail sample: %d\n", ret);
+		return ret;
+	}
+
+	if (response.result) {
+		dev_err(&svc->dev,
+			"UniPro error while getting rail power sample (%d %d): %d\n",
+			rail_id, measurement_type, response.result);
+		switch (response.result) {
+		case GB_SVC_PWRMON_GET_SAMPLE_INVAL:
+			return -EINVAL;
+		case GB_SVC_PWRMON_GET_SAMPLE_NOSUPP:
+			return -ENOMSG;
+		default:
+			return -EREMOTEIO;
+		}
+	}
+
+	*value = le32_to_cpu(response.measurement);
+
+	return 0;
+}
+
+int gb_svc_pwrmon_intf_sample_get(struct gb_svc *svc, u8 intf_id,
+				  u8 measurement_type, u32 *value)
+{
+	struct gb_svc_pwrmon_intf_sample_get_request request;
+	struct gb_svc_pwrmon_intf_sample_get_response response;
+	int ret;
+
+	request.intf_id = intf_id;
+	request.measurement_type = measurement_type;
+
+	ret = gb_operation_sync(svc->connection,
+				GB_SVC_TYPE_PWRMON_INTF_SAMPLE_GET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->dev, "failed to get intf sample: %d\n", ret);
+		return ret;
+	}
+
+	if (response.result) {
+		dev_err(&svc->dev,
+			"UniPro error while getting intf power sample (%d %d): %d\n",
+			intf_id, measurement_type, response.result);
+		switch (response.result) {
+		case GB_SVC_PWRMON_GET_SAMPLE_INVAL:
+			return -EINVAL;
+		case GB_SVC_PWRMON_GET_SAMPLE_NOSUPP:
+			return -ENOMSG;
+		default:
+			return -EREMOTEIO;
+		}
+	}
+
+	*value = le32_to_cpu(response.measurement);
+
+	return 0;
+}
+
+static struct attribute *svc_attrs[] = {
+	&dev_attr_endo_id.attr,
+	&dev_attr_ap_intf_id.attr,
+	&dev_attr_intf_eject.attr,
+	&dev_attr_watchdog.attr,
+	&dev_attr_watchdog_action.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(svc);
+
+int gb_svc_intf_device_id(struct gb_svc *svc, u8 intf_id, u8 device_id)
+{
+	struct gb_svc_intf_device_id_request request;
+
+	request.intf_id = intf_id;
+	request.device_id = device_id;
+
+	return gb_operation_sync(svc->connection, GB_SVC_TYPE_INTF_DEVICE_ID,
+				 &request, sizeof(request), NULL, 0);
+}
+
+int gb_svc_intf_eject(struct gb_svc *svc, u8 intf_id)
+{
+	struct gb_svc_intf_eject_request request;
+	int ret;
+
+	request.intf_id = intf_id;
+
+	/*
+	 * The pulse width for module release in svc is long so we need to
+	 * increase the timeout so the operation will not return to soon.
+	 */
+	ret = gb_operation_sync_timeout(svc->connection,
+					GB_SVC_TYPE_INTF_EJECT, &request,
+					sizeof(request), NULL, 0,
+					SVC_INTF_EJECT_TIMEOUT);
+	if (ret) {
+		dev_err(&svc->dev, "failed to eject interface %u\n", intf_id);
+		return ret;
+	}
+
+	return 0;
+}
+
+int gb_svc_intf_vsys_set(struct gb_svc *svc, u8 intf_id, bool enable)
+{
+	struct gb_svc_intf_vsys_request request;
+	struct gb_svc_intf_vsys_response response;
+	int type, ret;
+
+	request.intf_id = intf_id;
+
+	if (enable)
+		type = GB_SVC_TYPE_INTF_VSYS_ENABLE;
+	else
+		type = GB_SVC_TYPE_INTF_VSYS_DISABLE;
+
+	ret = gb_operation_sync(svc->connection, type,
+			&request, sizeof(request),
+			&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+	if (response.result_code != GB_SVC_INTF_VSYS_OK)
+		return -EREMOTEIO;
+	return 0;
+}
+
+int gb_svc_intf_refclk_set(struct gb_svc *svc, u8 intf_id, bool enable)
+{
+	struct gb_svc_intf_refclk_request request;
+	struct gb_svc_intf_refclk_response response;
+	int type, ret;
+
+	request.intf_id = intf_id;
+
+	if (enable)
+		type = GB_SVC_TYPE_INTF_REFCLK_ENABLE;
+	else
+		type = GB_SVC_TYPE_INTF_REFCLK_DISABLE;
+
+	ret = gb_operation_sync(svc->connection, type,
+			&request, sizeof(request),
+			&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+	if (response.result_code != GB_SVC_INTF_REFCLK_OK)
+		return -EREMOTEIO;
+	return 0;
+}
+
+int gb_svc_intf_unipro_set(struct gb_svc *svc, u8 intf_id, bool enable)
+{
+	struct gb_svc_intf_unipro_request request;
+	struct gb_svc_intf_unipro_response response;
+	int type, ret;
+
+	request.intf_id = intf_id;
+
+	if (enable)
+		type = GB_SVC_TYPE_INTF_UNIPRO_ENABLE;
+	else
+		type = GB_SVC_TYPE_INTF_UNIPRO_DISABLE;
+
+	ret = gb_operation_sync(svc->connection, type,
+			&request, sizeof(request),
+			&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+	if (response.result_code != GB_SVC_INTF_UNIPRO_OK)
+		return -EREMOTEIO;
+	return 0;
+}
+
+int gb_svc_intf_activate(struct gb_svc *svc, u8 intf_id, u8 *intf_type)
+{
+	struct gb_svc_intf_activate_request request;
+	struct gb_svc_intf_activate_response response;
+	int ret;
+
+	request.intf_id = intf_id;
+
+	ret = gb_operation_sync_timeout(svc->connection,
+			GB_SVC_TYPE_INTF_ACTIVATE,
+			&request, sizeof(request),
+			&response, sizeof(response),
+			SVC_INTF_ACTIVATE_TIMEOUT);
+	if (ret < 0)
+		return ret;
+	if (response.status != GB_SVC_OP_SUCCESS) {
+		dev_err(&svc->dev, "failed to activate interface %u: %u\n",
+				intf_id, response.status);
+		return -EREMOTEIO;
+	}
+
+	*intf_type = response.intf_type;
+
+	return 0;
+}
+
+int gb_svc_intf_resume(struct gb_svc *svc, u8 intf_id)
+{
+	struct gb_svc_intf_resume_request request;
+	struct gb_svc_intf_resume_response response;
+	int ret;
+
+	request.intf_id = intf_id;
+
+	ret = gb_operation_sync_timeout(svc->connection,
+					GB_SVC_TYPE_INTF_RESUME,
+					&request, sizeof(request),
+					&response, sizeof(response),
+					SVC_INTF_RESUME_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&svc->dev, "failed to send interface resume %u: %d\n",
+			intf_id, ret);
+		return ret;
+	}
+
+	if (response.status != GB_SVC_OP_SUCCESS) {
+		dev_err(&svc->dev, "failed to resume interface %u: %u\n",
+			intf_id, response.status);
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 *value)
+{
+	struct gb_svc_dme_peer_get_request request;
+	struct gb_svc_dme_peer_get_response response;
+	u16 result;
+	int ret;
+
+	request.intf_id = intf_id;
+	request.attr = cpu_to_le16(attr);
+	request.selector = cpu_to_le16(selector);
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_DME_PEER_GET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->dev, "failed to get DME attribute (%u 0x%04x %u): %d\n",
+				intf_id, attr, selector, ret);
+		return ret;
+	}
+
+	result = le16_to_cpu(response.result_code);
+	if (result) {
+		dev_err(&svc->dev, "UniPro error while getting DME attribute (%u 0x%04x %u): %u\n",
+				intf_id, attr, selector, result);
+		return -EREMOTEIO;
+	}
+
+	if (value)
+		*value = le32_to_cpu(response.attr_value);
+
+	return 0;
+}
+
+int gb_svc_dme_peer_set(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 value)
+{
+	struct gb_svc_dme_peer_set_request request;
+	struct gb_svc_dme_peer_set_response response;
+	u16 result;
+	int ret;
+
+	request.intf_id = intf_id;
+	request.attr = cpu_to_le16(attr);
+	request.selector = cpu_to_le16(selector);
+	request.value = cpu_to_le32(value);
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_DME_PEER_SET,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(&svc->dev, "failed to set DME attribute (%u 0x%04x %u %u): %d\n",
+				intf_id, attr, selector, value, ret);
+		return ret;
+	}
+
+	result = le16_to_cpu(response.result_code);
+	if (result) {
+		dev_err(&svc->dev, "UniPro error while setting DME attribute (%u 0x%04x %u %u): %u\n",
+				intf_id, attr, selector, value, result);
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+int gb_svc_connection_create(struct gb_svc *svc,
+				u8 intf1_id, u16 cport1_id,
+				u8 intf2_id, u16 cport2_id,
+				u8 cport_flags)
+{
+	struct gb_svc_conn_create_request request;
+
+	request.intf1_id = intf1_id;
+	request.cport1_id = cpu_to_le16(cport1_id);
+	request.intf2_id = intf2_id;
+	request.cport2_id = cpu_to_le16(cport2_id);
+	request.tc = 0;		/* TC0 */
+	request.flags = cport_flags;
+
+	return gb_operation_sync(svc->connection, GB_SVC_TYPE_CONN_CREATE,
+				 &request, sizeof(request), NULL, 0);
+}
+
+void gb_svc_connection_destroy(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
+			       u8 intf2_id, u16 cport2_id)
+{
+	struct gb_svc_conn_destroy_request request;
+	struct gb_connection *connection = svc->connection;
+	int ret;
+
+	request.intf1_id = intf1_id;
+	request.cport1_id = cpu_to_le16(cport1_id);
+	request.intf2_id = intf2_id;
+	request.cport2_id = cpu_to_le16(cport2_id);
+
+	ret = gb_operation_sync(connection, GB_SVC_TYPE_CONN_DESTROY,
+				&request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(&svc->dev, "failed to destroy connection (%u:%u %u:%u): %d\n",
+				intf1_id, cport1_id, intf2_id, cport2_id, ret);
+	}
+}
+
+int gb_svc_timesync_enable(struct gb_svc *svc, u8 count, u64 frame_time,
+			   u32 strobe_delay, u32 refclk)
+{
+	struct gb_connection *connection = svc->connection;
+	struct gb_svc_timesync_enable_request request;
+
+	request.count = count;
+	request.frame_time = cpu_to_le64(frame_time);
+	request.strobe_delay = cpu_to_le32(strobe_delay);
+	request.refclk = cpu_to_le32(refclk);
+	return gb_operation_sync(connection,
+				 GB_SVC_TYPE_TIMESYNC_ENABLE,
+				 &request, sizeof(request), NULL, 0);
+}
+
+int gb_svc_timesync_disable(struct gb_svc *svc)
+{
+	struct gb_connection *connection = svc->connection;
+
+	return gb_operation_sync(connection,
+				 GB_SVC_TYPE_TIMESYNC_DISABLE,
+				 NULL, 0, NULL, 0);
+}
+
+int gb_svc_timesync_authoritative(struct gb_svc *svc, u64 *frame_time)
+{
+	struct gb_connection *connection = svc->connection;
+	struct gb_svc_timesync_authoritative_response response;
+	int ret, i;
+
+	ret = gb_operation_sync(connection,
+				GB_SVC_TYPE_TIMESYNC_AUTHORITATIVE, NULL, 0,
+				&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
+		frame_time[i] = le64_to_cpu(response.frame_time[i]);
+	return 0;
+}
+
+int gb_svc_timesync_ping(struct gb_svc *svc, u64 *frame_time)
+{
+	struct gb_connection *connection = svc->connection;
+	struct gb_svc_timesync_ping_response response;
+	int ret;
+
+	ret = gb_operation_sync(connection,
+				GB_SVC_TYPE_TIMESYNC_PING,
+				NULL, 0,
+				&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+
+	*frame_time = le64_to_cpu(response.frame_time);
+	return 0;
+}
+
+int gb_svc_timesync_wake_pins_acquire(struct gb_svc *svc, u32 strobe_mask)
+{
+	struct gb_connection *connection = svc->connection;
+	struct gb_svc_timesync_wake_pins_acquire_request request;
+
+	request.strobe_mask = cpu_to_le32(strobe_mask);
+	return gb_operation_sync(connection,
+				 GB_SVC_TYPE_TIMESYNC_WAKE_PINS_ACQUIRE,
+				 &request, sizeof(request),
+				 NULL, 0);
+}
+
+int gb_svc_timesync_wake_pins_release(struct gb_svc *svc)
+{
+	struct gb_connection *connection = svc->connection;
+
+	return gb_operation_sync(connection,
+				 GB_SVC_TYPE_TIMESYNC_WAKE_PINS_RELEASE,
+				 NULL, 0, NULL, 0);
+}
+
+/* Creates bi-directional routes between the devices */
+int gb_svc_route_create(struct gb_svc *svc, u8 intf1_id, u8 dev1_id,
+			       u8 intf2_id, u8 dev2_id)
+{
+	struct gb_svc_route_create_request request;
+
+	request.intf1_id = intf1_id;
+	request.dev1_id = dev1_id;
+	request.intf2_id = intf2_id;
+	request.dev2_id = dev2_id;
+
+	return gb_operation_sync(svc->connection, GB_SVC_TYPE_ROUTE_CREATE,
+				 &request, sizeof(request), NULL, 0);
+}
+
+/* Destroys bi-directional routes between the devices */
+void gb_svc_route_destroy(struct gb_svc *svc, u8 intf1_id, u8 intf2_id)
+{
+	struct gb_svc_route_destroy_request request;
+	int ret;
+
+	request.intf1_id = intf1_id;
+	request.intf2_id = intf2_id;
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_ROUTE_DESTROY,
+				&request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(&svc->dev, "failed to destroy route (%u %u): %d\n",
+				intf1_id, intf2_id, ret);
+	}
+}
+
+int gb_svc_intf_set_power_mode(struct gb_svc *svc, u8 intf_id, u8 hs_series,
+			       u8 tx_mode, u8 tx_gear, u8 tx_nlanes,
+			       u8 tx_amplitude, u8 tx_hs_equalizer,
+			       u8 rx_mode, u8 rx_gear, u8 rx_nlanes,
+			       u8 flags, u32 quirks,
+			       struct gb_svc_l2_timer_cfg *local,
+			       struct gb_svc_l2_timer_cfg *remote)
+{
+	struct gb_svc_intf_set_pwrm_request request;
+	struct gb_svc_intf_set_pwrm_response response;
+	int ret;
+	u16 result_code;
+
+	memset(&request, 0, sizeof(request));
+
+	request.intf_id = intf_id;
+	request.hs_series = hs_series;
+	request.tx_mode = tx_mode;
+	request.tx_gear = tx_gear;
+	request.tx_nlanes = tx_nlanes;
+	request.tx_amplitude = tx_amplitude;
+	request.tx_hs_equalizer = tx_hs_equalizer;
+	request.rx_mode = rx_mode;
+	request.rx_gear = rx_gear;
+	request.rx_nlanes = rx_nlanes;
+	request.flags = flags;
+	request.quirks = cpu_to_le32(quirks);
+	if (local)
+		request.local_l2timerdata = *local;
+	if (remote)
+		request.remote_l2timerdata = *remote;
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_INTF_SET_PWRM,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret < 0)
+		return ret;
+
+	result_code = response.result_code;
+	if (result_code != GB_SVC_SETPWRM_PWR_LOCAL) {
+		dev_err(&svc->dev, "set power mode = %d\n", result_code);
+		return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gb_svc_intf_set_power_mode);
+
+int gb_svc_intf_set_power_mode_hibernate(struct gb_svc *svc, u8 intf_id)
+{
+	struct gb_svc_intf_set_pwrm_request request;
+	struct gb_svc_intf_set_pwrm_response response;
+	int ret;
+	u16 result_code;
+
+	memset(&request, 0, sizeof(request));
+
+	request.intf_id = intf_id;
+	request.hs_series = GB_SVC_UNIPRO_HS_SERIES_A;
+	request.tx_mode = GB_SVC_UNIPRO_HIBERNATE_MODE;
+	request.rx_mode = GB_SVC_UNIPRO_HIBERNATE_MODE;
+
+	ret = gb_operation_sync(svc->connection, GB_SVC_TYPE_INTF_SET_PWRM,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret < 0) {
+		dev_err(&svc->dev,
+			"failed to send set power mode operation to interface %u: %d\n",
+			intf_id, ret);
+		return ret;
+	}
+
+	result_code = response.result_code;
+	if (result_code != GB_SVC_SETPWRM_PWR_OK) {
+		dev_err(&svc->dev,
+			"failed to hibernate the link for interface %u: %u\n",
+			intf_id, result_code);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+int gb_svc_ping(struct gb_svc *svc)
+{
+	return gb_operation_sync_timeout(svc->connection, GB_SVC_TYPE_PING,
+					 NULL, 0, NULL, 0,
+					 GB_OPERATION_TIMEOUT_DEFAULT * 2);
+}
+
+static int gb_svc_version_request(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_svc_version_request *request;
+	struct gb_svc_version_response *response;
+
+	if (op->request->payload_size < sizeof(*request)) {
+		dev_err(&svc->dev, "short version request (%zu < %zu)\n",
+				op->request->payload_size,
+				sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	if (request->major > GB_SVC_VERSION_MAJOR) {
+		dev_warn(&svc->dev, "unsupported major version (%u > %u)\n",
+				request->major, GB_SVC_VERSION_MAJOR);
+		return -ENOTSUPP;
+	}
+
+	svc->protocol_major = request->major;
+	svc->protocol_minor = request->minor;
+
+	if (!gb_operation_response_alloc(op, sizeof(*response), GFP_KERNEL))
+		return -ENOMEM;
+
+	response = op->response->payload;
+	response->major = svc->protocol_major;
+	response->minor = svc->protocol_minor;
+
+	return 0;
+}
+
+static ssize_t pwr_debugfs_voltage_read(struct file *file, char __user *buf,
+					size_t len, loff_t *offset)
+{
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct gb_svc *svc = pwrmon_rails->svc;
+	int ret, desc;
+	u32 value;
+	char buff[16];
+
+	ret = gb_svc_pwrmon_sample_get(svc, pwrmon_rails->id,
+				       GB_SVC_PWRMON_TYPE_VOL, &value);
+	if (ret) {
+		dev_err(&svc->dev,
+			"failed to get voltage sample %u: %d\n",
+			pwrmon_rails->id, ret);
+		return ret;
+	}
+
+	desc = scnprintf(buff, sizeof(buff), "%u\n", value);
+
+	return simple_read_from_buffer(buf, len, offset, buff, desc);
+}
+
+static ssize_t pwr_debugfs_current_read(struct file *file, char __user *buf,
+					size_t len, loff_t *offset)
+{
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct gb_svc *svc = pwrmon_rails->svc;
+	int ret, desc;
+	u32 value;
+	char buff[16];
+
+	ret = gb_svc_pwrmon_sample_get(svc, pwrmon_rails->id,
+				       GB_SVC_PWRMON_TYPE_CURR, &value);
+	if (ret) {
+		dev_err(&svc->dev,
+			"failed to get current sample %u: %d\n",
+			pwrmon_rails->id, ret);
+		return ret;
+	}
+
+	desc = scnprintf(buff, sizeof(buff), "%u\n", value);
+
+	return simple_read_from_buffer(buf, len, offset, buff, desc);
+}
+
+static ssize_t pwr_debugfs_power_read(struct file *file, char __user *buf,
+				      size_t len, loff_t *offset)
+{
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct gb_svc *svc = pwrmon_rails->svc;
+	int ret, desc;
+	u32 value;
+	char buff[16];
+
+	ret = gb_svc_pwrmon_sample_get(svc, pwrmon_rails->id,
+				       GB_SVC_PWRMON_TYPE_PWR, &value);
+	if (ret) {
+		dev_err(&svc->dev, "failed to get power sample %u: %d\n",
+			pwrmon_rails->id, ret);
+		return ret;
+	}
+
+	desc = scnprintf(buff, sizeof(buff), "%u\n", value);
+
+	return simple_read_from_buffer(buf, len, offset, buff, desc);
+}
+
+static const struct file_operations pwrmon_debugfs_voltage_fops = {
+	.read		= pwr_debugfs_voltage_read,
+};
+
+static const struct file_operations pwrmon_debugfs_current_fops = {
+	.read		= pwr_debugfs_current_read,
+};
+
+static const struct file_operations pwrmon_debugfs_power_fops = {
+	.read		= pwr_debugfs_power_read,
+};
+
+static void gb_svc_pwrmon_debugfs_init(struct gb_svc *svc)
+{
+	int i;
+	size_t bufsize;
+	struct dentry *dent;
+	struct gb_svc_pwrmon_rail_names_get_response *rail_names;
+	u8 rail_count;
+
+	dent = debugfs_create_dir("pwrmon", svc->debugfs_dentry);
+	if (IS_ERR_OR_NULL(dent))
+		return;
+
+	if (gb_svc_pwrmon_rail_count_get(svc, &rail_count))
+		goto err_pwrmon_debugfs;
+
+	if (!rail_count || rail_count > GB_SVC_PWRMON_MAX_RAIL_COUNT)
+		goto err_pwrmon_debugfs;
+
+	bufsize = sizeof(*rail_names) +
+		GB_SVC_PWRMON_RAIL_NAME_BUFSIZE * rail_count;
+
+	rail_names = kzalloc(bufsize, GFP_KERNEL);
+	if (!rail_names)
+		goto err_pwrmon_debugfs;
+
+	svc->pwrmon_rails = kcalloc(rail_count, sizeof(*svc->pwrmon_rails),
+				    GFP_KERNEL);
+	if (!svc->pwrmon_rails)
+		goto err_pwrmon_debugfs_free;
+
+	if (gb_svc_pwrmon_rail_names_get(svc, rail_names, bufsize))
+		goto err_pwrmon_debugfs_free;
+
+	for (i = 0; i < rail_count; i++) {
+		struct dentry *dir;
+		struct svc_debugfs_pwrmon_rail *rail = &svc->pwrmon_rails[i];
+		char fname[GB_SVC_PWRMON_RAIL_NAME_BUFSIZE];
+
+		snprintf(fname, sizeof(fname), "%s",
+			 (char *)&rail_names->name[i]);
+
+		rail->id = i;
+		rail->svc = svc;
+
+		dir = debugfs_create_dir(fname, dent);
+		debugfs_create_file("voltage_now", S_IRUGO, dir, rail,
+				    &pwrmon_debugfs_voltage_fops);
+		debugfs_create_file("current_now", S_IRUGO, dir, rail,
+				    &pwrmon_debugfs_current_fops);
+		debugfs_create_file("power_now", S_IRUGO, dir, rail,
+				    &pwrmon_debugfs_power_fops);
+	}
+
+	kfree(rail_names);
+	return;
+
+err_pwrmon_debugfs_free:
+	kfree(rail_names);
+	kfree(svc->pwrmon_rails);
+	svc->pwrmon_rails = NULL;
+
+err_pwrmon_debugfs:
+	debugfs_remove(dent);
+}
+
+static void gb_svc_debugfs_init(struct gb_svc *svc)
+{
+	svc->debugfs_dentry = debugfs_create_dir(dev_name(&svc->dev),
+						 gb_debugfs_get());
+	gb_svc_pwrmon_debugfs_init(svc);
+}
+
+static void gb_svc_debugfs_exit(struct gb_svc *svc)
+{
+	debugfs_remove_recursive(svc->debugfs_dentry);
+	kfree(svc->pwrmon_rails);
+	svc->pwrmon_rails = NULL;
+}
+
+static int gb_svc_hello(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_svc_hello_request *hello_request;
+	int ret;
+
+	if (op->request->payload_size < sizeof(*hello_request)) {
+		dev_warn(&svc->dev, "short hello request (%zu < %zu)\n",
+				op->request->payload_size,
+				sizeof(*hello_request));
+		return -EINVAL;
+	}
+
+	hello_request = op->request->payload;
+	svc->endo_id = le16_to_cpu(hello_request->endo_id);
+	svc->ap_intf_id = hello_request->interface_id;
+
+	ret = device_add(&svc->dev);
+	if (ret) {
+		dev_err(&svc->dev, "failed to register svc device: %d\n", ret);
+		return ret;
+	}
+
+	ret = gb_svc_watchdog_create(svc);
+	if (ret) {
+		dev_err(&svc->dev, "failed to create watchdog: %d\n", ret);
+		goto err_unregister_device;
+	}
+
+	gb_svc_debugfs_init(svc);
+
+	ret = gb_timesync_svc_add(svc);
+	if (ret) {
+		dev_err(&svc->dev, "failed to add SVC to timesync: %d\n", ret);
+		gb_svc_debugfs_exit(svc);
+		goto err_unregister_device;
+	}
+
+	return gb_svc_queue_deferred_request(op);
+
+err_unregister_device:
+	gb_svc_watchdog_destroy(svc);
+	device_del(&svc->dev);
+	return ret;
+}
+
+static struct gb_interface *gb_svc_interface_lookup(struct gb_svc *svc,
+							u8 intf_id)
+{
+	struct gb_host_device *hd = svc->hd;
+	struct gb_module *module;
+	size_t num_interfaces;
+	u8 module_id;
+
+	list_for_each_entry(module, &hd->modules, hd_node) {
+		module_id = module->module_id;
+		num_interfaces = module->num_interfaces;
+
+		if (intf_id >= module_id &&
+				intf_id < module_id + num_interfaces) {
+			return module->interfaces[intf_id - module_id];
+		}
+	}
+
+	return NULL;
+}
+
+static struct gb_module *gb_svc_module_lookup(struct gb_svc *svc, u8 module_id)
+{
+	struct gb_host_device *hd = svc->hd;
+	struct gb_module *module;
+
+	list_for_each_entry(module, &hd->modules, hd_node) {
+		if (module->module_id == module_id)
+			return module;
+	}
+
+	return NULL;
+}
+
+static void gb_svc_process_hello_deferred(struct gb_operation *operation)
+{
+	struct gb_connection *connection = operation->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	int ret;
+
+	/*
+	 * XXX This is a hack/work-around to reconfigure the APBridgeA-Switch
+	 * link to PWM G2, 1 Lane, Slow Auto, so that it has sufficient
+	 * bandwidth for 3 audio streams plus boot-over-UniPro of a hot-plugged
+	 * module.
+	 *
+	 * The code should be removed once SW-2217, Heuristic for UniPro
+	 * Power Mode Changes is resolved.
+	 */
+	ret = gb_svc_intf_set_power_mode(svc, svc->ap_intf_id,
+					GB_SVC_UNIPRO_HS_SERIES_A,
+					GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+					2, 1,
+					GB_SVC_SMALL_AMPLITUDE, GB_SVC_NO_DE_EMPHASIS,
+					GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+					2, 1,
+					0, 0,
+					NULL, NULL);
+
+	if (ret)
+		dev_warn(&svc->dev,
+			"power mode change failed on AP to switch link: %d\n",
+			ret);
+}
+
+static void gb_svc_process_module_inserted(struct gb_operation *operation)
+{
+	struct gb_svc_module_inserted_request *request;
+	struct gb_connection *connection = operation->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_host_device *hd = svc->hd;
+	struct gb_module *module;
+	size_t num_interfaces;
+	u8 module_id;
+	u16 flags;
+	int ret;
+
+	/* The request message size has already been verified. */
+	request = operation->request->payload;
+	module_id = request->primary_intf_id;
+	num_interfaces = request->intf_count;
+	flags = le16_to_cpu(request->flags);
+
+	dev_dbg(&svc->dev, "%s - id = %u, num_interfaces = %zu, flags = 0x%04x\n",
+			__func__, module_id, num_interfaces, flags);
+
+	if (flags & GB_SVC_MODULE_INSERTED_FLAG_NO_PRIMARY) {
+		dev_warn(&svc->dev, "no primary interface detected on module %u\n",
+				module_id);
+	}
+
+	module = gb_svc_module_lookup(svc, module_id);
+	if (module) {
+		dev_warn(&svc->dev, "unexpected module-inserted event %u\n",
+				module_id);
+		return;
+	}
+
+	module = gb_module_create(hd, module_id, num_interfaces);
+	if (!module) {
+		dev_err(&svc->dev, "failed to create module\n");
+		return;
+	}
+
+	ret = gb_module_add(module);
+	if (ret) {
+		gb_module_put(module);
+		return;
+	}
+
+	list_add(&module->hd_node, &hd->modules);
+}
+
+static void gb_svc_process_module_removed(struct gb_operation *operation)
+{
+	struct gb_svc_module_removed_request *request;
+	struct gb_connection *connection = operation->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_module *module;
+	u8 module_id;
+
+	/* The request message size has already been verified. */
+	request = operation->request->payload;
+	module_id = request->primary_intf_id;
+
+	dev_dbg(&svc->dev, "%s - id = %u\n", __func__, module_id);
+
+	module = gb_svc_module_lookup(svc, module_id);
+	if (!module) {
+		dev_warn(&svc->dev, "unexpected module-removed event %u\n",
+				module_id);
+		return;
+	}
+
+	module->disconnected = true;
+
+	gb_module_del(module);
+	list_del(&module->hd_node);
+	gb_module_put(module);
+}
+
+static void gb_svc_process_intf_oops(struct gb_operation *operation)
+{
+	struct gb_svc_intf_oops_request *request;
+	struct gb_connection *connection = operation->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_interface *intf;
+	u8 intf_id;
+	u8 reason;
+
+	/* The request message size has already been verified. */
+	request = operation->request->payload;
+	intf_id = request->intf_id;
+	reason = request->reason;
+
+	intf = gb_svc_interface_lookup(svc, intf_id);
+	if (!intf) {
+		dev_warn(&svc->dev, "unexpected interface-oops event %u\n",
+			 intf_id);
+		return;
+	}
+
+	dev_info(&svc->dev, "Deactivating interface %u, interface oops reason = %u\n",
+		 intf_id, reason);
+
+	mutex_lock(&intf->mutex);
+	intf->disconnected = true;
+	gb_interface_disable(intf);
+	gb_interface_deactivate(intf);
+	mutex_unlock(&intf->mutex);
+}
+
+static void gb_svc_process_intf_mailbox_event(struct gb_operation *operation)
+{
+	struct gb_svc_intf_mailbox_event_request *request;
+	struct gb_connection *connection = operation->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	struct gb_interface *intf;
+	u8 intf_id;
+	u16 result_code;
+	u32 mailbox;
+
+	/* The request message size has already been verified. */
+	request = operation->request->payload;
+	intf_id = request->intf_id;
+	result_code = le16_to_cpu(request->result_code);
+	mailbox = le32_to_cpu(request->mailbox);
+
+	dev_dbg(&svc->dev, "%s - id = %u, result = 0x%04x, mailbox = 0x%08x\n",
+			__func__, intf_id, result_code, mailbox);
+
+	intf = gb_svc_interface_lookup(svc, intf_id);
+	if (!intf) {
+		dev_warn(&svc->dev, "unexpected mailbox event %u\n", intf_id);
+		return;
+	}
+
+	gb_interface_mailbox_event(intf, result_code, mailbox);
+}
+
+static void gb_svc_process_deferred_request(struct work_struct *work)
+{
+	struct gb_svc_deferred_request *dr;
+	struct gb_operation *operation;
+	struct gb_svc *svc;
+	u8 type;
+
+	dr = container_of(work, struct gb_svc_deferred_request, work);
+	operation = dr->operation;
+	svc = gb_connection_get_data(operation->connection);
+	type = operation->request->header->type;
+
+	switch (type) {
+	case GB_SVC_TYPE_SVC_HELLO:
+		gb_svc_process_hello_deferred(operation);
+		break;
+	case GB_SVC_TYPE_MODULE_INSERTED:
+		gb_svc_process_module_inserted(operation);
+		break;
+	case GB_SVC_TYPE_MODULE_REMOVED:
+		gb_svc_process_module_removed(operation);
+		break;
+	case GB_SVC_TYPE_INTF_MAILBOX_EVENT:
+		gb_svc_process_intf_mailbox_event(operation);
+		break;
+	case GB_SVC_TYPE_INTF_OOPS:
+		gb_svc_process_intf_oops(operation);
+		break;
+	default:
+		dev_err(&svc->dev, "bad deferred request type: 0x%02x\n", type);
+	}
+
+	gb_operation_put(operation);
+	kfree(dr);
+}
+
+static int gb_svc_queue_deferred_request(struct gb_operation *operation)
+{
+	struct gb_svc *svc = gb_connection_get_data(operation->connection);
+	struct gb_svc_deferred_request *dr;
+
+	dr = kmalloc(sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	gb_operation_get(operation);
+
+	dr->operation = operation;
+	INIT_WORK(&dr->work, gb_svc_process_deferred_request);
+
+	queue_work(svc->wq, &dr->work);
+
+	return 0;
+}
+
+static int gb_svc_intf_reset_recv(struct gb_operation *op)
+{
+	struct gb_svc *svc = gb_connection_get_data(op->connection);
+	struct gb_message *request = op->request;
+	struct gb_svc_intf_reset_request *reset;
+	u8 intf_id;
+
+	if (request->payload_size < sizeof(*reset)) {
+		dev_warn(&svc->dev, "short reset request received (%zu < %zu)\n",
+				request->payload_size, sizeof(*reset));
+		return -EINVAL;
+	}
+	reset = request->payload;
+
+	intf_id = reset->intf_id;
+
+	/* FIXME Reset the interface here */
+
+	return 0;
+}
+
+static int gb_svc_module_inserted_recv(struct gb_operation *op)
+{
+	struct gb_svc *svc = gb_connection_get_data(op->connection);
+	struct gb_svc_module_inserted_request *request;
+
+	if (op->request->payload_size < sizeof(*request)) {
+		dev_warn(&svc->dev, "short module-inserted request received (%zu < %zu)\n",
+				op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	dev_dbg(&svc->dev, "%s - id = %u\n", __func__,
+			request->primary_intf_id);
+
+	return gb_svc_queue_deferred_request(op);
+}
+
+static int gb_svc_module_removed_recv(struct gb_operation *op)
+{
+	struct gb_svc *svc = gb_connection_get_data(op->connection);
+	struct gb_svc_module_removed_request *request;
+
+	if (op->request->payload_size < sizeof(*request)) {
+		dev_warn(&svc->dev, "short module-removed request received (%zu < %zu)\n",
+				op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	dev_dbg(&svc->dev, "%s - id = %u\n", __func__,
+			request->primary_intf_id);
+
+	return gb_svc_queue_deferred_request(op);
+}
+
+static int gb_svc_intf_oops_recv(struct gb_operation *op)
+{
+	struct gb_svc *svc = gb_connection_get_data(op->connection);
+	struct gb_svc_intf_oops_request *request;
+
+	if (op->request->payload_size < sizeof(*request)) {
+		dev_warn(&svc->dev, "short intf-oops request received (%zu < %zu)\n",
+			 op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	return gb_svc_queue_deferred_request(op);
+}
+
+static int gb_svc_intf_mailbox_event_recv(struct gb_operation *op)
+{
+	struct gb_svc *svc = gb_connection_get_data(op->connection);
+	struct gb_svc_intf_mailbox_event_request *request;
+
+	if (op->request->payload_size < sizeof(*request)) {
+		dev_warn(&svc->dev, "short mailbox request received (%zu < %zu)\n",
+				op->request->payload_size, sizeof(*request));
+		return -EINVAL;
+	}
+
+	request = op->request->payload;
+
+	dev_dbg(&svc->dev, "%s - id = %u\n", __func__, request->intf_id);
+
+	return gb_svc_queue_deferred_request(op);
+}
+
+static int gb_svc_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_svc *svc = gb_connection_get_data(connection);
+	u8 type = op->type;
+	int ret = 0;
+
+	/*
+	 * SVC requests need to follow a specific order (at least initially) and
+	 * below code takes care of enforcing that. The expected order is:
+	 * - PROTOCOL_VERSION
+	 * - SVC_HELLO
+	 * - Any other request, but the earlier two.
+	 *
+	 * Incoming requests are guaranteed to be serialized and so we don't
+	 * need to protect 'state' for any races.
+	 */
+	switch (type) {
+	case GB_SVC_TYPE_PROTOCOL_VERSION:
+		if (svc->state != GB_SVC_STATE_RESET)
+			ret = -EINVAL;
+		break;
+	case GB_SVC_TYPE_SVC_HELLO:
+		if (svc->state != GB_SVC_STATE_PROTOCOL_VERSION)
+			ret = -EINVAL;
+		break;
+	default:
+		if (svc->state != GB_SVC_STATE_SVC_HELLO)
+			ret = -EINVAL;
+		break;
+	}
+
+	if (ret) {
+		dev_warn(&svc->dev, "unexpected request 0x%02x received (state %u)\n",
+				type, svc->state);
+		return ret;
+	}
+
+	switch (type) {
+	case GB_SVC_TYPE_PROTOCOL_VERSION:
+		ret = gb_svc_version_request(op);
+		if (!ret)
+			svc->state = GB_SVC_STATE_PROTOCOL_VERSION;
+		return ret;
+	case GB_SVC_TYPE_SVC_HELLO:
+		ret = gb_svc_hello(op);
+		if (!ret)
+			svc->state = GB_SVC_STATE_SVC_HELLO;
+		return ret;
+	case GB_SVC_TYPE_INTF_RESET:
+		return gb_svc_intf_reset_recv(op);
+	case GB_SVC_TYPE_MODULE_INSERTED:
+		return gb_svc_module_inserted_recv(op);
+	case GB_SVC_TYPE_MODULE_REMOVED:
+		return gb_svc_module_removed_recv(op);
+	case GB_SVC_TYPE_INTF_MAILBOX_EVENT:
+		return gb_svc_intf_mailbox_event_recv(op);
+	case GB_SVC_TYPE_INTF_OOPS:
+		return gb_svc_intf_oops_recv(op);
+	default:
+		dev_warn(&svc->dev, "unsupported request 0x%02x\n", type);
+		return -EINVAL;
+	}
+}
+
+static void gb_svc_release(struct device *dev)
+{
+	struct gb_svc *svc = to_gb_svc(dev);
+
+	if (svc->connection)
+		gb_connection_destroy(svc->connection);
+	ida_destroy(&svc->device_id_map);
+	destroy_workqueue(svc->wq);
+	kfree(svc);
+}
+
+struct device_type greybus_svc_type = {
+	.name		= "greybus_svc",
+	.release	= gb_svc_release,
+};
+
+struct gb_svc *gb_svc_create(struct gb_host_device *hd)
+{
+	struct gb_svc *svc;
+
+	svc = kzalloc(sizeof(*svc), GFP_KERNEL);
+	if (!svc)
+		return NULL;
+
+	svc->wq = alloc_workqueue("%s:svc", WQ_UNBOUND, 1, dev_name(&hd->dev));
+	if (!svc->wq) {
+		kfree(svc);
+		return NULL;
+	}
+
+	svc->dev.parent = &hd->dev;
+	svc->dev.bus = &greybus_bus_type;
+	svc->dev.type = &greybus_svc_type;
+	svc->dev.groups = svc_groups;
+	svc->dev.dma_mask = svc->dev.parent->dma_mask;
+	device_initialize(&svc->dev);
+
+	dev_set_name(&svc->dev, "%d-svc", hd->bus_id);
+
+	ida_init(&svc->device_id_map);
+	svc->state = GB_SVC_STATE_RESET;
+	svc->hd = hd;
+
+	svc->connection = gb_connection_create_static(hd, GB_SVC_CPORT_ID,
+						gb_svc_request_handler);
+	if (IS_ERR(svc->connection)) {
+		dev_err(&svc->dev, "failed to create connection: %ld\n",
+				PTR_ERR(svc->connection));
+		goto err_put_device;
+	}
+
+	gb_connection_set_data(svc->connection, svc);
+
+	return svc;
+
+err_put_device:
+	put_device(&svc->dev);
+	return NULL;
+}
+
+int gb_svc_add(struct gb_svc *svc)
+{
+	int ret;
+
+	/*
+	 * The SVC protocol is currently driven by the SVC, so the SVC device
+	 * is added from the connection request handler when enough
+	 * information has been received.
+	 */
+	ret = gb_connection_enable(svc->connection);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void gb_svc_remove_modules(struct gb_svc *svc)
+{
+	struct gb_host_device *hd = svc->hd;
+	struct gb_module *module, *tmp;
+
+	list_for_each_entry_safe(module, tmp, &hd->modules, hd_node) {
+		gb_module_del(module);
+		list_del(&module->hd_node);
+		gb_module_put(module);
+	}
+}
+
+void gb_svc_del(struct gb_svc *svc)
+{
+	gb_connection_disable_rx(svc->connection);
+
+	/*
+	 * The SVC device may have been registered from the request handler.
+	 */
+	if (device_is_registered(&svc->dev)) {
+		gb_timesync_svc_remove(svc);
+		gb_svc_debugfs_exit(svc);
+		gb_svc_watchdog_destroy(svc);
+		device_del(&svc->dev);
+	}
+
+	flush_workqueue(svc->wq);
+
+	gb_svc_remove_modules(svc);
+
+	gb_connection_disable(svc->connection);
+}
+
+void gb_svc_put(struct gb_svc *svc)
+{
+	put_device(&svc->dev);
+}
diff --git a/drivers/staging/greybus/svc.h b/drivers/staging/greybus/svc.h
new file mode 100644
index 000000000000..d1d7ef967385
--- /dev/null
+++ b/drivers/staging/greybus/svc.h
@@ -0,0 +1,109 @@
+/*
+ * Greybus SVC code
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __SVC_H
+#define __SVC_H
+
+#define GB_SVC_CPORT_FLAG_E2EFC		BIT(0)
+#define GB_SVC_CPORT_FLAG_CSD_N		BIT(1)
+#define GB_SVC_CPORT_FLAG_CSV_N		BIT(2)
+
+enum gb_svc_state {
+	GB_SVC_STATE_RESET,
+	GB_SVC_STATE_PROTOCOL_VERSION,
+	GB_SVC_STATE_SVC_HELLO,
+};
+
+enum gb_svc_watchdog_bite {
+	GB_SVC_WATCHDOG_BITE_RESET_UNIPRO = 0,
+	GB_SVC_WATCHDOG_BITE_PANIC_KERNEL,
+};
+
+struct gb_svc_watchdog;
+
+struct svc_debugfs_pwrmon_rail {
+	u8 id;
+	struct gb_svc *svc;
+};
+
+struct gb_svc {
+	struct device		dev;
+
+	struct gb_host_device	*hd;
+	struct gb_connection	*connection;
+	enum gb_svc_state	state;
+	struct ida		device_id_map;
+	struct workqueue_struct	*wq;
+
+	u16 endo_id;
+	u8 ap_intf_id;
+
+	u8 protocol_major;
+	u8 protocol_minor;
+
+	struct gb_svc_watchdog	*watchdog;
+	enum gb_svc_watchdog_bite action;
+
+	struct dentry *debugfs_dentry;
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails;
+};
+#define to_gb_svc(d) container_of(d, struct gb_svc, dev)
+
+struct gb_svc *gb_svc_create(struct gb_host_device *hd);
+int gb_svc_add(struct gb_svc *svc);
+void gb_svc_del(struct gb_svc *svc);
+void gb_svc_put(struct gb_svc *svc);
+
+int gb_svc_pwrmon_intf_sample_get(struct gb_svc *svc, u8 intf_id,
+				  u8 measurement_type, u32 *value);
+int gb_svc_intf_device_id(struct gb_svc *svc, u8 intf_id, u8 device_id);
+int gb_svc_route_create(struct gb_svc *svc, u8 intf1_id, u8 dev1_id,
+			       u8 intf2_id, u8 dev2_id);
+void gb_svc_route_destroy(struct gb_svc *svc, u8 intf1_id, u8 intf2_id);
+int gb_svc_connection_create(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
+			     u8 intf2_id, u16 cport2_id, u8 cport_flags);
+void gb_svc_connection_destroy(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
+			       u8 intf2_id, u16 cport2_id);
+int gb_svc_intf_eject(struct gb_svc *svc, u8 intf_id);
+int gb_svc_intf_vsys_set(struct gb_svc *svc, u8 intf_id, bool enable);
+int gb_svc_intf_refclk_set(struct gb_svc *svc, u8 intf_id, bool enable);
+int gb_svc_intf_unipro_set(struct gb_svc *svc, u8 intf_id, bool enable);
+int gb_svc_intf_activate(struct gb_svc *svc, u8 intf_id, u8 *intf_type);
+int gb_svc_intf_resume(struct gb_svc *svc, u8 intf_id);
+
+int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 *value);
+int gb_svc_dme_peer_set(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
+			u32 value);
+int gb_svc_intf_set_power_mode(struct gb_svc *svc, u8 intf_id, u8 hs_series,
+			       u8 tx_mode, u8 tx_gear, u8 tx_nlanes,
+			       u8 tx_amplitude, u8 tx_hs_equalizer,
+			       u8 rx_mode, u8 rx_gear, u8 rx_nlanes,
+			       u8 flags, u32 quirks,
+			       struct gb_svc_l2_timer_cfg *local,
+			       struct gb_svc_l2_timer_cfg *remote);
+int gb_svc_intf_set_power_mode_hibernate(struct gb_svc *svc, u8 intf_id);
+int gb_svc_ping(struct gb_svc *svc);
+int gb_svc_watchdog_create(struct gb_svc *svc);
+void gb_svc_watchdog_destroy(struct gb_svc *svc);
+bool gb_svc_watchdog_enabled(struct gb_svc *svc);
+int gb_svc_watchdog_enable(struct gb_svc *svc);
+int gb_svc_watchdog_disable(struct gb_svc *svc);
+int gb_svc_timesync_enable(struct gb_svc *svc, u8 count, u64 frame_time,
+			   u32 strobe_delay, u32 refclk);
+int gb_svc_timesync_disable(struct gb_svc *svc);
+int gb_svc_timesync_authoritative(struct gb_svc *svc, u64 *frame_time);
+int gb_svc_timesync_ping(struct gb_svc *svc, u64 *frame_time);
+int gb_svc_timesync_wake_pins_acquire(struct gb_svc *svc, u32 strobe_mask);
+int gb_svc_timesync_wake_pins_release(struct gb_svc *svc);
+
+int gb_svc_protocol_init(void);
+void gb_svc_protocol_exit(void);
+
+#endif /* __SVC_H */
diff --git a/drivers/staging/greybus/svc_watchdog.c b/drivers/staging/greybus/svc_watchdog.c
new file mode 100644
index 000000000000..3729460fb954
--- /dev/null
+++ b/drivers/staging/greybus/svc_watchdog.c
@@ -0,0 +1,198 @@
+/*
+ * SVC Greybus "watchdog" driver.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/delay.h>
+#include <linux/suspend.h>
+#include <linux/workqueue.h>
+#include "greybus.h"
+
+#define SVC_WATCHDOG_PERIOD	(2*HZ)
+
+struct gb_svc_watchdog {
+	struct delayed_work	work;
+	struct gb_svc		*svc;
+	bool			enabled;
+	struct notifier_block pm_notifier;
+};
+
+static struct delayed_work reset_work;
+
+static int svc_watchdog_pm_notifier(struct notifier_block *notifier,
+				    unsigned long pm_event, void *unused)
+{
+	struct gb_svc_watchdog *watchdog =
+		container_of(notifier, struct gb_svc_watchdog, pm_notifier);
+
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		gb_svc_watchdog_disable(watchdog->svc);
+		break;
+	case PM_POST_SUSPEND:
+		gb_svc_watchdog_enable(watchdog->svc);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static void greybus_reset(struct work_struct *work)
+{
+	static char start_path[256] = "/system/bin/start";
+	static char *envp[] = {
+		"HOME=/",
+		"PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",
+		NULL,
+	};
+	static char *argv[] = {
+		start_path,
+		"unipro_reset",
+		NULL,
+	};
+
+	printk(KERN_ERR "svc_watchdog: calling \"%s %s\" to reset greybus network!\n",
+	       argv[0], argv[1]);
+	call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);
+}
+
+static void do_work(struct work_struct *work)
+{
+	struct gb_svc_watchdog *watchdog;
+	struct gb_svc *svc;
+	int retval;
+
+	watchdog = container_of(work, struct gb_svc_watchdog, work.work);
+	svc = watchdog->svc;
+
+	dev_dbg(&svc->dev, "%s: ping.\n", __func__);
+	retval = gb_svc_ping(svc);
+	if (retval) {
+		/*
+		 * Something went really wrong, let's warn userspace and then
+		 * pull the plug and reset the whole greybus network.
+		 * We need to do this outside of this workqueue as we will be
+		 * tearing down the svc device itself.  So queue up
+		 * yet-another-callback to do that.
+		 */
+		dev_err(&svc->dev,
+			"SVC ping has returned %d, something is wrong!!!\n",
+			retval);
+
+		if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL) {
+			panic("SVC is not responding\n");
+		} else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO) {
+			dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");
+
+			INIT_DELAYED_WORK(&reset_work, greybus_reset);
+			schedule_delayed_work(&reset_work, HZ / 2);
+
+			/*
+			 * Disable ourselves, we don't want to trip again unless
+			 * userspace wants us to.
+			 */
+			watchdog->enabled = false;
+		}
+	}
+
+	/* resubmit our work to happen again, if we are still "alive" */
+	if (watchdog->enabled)
+		schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
+}
+
+int gb_svc_watchdog_create(struct gb_svc *svc)
+{
+	struct gb_svc_watchdog *watchdog;
+	int retval;
+
+	if (svc->watchdog)
+		return 0;
+
+	watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);
+	if (!watchdog)
+		return -ENOMEM;
+
+	watchdog->enabled = false;
+	watchdog->svc = svc;
+	INIT_DELAYED_WORK(&watchdog->work, do_work);
+	svc->watchdog = watchdog;
+
+	watchdog->pm_notifier.notifier_call = svc_watchdog_pm_notifier;
+	retval = register_pm_notifier(&watchdog->pm_notifier);
+	if (retval) {
+		dev_err(&svc->dev, "error registering pm notifier(%d)\n",
+			retval);
+		goto svc_watchdog_create_err;
+	}
+
+	retval = gb_svc_watchdog_enable(svc);
+	if (retval) {
+		dev_err(&svc->dev, "error enabling watchdog (%d)\n", retval);
+		unregister_pm_notifier(&watchdog->pm_notifier);
+		goto svc_watchdog_create_err;
+	}
+	return retval;
+
+svc_watchdog_create_err:
+	svc->watchdog = NULL;
+	kfree(watchdog);
+
+	return retval;
+}
+
+void gb_svc_watchdog_destroy(struct gb_svc *svc)
+{
+	struct gb_svc_watchdog *watchdog = svc->watchdog;
+
+	if (!watchdog)
+		return;
+
+	unregister_pm_notifier(&watchdog->pm_notifier);
+	gb_svc_watchdog_disable(svc);
+	svc->watchdog = NULL;
+	kfree(watchdog);
+}
+
+bool gb_svc_watchdog_enabled(struct gb_svc *svc)
+{
+	if (!svc || !svc->watchdog)
+		return false;
+	return svc->watchdog->enabled;
+}
+
+int gb_svc_watchdog_enable(struct gb_svc *svc)
+{
+	struct gb_svc_watchdog *watchdog;
+
+	if (!svc->watchdog)
+		return -ENODEV;
+
+	watchdog = svc->watchdog;
+	if (watchdog->enabled)
+		return 0;
+
+	watchdog->enabled = true;
+	schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
+	return 0;
+}
+
+int gb_svc_watchdog_disable(struct gb_svc *svc)
+{
+	struct gb_svc_watchdog *watchdog;
+
+	if (!svc->watchdog)
+		return -ENODEV;
+
+	watchdog = svc->watchdog;
+	if (!watchdog->enabled)
+		return 0;
+
+	watchdog->enabled = false;
+	cancel_delayed_work_sync(&watchdog->work);
+	return 0;
+}
diff --git a/drivers/staging/greybus/timesync.c b/drivers/staging/greybus/timesync.c
new file mode 100644
index 000000000000..2e68af7dea6d
--- /dev/null
+++ b/drivers/staging/greybus/timesync.c
@@ -0,0 +1,1357 @@
+/*
+ * TimeSync API driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/debugfs.h>
+#include <linux/hrtimer.h>
+#include "greybus.h"
+#include "timesync.h"
+#include "greybus_trace.h"
+
+/*
+ * Minimum inter-strobe value of one millisecond is chosen because it
+ * just-about fits the common definition of a jiffy.
+ *
+ * Maximum value OTOH is constrained by the number of bits the SVC can fit
+ * into a 16 bit up-counter. The SVC configures the timer in microseconds
+ * so the maximum allowable value is 65535 microseconds. We clip that value
+ * to 10000 microseconds for the sake of using nice round base 10 numbers
+ * and since right-now there's no imaginable use-case requiring anything
+ * other than a one millisecond inter-strobe time, let alone something
+ * higher than ten milliseconds.
+ */
+#define GB_TIMESYNC_STROBE_DELAY_US		1000
+#define GB_TIMESYNC_DEFAULT_OFFSET_US		1000
+
+/* Work queue timers long, short and SVC strobe timeout */
+#define GB_TIMESYNC_DELAYED_WORK_LONG		msecs_to_jiffies(10)
+#define GB_TIMESYNC_DELAYED_WORK_SHORT		msecs_to_jiffies(1)
+#define GB_TIMESYNC_MAX_WAIT_SVC		msecs_to_jiffies(5000)
+#define GB_TIMESYNC_KTIME_UPDATE		msecs_to_jiffies(1000)
+#define GB_TIMESYNC_MAX_KTIME_CONVERSION	15
+
+/* Maximum number of times we'll retry a failed synchronous sync */
+#define GB_TIMESYNC_MAX_RETRIES			5
+
+/* Reported nanoseconds/femtoseconds per clock */
+static u64 gb_timesync_ns_per_clock;
+static u64 gb_timesync_fs_per_clock;
+
+/* Maximum difference we will accept converting FrameTime to ktime */
+static u32 gb_timesync_max_ktime_diff;
+
+/* Reported clock rate */
+static unsigned long gb_timesync_clock_rate;
+
+/* Workqueue */
+static void gb_timesync_worker(struct work_struct *work);
+
+/* List of SVCs with one FrameTime per SVC */
+static LIST_HEAD(gb_timesync_svc_list);
+
+/* Synchronize parallel contexts accessing a valid timesync_svc pointer */
+static DEFINE_MUTEX(gb_timesync_svc_list_mutex);
+
+/* Structure to convert from FrameTime to timespec/ktime */
+struct gb_timesync_frame_time_data {
+	u64 frame_time;
+	struct timespec ts;
+};
+
+struct gb_timesync_svc {
+	struct list_head list;
+	struct list_head interface_list;
+	struct gb_svc *svc;
+	struct gb_timesync_host_device *timesync_hd;
+
+	spinlock_t spinlock;	/* Per SVC spinlock to sync with ISR */
+	struct mutex mutex;	/* Per SVC mutex for regular synchronization */
+
+	struct dentry *frame_time_dentry;
+	struct dentry *frame_ktime_dentry;
+	struct workqueue_struct *work_queue;
+	wait_queue_head_t wait_queue;
+	struct delayed_work delayed_work;
+	struct timer_list ktime_timer;
+
+	/* The current local FrameTime */
+	u64 frame_time_offset;
+	struct gb_timesync_frame_time_data strobe_data[GB_TIMESYNC_MAX_STROBES];
+	struct gb_timesync_frame_time_data ktime_data;
+
+	/* The SVC FrameTime and relative AP FrameTime @ last TIMESYNC_PING */
+	u64 svc_ping_frame_time;
+	u64 ap_ping_frame_time;
+
+	/* Transitory settings */
+	u32 strobe_mask;
+	bool offset_down;
+	bool print_ping;
+	bool capture_ping;
+	int strobe;
+
+	/* Current state */
+	int state;
+};
+
+struct gb_timesync_host_device {
+	struct list_head list;
+	struct gb_host_device *hd;
+	u64 ping_frame_time;
+};
+
+struct gb_timesync_interface {
+	struct list_head list;
+	struct gb_interface *interface;
+	u64 ping_frame_time;
+};
+
+enum gb_timesync_state {
+	GB_TIMESYNC_STATE_INVALID		= 0,
+	GB_TIMESYNC_STATE_INACTIVE		= 1,
+	GB_TIMESYNC_STATE_INIT			= 2,
+	GB_TIMESYNC_STATE_WAIT_SVC		= 3,
+	GB_TIMESYNC_STATE_AUTHORITATIVE		= 4,
+	GB_TIMESYNC_STATE_PING			= 5,
+	GB_TIMESYNC_STATE_ACTIVE		= 6,
+};
+
+static void gb_timesync_ktime_timer_fn(unsigned long data);
+
+static u64 gb_timesync_adjust_count(struct gb_timesync_svc *timesync_svc,
+				    u64 counts)
+{
+	if (timesync_svc->offset_down)
+		return counts - timesync_svc->frame_time_offset;
+	else
+		return counts + timesync_svc->frame_time_offset;
+}
+
+/*
+ * This function provides the authoritative FrameTime to a calling function. It
+ * is designed to be lockless and should remain that way the caller is assumed
+ * to be state-aware.
+ */
+static u64 __gb_timesync_get_frame_time(struct gb_timesync_svc *timesync_svc)
+{
+	u64 clocks = gb_timesync_platform_get_counter();
+
+	return gb_timesync_adjust_count(timesync_svc, clocks);
+}
+
+static void gb_timesync_schedule_svc_timeout(struct gb_timesync_svc
+					     *timesync_svc)
+{
+	queue_delayed_work(timesync_svc->work_queue,
+			   &timesync_svc->delayed_work,
+			   GB_TIMESYNC_MAX_WAIT_SVC);
+}
+
+static void gb_timesync_set_state(struct gb_timesync_svc *timesync_svc,
+				  int state)
+{
+	switch (state) {
+	case GB_TIMESYNC_STATE_INVALID:
+		timesync_svc->state = state;
+		wake_up(&timesync_svc->wait_queue);
+		break;
+	case GB_TIMESYNC_STATE_INACTIVE:
+		timesync_svc->state = state;
+		wake_up(&timesync_svc->wait_queue);
+		break;
+	case GB_TIMESYNC_STATE_INIT:
+		if (timesync_svc->state != GB_TIMESYNC_STATE_INVALID) {
+			timesync_svc->strobe = 0;
+			timesync_svc->frame_time_offset = 0;
+			timesync_svc->state = state;
+			cancel_delayed_work(&timesync_svc->delayed_work);
+			queue_delayed_work(timesync_svc->work_queue,
+					   &timesync_svc->delayed_work,
+					   GB_TIMESYNC_DELAYED_WORK_LONG);
+		}
+		break;
+	case GB_TIMESYNC_STATE_WAIT_SVC:
+		if (timesync_svc->state == GB_TIMESYNC_STATE_INIT)
+			timesync_svc->state = state;
+		break;
+	case GB_TIMESYNC_STATE_AUTHORITATIVE:
+		if (timesync_svc->state == GB_TIMESYNC_STATE_WAIT_SVC) {
+			timesync_svc->state = state;
+			cancel_delayed_work(&timesync_svc->delayed_work);
+			queue_delayed_work(timesync_svc->work_queue,
+					   &timesync_svc->delayed_work, 0);
+		}
+		break;
+	case GB_TIMESYNC_STATE_PING:
+		if (timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE) {
+			timesync_svc->state = state;
+			queue_delayed_work(timesync_svc->work_queue,
+					   &timesync_svc->delayed_work,
+					   GB_TIMESYNC_DELAYED_WORK_SHORT);
+		}
+		break;
+	case GB_TIMESYNC_STATE_ACTIVE:
+		if (timesync_svc->state == GB_TIMESYNC_STATE_AUTHORITATIVE ||
+		    timesync_svc->state == GB_TIMESYNC_STATE_PING) {
+			timesync_svc->state = state;
+			wake_up(&timesync_svc->wait_queue);
+		}
+		break;
+	}
+
+	if (WARN_ON(timesync_svc->state != state)) {
+		pr_err("Invalid state transition %d=>%d\n",
+		       timesync_svc->state, state);
+	}
+}
+
+static void gb_timesync_set_state_atomic(struct gb_timesync_svc *timesync_svc,
+					 int state)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+	gb_timesync_set_state(timesync_svc, state);
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+}
+
+static u64 gb_timesync_diff(u64 x, u64 y)
+{
+	if (x > y)
+		return x - y;
+	else
+		return y - x;
+}
+
+static void gb_timesync_adjust_to_svc(struct gb_timesync_svc *svc,
+				      u64 svc_frame_time, u64 ap_frame_time)
+{
+	if (svc_frame_time > ap_frame_time) {
+		svc->frame_time_offset = svc_frame_time - ap_frame_time;
+		svc->offset_down = false;
+	} else {
+		svc->frame_time_offset = ap_frame_time - svc_frame_time;
+		svc->offset_down = true;
+	}
+}
+
+/*
+ * Associate a FrameTime with a ktime timestamp represented as struct timespec
+ * Requires the calling context to hold timesync_svc->mutex
+ */
+static void gb_timesync_store_ktime(struct gb_timesync_svc *timesync_svc,
+				    struct timespec ts, u64 frame_time)
+{
+	timesync_svc->ktime_data.ts = ts;
+	timesync_svc->ktime_data.frame_time = frame_time;
+}
+
+/*
+ * Find the two pulses that best-match our expected inter-strobe gap and
+ * then calculate the difference between the SVC time at the second pulse
+ * to the local time at the second pulse.
+ */
+static void gb_timesync_collate_frame_time(struct gb_timesync_svc *timesync_svc,
+					   u64 *frame_time)
+{
+	int i = 0;
+	u64 delta, ap_frame_time;
+	u64 strobe_delay_ns = GB_TIMESYNC_STROBE_DELAY_US * NSEC_PER_USEC;
+	u64 least = 0;
+
+	for (i = 1; i < GB_TIMESYNC_MAX_STROBES; i++) {
+		delta = timesync_svc->strobe_data[i].frame_time -
+			timesync_svc->strobe_data[i - 1].frame_time;
+		delta *= gb_timesync_ns_per_clock;
+		delta = gb_timesync_diff(delta, strobe_delay_ns);
+
+		if (!least || delta < least) {
+			least = delta;
+			gb_timesync_adjust_to_svc(timesync_svc, frame_time[i],
+						  timesync_svc->strobe_data[i].frame_time);
+
+			ap_frame_time = timesync_svc->strobe_data[i].frame_time;
+			ap_frame_time = gb_timesync_adjust_count(timesync_svc,
+								 ap_frame_time);
+			gb_timesync_store_ktime(timesync_svc,
+						timesync_svc->strobe_data[i].ts,
+						ap_frame_time);
+
+			pr_debug("adjust %s local %llu svc %llu delta %llu\n",
+				 timesync_svc->offset_down ? "down" : "up",
+				 timesync_svc->strobe_data[i].frame_time,
+				 frame_time[i], delta);
+		}
+	}
+}
+
+static void gb_timesync_teardown(struct gb_timesync_svc *timesync_svc)
+{
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_interface *interface;
+	struct gb_host_device *hd;
+	int ret;
+
+	list_for_each_entry(timesync_interface,
+			    &timesync_svc->interface_list, list) {
+		interface = timesync_interface->interface;
+		ret = gb_interface_timesync_disable(interface);
+		if (ret) {
+			dev_err(&interface->dev,
+				"interface timesync_disable %d\n", ret);
+		}
+	}
+
+	hd = timesync_svc->timesync_hd->hd;
+	ret = hd->driver->timesync_disable(hd);
+	if (ret < 0) {
+		dev_err(&hd->dev, "host timesync_disable %d\n",
+			ret);
+	}
+
+	gb_svc_timesync_wake_pins_release(svc);
+	gb_svc_timesync_disable(svc);
+	gb_timesync_platform_unlock_bus();
+
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
+}
+
+static void gb_timesync_platform_lock_bus_fail(struct gb_timesync_svc
+						*timesync_svc, int ret)
+{
+	if (ret == -EAGAIN) {
+		gb_timesync_set_state(timesync_svc, timesync_svc->state);
+	} else {
+		pr_err("Failed to lock timesync bus %d\n", ret);
+		gb_timesync_set_state(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
+	}
+}
+
+static void gb_timesync_enable(struct gb_timesync_svc *timesync_svc)
+{
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_host_device *hd;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_interface *interface;
+	u64 init_frame_time;
+	unsigned long clock_rate = gb_timesync_clock_rate;
+	int ret;
+
+	/*
+	 * Get access to the wake pins in the AP and SVC
+	 * Release these pins either in gb_timesync_teardown() or in
+	 * gb_timesync_authoritative()
+	 */
+	ret = gb_timesync_platform_lock_bus(timesync_svc);
+	if (ret < 0) {
+		gb_timesync_platform_lock_bus_fail(timesync_svc, ret);
+		return;
+	}
+	ret = gb_svc_timesync_wake_pins_acquire(svc, timesync_svc->strobe_mask);
+	if (ret) {
+		dev_err(&svc->dev,
+			"gb_svc_timesync_wake_pins_acquire %d\n", ret);
+		gb_timesync_teardown(timesync_svc);
+		return;
+	}
+
+	/* Choose an initial time in the future */
+	init_frame_time = __gb_timesync_get_frame_time(timesync_svc) + 100000UL;
+
+	/* Send enable command to all relevant participants */
+	list_for_each_entry(timesync_interface, &timesync_svc->interface_list,
+			    list) {
+		interface = timesync_interface->interface;
+		ret = gb_interface_timesync_enable(interface,
+						   GB_TIMESYNC_MAX_STROBES,
+						   init_frame_time,
+						   GB_TIMESYNC_STROBE_DELAY_US,
+						   clock_rate);
+		if (ret) {
+			dev_err(&interface->dev,
+				"interface timesync_enable %d\n", ret);
+		}
+	}
+
+	hd = timesync_svc->timesync_hd->hd;
+	ret = hd->driver->timesync_enable(hd, GB_TIMESYNC_MAX_STROBES,
+					  init_frame_time,
+					  GB_TIMESYNC_STROBE_DELAY_US,
+					  clock_rate);
+	if (ret < 0) {
+		dev_err(&hd->dev, "host timesync_enable %d\n",
+			ret);
+	}
+
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_WAIT_SVC);
+	ret = gb_svc_timesync_enable(svc, GB_TIMESYNC_MAX_STROBES,
+				     init_frame_time,
+				     GB_TIMESYNC_STROBE_DELAY_US,
+				     clock_rate);
+	if (ret) {
+		dev_err(&svc->dev,
+			"gb_svc_timesync_enable %d\n", ret);
+		gb_timesync_teardown(timesync_svc);
+		return;
+	}
+
+	/* Schedule a timeout waiting for SVC to complete strobing */
+	gb_timesync_schedule_svc_timeout(timesync_svc);
+}
+
+static void gb_timesync_authoritative(struct gb_timesync_svc *timesync_svc)
+{
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_host_device *hd;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_interface *interface;
+	u64 svc_frame_time[GB_TIMESYNC_MAX_STROBES];
+	int ret;
+
+	/* Get authoritative time from SVC and adjust local clock */
+	ret = gb_svc_timesync_authoritative(svc, svc_frame_time);
+	if (ret) {
+		dev_err(&svc->dev,
+			"gb_svc_timesync_authoritative %d\n", ret);
+		gb_timesync_teardown(timesync_svc);
+		return;
+	}
+	gb_timesync_collate_frame_time(timesync_svc, svc_frame_time);
+
+	/* Transmit authoritative time to downstream slaves */
+	hd = timesync_svc->timesync_hd->hd;
+	ret = hd->driver->timesync_authoritative(hd, svc_frame_time);
+	if (ret < 0)
+		dev_err(&hd->dev, "host timesync_authoritative %d\n", ret);
+
+	list_for_each_entry(timesync_interface,
+			    &timesync_svc->interface_list, list) {
+		interface = timesync_interface->interface;
+		ret = gb_interface_timesync_authoritative(
+						interface,
+						svc_frame_time);
+		if (ret) {
+			dev_err(&interface->dev,
+				"interface timesync_authoritative %d\n", ret);
+		}
+	}
+
+	/* Release wake pins */
+	gb_svc_timesync_wake_pins_release(svc);
+	gb_timesync_platform_unlock_bus();
+
+	/* Transition to state ACTIVE */
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_ACTIVE);
+
+	/* Schedule a ping to verify the synchronized system time */
+	timesync_svc->print_ping = true;
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_PING);
+}
+
+static int __gb_timesync_get_status(struct gb_timesync_svc *timesync_svc)
+{
+	int ret = -EINVAL;
+
+	switch (timesync_svc->state) {
+	case GB_TIMESYNC_STATE_INVALID:
+	case GB_TIMESYNC_STATE_INACTIVE:
+		ret = -ENODEV;
+		break;
+	case GB_TIMESYNC_STATE_INIT:
+	case GB_TIMESYNC_STATE_WAIT_SVC:
+	case GB_TIMESYNC_STATE_AUTHORITATIVE:
+		ret = -EAGAIN;
+		break;
+	case GB_TIMESYNC_STATE_PING:
+	case GB_TIMESYNC_STATE_ACTIVE:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/*
+ * This routine takes a FrameTime and derives the difference with-respect
+ * to a reference FrameTime/ktime pair. It then returns the calculated
+ * ktime based on the difference between the supplied FrameTime and
+ * the reference FrameTime.
+ *
+ * The time difference is calculated to six decimal places. Taking 19.2MHz
+ * as an example this means we have 52.083333~ nanoseconds per clock or
+ * 52083333~ femtoseconds per clock.
+ *
+ * Naively taking the count difference and converting to
+ * seconds/nanoseconds would quickly see the 0.0833 component produce
+ * noticeable errors. For example a time difference of one second would
+ * loose 19200000 * 0.08333x nanoseconds or 1.59 seconds.
+ *
+ * In contrast calculating in femtoseconds the same example of 19200000 *
+ * 0.000000083333x nanoseconds per count of error is just 1.59 nanoseconds!
+ *
+ * Continuing the example of 19.2 MHz we cap the maximum error difference
+ * at a worst-case 0.3 microseconds over a potential calculation window of
+ * abount 15 seconds, meaning you can convert a FrameTime that is <= 15
+ * seconds older/younger than the reference time with a maximum error of
+ * 0.2385 useconds. Note 19.2MHz is an example frequency not a requirement.
+ */
+static int gb_timesync_to_timespec(struct gb_timesync_svc *timesync_svc,
+				   u64 frame_time, struct timespec *ts)
+{
+	unsigned long flags;
+	u64 delta_fs, counts, sec, nsec;
+	bool add;
+	int ret = 0;
+
+	memset(ts, 0x00, sizeof(*ts));
+	mutex_lock(&timesync_svc->mutex);
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+
+	ret = __gb_timesync_get_status(timesync_svc);
+	if (ret)
+		goto done;
+
+	/* Support calculating ktime upwards or downwards from the reference */
+	if (frame_time < timesync_svc->ktime_data.frame_time) {
+		add = false;
+		counts = timesync_svc->ktime_data.frame_time - frame_time;
+	} else {
+		add = true;
+		counts = frame_time - timesync_svc->ktime_data.frame_time;
+	}
+
+	/* Enforce the .23 of a usecond boundary @ 19.2MHz */
+	if (counts > gb_timesync_max_ktime_diff) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	/* Determine the time difference in femtoseconds */
+	delta_fs = counts * gb_timesync_fs_per_clock;
+
+	/* Convert to seconds */
+	sec = delta_fs;
+	do_div(sec, NSEC_PER_SEC);
+	do_div(sec, 1000000UL);
+
+	/* Get the nanosecond remainder */
+	nsec = do_div(delta_fs, sec);
+	do_div(nsec, 1000000UL);
+
+	if (add) {
+		/* Add the calculated offset - overflow nanoseconds upwards */
+		ts->tv_sec = timesync_svc->ktime_data.ts.tv_sec + sec;
+		ts->tv_nsec = timesync_svc->ktime_data.ts.tv_nsec + nsec;
+		if (ts->tv_nsec >= NSEC_PER_SEC) {
+			ts->tv_sec++;
+			ts->tv_nsec -= NSEC_PER_SEC;
+		}
+	} else {
+		/* Subtract the difference over/underflow as necessary */
+		if (nsec > timesync_svc->ktime_data.ts.tv_nsec) {
+			sec++;
+			nsec = nsec + timesync_svc->ktime_data.ts.tv_nsec;
+			nsec = do_div(nsec, NSEC_PER_SEC);
+		} else {
+			nsec = timesync_svc->ktime_data.ts.tv_nsec - nsec;
+		}
+		/* Cannot return a negative second value */
+		if (sec > timesync_svc->ktime_data.ts.tv_sec) {
+			ret = -EINVAL;
+			goto done;
+		}
+		ts->tv_sec = timesync_svc->ktime_data.ts.tv_sec - sec;
+		ts->tv_nsec = nsec;
+	}
+done:
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+	mutex_unlock(&timesync_svc->mutex);
+	return ret;
+}
+
+static size_t gb_timesync_log_frame_time(struct gb_timesync_svc *timesync_svc,
+					 char *buf, size_t buflen)
+{
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_host_device *hd;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_interface *interface;
+	unsigned int len;
+	size_t off;
+
+	/* AP/SVC */
+	off = snprintf(buf, buflen, "%s frametime: ap=%llu %s=%llu ",
+		       greybus_bus_type.name,
+		       timesync_svc->ap_ping_frame_time, dev_name(&svc->dev),
+		       timesync_svc->svc_ping_frame_time);
+	len = buflen - off;
+
+	/* APB/GPB */
+	if (len < buflen) {
+		hd = timesync_svc->timesync_hd->hd;
+		off += snprintf(&buf[off], len, "%s=%llu ", dev_name(&hd->dev),
+				timesync_svc->timesync_hd->ping_frame_time);
+		len = buflen - off;
+	}
+
+	list_for_each_entry(timesync_interface,
+			    &timesync_svc->interface_list, list) {
+		if (len < buflen) {
+			interface = timesync_interface->interface;
+			off += snprintf(&buf[off], len, "%s=%llu ",
+					dev_name(&interface->dev),
+					timesync_interface->ping_frame_time);
+			len = buflen - off;
+		}
+	}
+	if (len < buflen)
+		off += snprintf(&buf[off], len, "\n");
+	return off;
+}
+
+static size_t gb_timesync_log_frame_ktime(struct gb_timesync_svc *timesync_svc,
+					  char *buf, size_t buflen)
+{
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_host_device *hd;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_interface *interface;
+	struct timespec ts;
+	unsigned int len;
+	size_t off;
+
+	/* AP */
+	gb_timesync_to_timespec(timesync_svc, timesync_svc->ap_ping_frame_time,
+				&ts);
+	off = snprintf(buf, buflen, "%s frametime: ap=%lu.%lu ",
+		       greybus_bus_type.name, ts.tv_sec, ts.tv_nsec);
+	len = buflen - off;
+	if (len >= buflen)
+		goto done;
+
+	/* SVC */
+	gb_timesync_to_timespec(timesync_svc, timesync_svc->svc_ping_frame_time,
+				&ts);
+	off += snprintf(&buf[off], len, "%s=%lu.%lu ", dev_name(&svc->dev),
+			ts.tv_sec, ts.tv_nsec);
+	len = buflen - off;
+	if (len >= buflen)
+		goto done;
+
+	/* APB/GPB */
+	hd = timesync_svc->timesync_hd->hd;
+	gb_timesync_to_timespec(timesync_svc,
+				timesync_svc->timesync_hd->ping_frame_time,
+				&ts);
+	off += snprintf(&buf[off], len, "%s=%lu.%lu ",
+			dev_name(&hd->dev),
+			ts.tv_sec, ts.tv_nsec);
+	len = buflen - off;
+	if (len >= buflen)
+		goto done;
+
+	list_for_each_entry(timesync_interface,
+			    &timesync_svc->interface_list, list) {
+		interface = timesync_interface->interface;
+		gb_timesync_to_timespec(timesync_svc,
+					timesync_interface->ping_frame_time,
+					&ts);
+		off += snprintf(&buf[off], len, "%s=%lu.%lu ",
+				dev_name(&interface->dev),
+				ts.tv_sec, ts.tv_nsec);
+		len = buflen - off;
+		if (len >= buflen)
+			goto done;
+	}
+	off += snprintf(&buf[off], len, "\n");
+done:
+	return off;
+}
+
+/*
+ * Send an SVC initiated wake 'ping' to each TimeSync participant.
+ * Get the FrameTime from each participant associated with the wake
+ * ping.
+ */
+static void gb_timesync_ping(struct gb_timesync_svc *timesync_svc)
+{
+	struct gb_svc *svc = timesync_svc->svc;
+	struct gb_host_device *hd;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_control *control;
+	u64 *ping_frame_time;
+	int ret;
+
+	/* Get access to the wake pins in the AP and SVC */
+	ret = gb_timesync_platform_lock_bus(timesync_svc);
+	if (ret < 0) {
+		gb_timesync_platform_lock_bus_fail(timesync_svc, ret);
+		return;
+	}
+	ret = gb_svc_timesync_wake_pins_acquire(svc, timesync_svc->strobe_mask);
+	if (ret) {
+		dev_err(&svc->dev,
+			"gb_svc_timesync_wake_pins_acquire %d\n", ret);
+		gb_timesync_teardown(timesync_svc);
+		return;
+	}
+
+	/* Have SVC generate a timesync ping */
+	timesync_svc->capture_ping = true;
+	timesync_svc->svc_ping_frame_time = 0;
+	ret = gb_svc_timesync_ping(svc, &timesync_svc->svc_ping_frame_time);
+	timesync_svc->capture_ping = false;
+	if (ret) {
+		dev_err(&svc->dev,
+			"gb_svc_timesync_ping %d\n", ret);
+		gb_timesync_teardown(timesync_svc);
+		return;
+	}
+
+	/* Get the ping FrameTime from each APB/GPB */
+	hd = timesync_svc->timesync_hd->hd;
+	timesync_svc->timesync_hd->ping_frame_time = 0;
+	ret = hd->driver->timesync_get_last_event(hd,
+		&timesync_svc->timesync_hd->ping_frame_time);
+	if (ret)
+		dev_err(&hd->dev, "host timesync_get_last_event %d\n", ret);
+
+	list_for_each_entry(timesync_interface,
+			    &timesync_svc->interface_list, list) {
+		control = timesync_interface->interface->control;
+		timesync_interface->ping_frame_time = 0;
+		ping_frame_time = &timesync_interface->ping_frame_time;
+		ret = gb_control_timesync_get_last_event(control,
+							 ping_frame_time);
+		if (ret) {
+			dev_err(&timesync_interface->interface->dev,
+				"gb_control_timesync_get_last_event %d\n", ret);
+		}
+	}
+
+	/* Ping success - move to timesync active */
+	gb_svc_timesync_wake_pins_release(svc);
+	gb_timesync_platform_unlock_bus();
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_ACTIVE);
+}
+
+static void gb_timesync_log_ping_time(struct gb_timesync_svc *timesync_svc)
+{
+	char *buf;
+
+	if (!timesync_svc->print_ping)
+		return;
+
+	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (buf) {
+		gb_timesync_log_frame_time(timesync_svc, buf, PAGE_SIZE);
+		dev_dbg(&timesync_svc->svc->dev, "%s", buf);
+		kfree(buf);
+	}
+}
+
+/*
+ * Perform the actual work of scheduled TimeSync logic.
+ */
+static void gb_timesync_worker(struct work_struct *work)
+{
+	struct delayed_work *delayed_work = to_delayed_work(work);
+	struct gb_timesync_svc *timesync_svc =
+		container_of(delayed_work, struct gb_timesync_svc, delayed_work);
+
+	mutex_lock(&timesync_svc->mutex);
+
+	switch (timesync_svc->state) {
+	case GB_TIMESYNC_STATE_INIT:
+		gb_timesync_enable(timesync_svc);
+		break;
+
+	case GB_TIMESYNC_STATE_WAIT_SVC:
+		dev_err(&timesync_svc->svc->dev,
+			"timeout SVC strobe completion %d/%d\n",
+			timesync_svc->strobe, GB_TIMESYNC_MAX_STROBES);
+		gb_timesync_teardown(timesync_svc);
+		break;
+
+	case GB_TIMESYNC_STATE_AUTHORITATIVE:
+		gb_timesync_authoritative(timesync_svc);
+		break;
+
+	case GB_TIMESYNC_STATE_PING:
+		gb_timesync_ping(timesync_svc);
+		gb_timesync_log_ping_time(timesync_svc);
+		break;
+
+	default:
+		pr_err("Invalid state %d for delayed work\n",
+		       timesync_svc->state);
+		break;
+	}
+
+	mutex_unlock(&timesync_svc->mutex);
+}
+
+/*
+ * Schedule a new TimeSync INIT or PING operation serialized w/r to
+ * gb_timesync_worker().
+ */
+static int gb_timesync_schedule(struct gb_timesync_svc *timesync_svc, int state)
+{
+	int ret = 0;
+
+	if (state != GB_TIMESYNC_STATE_INIT && state != GB_TIMESYNC_STATE_PING)
+		return -EINVAL;
+
+	mutex_lock(&timesync_svc->mutex);
+	if (timesync_svc->state !=  GB_TIMESYNC_STATE_INVALID) {
+		gb_timesync_set_state_atomic(timesync_svc, state);
+	} else {
+		ret = -ENODEV;
+	}
+	mutex_unlock(&timesync_svc->mutex);
+	return ret;
+}
+
+static int __gb_timesync_schedule_synchronous(
+	struct gb_timesync_svc *timesync_svc, int state)
+{
+	unsigned long flags;
+	int ret;
+
+	ret = gb_timesync_schedule(timesync_svc, state);
+	if (ret)
+		return ret;
+
+	ret = wait_event_interruptible(timesync_svc->wait_queue,
+			(timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE ||
+			 timesync_svc->state == GB_TIMESYNC_STATE_INACTIVE ||
+			 timesync_svc->state == GB_TIMESYNC_STATE_INVALID));
+	if (ret)
+		return ret;
+
+	mutex_lock(&timesync_svc->mutex);
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+
+	ret = __gb_timesync_get_status(timesync_svc);
+
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+	mutex_unlock(&timesync_svc->mutex);
+
+	return ret;
+}
+
+static struct gb_timesync_svc *gb_timesync_find_timesync_svc(
+	struct gb_host_device *hd)
+{
+	struct gb_timesync_svc *timesync_svc;
+
+	list_for_each_entry(timesync_svc, &gb_timesync_svc_list, list) {
+		if (timesync_svc->svc == hd->svc)
+			return timesync_svc;
+	}
+	return NULL;
+}
+
+static struct gb_timesync_interface *gb_timesync_find_timesync_interface(
+	struct gb_timesync_svc *timesync_svc,
+	struct gb_interface *interface)
+{
+	struct gb_timesync_interface *timesync_interface;
+
+	list_for_each_entry(timesync_interface, &timesync_svc->interface_list, list) {
+		if (timesync_interface->interface == interface)
+			return timesync_interface;
+	}
+	return NULL;
+}
+
+int gb_timesync_schedule_synchronous(struct gb_interface *interface)
+{
+	int ret;
+	struct gb_timesync_svc *timesync_svc;
+	int retries;
+
+	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
+		return 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	for (retries = 0; retries < GB_TIMESYNC_MAX_RETRIES; retries++) {
+		timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+		if (!timesync_svc) {
+			ret = -ENODEV;
+			goto done;
+		}
+
+		ret = __gb_timesync_schedule_synchronous(timesync_svc,
+						 GB_TIMESYNC_STATE_INIT);
+		if (!ret)
+			break;
+	}
+	if (ret && retries == GB_TIMESYNC_MAX_RETRIES)
+		ret = -ETIMEDOUT;
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_schedule_synchronous);
+
+void gb_timesync_schedule_asynchronous(struct gb_interface *interface)
+{
+	struct gb_timesync_svc *timesync_svc;
+
+	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
+		return;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+	if (!timesync_svc)
+		goto done;
+
+	gb_timesync_schedule(timesync_svc, GB_TIMESYNC_STATE_INIT);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_schedule_asynchronous);
+
+static ssize_t gb_timesync_ping_read(struct file *file, char __user *ubuf,
+				     size_t len, loff_t *offset, bool ktime)
+{
+	struct gb_timesync_svc *timesync_svc = file->f_inode->i_private;
+	char *buf;
+	ssize_t ret = 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	mutex_lock(&timesync_svc->mutex);
+	if (list_empty(&timesync_svc->interface_list))
+		ret = -ENODEV;
+	timesync_svc->print_ping = false;
+	mutex_unlock(&timesync_svc->mutex);
+	if (ret)
+		goto done;
+
+	ret = __gb_timesync_schedule_synchronous(timesync_svc,
+						 GB_TIMESYNC_STATE_PING);
+	if (ret)
+		goto done;
+
+	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	if (ktime)
+		ret = gb_timesync_log_frame_ktime(timesync_svc, buf, PAGE_SIZE);
+	else
+		ret = gb_timesync_log_frame_time(timesync_svc, buf, PAGE_SIZE);
+	if (ret > 0)
+		ret = simple_read_from_buffer(ubuf, len, offset, buf, ret);
+	kfree(buf);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+
+static ssize_t gb_timesync_ping_read_frame_time(struct file *file,
+						char __user *buf,
+						size_t len, loff_t *offset)
+{
+	return gb_timesync_ping_read(file, buf, len, offset, false);
+}
+
+static ssize_t gb_timesync_ping_read_frame_ktime(struct file *file,
+						 char __user *buf,
+						 size_t len, loff_t *offset)
+{
+	return gb_timesync_ping_read(file, buf, len, offset, true);
+}
+
+static const struct file_operations gb_timesync_debugfs_frame_time_ops = {
+	.read		= gb_timesync_ping_read_frame_time,
+};
+
+static const struct file_operations gb_timesync_debugfs_frame_ktime_ops = {
+	.read		= gb_timesync_ping_read_frame_ktime,
+};
+
+static int gb_timesync_hd_add(struct gb_timesync_svc *timesync_svc,
+			      struct gb_host_device *hd)
+{
+	struct gb_timesync_host_device *timesync_hd;
+
+	timesync_hd = kzalloc(sizeof(*timesync_hd), GFP_KERNEL);
+	if (!timesync_hd)
+		return -ENOMEM;
+
+	WARN_ON(timesync_svc->timesync_hd);
+	timesync_hd->hd = hd;
+	timesync_svc->timesync_hd = timesync_hd;
+
+	return 0;
+}
+
+static void gb_timesync_hd_remove(struct gb_timesync_svc *timesync_svc,
+				  struct gb_host_device *hd)
+{
+	if (timesync_svc->timesync_hd->hd == hd) {
+		kfree(timesync_svc->timesync_hd);
+		timesync_svc->timesync_hd = NULL;
+		return;
+	}
+	WARN_ON(1);
+}
+
+int gb_timesync_svc_add(struct gb_svc *svc)
+{
+	struct gb_timesync_svc *timesync_svc;
+	int ret;
+
+	timesync_svc = kzalloc(sizeof(*timesync_svc), GFP_KERNEL);
+	if (!timesync_svc)
+		return -ENOMEM;
+
+	timesync_svc->work_queue =
+		create_singlethread_workqueue("gb-timesync-work_queue");
+
+	if (!timesync_svc->work_queue) {
+		kfree(timesync_svc);
+		return -ENOMEM;
+	}
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	INIT_LIST_HEAD(&timesync_svc->interface_list);
+	INIT_DELAYED_WORK(&timesync_svc->delayed_work, gb_timesync_worker);
+	mutex_init(&timesync_svc->mutex);
+	spin_lock_init(&timesync_svc->spinlock);
+	init_waitqueue_head(&timesync_svc->wait_queue);
+
+	timesync_svc->svc = svc;
+	timesync_svc->frame_time_offset = 0;
+	timesync_svc->capture_ping = false;
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
+
+	timesync_svc->frame_time_dentry =
+		debugfs_create_file("frame-time", S_IRUGO, svc->debugfs_dentry,
+				    timesync_svc,
+				    &gb_timesync_debugfs_frame_time_ops);
+	timesync_svc->frame_ktime_dentry =
+		debugfs_create_file("frame-ktime", S_IRUGO, svc->debugfs_dentry,
+				    timesync_svc,
+				    &gb_timesync_debugfs_frame_ktime_ops);
+
+	list_add(&timesync_svc->list, &gb_timesync_svc_list);
+	ret = gb_timesync_hd_add(timesync_svc, svc->hd);
+	if (ret) {
+		list_del(&timesync_svc->list);
+		debugfs_remove(timesync_svc->frame_ktime_dentry);
+		debugfs_remove(timesync_svc->frame_time_dentry);
+		destroy_workqueue(timesync_svc->work_queue);
+		kfree(timesync_svc);
+		goto done;
+	}
+
+	init_timer(&timesync_svc->ktime_timer);
+	timesync_svc->ktime_timer.function = gb_timesync_ktime_timer_fn;
+	timesync_svc->ktime_timer.expires = jiffies + GB_TIMESYNC_KTIME_UPDATE;
+	timesync_svc->ktime_timer.data = (unsigned long)timesync_svc;
+	add_timer(&timesync_svc->ktime_timer);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_svc_add);
+
+void gb_timesync_svc_remove(struct gb_svc *svc)
+{
+	struct gb_timesync_svc *timesync_svc;
+	struct gb_timesync_interface *timesync_interface;
+	struct gb_timesync_interface *next;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
+	if (!timesync_svc)
+		goto done;
+
+	cancel_delayed_work_sync(&timesync_svc->delayed_work);
+
+	mutex_lock(&timesync_svc->mutex);
+
+	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INVALID);
+	del_timer_sync(&timesync_svc->ktime_timer);
+	gb_timesync_teardown(timesync_svc);
+
+	gb_timesync_hd_remove(timesync_svc, svc->hd);
+	list_for_each_entry_safe(timesync_interface, next,
+				 &timesync_svc->interface_list, list) {
+		list_del(&timesync_interface->list);
+		kfree(timesync_interface);
+	}
+	debugfs_remove(timesync_svc->frame_ktime_dentry);
+	debugfs_remove(timesync_svc->frame_time_dentry);
+	destroy_workqueue(timesync_svc->work_queue);
+	list_del(&timesync_svc->list);
+
+	mutex_unlock(&timesync_svc->mutex);
+
+	kfree(timesync_svc);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+}
+EXPORT_SYMBOL_GPL(gb_timesync_svc_remove);
+
+/*
+ * Add a Greybus Interface to the set of TimeSync Interfaces.
+ */
+int gb_timesync_interface_add(struct gb_interface *interface)
+{
+	struct gb_timesync_svc *timesync_svc;
+	struct gb_timesync_interface *timesync_interface;
+	int ret = 0;
+
+	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
+		return 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+	if (!timesync_svc) {
+		ret = -ENODEV;
+		goto done;
+	}
+
+	timesync_interface = kzalloc(sizeof(*timesync_interface), GFP_KERNEL);
+	if (!timesync_interface) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	mutex_lock(&timesync_svc->mutex);
+	timesync_interface->interface = interface;
+	list_add(&timesync_interface->list, &timesync_svc->interface_list);
+	timesync_svc->strobe_mask |= 1 << interface->interface_id;
+	mutex_unlock(&timesync_svc->mutex);
+
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_interface_add);
+
+/*
+ * Remove a Greybus Interface from the set of TimeSync Interfaces.
+ */
+void gb_timesync_interface_remove(struct gb_interface *interface)
+{
+	struct gb_timesync_svc *timesync_svc;
+	struct gb_timesync_interface *timesync_interface;
+
+	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
+		return;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+	if (!timesync_svc)
+		goto done;
+
+	timesync_interface = gb_timesync_find_timesync_interface(timesync_svc,
+								 interface);
+	if (!timesync_interface)
+		goto done;
+
+	mutex_lock(&timesync_svc->mutex);
+	timesync_svc->strobe_mask &= ~(1 << interface->interface_id);
+	list_del(&timesync_interface->list);
+	kfree(timesync_interface);
+	mutex_unlock(&timesync_svc->mutex);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+}
+EXPORT_SYMBOL_GPL(gb_timesync_interface_remove);
+
+/*
+ * Give the authoritative FrameTime to the calling function. Returns zero if we
+ * are not in GB_TIMESYNC_STATE_ACTIVE.
+ */
+static u64 gb_timesync_get_frame_time(struct gb_timesync_svc *timesync_svc)
+{
+	unsigned long flags;
+	u64 ret;
+
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+	if (timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE)
+		ret = __gb_timesync_get_frame_time(timesync_svc);
+	else
+		ret = 0;
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+	return ret;
+}
+
+u64 gb_timesync_get_frame_time_by_interface(struct gb_interface *interface)
+{
+	struct gb_timesync_svc *timesync_svc;
+	u64 ret = 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+	if (!timesync_svc)
+		goto done;
+
+	ret = gb_timesync_get_frame_time(timesync_svc);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_get_frame_time_by_interface);
+
+u64 gb_timesync_get_frame_time_by_svc(struct gb_svc *svc)
+{
+	struct gb_timesync_svc *timesync_svc;
+	u64 ret = 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
+	if (!timesync_svc)
+		goto done;
+
+	ret = gb_timesync_get_frame_time(timesync_svc);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_get_frame_time_by_svc);
+
+/* Incrementally updates the conversion base from FrameTime to ktime */
+static void gb_timesync_ktime_timer_fn(unsigned long data)
+{
+	struct gb_timesync_svc *timesync_svc =
+		(struct gb_timesync_svc *)data;
+	unsigned long flags;
+	u64 frame_time;
+	struct timespec ts;
+
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+
+	if (timesync_svc->state != GB_TIMESYNC_STATE_ACTIVE)
+		goto done;
+
+	ktime_get_ts(&ts);
+	frame_time = __gb_timesync_get_frame_time(timesync_svc);
+	gb_timesync_store_ktime(timesync_svc, ts, frame_time);
+
+done:
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+	mod_timer(&timesync_svc->ktime_timer,
+		  jiffies + GB_TIMESYNC_KTIME_UPDATE);
+}
+
+int gb_timesync_to_timespec_by_svc(struct gb_svc *svc, u64 frame_time,
+				   struct timespec *ts)
+{
+	struct gb_timesync_svc *timesync_svc;
+	int ret = 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
+	if (!timesync_svc) {
+		ret = -ENODEV;
+		goto done;
+	}
+	ret = gb_timesync_to_timespec(timesync_svc, frame_time, ts);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_to_timespec_by_svc);
+
+int gb_timesync_to_timespec_by_interface(struct gb_interface *interface,
+					 u64 frame_time, struct timespec *ts)
+{
+	struct gb_timesync_svc *timesync_svc;
+	int ret = 0;
+
+	mutex_lock(&gb_timesync_svc_list_mutex);
+	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
+	if (!timesync_svc) {
+		ret = -ENODEV;
+		goto done;
+	}
+
+	ret = gb_timesync_to_timespec(timesync_svc, frame_time, ts);
+done:
+	mutex_unlock(&gb_timesync_svc_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gb_timesync_to_timespec_by_interface);
+
+void gb_timesync_irq(struct gb_timesync_svc *timesync_svc)
+{
+	unsigned long flags;
+	u64 strobe_time;
+	bool strobe_is_ping = true;
+	struct timespec ts;
+
+	ktime_get_ts(&ts);
+	strobe_time = __gb_timesync_get_frame_time(timesync_svc);
+
+	spin_lock_irqsave(&timesync_svc->spinlock, flags);
+
+	if (timesync_svc->state == GB_TIMESYNC_STATE_PING) {
+		if (!timesync_svc->capture_ping)
+			goto done_nolog;
+		timesync_svc->ap_ping_frame_time = strobe_time;
+		goto done_log;
+	} else if (timesync_svc->state != GB_TIMESYNC_STATE_WAIT_SVC) {
+		goto done_nolog;
+	}
+
+	timesync_svc->strobe_data[timesync_svc->strobe].frame_time = strobe_time;
+	timesync_svc->strobe_data[timesync_svc->strobe].ts = ts;
+
+	if (++timesync_svc->strobe == GB_TIMESYNC_MAX_STROBES) {
+		gb_timesync_set_state(timesync_svc,
+				      GB_TIMESYNC_STATE_AUTHORITATIVE);
+	}
+	strobe_is_ping = false;
+done_log:
+	trace_gb_timesync_irq(strobe_is_ping, timesync_svc->strobe,
+			      GB_TIMESYNC_MAX_STROBES, strobe_time);
+done_nolog:
+	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
+}
+EXPORT_SYMBOL(gb_timesync_irq);
+
+int __init gb_timesync_init(void)
+{
+	int ret = 0;
+
+	ret = gb_timesync_platform_init();
+	if (ret) {
+		pr_err("timesync platform init fail!\n");
+		return ret;
+	}
+
+	gb_timesync_clock_rate = gb_timesync_platform_get_clock_rate();
+
+	/* Calculate nanoseconds and femtoseconds per clock */
+	gb_timesync_fs_per_clock = FSEC_PER_SEC;
+	do_div(gb_timesync_fs_per_clock, gb_timesync_clock_rate);
+	gb_timesync_ns_per_clock = NSEC_PER_SEC;
+	do_div(gb_timesync_ns_per_clock, gb_timesync_clock_rate);
+
+	/* Calculate the maximum number of clocks we will convert to ktime */
+	gb_timesync_max_ktime_diff =
+		GB_TIMESYNC_MAX_KTIME_CONVERSION * gb_timesync_clock_rate;
+
+	pr_info("Time-Sync @ %lu Hz max ktime conversion +/- %d seconds\n",
+		gb_timesync_clock_rate, GB_TIMESYNC_MAX_KTIME_CONVERSION);
+	return 0;
+}
+
+void gb_timesync_exit(void)
+{
+	gb_timesync_platform_exit();
+}
diff --git a/drivers/staging/greybus/timesync.h b/drivers/staging/greybus/timesync.h
new file mode 100644
index 000000000000..72fc9a35a002
--- /dev/null
+++ b/drivers/staging/greybus/timesync.h
@@ -0,0 +1,45 @@
+/*
+ * TimeSync API driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __TIMESYNC_H
+#define __TIMESYNC_H
+
+struct gb_svc;
+struct gb_interface;
+struct gb_timesync_svc;
+
+/* Platform */
+u64 gb_timesync_platform_get_counter(void);
+u32 gb_timesync_platform_get_clock_rate(void);
+int gb_timesync_platform_lock_bus(struct gb_timesync_svc *pdata);
+void gb_timesync_platform_unlock_bus(void);
+
+int gb_timesync_platform_init(void);
+void gb_timesync_platform_exit(void);
+
+/* Core API */
+int gb_timesync_interface_add(struct gb_interface *interface);
+void gb_timesync_interface_remove(struct gb_interface *interface);
+int gb_timesync_svc_add(struct gb_svc *svc);
+void gb_timesync_svc_remove(struct gb_svc *svc);
+
+u64 gb_timesync_get_frame_time_by_interface(struct gb_interface *interface);
+u64 gb_timesync_get_frame_time_by_svc(struct gb_svc *svc);
+int gb_timesync_to_timespec_by_svc(struct gb_svc *svc, u64 frame_time,
+				   struct timespec *ts);
+int gb_timesync_to_timespec_by_interface(struct gb_interface *interface,
+					 u64 frame_time, struct timespec *ts);
+
+int gb_timesync_schedule_synchronous(struct gb_interface *intf);
+void gb_timesync_schedule_asynchronous(struct gb_interface *intf);
+void gb_timesync_irq(struct gb_timesync_svc *timesync_svc);
+int gb_timesync_init(void);
+void gb_timesync_exit(void);
+
+#endif /* __TIMESYNC_H */
diff --git a/drivers/staging/greybus/timesync_platform.c b/drivers/staging/greybus/timesync_platform.c
new file mode 100644
index 000000000000..50e8883f932f
--- /dev/null
+++ b/drivers/staging/greybus/timesync_platform.c
@@ -0,0 +1,77 @@
+/*
+ * TimeSync API driver.
+ *
+ * Copyright 2016 Google Inc.
+ * Copyright 2016 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ *
+ * This code reads directly from an ARMv7 memory-mapped timer that lives in
+ * MMIO space. Since this counter lives inside of MMIO space its shared between
+ * cores and that means we don't have to worry about issues like TSC on x86
+ * where each time-stamp-counter (TSC) is local to a particular core.
+ *
+ * Register-level access code is based on
+ * drivers/clocksource/arm_arch_timer.c
+ */
+#include <linux/cpufreq.h>
+#include <linux/of_platform.h>
+
+#include "greybus.h"
+#include "arche_platform.h"
+
+static u32 gb_timesync_clock_frequency;
+int (*arche_platform_change_state_cb)(enum arche_platform_state state,
+				      struct gb_timesync_svc *pdata);
+EXPORT_SYMBOL_GPL(arche_platform_change_state_cb);
+
+u64 gb_timesync_platform_get_counter(void)
+{
+	return (u64)get_cycles();
+}
+
+u32 gb_timesync_platform_get_clock_rate(void)
+{
+	if (unlikely(!gb_timesync_clock_frequency))
+		return cpufreq_get(0);
+
+	return gb_timesync_clock_frequency;
+}
+
+int gb_timesync_platform_lock_bus(struct gb_timesync_svc *pdata)
+{
+	return arche_platform_change_state_cb(ARCHE_PLATFORM_STATE_TIME_SYNC,
+					      pdata);
+}
+
+void gb_timesync_platform_unlock_bus(void)
+{
+	arche_platform_change_state_cb(ARCHE_PLATFORM_STATE_ACTIVE, NULL);
+}
+
+static const struct of_device_id arch_timer_of_match[] = {
+	{ .compatible   = "google,greybus-frame-time-counter", },
+	{},
+};
+
+int __init gb_timesync_platform_init(void)
+{
+	struct device_node *np;
+
+	np = of_find_matching_node(NULL, arch_timer_of_match);
+	if (!np) {
+		/* Tolerate not finding to allow BBB etc to continue */
+		pr_warn("Unable to find a compatible ARMv7 timer\n");
+		return 0;
+	}
+
+	if (of_property_read_u32(np, "clock-frequency",
+				 &gb_timesync_clock_frequency)) {
+		pr_err("Unable to find timer clock-frequency\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+void gb_timesync_platform_exit(void) {}
diff --git a/drivers/staging/greybus/tools/.gitignore b/drivers/staging/greybus/tools/.gitignore
new file mode 100644
index 000000000000..023654c83068
--- /dev/null
+++ b/drivers/staging/greybus/tools/.gitignore
@@ -0,0 +1 @@
+loopback_test
diff --git a/drivers/staging/greybus/tools/Android.mk b/drivers/staging/greybus/tools/Android.mk
new file mode 100644
index 000000000000..fdadbf611757
--- /dev/null
+++ b/drivers/staging/greybus/tools/Android.mk
@@ -0,0 +1,10 @@
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= loopback_test.c
+LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE := gb_loopback_test
+
+include $(BUILD_EXECUTABLE)
+
diff --git a/drivers/staging/greybus/tools/Makefile b/drivers/staging/greybus/tools/Makefile
new file mode 100644
index 000000000000..852b12b71149
--- /dev/null
+++ b/drivers/staging/greybus/tools/Makefile
@@ -0,0 +1,31 @@
+ifeq ($(strip $(V)), 1)
+  Q =
+else
+  Q = @
+endif
+
+CFLAGS	+= -std=gnu99 -Wall -Wextra -g \
+	    -D_GNU_SOURCE \
+	    -Wno-unused-parameter \
+	    -Wmaybe-uninitialized \
+	    -Wredundant-decls \
+	    -Wcast-align \
+	    -Wsign-compare \
+	    -Wno-missing-field-initializers
+
+CC	:= $(CROSS_COMPILE)gcc
+
+TOOLS = loopback_test
+
+all: $(TOOLS)
+
+%.o: %.c ../greybus_protocols.h
+	@echo '  TARGET_CC $@'
+	$(Q)$(CC) $(CFLAGS) -c $< -o $@
+
+loopback_%: loopback_%.o
+	@echo '  TARGET_LD $@'
+	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@
+
+clean::
+	rm -f *.o $(TOOLS)
diff --git a/drivers/staging/greybus/tools/README.loopback b/drivers/staging/greybus/tools/README.loopback
new file mode 100644
index 000000000000..845b08dc4696
--- /dev/null
+++ b/drivers/staging/greybus/tools/README.loopback
@@ -0,0 +1,198 @@
+
+
+        1 - LOOPBACK DRIVER
+
+The driver implements the main logic of the loopback test and provides
+sysfs files to configure the test and retrieve the results.
+A user could run a test without the need of the test application given
+that he understands the sysfs interface of the loopback driver.
+
+The loopback kernel driver needs to be loaded and at least one module
+with the loopback feature enabled must be present for the sysfs files to be
+created and for the loopback test application to be able to run.
+
+To load the module:
+# modprobe gb-loopback
+
+
+When the module is probed,  New files are available on the sysfs
+directory of the detected loopback device.
+(typically under "/sys/bus/graybus/devices").
+
+Here is a short summary of the sysfs interface files that should be visible:
+
+* Loopback Configuration Files:
+    async - Use asynchronous operations.
+    iteration_max - Number of tests iterations to perform.
+    size - payload size of the transfer.
+    timeout - The number of microseconds to give an individual
+              asynchronous request before timing out.
+    us_wait - Time to wait between 2 messages
+    type - By writing the test type to this file, the test starts.
+           Valid tests are:
+             0 stop the test
+             2 - ping
+             3 - transfer
+             4 - sink
+
+* Loopback feedback files:
+    error - number of errors that have occurred.
+    iteration_count - Number of iterations performed.
+    requests_completed - Number of requests successfully completed.
+    requests_timedout - Number of requests that have timed out.
+    timeout_max - Max allowed timeout
+    timeout_min - Min allowed timeout.
+
+* Loopback result files:
+    apbridge_unipro_latency_avg
+    apbridge_unipro_latency_max
+    apbridge_unipro_latency_min
+    gpbridge_firmware_latency_avg
+    gpbridge_firmware_latency_max
+    gpbridge_firmware_latency_min
+    requests_per_second_avg
+    requests_per_second_max
+    requests_per_second_min
+    latency_avg
+    latency_max
+    latency_min
+    throughput_avg
+    throughput_max
+    throughput_min
+
+
+
+            2 - LOOPBACK TEST APPLICATION
+
+The loopback test application manages and formats the results provided by
+the loopback kernel module. The purpose of this application
+is to:
+    - Start and manage multiple loopback device tests concurrently.
+    - Calculate the aggregate results for multiple devices.
+    - Gather and format test results (csv or human readable).
+
+The best way to get up to date usage information for the application is
+usually to pass the "-h" parameter.
+Here is the summary of the available options:
+
+ Mandatory arguments
+   -t     must be one of the test names - sink, transfer or ping
+   -i     iteration count - the number of iterations to run the test over
+ Optional arguments
+   -S     sysfs location - location for greybus 'endo' entires default /sys/bus/greybus/devices/
+   -D     debugfs location - location for loopback debugfs entries default /sys/kernel/debug/gb_loopback/
+   -s     size of data packet to send during test - defaults to zero
+   -m     mask - a bit mask of connections to include example: -m 8 = 4th connection -m 9 = 1st and 4th connection etc
+                 default is zero which means broadcast to all connections
+   -v     verbose output
+   -d     debug output
+   -r     raw data output - when specified the full list of latency values are included in the output CSV
+   -p     porcelain - when specified printout is in a user-friendly non-CSV format. This option suppresses writing to CSV file
+   -a     aggregate - show aggregation of all enabled devies
+   -l     list found loopback devices and exit.
+   -x     Async - Enable async transfers.
+   -o     Timeout - Timeout in microseconds for async operations.
+
+
+
+             3 - REAL WORLD EXAMPLE USAGES
+
+ 3.1 - Using the driver sysfs files to run a test on a single device:
+
+* Run a 1000 transfers of a 100 byte packet. Each transfer is started only
+after the previous one finished successfully:
+    echo 0 > /sys/bus/greybus/devices/1-2.17/type
+    echo 0 > /sys/bus/greybus/devices/1-2.17/async
+    echo 2000 > /sys/bus/greybus/devices/1-2.17/us_wait
+    echo 100 > /sys/bus/greybus/devices/1-2.17/size
+    echo 1000 > /sys/bus/greybus/devices/1-2.17/iteration_max
+    echo 0 > /sys/bus/greybus/devices/1-2.17/mask
+    echo 200000 > /sys/bus/greybus/devices/1-2.17/timeout
+    echo 3 > /sys/bus/greybus/devices/1-2.17/type
+
+* Run a 1000 transfers of a 100 byte packet. Transfers are started without
+waiting for the previous one to finish:
+    echo 0 > /sys/bus/greybus/devices/1-2.17/type
+    echo 3 > /sys/bus/greybus/devices/1-2.17/async
+    echo 0 > /sys/bus/greybus/devices/1-2.17/us_wait
+    echo 100 > /sys/bus/greybus/devices/1-2.17/size
+    echo 1000 > /sys/bus/greybus/devices/1-2.17/iteration_max
+    echo 0 > /sys/bus/greybus/devices/1-2.17/mask
+    echo 200000 > /sys/bus/greybus/devices/1-2.17/timeout
+    echo 3 > /sys/bus/greybus/devices/1-2.17/type
+
+* Read the results from sysfs:
+    cat /sys/bus/greybus/devices/1-2.17/requests_per_second_min
+    cat /sys/bus/greybus/devices/1-2.17/requests_per_second_max
+    cat /sys/bus/greybus/devices/1-2.17/requests_per_second_avg
+
+    cat /sys/bus/greybus/devices/1-2.17/latency_min
+    cat /sys/bus/greybus/devices/1-2.17/latency_max
+    cat /sys/bus/greybus/devices/1-2.17/latency_avg
+
+    cat /sys/bus/greybus/devices/1-2.17/apbridge_unipro_latency_min
+    cat /sys/bus/greybus/devices/1-2.17/apbridge_unipro_latency_max
+    cat /sys/bus/greybus/devices/1-2.17/apbridge_unipro_latency_avg
+
+    cat /sys/bus/greybus/devices/1-2.17/gpbridge_firmware_latency_min
+    cat /sys/bus/greybus/devices/1-2.17/gpbridge_firmware_latency_max
+    cat /sys/bus/greybus/devices/1-2.17/gpbridge_firmware_latency_avg
+
+    cat /sys/bus/greybus/devices/1-2.17/error
+    cat /sys/bus/greybus/devices/1-2.17/requests_completed
+    cat /sys/bus/greybus/devices/1-2.17/requests_timedout
+
+
+3.2 - using the test application:
+
+* Run a transfer test 10 iterations of size 100 bytes on all available devices
+    #/loopback_test -t transfer -i 10 -s 100
+    1970-1-1 0:10:7,transfer,1-4.17,100,10,0,443,509,471.700012,66,1963,2256,2124.600098,293,102776,118088,109318.898438,15312,1620,1998,1894.099976,378,56,57,56.799999,1
+    1970-1-1 0:10:7,transfer,1-5.17,100,10,0,399,542,463.399994,143,1845,2505,2175.800049,660,92568,125744,107393.296875,33176,1469,2305,1806.500000,836,56,57,56.799999,1
+
+
+* Show the aggregate results of both devices. ("-a")
+    #/loopback_test -t transfer -i 10 -s 100  -a
+    1970-1-1 0:10:35,transfer,1-4.17,100,10,0,448,580,494.100006,132,1722,2230,2039.400024,508,103936,134560,114515.703125,30624,1513,1980,1806.900024,467,56,57,57.299999,1
+    1970-1-1 0:10:35,transfer,1-5.17,100,10,0,383,558,478.600006,175,1791,2606,2115.199951,815,88856,129456,110919.703125,40600,1457,2246,1773.599976,789,56,57,57.099998,1
+    1970-1-1 0:10:35,transfer,aggregate,100,10,0,383,580,486.000000,197,1722,2606,2077.000000,884,88856,134560,112717.000000,45704,1457,2246,1789.000000,789,56,57,57.000000,1
+
+* Example usage of the mask option to select which devices will
+  run the test (1st, 2nd, or both devices):
+    # /loopback_test -t transfer -i 10 -s 100 -m 1
+    1970-1-1 0:11:56,transfer,1-4.17,100,10,0,514,558,544.900024,44,1791,1943,1836.599976,152,119248,129456,126301.296875,10208,1600,1001609,101613.601562,1000009,56,57,56.900002,1
+    # /loopback_test -t transfer -i 10 -s 100 -m 2
+    1970-1-1 0:12:0,transfer,1-5.17,100,10,0,468,554,539.000000,86,1804,2134,1859.500000,330,108576,128528,124932.500000,19952,1606,1626,1619.300049,20,56,57,57.400002,1
+    # /loopback_test -t transfer -i 10 -s 100 -m 3
+    1970-1-1 0:12:3,transfer,1-4.17,100,10,0,432,510,469.399994,78,1959,2313,2135.800049,354,100224,118320,108785.296875,18096,1610,2024,1893.500000,414,56,57,57.200001,1
+    1970-1-1 0:12:3,transfer,1-5.17,100,10,0,404,542,468.799988,138,1843,2472,2152.500000,629,93728,125744,108646.101562,32016,1504,2247,1853.099976,743,56,57,57.099998,1
+
+* Show output in human readable format ("-p")
+    # /loopback_test -t transfer -i 10 -s 100 -m 3 -p
+
+    1970-1-1 0:12:37
+    test:                       transfer
+    path:                       1-4.17
+    size:                       100
+    iterations:                 10
+    errors:                     0
+    async:                      Disabled
+    requests per-sec:           min=390, max=547, average=469.299988, jitter=157
+    ap-throughput B/s:          min=90480 max=126904 average=108762.101562 jitter=36424
+    ap-latency usec:            min=1826 max=2560 average=2146.000000 jitter=734
+    apbridge-latency usec:      min=1620 max=1982 average=1882.099976 jitter=362
+    gpbridge-latency usec:      min=56 max=57 average=57.099998 jitter=1
+
+
+    1970-1-1 0:12:37
+    test:                       transfer
+    path:                       1-5.17
+    size:                       100
+    iterations:                 10
+    errors:                     0
+    async:                      Disabled
+    requests per-sec:           min=397, max=538, average=461.700012, jitter=141
+    ap-throughput B/s:          min=92104 max=124816 average=106998.898438 jitter=32712
+    ap-latency usec:            min=1856 max=2514 average=2185.699951 jitter=658
+    apbridge-latency usec:      min=1460 max=2296 average=1828.599976 jitter=836
+    gpbridge-latency usec:      min=56 max=57 average=57.099998 jitter=1
diff --git a/drivers/staging/greybus/tools/lbtest b/drivers/staging/greybus/tools/lbtest
new file mode 100755
index 000000000000..d7353f1a2a6f
--- /dev/null
+++ b/drivers/staging/greybus/tools/lbtest
@@ -0,0 +1,168 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2015 Google, Inc.
+# Copyright (c) 2015 Linaro, Ltd.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+# 3. Neither the name of the copyright holder nor the names of its
+# contributors may be used to endorse or promote products derived from this
+# software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import print_function
+import csv
+import datetime
+import sys
+import time
+
+dict = {'ping': '2', 'transfer': '3', 'sink': '4'}
+verbose = 1
+
+def abort():
+	sys.exit(1)
+
+def usage():
+	print('Usage: looptest TEST SIZE ITERATIONS PATH\n\n'
+	'  Run TEST for a number of ITERATIONS with operation data SIZE bytes\n'
+	'  TEST may be \'ping\' \'transfer\' or \'sink\'\n'
+	'  SIZE indicates the size of transfer <= greybus max payload bytes\n'
+	'  ITERATIONS indicates the number of times to execute TEST at SIZE bytes\n'
+	'             Note if ITERATIONS is set to zero then this utility will\n'
+	'             initiate an infinite (non terminating) test and exit\n'
+	'             without logging any metrics data\n'
+	'  PATH indicates the sysfs path for the loopback greybus entries e.g.\n'
+	'             /sys/bus/greybus/devices/endo0:1:1:1:1/\n'
+	'Examples:\n'
+	'  looptest transfer 128 10000\n'
+	'  looptest ping 0 128\n'
+	'  looptest sink 2030 32768\n'
+	.format(sys.argv[0]), file=sys.stderr)
+
+	abort()
+
+def read_sysfs_int(path):
+	try:
+		f = open(path, "r");
+		val = f.read();
+		f.close()
+		return int(val)
+	except IOError as e:
+		print("I/O error({0}): {1}".format(e.errno, e.strerror))
+		print("Invalid path %s" % path)
+
+def write_sysfs_val(path, val):
+	try:
+		f = open(path, "r+")
+		f.write(val)
+		f.close()
+	except IOError as e:
+		print("I/O error({0}): {1}".format(e.errno, e.strerror))
+		print("Invalid path %s" % path)
+
+def log_csv(test_name, size, iteration_max, sys_pfx):
+	# file name will test_name_size_iteration_max.csv
+	# every time the same test with the same parameters is run we will then
+	# append to the same CSV with datestamp - representing each test dataset
+	fname = test_name + '_' + size + '_' + str(iteration_max) + '.csv'
+
+	try:
+		# gather data set
+		date = str(datetime.datetime.now())
+		error = read_sysfs_int(sys_pfx + 'error')
+		request_min = read_sysfs_int(sys_pfx + 'requests_per_second_min')
+		request_max = read_sysfs_int(sys_pfx + 'requests_per_second_max')
+		request_avg = read_sysfs_int(sys_pfx + 'requests_per_second_avg')
+		latency_min = read_sysfs_int(sys_pfx + 'latency_min')
+		latency_max = read_sysfs_int(sys_pfx + 'latency_max')
+		latency_avg = read_sysfs_int(sys_pfx + 'latency_avg')
+		throughput_min = read_sysfs_int(sys_pfx + 'throughput_min')
+		throughput_max = read_sysfs_int(sys_pfx + 'throughput_max')
+		throughput_avg = read_sysfs_int(sys_pfx + 'throughput_avg')
+
+		# derive jitter
+		request_jitter = request_max - request_min
+		latency_jitter = latency_max - latency_min
+		throughput_jitter = throughput_max - throughput_min
+
+		# append data set to file
+		with open(fname, 'a') as csvf:
+			row = csv.writer(csvf, delimiter=",", quotechar="'",
+					quoting=csv.QUOTE_MINIMAL)
+			row.writerow([date, test_name, size, iteration_max, error,
+					request_min, request_max, request_avg, request_jitter,
+					latency_min, latency_max, latency_avg, latency_jitter,
+					throughput_min, throughput_max, throughput_avg, throughput_jitter])
+	except IOError as e:
+		print("I/O error({0}): {1}".format(e.errno, e.strerror))
+
+def loopback_run(test_name, size, iteration_max, sys_pfx):
+	test_id = dict[test_name]
+	try:
+		# Terminate any currently running test
+		write_sysfs_val(sys_pfx + 'type', '0')
+		# Set parameter for no wait between messages
+		write_sysfs_val(sys_pfx + 'ms_wait', '0')
+		# Set operation size
+		write_sysfs_val(sys_pfx + 'size', size)
+		# Set iterations
+		write_sysfs_val(sys_pfx + 'iteration_max', str(iteration_max))
+		# Initiate by setting loopback operation type
+		write_sysfs_val(sys_pfx + 'type', test_id)
+		time.sleep(1)
+
+		if iteration_max == 0:
+			print ("Infinite test initiated CSV won't be logged\n")
+			return
+
+		previous = 0
+		err = 0
+		while True:
+			# get current count bail out if it hasn't changed
+			iteration_count = read_sysfs_int(sys_pfx + 'iteration_count')
+			if previous == iteration_count:
+				err = 1
+				break
+			elif iteration_count == iteration_max:
+				break
+			previous = iteration_count
+			if verbose:
+				print('%02d%% complete %d of %d ' %
+					(100 * iteration_count / iteration_max,
+					iteration_count, iteration_max))
+			time.sleep(1)
+		if err:
+			print ('\nError executing test\n')
+		else:
+			log_csv(test_name, size, iteration_max, sys_pfx)
+	except ValueError as ve:
+		print("Error: %s " % format(e.strerror), file=sys.stderr)
+		abort()
+
+def main():
+	if len(sys.argv) < 5:
+		usage()
+
+	if sys.argv[1] in dict.keys():
+		loopback_run(sys.argv[1], sys.argv[2], int(sys.argv[3]), sys.argv[4])
+	else:
+		usage()
+if __name__ == '__main__':
+	main()
diff --git a/drivers/staging/greybus/tools/loopback_test.c b/drivers/staging/greybus/tools/loopback_test.c
new file mode 100644
index 000000000000..f7f4cd6fb55b
--- /dev/null
+++ b/drivers/staging/greybus/tools/loopback_test.c
@@ -0,0 +1,1000 @@
+/*
+ * Loopback test application
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Provided under the three clause BSD license found in the LICENSE file.
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <poll.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <signal.h>
+
+#define MAX_NUM_DEVICES 10
+#define MAX_SYSFS_PATH	0x200
+#define CSV_MAX_LINE	0x1000
+#define SYSFS_MAX_INT	0x20
+#define MAX_STR_LEN	255
+#define DEFAULT_ASYNC_TIMEOUT 200000
+
+struct dict {
+	char *name;
+	int type;
+};
+
+static struct dict dict[] = {
+	{"ping", 2},
+	{"transfer", 3},
+	{"sink", 4},
+	{NULL,}		/* list termination */
+};
+
+struct loopback_results {
+	float latency_avg;
+	uint32_t latency_max;
+	uint32_t latency_min;
+	uint32_t latency_jitter;
+
+	float request_avg;
+	uint32_t request_max;
+	uint32_t request_min;
+	uint32_t request_jitter;
+
+	float throughput_avg;
+	uint32_t throughput_max;
+	uint32_t throughput_min;
+	uint32_t throughput_jitter;
+
+	float apbridge_unipro_latency_avg;
+	uint32_t apbridge_unipro_latency_max;
+	uint32_t apbridge_unipro_latency_min;
+	uint32_t apbridge_unipro_latency_jitter;
+
+	float gbphy_firmware_latency_avg;
+	uint32_t gbphy_firmware_latency_max;
+	uint32_t gbphy_firmware_latency_min;
+	uint32_t gbphy_firmware_latency_jitter;
+
+	uint32_t error;
+};
+
+struct loopback_device {
+	char name[MAX_SYSFS_PATH];
+	char sysfs_entry[MAX_SYSFS_PATH];
+	char debugfs_entry[MAX_SYSFS_PATH];
+	struct loopback_results results;
+};
+
+struct loopback_test {
+	int verbose;
+	int debug;
+	int raw_data_dump;
+	int porcelain;
+	int mask;
+	int size;
+	int iteration_max;
+	int aggregate_output;
+	int test_id;
+	int device_count;
+	int list_devices;
+	int use_async;
+	int async_timeout;
+	int async_outstanding_operations;
+	int us_wait;
+	int file_output;
+	int stop_all;
+	int poll_count;
+	char test_name[MAX_STR_LEN];
+	char sysfs_prefix[MAX_SYSFS_PATH];
+	char debugfs_prefix[MAX_SYSFS_PATH];
+	struct timespec poll_timeout;
+	struct loopback_device devices[MAX_NUM_DEVICES];
+	struct loopback_results aggregate_results;
+	struct pollfd fds[MAX_NUM_DEVICES];
+};
+
+struct loopback_test t;
+
+/* Helper macros to calculate the aggregate results for all devices */
+static inline int device_enabled(struct loopback_test *t, int dev_idx);
+
+#define GET_MAX(field)							\
+static int get_##field##_aggregate(struct loopback_test *t)		\
+{									\
+	uint32_t max = 0;						\
+	int i;								\
+	for (i = 0; i < t->device_count; i++) {				\
+		if (!device_enabled(t, i))				\
+			continue;					\
+		if (t->devices[i].results.field > max)			\
+			max = t->devices[i].results.field;		\
+	}								\
+	return max;							\
+}									\
+
+#define GET_MIN(field)							\
+static int get_##field##_aggregate(struct loopback_test *t)		\
+{									\
+	uint32_t min = ~0;						\
+	int i;								\
+	for (i = 0; i < t->device_count; i++) {				\
+		if (!device_enabled(t, i))				\
+			continue;					\
+		if (t->devices[i].results.field < min)			\
+			min = t->devices[i].results.field;		\
+	}								\
+	return min;							\
+}									\
+
+#define GET_AVG(field)							\
+static int get_##field##_aggregate(struct loopback_test *t)		\
+{									\
+	uint32_t val = 0;						\
+	uint32_t count = 0;						\
+	int i;								\
+	for (i = 0; i < t->device_count; i++) {				\
+		if (!device_enabled(t, i))				\
+			continue;					\
+		count++;						\
+		val += t->devices[i].results.field;			\
+	}								\
+	if (count)							\
+		val /= count;						\
+	return val;							\
+}									\
+
+GET_MAX(throughput_max);
+GET_MAX(request_max);
+GET_MAX(latency_max);
+GET_MAX(apbridge_unipro_latency_max);
+GET_MAX(gbphy_firmware_latency_max);
+GET_MIN(throughput_min);
+GET_MIN(request_min);
+GET_MIN(latency_min);
+GET_MIN(apbridge_unipro_latency_min);
+GET_MIN(gbphy_firmware_latency_min);
+GET_AVG(throughput_avg);
+GET_AVG(request_avg);
+GET_AVG(latency_avg);
+GET_AVG(apbridge_unipro_latency_avg);
+GET_AVG(gbphy_firmware_latency_avg);
+
+void abort()
+{
+	_exit(1);
+}
+
+void usage(void)
+{
+	fprintf(stderr, "Usage: loopback_test TEST [SIZE] ITERATIONS [SYSPATH] [DBGPATH]\n\n"
+	"  Run TEST for a number of ITERATIONS with operation data SIZE bytes\n"
+	"  TEST may be \'ping\' \'transfer\' or \'sink\'\n"
+	"  SIZE indicates the size of transfer <= greybus max payload bytes\n"
+	"  ITERATIONS indicates the number of times to execute TEST at SIZE bytes\n"
+	"             Note if ITERATIONS is set to zero then this utility will\n"
+	"             initiate an infinite (non terminating) test and exit\n"
+	"             without logging any metrics data\n"
+	"  SYSPATH indicates the sysfs path for the loopback greybus entries e.g.\n"
+	"          /sys/bus/greybus/devices\n"
+	"  DBGPATH indicates the debugfs path for the loopback greybus entries e.g.\n"
+	"          /sys/kernel/debug/gb_loopback/\n"
+	" Mandatory arguments\n"
+	"   -t     must be one of the test names - sink, transfer or ping\n"
+	"   -i     iteration count - the number of iterations to run the test over\n"
+	" Optional arguments\n"
+	"   -S     sysfs location - location for greybus 'endo' entires default /sys/bus/greybus/devices/\n"
+	"   -D     debugfs location - location for loopback debugfs entries default /sys/kernel/debug/gb_loopback/\n"
+	"   -s     size of data packet to send during test - defaults to zero\n"
+	"   -m     mask - a bit mask of connections to include example: -m 8 = 4th connection -m 9 = 1st and 4th connection etc\n"
+	"                 default is zero which means broadcast to all connections\n"
+	"   -v     verbose output\n"
+	"   -d     debug output\n"
+	"   -r     raw data output - when specified the full list of latency values are included in the output CSV\n"
+	"   -p     porcelain - when specified printout is in a user-friendly non-CSV format. This option suppresses writing to CSV file\n"
+	"   -a     aggregate - show aggregation of all enabled devices\n"
+	"   -l     list found loopback devices and exit\n"
+	"   -x     Async - Enable async transfers\n"
+	"   -o     Async Timeout - Timeout in uSec for async operations\n"
+	"   -O     Poll loop time out in seconds(max time a test is expected to last, default: 30sec)\n"
+	"   -c     Max number of outstanding operations for async operations\n"
+	"   -w     Wait in uSec between operations\n"
+	"   -z     Enable output to a CSV file (incompatible with -p)\n"
+	"   -f     When starting new loopback test, stop currently running tests on all devices\n"
+	"Examples:\n"
+	"  Send 10000 transfers with a packet size of 128 bytes to all active connections\n"
+	"  loopback_test -t transfer -s 128 -i 10000 -S /sys/bus/greybus/devices/ -D /sys/kernel/debug/gb_loopback/\n"
+	"  loopback_test -t transfer -s 128 -i 10000 -m 0\n"
+	"  Send 10000 transfers with a packet size of 128 bytes to connection 1 and 4\n"
+	"  loopback_test -t transfer -s 128 -i 10000 -m 9\n"
+	"  loopback_test -t ping -s 0 128 -i -S /sys/bus/greybus/devices/ -D /sys/kernel/debug/gb_loopback/\n"
+	"  loopback_test -t sink -s 2030 -i 32768 -S /sys/bus/greybus/devices/ -D /sys/kernel/debug/gb_loopback/\n");
+	abort();
+}
+
+static inline int device_enabled(struct loopback_test *t, int dev_idx)
+{
+	if (!t->mask || (t->mask & (1 << dev_idx)))
+		return 1;
+
+	return 0;
+}
+
+static void show_loopback_devices(struct loopback_test *t)
+{
+	int i;
+
+	if (t->device_count == 0) {
+		printf("No loopback devices.\n");
+		return;
+	}
+
+	for (i = 0; i < t->device_count; i++)
+		printf("device[%d] = %s\n", i, t->devices[i].name);
+
+}
+
+int open_sysfs(const char *sys_pfx, const char *node, int flags)
+{
+	int fd;
+	char path[MAX_SYSFS_PATH];
+
+	snprintf(path, sizeof(path), "%s%s", sys_pfx, node);
+	fd = open(path, flags);
+	if (fd < 0) {
+		fprintf(stderr, "unable to open %s\n", path);
+		abort();
+	}
+	return fd;
+}
+
+int read_sysfs_int_fd(int fd, const char *sys_pfx, const char *node)
+{
+	char buf[SYSFS_MAX_INT];
+
+	if (read(fd, buf, sizeof(buf)) < 0) {
+		fprintf(stderr, "unable to read from %s%s %s\n", sys_pfx, node,
+			strerror(errno));
+		close(fd);
+		abort();
+	}
+	return atoi(buf);
+}
+
+float read_sysfs_float_fd(int fd, const char *sys_pfx, const char *node)
+{
+	char buf[SYSFS_MAX_INT];
+
+	if (read(fd, buf, sizeof(buf)) < 0) {
+
+		fprintf(stderr, "unable to read from %s%s %s\n", sys_pfx, node,
+			strerror(errno));
+		close(fd);
+		abort();
+	}
+	return atof(buf);
+}
+
+int read_sysfs_int(const char *sys_pfx, const char *node)
+{
+	int fd, val;
+
+	fd = open_sysfs(sys_pfx, node, O_RDONLY);
+	val = read_sysfs_int_fd(fd, sys_pfx, node);
+	close(fd);
+	return val;
+}
+
+float read_sysfs_float(const char *sys_pfx, const char *node)
+{
+	int fd;
+	float val;
+
+	fd = open_sysfs(sys_pfx, node, O_RDONLY);
+	val = read_sysfs_float_fd(fd, sys_pfx, node);
+	close(fd);
+	return val;
+}
+
+void write_sysfs_val(const char *sys_pfx, const char *node, int val)
+{
+	int fd, len;
+	char buf[SYSFS_MAX_INT];
+
+	fd = open_sysfs(sys_pfx, node, O_RDWR);
+	len = snprintf(buf, sizeof(buf), "%d", val);
+	if (write(fd, buf, len) < 0) {
+		fprintf(stderr, "unable to write to %s%s %s\n", sys_pfx, node,
+			strerror(errno));
+		close(fd);
+		abort();
+	}
+	close(fd);
+}
+
+static int get_results(struct loopback_test *t)
+{
+	struct loopback_device *d;
+	struct loopback_results *r;
+	int i;
+
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		d = &t->devices[i];
+		r = &d->results;
+
+		r->error = read_sysfs_int(d->sysfs_entry, "error");
+		r->request_min = read_sysfs_int(d->sysfs_entry, "requests_per_second_min");
+		r->request_max = read_sysfs_int(d->sysfs_entry, "requests_per_second_max");
+		r->request_avg = read_sysfs_float(d->sysfs_entry, "requests_per_second_avg");
+
+		r->latency_min = read_sysfs_int(d->sysfs_entry, "latency_min");
+		r->latency_max = read_sysfs_int(d->sysfs_entry, "latency_max");
+		r->latency_avg = read_sysfs_float(d->sysfs_entry, "latency_avg");
+
+		r->throughput_min = read_sysfs_int(d->sysfs_entry, "throughput_min");
+		r->throughput_max = read_sysfs_int(d->sysfs_entry, "throughput_max");
+		r->throughput_avg = read_sysfs_float(d->sysfs_entry, "throughput_avg");
+
+		r->apbridge_unipro_latency_min =
+			read_sysfs_int(d->sysfs_entry, "apbridge_unipro_latency_min");
+		r->apbridge_unipro_latency_max =
+			read_sysfs_int(d->sysfs_entry, "apbridge_unipro_latency_max");
+		r->apbridge_unipro_latency_avg =
+			read_sysfs_float(d->sysfs_entry, "apbridge_unipro_latency_avg");
+
+		r->gbphy_firmware_latency_min =
+			read_sysfs_int(d->sysfs_entry, "gbphy_firmware_latency_min");
+		r->gbphy_firmware_latency_max =
+			read_sysfs_int(d->sysfs_entry, "gbphy_firmware_latency_max");
+		r->gbphy_firmware_latency_avg =
+			read_sysfs_float(d->sysfs_entry, "gbphy_firmware_latency_avg");
+
+		r->request_jitter = r->request_max - r->request_min;
+		r->latency_jitter = r->latency_max - r->latency_min;
+		r->throughput_jitter = r->throughput_max - r->throughput_min;
+		r->apbridge_unipro_latency_jitter =
+			r->apbridge_unipro_latency_max - r->apbridge_unipro_latency_min;
+		r->gbphy_firmware_latency_jitter =
+			r->gbphy_firmware_latency_max - r->gbphy_firmware_latency_min;
+
+	}
+
+	/*calculate the aggregate results of all enabled devices */
+	if (t->aggregate_output) {
+		r = &t->aggregate_results;
+
+		r->request_min = get_request_min_aggregate(t);
+		r->request_max = get_request_max_aggregate(t);
+		r->request_avg = get_request_avg_aggregate(t);
+
+		r->latency_min = get_latency_min_aggregate(t);
+		r->latency_max = get_latency_max_aggregate(t);
+		r->latency_avg = get_latency_avg_aggregate(t);
+
+		r->throughput_min = get_throughput_min_aggregate(t);
+		r->throughput_max = get_throughput_max_aggregate(t);
+		r->throughput_avg = get_throughput_avg_aggregate(t);
+
+		r->apbridge_unipro_latency_min =
+			get_apbridge_unipro_latency_min_aggregate(t);
+		r->apbridge_unipro_latency_max =
+			get_apbridge_unipro_latency_max_aggregate(t);
+		r->apbridge_unipro_latency_avg =
+			get_apbridge_unipro_latency_avg_aggregate(t);
+
+		r->gbphy_firmware_latency_min =
+			get_gbphy_firmware_latency_min_aggregate(t);
+		r->gbphy_firmware_latency_max =
+			get_gbphy_firmware_latency_max_aggregate(t);
+		r->gbphy_firmware_latency_avg =
+			get_gbphy_firmware_latency_avg_aggregate(t);
+
+		r->request_jitter = r->request_max - r->request_min;
+		r->latency_jitter = r->latency_max - r->latency_min;
+		r->throughput_jitter = r->throughput_max - r->throughput_min;
+		r->apbridge_unipro_latency_jitter =
+			r->apbridge_unipro_latency_max - r->apbridge_unipro_latency_min;
+		r->gbphy_firmware_latency_jitter =
+			r->gbphy_firmware_latency_max - r->gbphy_firmware_latency_min;
+
+	}
+
+	return 0;
+}
+
+void log_csv_error(int len, int err)
+{
+	fprintf(stderr, "unable to write %d bytes to csv %s\n", len,
+		strerror(err));
+}
+
+int format_output(struct loopback_test *t,
+			struct loopback_results *r,
+			const char *dev_name,
+			char *buf, int buf_len,
+			struct tm *tm)
+{
+	int len = 0;
+
+	memset(buf, 0x00, buf_len);
+	len = snprintf(buf, buf_len, "%u-%u-%u %u:%u:%u",
+		       tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
+		       tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	if (t->porcelain) {
+		len += snprintf(&buf[len], buf_len - len,
+			"\n test:\t\t\t%s\n path:\t\t\t%s\n size:\t\t\t%u\n iterations:\t\t%u\n errors:\t\t%u\n async:\t\t\t%s\n",
+			t->test_name,
+			dev_name,
+			t->size,
+			t->iteration_max,
+			r->error,
+			t->use_async ? "Enabled" : "Disabled");
+
+		len += snprintf(&buf[len], buf_len - len,
+			" requests per-sec:\tmin=%u, max=%u, average=%f, jitter=%u\n",
+			r->request_min,
+			r->request_max,
+			r->request_avg,
+			r->request_jitter);
+
+		len += snprintf(&buf[len], buf_len - len,
+			" ap-throughput B/s:\tmin=%u max=%u average=%f jitter=%u\n",
+			r->throughput_min,
+			r->throughput_max,
+			r->throughput_avg,
+			r->throughput_jitter);
+		len += snprintf(&buf[len], buf_len - len,
+			" ap-latency usec:\tmin=%u max=%u average=%f jitter=%u\n",
+			r->latency_min,
+			r->latency_max,
+			r->latency_avg,
+			r->latency_jitter);
+		len += snprintf(&buf[len], buf_len - len,
+			" apbridge-latency usec:\tmin=%u max=%u average=%f jitter=%u\n",
+			r->apbridge_unipro_latency_min,
+			r->apbridge_unipro_latency_max,
+			r->apbridge_unipro_latency_avg,
+			r->apbridge_unipro_latency_jitter);
+
+		len += snprintf(&buf[len], buf_len - len,
+			" gbphy-latency usec:\tmin=%u max=%u average=%f jitter=%u\n",
+			r->gbphy_firmware_latency_min,
+			r->gbphy_firmware_latency_max,
+			r->gbphy_firmware_latency_avg,
+			r->gbphy_firmware_latency_jitter);
+
+	} else {
+		len += snprintf(&buf[len], buf_len- len, ",%s,%s,%u,%u,%u",
+			t->test_name, dev_name, t->size, t->iteration_max,
+			r->error);
+
+		len += snprintf(&buf[len], buf_len - len, ",%u,%u,%f,%u",
+			r->request_min,
+			r->request_max,
+			r->request_avg,
+			r->request_jitter);
+
+		len += snprintf(&buf[len], buf_len - len, ",%u,%u,%f,%u",
+			r->latency_min,
+			r->latency_max,
+			r->latency_avg,
+			r->latency_jitter);
+
+		len += snprintf(&buf[len], buf_len - len, ",%u,%u,%f,%u",
+			r->throughput_min,
+			r->throughput_max,
+			r->throughput_avg,
+			r->throughput_jitter);
+
+		len += snprintf(&buf[len], buf_len - len, ",%u,%u,%f,%u",
+			r->apbridge_unipro_latency_min,
+			r->apbridge_unipro_latency_max,
+			r->apbridge_unipro_latency_avg,
+			r->apbridge_unipro_latency_jitter);
+
+		len += snprintf(&buf[len], buf_len - len, ",%u,%u,%f,%u",
+			r->gbphy_firmware_latency_min,
+			r->gbphy_firmware_latency_max,
+			r->gbphy_firmware_latency_avg,
+			r->gbphy_firmware_latency_jitter);
+	}
+
+	printf("\n%s\n", buf);
+
+	return len;
+}
+
+static int log_results(struct loopback_test *t)
+{
+	int fd, i, len, ret;
+	struct tm tm;
+	time_t local_time;
+	mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+	char file_name[MAX_SYSFS_PATH];
+	char data[CSV_MAX_LINE];
+
+	local_time = time(NULL);
+	tm = *localtime(&local_time);
+
+	/*
+	* file name will test_name_size_iteration_max.csv
+	* every time the same test with the same parameters is run we will then
+	* append to the same CSV with datestamp - representing each test
+	* dataset.
+	*/
+	if (t->file_output && !t->porcelain) {
+		snprintf(file_name, sizeof(file_name), "%s_%d_%d.csv",
+			t->test_name, t->size, t->iteration_max);
+
+		fd = open(file_name, O_WRONLY | O_CREAT | O_APPEND, mode);
+		if (fd < 0) {
+			fprintf(stderr, "unable to open %s for appendation\n", file_name);
+			abort();
+		}
+
+	}
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		len = format_output(t, &t->devices[i].results,
+					t->devices[i].name,
+					data, sizeof(data), &tm);
+		if (t->file_output && !t->porcelain) {
+			ret = write(fd, data, len);
+			if (ret == -1)
+				fprintf(stderr, "unable to write %d bytes to csv.\n", len);
+		}
+
+	}
+
+
+	if (t->aggregate_output) {
+		len = format_output(t, &t->aggregate_results, "aggregate",
+					data, sizeof(data), &tm);
+		if (t->file_output && !t->porcelain) {
+			ret = write(fd, data, len);
+			if (ret == -1)
+				fprintf(stderr, "unable to write %d bytes to csv.\n", len);
+		}
+	}
+
+	if (t->file_output && !t->porcelain)
+		close(fd);
+
+	return 0;
+}
+
+int is_loopback_device(const char *path, const char *node)
+{
+	char file[MAX_SYSFS_PATH];
+
+	snprintf(file, MAX_SYSFS_PATH, "%s%s/iteration_count", path, node);
+	if (access(file, F_OK) == 0)
+		return 1;
+	return 0;
+}
+
+int find_loopback_devices(struct loopback_test *t)
+{
+	struct dirent **namelist;
+	int i, n, ret;
+	unsigned int dev_id;
+	struct loopback_device *d;
+
+	n = scandir(t->sysfs_prefix, &namelist, NULL, alphasort);
+	if (n < 0) {
+		perror("scandir");
+		ret = -ENODEV;
+		goto baddir;
+	}
+
+	/* Don't include '.' and '..' */
+	if (n <= 2) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	for (i = 0; i < n; i++) {
+		ret = sscanf(namelist[i]->d_name, "gb_loopback%u", &dev_id);
+		if (ret != 1)
+			continue;
+
+		if (!is_loopback_device(t->sysfs_prefix, namelist[i]->d_name))
+			continue;
+
+		if (t->device_count == MAX_NUM_DEVICES) {
+			fprintf(stderr, "max number of devices reached!\n");
+			break;
+		}
+
+		d = &t->devices[t->device_count++];
+		snprintf(d->name, MAX_STR_LEN, "gb_loopback%u", dev_id);
+
+		snprintf(d->sysfs_entry, MAX_SYSFS_PATH, "%s%s/",
+			t->sysfs_prefix, d->name);
+
+		snprintf(d->debugfs_entry, MAX_SYSFS_PATH, "%sraw_latency_%s",
+			t->debugfs_prefix, d->name);
+
+		if (t->debug)
+			printf("add %s %s\n", d->sysfs_entry,
+				d->debugfs_entry);
+	}
+
+	ret = 0;
+done:
+	for (i = 0; i < n; i++)
+		free(namelist[n]);
+	free(namelist);
+baddir:
+	return ret;
+}
+
+static int open_poll_files(struct loopback_test *t)
+{
+	struct loopback_device *dev;
+	char buf[MAX_STR_LEN];
+	char dummy;
+	int fds_idx = 0;
+	int i;
+
+	for (i = 0; i < t->device_count; i++) {
+		dev = &t->devices[i];
+
+		if (!device_enabled(t, i))
+			continue;
+
+		snprintf(buf, sizeof(buf), "%s%s", dev->sysfs_entry, "iteration_count");
+		t->fds[fds_idx].fd = open(buf, O_RDONLY);
+		if (t->fds[fds_idx].fd < 0) {
+			fprintf(stderr, "Error opening poll file!\n");
+			goto err;
+		}
+		read(t->fds[fds_idx].fd, &dummy, 1);
+		t->fds[fds_idx].events = POLLERR|POLLPRI;
+		t->fds[fds_idx].revents = 0;
+		fds_idx++;
+	}
+
+	t->poll_count = fds_idx;
+
+	return 0;
+
+err:
+	for (i = 0; i < fds_idx; i++)
+		close(t->fds[fds_idx].fd);
+
+	return -1;
+}
+
+static int close_poll_files(struct loopback_test *t)
+{
+	int i;
+	for (i = 0; i < t->poll_count; i++)
+		close(t->fds[i].fd);
+
+	return 0;
+}
+static int is_complete(struct loopback_test *t)
+{
+	int iteration_count;
+	int i;
+
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		iteration_count = read_sysfs_int(t->devices[i].sysfs_entry,
+						 "iteration_count");
+
+		/* at least one device did not finish yet */
+		if (iteration_count != t->iteration_max)
+			return 0;
+	}
+
+	return 1;
+}
+
+static void stop_tests(struct loopback_test *t)
+{
+	int i;
+
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+		write_sysfs_val(t->devices[i].sysfs_entry, "type", 0);
+	}
+}
+
+static void handler(int sig) { /* do nothing */  }
+
+static int wait_for_complete(struct loopback_test *t)
+{
+	int number_of_events = 0;
+	char dummy;
+	int ret;
+	int i;
+	struct timespec *ts = NULL;
+	struct sigaction sa;
+	sigset_t mask_old, mask;
+
+	sigemptyset(&mask);
+	sigemptyset(&mask_old);
+	sigaddset(&mask, SIGINT);
+	sigprocmask(SIG_BLOCK, &mask, &mask_old);
+
+	sa.sa_handler = handler;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(SIGINT, &sa, NULL) == -1) {
+		fprintf(stderr, "sigaction error\n");
+		return -1;
+	}
+
+	if (t->poll_timeout.tv_sec != 0)
+		ts = &t->poll_timeout;
+
+	while (1) {
+
+		ret = ppoll(t->fds, t->poll_count, ts, &mask_old);
+		if (ret <= 0) {
+			stop_tests(t);
+			fprintf(stderr, "Poll exit with errno %d\n", errno);
+			return -1;
+		}
+
+		for (i = 0; i < t->poll_count; i++) {
+			if (t->fds[i].revents & POLLPRI) {
+				/* Dummy read to clear the event */
+				read(t->fds[i].fd, &dummy, 1);
+				number_of_events++;
+			}
+		}
+
+		if (number_of_events == t->poll_count)
+			break;
+	}
+
+	if (!is_complete(t)) {
+		fprintf(stderr, "Iteration count did not finish!\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void prepare_devices(struct loopback_test *t)
+{
+	int i;
+
+	/* Cancel any running tests on enabled devices. If
+	 * stop_all option is given, stop test on all devices.
+	 */
+	for (i = 0; i < t->device_count; i++)
+		if (t->stop_all || device_enabled(t, i))
+			write_sysfs_val(t->devices[i].sysfs_entry, "type", 0);
+
+
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		write_sysfs_val(t->devices[i].sysfs_entry, "us_wait",
+				t->us_wait);
+
+		/* Set operation size */
+		write_sysfs_val(t->devices[i].sysfs_entry, "size", t->size);
+
+		/* Set iterations */
+		write_sysfs_val(t->devices[i].sysfs_entry, "iteration_max",
+				t->iteration_max);
+
+		if (t->use_async) {
+			write_sysfs_val(t->devices[i].sysfs_entry,
+				"async", 1);
+			write_sysfs_val(t->devices[i].sysfs_entry,
+				"timeout", t->async_timeout);
+			write_sysfs_val(t->devices[i].sysfs_entry,
+				"outstanding_operations_max",
+				t->async_outstanding_operations);
+		} else
+			write_sysfs_val(t->devices[i].sysfs_entry,
+				"async", 0);
+	}
+}
+
+static int start(struct loopback_test *t)
+{
+	int i;
+
+	/* the test starts by writing test_id to the type file. */
+	for (i = 0; i < t->device_count; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		write_sysfs_val(t->devices[i].sysfs_entry, "type", t->test_id);
+	}
+
+	return 0;
+}
+
+
+void loopback_run(struct loopback_test *t)
+{
+	int i;
+	int ret;
+
+	for (i = 0; dict[i].name != NULL; i++) {
+		if (strstr(dict[i].name, t->test_name))
+			t->test_id = dict[i].type;
+	}
+	if (!t->test_id) {
+		fprintf(stderr, "invalid test %s\n", t->test_name);
+		usage();
+		return;
+	}
+
+	prepare_devices(t);
+
+	ret = open_poll_files(t);
+	if (ret)
+		goto err;
+
+	start(t);
+
+	ret = wait_for_complete(t);
+	close_poll_files(t);
+	if (ret)
+		goto err;
+
+
+	get_results(t);
+
+	log_results(t);
+
+	return;
+
+err:
+	printf("Error running test\n");
+	return;
+}
+
+static int sanity_check(struct loopback_test *t)
+{
+	int i;
+
+	if (t->device_count == 0) {
+		fprintf(stderr, "No loopback devices found\n");
+		return -1;
+	}
+
+	for (i = 0; i < MAX_NUM_DEVICES; i++) {
+		if (!device_enabled(t, i))
+			continue;
+
+		if (t->mask && !strcmp(t->devices[i].name, "")) {
+			fprintf(stderr, "Bad device mask %x\n", (1 << i));
+			return -1;
+		}
+
+	}
+
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int o, ret;
+	char *sysfs_prefix = "/sys/class/gb_loopback/";
+	char *debugfs_prefix = "/sys/kernel/debug/gb_loopback/";
+
+	memset(&t, 0, sizeof(t));
+
+	while ((o = getopt(argc, argv,
+			   "t:s:i:S:D:m:v::d::r::p::a::l::x::o:O:c:w:z::f::")) != -1) {
+		switch (o) {
+		case 't':
+			snprintf(t.test_name, MAX_STR_LEN, "%s", optarg);
+			break;
+		case 's':
+			t.size = atoi(optarg);
+			break;
+		case 'i':
+			t.iteration_max = atoi(optarg);
+			break;
+		case 'S':
+			snprintf(t.sysfs_prefix, MAX_SYSFS_PATH, "%s", optarg);
+			break;
+		case 'D':
+			snprintf(t.debugfs_prefix, MAX_SYSFS_PATH, "%s", optarg);
+			break;
+		case 'm':
+			t.mask = atol(optarg);
+			break;
+		case 'v':
+			t.verbose = 1;
+			break;
+		case 'd':
+			t.debug = 1;
+			break;
+		case 'r':
+			t.raw_data_dump = 1;
+			break;
+		case 'p':
+			t.porcelain = 1;
+			break;
+		case 'a':
+			t.aggregate_output = 1;
+			break;
+		case 'l':
+			t.list_devices = 1;
+			break;
+		case 'x':
+			t.use_async = 1;
+			break;
+		case 'o':
+			t.async_timeout = atoi(optarg);
+			break;
+		case 'O':
+			t.poll_timeout.tv_sec = atoi(optarg);
+			break;
+		case 'c':
+			t.async_outstanding_operations = atoi(optarg);
+			break;
+		case 'w':
+			t.us_wait = atoi(optarg);
+			break;
+		case 'z':
+			t.file_output = 1;
+			break;
+		case 'f':
+			t.stop_all = 1;
+			break;
+		default:
+			usage();
+			return -EINVAL;
+		}
+	}
+
+	if (!strcmp(t.sysfs_prefix, ""))
+		snprintf(t.sysfs_prefix, MAX_SYSFS_PATH, "%s", sysfs_prefix);
+
+	if (!strcmp(t.debugfs_prefix, ""))
+		snprintf(t.debugfs_prefix, MAX_SYSFS_PATH, "%s", debugfs_prefix);
+
+	ret = find_loopback_devices(&t);
+	if (ret)
+		return ret;
+	ret = sanity_check(&t);
+	if (ret)
+		return ret;
+
+	if (t.list_devices) {
+		show_loopback_devices(&t);
+		return 0;
+	}
+
+	if (t.test_name[0] == '\0' || t.iteration_max == 0)
+		usage();
+
+	if (t.async_timeout == 0)
+		t.async_timeout = DEFAULT_ASYNC_TIMEOUT;
+
+	loopback_run(&t);
+
+	return 0;
+}
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
new file mode 100644
index 000000000000..01aeed1b3a9c
--- /dev/null
+++ b/drivers/staging/greybus/uart.c
@@ -0,0 +1,1075 @@
+/*
+ * UART driver for the Greybus "generic" UART module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ *
+ * Heavily based on drivers/usb/class/cdc-acm.c and
+ * drivers/usb/serial/usb-serial.c.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/mutex.h>
+#include <linux/tty.h>
+#include <linux/serial.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/idr.h>
+#include <linux/fs.h>
+#include <linux/kdev_t.h>
+#include <linux/kfifo.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+#define GB_NUM_MINORS	16	/* 16 is is more than enough */
+#define GB_NAME		"ttyGB"
+
+#define GB_UART_WRITE_FIFO_SIZE		PAGE_SIZE
+#define GB_UART_WRITE_ROOM_MARGIN	1	/* leave some space in fifo */
+#define GB_UART_FIRMWARE_CREDITS	4096
+#define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC	10000
+
+struct gb_tty_line_coding {
+	__le32	rate;
+	__u8	format;
+	__u8	parity;
+	__u8	data_bits;
+	__u8	flow_control;
+};
+
+struct gb_tty {
+	struct gbphy_device *gbphy_dev;
+	struct tty_port port;
+	void *buffer;
+	size_t buffer_payload_max;
+	struct gb_connection *connection;
+	u16 cport_id;
+	unsigned int minor;
+	unsigned char clocal;
+	bool disconnected;
+	spinlock_t read_lock;
+	spinlock_t write_lock;
+	struct async_icount iocount;
+	struct async_icount oldcount;
+	wait_queue_head_t wioctl;
+	struct mutex mutex;
+	u8 ctrlin;	/* input control lines */
+	u8 ctrlout;	/* output control lines */
+	struct gb_tty_line_coding line_coding;
+	struct work_struct tx_work;
+	struct kfifo write_fifo;
+	bool close_pending;
+	unsigned int credits;
+	struct completion credits_complete;
+};
+
+static struct tty_driver *gb_tty_driver;
+static DEFINE_IDR(tty_minors);
+static DEFINE_MUTEX(table_lock);
+
+static int gb_uart_receive_data_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_tty *gb_tty = gb_connection_get_data(connection);
+	struct tty_port *port = &gb_tty->port;
+	struct gb_message *request = op->request;
+	struct gb_uart_recv_data_request *receive_data;
+	u16 recv_data_size;
+	int count;
+	unsigned long tty_flags = TTY_NORMAL;
+
+	if (request->payload_size < sizeof(*receive_data)) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+				"short receive-data request received (%zu < %zu)\n",
+				request->payload_size, sizeof(*receive_data));
+		return -EINVAL;
+	}
+
+	receive_data = op->request->payload;
+	recv_data_size = le16_to_cpu(receive_data->size);
+
+	if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+				"malformed receive-data request received (%u != %zu)\n",
+				recv_data_size,
+				request->payload_size - sizeof(*receive_data));
+		return -EINVAL;
+	}
+
+	if (!recv_data_size)
+		return -EINVAL;
+
+	if (receive_data->flags) {
+		if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
+			tty_flags = TTY_BREAK;
+		else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
+			tty_flags = TTY_PARITY;
+		else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
+			tty_flags = TTY_FRAME;
+
+		/* overrun is special, not associated with a char */
+		if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
+			tty_insert_flip_char(port, 0, TTY_OVERRUN);
+	}
+	count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
+						  tty_flags, recv_data_size);
+	if (count != recv_data_size) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"UART: RX 0x%08x bytes only wrote 0x%08x\n",
+			recv_data_size, count);
+	}
+	if (count)
+		tty_flip_buffer_push(port);
+	return 0;
+}
+
+static int gb_uart_serial_state_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_tty *gb_tty = gb_connection_get_data(connection);
+	struct gb_message *request = op->request;
+	struct gb_uart_serial_state_request *serial_state;
+
+	if (request->payload_size < sizeof(*serial_state)) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+				"short serial-state event received (%zu < %zu)\n",
+				request->payload_size, sizeof(*serial_state));
+		return -EINVAL;
+	}
+
+	serial_state = request->payload;
+	gb_tty->ctrlin = serial_state->control;
+
+	return 0;
+}
+
+static int gb_uart_receive_credits_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_tty *gb_tty = gb_connection_get_data(connection);
+	struct gb_message *request = op->request;
+	struct gb_uart_receive_credits_request *credit_request;
+	unsigned long flags;
+	unsigned int incoming_credits;
+	int ret = 0;
+
+	if (request->payload_size < sizeof(*credit_request)) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+				"short receive_credits event received (%zu < %zu)\n",
+				request->payload_size,
+				sizeof(*credit_request));
+		return -EINVAL;
+	}
+
+	credit_request = request->payload;
+	incoming_credits = le16_to_cpu(credit_request->count);
+
+	spin_lock_irqsave(&gb_tty->write_lock, flags);
+	gb_tty->credits += incoming_credits;
+	if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
+		gb_tty->credits -= incoming_credits;
+		ret = -EINVAL;
+	}
+	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+	if (ret) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"invalid number of incoming credits: %d\n",
+			incoming_credits);
+		return ret;
+	}
+
+	if (!gb_tty->close_pending)
+		schedule_work(&gb_tty->tx_work);
+
+	/*
+	 * the port the tty layer may be waiting for credits
+	 */
+	tty_port_tty_wakeup(&gb_tty->port);
+
+	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
+		complete(&gb_tty->credits_complete);
+
+	return ret;
+}
+
+static int gb_uart_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_tty *gb_tty = gb_connection_get_data(connection);
+	int type = op->type;
+	int ret;
+
+	switch (type) {
+	case GB_UART_TYPE_RECEIVE_DATA:
+		ret = gb_uart_receive_data_handler(op);
+		break;
+	case GB_UART_TYPE_SERIAL_STATE:
+		ret = gb_uart_serial_state_handler(op);
+		break;
+	case GB_UART_TYPE_RECEIVE_CREDITS:
+		ret = gb_uart_receive_credits_handler(op);
+		break;
+	default:
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"unsupported unsolicited request: 0x%02x\n", type);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static void  gb_uart_tx_write_work(struct work_struct *work)
+{
+	struct gb_uart_send_data_request *request;
+	struct gb_tty *gb_tty;
+	unsigned long flags;
+	unsigned int send_size;
+	int ret;
+
+	gb_tty = container_of(work, struct gb_tty, tx_work);
+	request = gb_tty->buffer;
+
+	while (1) {
+		if (gb_tty->close_pending)
+			break;
+
+		spin_lock_irqsave(&gb_tty->write_lock, flags);
+		send_size = gb_tty->buffer_payload_max;
+		if (send_size > gb_tty->credits)
+			send_size = gb_tty->credits;
+
+		send_size = kfifo_out_peek(&gb_tty->write_fifo,
+					&request->data[0],
+					send_size);
+		if (!send_size) {
+			spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+			break;
+		}
+
+		gb_tty->credits -= send_size;
+		spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+		request->size = cpu_to_le16(send_size);
+		ret = gb_operation_sync(gb_tty->connection,
+					GB_UART_TYPE_SEND_DATA,
+					request, sizeof(*request) + send_size,
+					NULL, 0);
+		if (ret) {
+			dev_err(&gb_tty->gbphy_dev->dev,
+				"send data error: %d\n", ret);
+			spin_lock_irqsave(&gb_tty->write_lock, flags);
+			gb_tty->credits += send_size;
+			spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+			if (!gb_tty->close_pending)
+				schedule_work(work);
+			return;
+		}
+
+		spin_lock_irqsave(&gb_tty->write_lock, flags);
+		ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
+				send_size);
+		spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+		tty_port_tty_wakeup(&gb_tty->port);
+	}
+}
+
+static int send_line_coding(struct gb_tty *tty)
+{
+	struct gb_uart_set_line_coding_request request;
+
+	memcpy(&request, &tty->line_coding,
+	       sizeof(tty->line_coding));
+	return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
+				 &request, sizeof(request), NULL, 0);
+}
+
+static int send_control(struct gb_tty *gb_tty, u8 control)
+{
+	struct gb_uart_set_control_line_state_request request;
+
+	request.control = control;
+	return gb_operation_sync(gb_tty->connection,
+				 GB_UART_TYPE_SET_CONTROL_LINE_STATE,
+				 &request, sizeof(request), NULL, 0);
+}
+
+static int send_break(struct gb_tty *gb_tty, u8 state)
+{
+	struct gb_uart_set_break_request request;
+
+	if ((state != 0) && (state != 1)) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"invalid break state of %d\n", state);
+		return -EINVAL;
+	}
+
+	request.state = state;
+	return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
+				 &request, sizeof(request), NULL, 0);
+}
+
+static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
+{
+	int ret;
+
+	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
+		return 0;
+
+	ret = wait_for_completion_timeout(&gb_tty->credits_complete,
+			msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
+	if (!ret) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"time out waiting for credits\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
+{
+	struct gb_uart_serial_flush_request request;
+
+	request.flags = flags;
+	return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
+				 &request, sizeof(request), NULL, 0);
+}
+
+static struct gb_tty *get_gb_by_minor(unsigned minor)
+{
+	struct gb_tty *gb_tty;
+
+	mutex_lock(&table_lock);
+	gb_tty = idr_find(&tty_minors, minor);
+	if (gb_tty) {
+		mutex_lock(&gb_tty->mutex);
+		if (gb_tty->disconnected) {
+			mutex_unlock(&gb_tty->mutex);
+			gb_tty = NULL;
+		} else {
+			tty_port_get(&gb_tty->port);
+			mutex_unlock(&gb_tty->mutex);
+		}
+	}
+	mutex_unlock(&table_lock);
+	return gb_tty;
+}
+
+static int alloc_minor(struct gb_tty *gb_tty)
+{
+	int minor;
+
+	mutex_lock(&table_lock);
+	minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
+	mutex_unlock(&table_lock);
+	if (minor >= 0)
+		gb_tty->minor = minor;
+	return minor;
+}
+
+static void release_minor(struct gb_tty *gb_tty)
+{
+	int minor = gb_tty->minor;
+
+	gb_tty->minor = 0;	/* Maybe should use an invalid value instead */
+	mutex_lock(&table_lock);
+	idr_remove(&tty_minors, minor);
+	mutex_unlock(&table_lock);
+}
+
+static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty;
+	int retval;
+
+	gb_tty = get_gb_by_minor(tty->index);
+	if (!gb_tty)
+		return -ENODEV;
+
+	retval = tty_standard_install(driver, tty);
+	if (retval)
+		goto error;
+
+	tty->driver_data = gb_tty;
+	return 0;
+error:
+	tty_port_put(&gb_tty->port);
+	return retval;
+}
+
+static int gb_tty_open(struct tty_struct *tty, struct file *file)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	return tty_port_open(&gb_tty->port, tty, file);
+}
+
+static void gb_tty_close(struct tty_struct *tty, struct file *file)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	tty_port_close(&gb_tty->port, tty, file);
+}
+
+static void gb_tty_cleanup(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	tty_port_put(&gb_tty->port);
+}
+
+static void gb_tty_hangup(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	tty_port_hangup(&gb_tty->port);
+}
+
+static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
+			int count)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	count =  kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
+					&gb_tty->write_lock);
+	if (count && !gb_tty->close_pending)
+		schedule_work(&gb_tty->tx_work);
+
+	return count;
+}
+
+static int gb_tty_write_room(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	unsigned long flags;
+	int room;
+
+	spin_lock_irqsave(&gb_tty->write_lock, flags);
+	room = kfifo_avail(&gb_tty->write_fifo);
+	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+	room -= GB_UART_WRITE_ROOM_MARGIN;
+	if (room < 0)
+		return 0;
+
+	return room;
+}
+
+static int gb_tty_chars_in_buffer(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	unsigned long flags;
+	int chars;
+
+	spin_lock_irqsave(&gb_tty->write_lock, flags);
+	chars = kfifo_len(&gb_tty->write_fifo);
+	if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
+		chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
+	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+	return chars;
+}
+
+static int gb_tty_break_ctl(struct tty_struct *tty, int state)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	return send_break(gb_tty, state ? 1 : 0);
+}
+
+static void gb_tty_set_termios(struct tty_struct *tty,
+			       struct ktermios *termios_old)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	struct ktermios *termios = &tty->termios;
+	struct gb_tty_line_coding newline;
+	u8 newctrl = gb_tty->ctrlout;
+
+	newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
+	newline.format = termios->c_cflag & CSTOPB ?
+				GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
+	newline.parity = termios->c_cflag & PARENB ?
+				(termios->c_cflag & PARODD ? 1 : 2) +
+				(termios->c_cflag & CMSPAR ? 2 : 0) : 0;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		newline.data_bits = 5;
+		break;
+	case CS6:
+		newline.data_bits = 6;
+		break;
+	case CS7:
+		newline.data_bits = 7;
+		break;
+	case CS8:
+	default:
+		newline.data_bits = 8;
+		break;
+	}
+
+	/* FIXME: needs to clear unsupported bits in the termios */
+	gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
+
+	if (C_BAUD(tty) == B0) {
+		newline.rate = gb_tty->line_coding.rate;
+		newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
+	} else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
+		newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
+	}
+
+	if (newctrl != gb_tty->ctrlout) {
+		gb_tty->ctrlout = newctrl;
+		send_control(gb_tty, newctrl);
+	}
+
+	if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
+		newline.flow_control |= GB_SERIAL_AUTO_RTSCTS_EN;
+	else
+		newline.flow_control &= ~GB_SERIAL_AUTO_RTSCTS_EN;
+
+	if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
+		memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
+		send_line_coding(gb_tty);
+	}
+}
+
+static int gb_tty_tiocmget(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
+	       (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
+	       (gb_tty->ctrlin  & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
+	       (gb_tty->ctrlin  & GB_UART_CTRL_RI  ? TIOCM_RI  : 0) |
+	       (gb_tty->ctrlin  & GB_UART_CTRL_DCD ? TIOCM_CD  : 0) |
+	       TIOCM_CTS;
+}
+
+static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
+			   unsigned int clear)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	u8 newctrl = gb_tty->ctrlout;
+
+	set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
+	      (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
+	clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
+		(clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
+
+	newctrl = (newctrl & ~clear) | set;
+	if (gb_tty->ctrlout == newctrl)
+		return 0;
+
+	gb_tty->ctrlout = newctrl;
+	return send_control(gb_tty, newctrl);
+}
+
+static void gb_tty_throttle(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	unsigned char stop_char;
+	int retval;
+
+	if (I_IXOFF(tty)) {
+		stop_char = STOP_CHAR(tty);
+		retval = gb_tty_write(tty, &stop_char, 1);
+		if (retval <= 0)
+			return;
+	}
+
+	if (tty->termios.c_cflag & CRTSCTS) {
+		gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
+		retval = send_control(gb_tty, gb_tty->ctrlout);
+	}
+}
+
+static void gb_tty_unthrottle(struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+	unsigned char start_char;
+	int retval;
+
+	if (I_IXOFF(tty)) {
+		start_char = START_CHAR(tty);
+		retval = gb_tty_write(tty, &start_char, 1);
+		if (retval <= 0)
+			return;
+	}
+
+	if (tty->termios.c_cflag & CRTSCTS) {
+		gb_tty->ctrlout |= GB_UART_CTRL_RTS;
+		retval = send_control(gb_tty, gb_tty->ctrlout);
+	}
+}
+
+static int get_serial_info(struct gb_tty *gb_tty,
+			   struct serial_struct __user *info)
+{
+	struct serial_struct tmp;
+
+	if (!info)
+		return -EINVAL;
+
+	memset(&tmp, 0, sizeof(tmp));
+	tmp.flags = ASYNC_LOW_LATENCY | ASYNC_SKIP_TEST;
+	tmp.type = PORT_16550A;
+	tmp.line = gb_tty->minor;
+	tmp.xmit_fifo_size = 16;
+	tmp.baud_base = 9600;
+	tmp.close_delay = gb_tty->port.close_delay / 10;
+	tmp.closing_wait = gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
+				ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
+
+	if (copy_to_user(info, &tmp, sizeof(tmp)))
+		return -EFAULT;
+	return 0;
+}
+
+static int set_serial_info(struct gb_tty *gb_tty,
+			   struct serial_struct __user *newinfo)
+{
+	struct serial_struct new_serial;
+	unsigned int closing_wait;
+	unsigned int close_delay;
+	int retval = 0;
+
+	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
+		return -EFAULT;
+
+	close_delay = new_serial.close_delay * 10;
+	closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
+			ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
+
+	mutex_lock(&gb_tty->port.mutex);
+	if (!capable(CAP_SYS_ADMIN)) {
+		if ((close_delay != gb_tty->port.close_delay) ||
+		    (closing_wait != gb_tty->port.closing_wait))
+			retval = -EPERM;
+		else
+			retval = -EOPNOTSUPP;
+	} else {
+		gb_tty->port.close_delay = close_delay;
+		gb_tty->port.closing_wait = closing_wait;
+	}
+	mutex_unlock(&gb_tty->port.mutex);
+	return retval;
+}
+
+static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
+{
+	int retval = 0;
+	DECLARE_WAITQUEUE(wait, current);
+	struct async_icount old;
+	struct async_icount new;
+
+	if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
+		return -EINVAL;
+
+	do {
+		spin_lock_irq(&gb_tty->read_lock);
+		old = gb_tty->oldcount;
+		new = gb_tty->iocount;
+		gb_tty->oldcount = new;
+		spin_unlock_irq(&gb_tty->read_lock);
+
+		if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
+			break;
+		if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
+			break;
+		if ((arg & TIOCM_RI) && (old.rng != new.rng))
+			break;
+
+		add_wait_queue(&gb_tty->wioctl, &wait);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+		remove_wait_queue(&gb_tty->wioctl, &wait);
+		if (gb_tty->disconnected) {
+			if (arg & TIOCM_CD)
+				break;
+			retval = -ENODEV;
+		} else if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+		}
+	} while (!retval);
+
+	return retval;
+}
+
+static int get_serial_usage(struct gb_tty *gb_tty,
+			    struct serial_icounter_struct __user *count)
+{
+	struct serial_icounter_struct icount;
+	int retval = 0;
+
+	memset(&icount, 0, sizeof(icount));
+	icount.dsr = gb_tty->iocount.dsr;
+	icount.rng = gb_tty->iocount.rng;
+	icount.dcd = gb_tty->iocount.dcd;
+	icount.frame = gb_tty->iocount.frame;
+	icount.overrun = gb_tty->iocount.overrun;
+	icount.parity = gb_tty->iocount.parity;
+	icount.brk = gb_tty->iocount.brk;
+
+	if (copy_to_user(count, &icount, sizeof(icount)) > 0)
+		retval = -EFAULT;
+
+	return retval;
+}
+
+static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
+			unsigned long arg)
+{
+	struct gb_tty *gb_tty = tty->driver_data;
+
+	switch (cmd) {
+	case TIOCGSERIAL:
+		return get_serial_info(gb_tty,
+				       (struct serial_struct __user *)arg);
+	case TIOCSSERIAL:
+		return set_serial_info(gb_tty,
+				       (struct serial_struct __user *)arg);
+	case TIOCMIWAIT:
+		return wait_serial_change(gb_tty, arg);
+	case TIOCGICOUNT:
+		return get_serial_usage(gb_tty,
+					(struct serial_icounter_struct __user *)arg);
+	}
+
+	return -ENOIOCTLCMD;
+}
+
+static void gb_tty_dtr_rts(struct tty_port *port, int on)
+{
+	struct gb_tty *gb_tty;
+	u8 newctrl;
+
+	gb_tty = container_of(port, struct gb_tty, port);
+	newctrl = gb_tty->ctrlout;
+
+	if (on)
+		newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
+	else
+		newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
+
+	gb_tty->ctrlout = newctrl;
+	send_control(gb_tty, newctrl);
+}
+
+static int gb_tty_port_activate(struct tty_port *port,
+				struct tty_struct *tty)
+{
+	struct gb_tty *gb_tty;
+
+	gb_tty = container_of(port, struct gb_tty, port);
+
+	return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
+}
+
+static void gb_tty_port_shutdown(struct tty_port *port)
+{
+	struct gb_tty *gb_tty;
+	unsigned long flags;
+	int ret;
+
+	gb_tty = container_of(port, struct gb_tty, port);
+
+	gb_tty->close_pending = true;
+
+	cancel_work_sync(&gb_tty->tx_work);
+
+	spin_lock_irqsave(&gb_tty->write_lock, flags);
+	kfifo_reset_out(&gb_tty->write_fifo);
+	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
+
+	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
+		goto out;
+
+	ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
+	if (ret) {
+		dev_err(&gb_tty->gbphy_dev->dev,
+			"error flushing transmitter: %d\n", ret);
+	}
+
+	gb_uart_wait_for_all_credits(gb_tty);
+
+out:
+	gb_tty->close_pending = false;
+
+	gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
+}
+
+static const struct tty_operations gb_ops = {
+	.install =		gb_tty_install,
+	.open =			gb_tty_open,
+	.close =		gb_tty_close,
+	.cleanup =		gb_tty_cleanup,
+	.hangup =		gb_tty_hangup,
+	.write =		gb_tty_write,
+	.write_room =		gb_tty_write_room,
+	.ioctl =		gb_tty_ioctl,
+	.throttle =		gb_tty_throttle,
+	.unthrottle =		gb_tty_unthrottle,
+	.chars_in_buffer =	gb_tty_chars_in_buffer,
+	.break_ctl =		gb_tty_break_ctl,
+	.set_termios =		gb_tty_set_termios,
+	.tiocmget =		gb_tty_tiocmget,
+	.tiocmset =		gb_tty_tiocmset,
+};
+
+static struct tty_port_operations gb_port_ops = {
+	.dtr_rts =		gb_tty_dtr_rts,
+	.activate =		gb_tty_port_activate,
+	.shutdown =		gb_tty_port_shutdown,
+};
+
+static int gb_uart_probe(struct gbphy_device *gbphy_dev,
+			 const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	size_t max_payload;
+	struct gb_tty *gb_tty;
+	struct device *tty_dev;
+	int retval;
+	int minor;
+
+	gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
+	if (!gb_tty)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  gb_uart_request_handler);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto exit_tty_free;
+	}
+
+	max_payload = gb_operation_get_payload_size_max(connection);
+	if (max_payload < sizeof(struct gb_uart_send_data_request)) {
+		retval = -EINVAL;
+		goto exit_connection_destroy;
+	}
+
+	gb_tty->buffer_payload_max = max_payload -
+			sizeof(struct gb_uart_send_data_request);
+
+	gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
+	if (!gb_tty->buffer) {
+		retval = -ENOMEM;
+		goto exit_connection_destroy;
+	}
+
+	INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
+
+	retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
+				GFP_KERNEL);
+	if (retval)
+		goto exit_buf_free;
+
+	gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
+	init_completion(&gb_tty->credits_complete);
+
+	minor = alloc_minor(gb_tty);
+	if (minor < 0) {
+		if (minor == -ENOSPC) {
+			dev_err(&connection->bundle->dev,
+				"no more free minor numbers\n");
+			retval = -ENODEV;
+		} else {
+			retval = minor;
+		}
+		goto exit_kfifo_free;
+	}
+
+	gb_tty->minor = minor;
+	spin_lock_init(&gb_tty->write_lock);
+	spin_lock_init(&gb_tty->read_lock);
+	init_waitqueue_head(&gb_tty->wioctl);
+	mutex_init(&gb_tty->mutex);
+
+	tty_port_init(&gb_tty->port);
+	gb_tty->port.ops = &gb_port_ops;
+
+	gb_tty->connection = connection;
+	gb_tty->gbphy_dev = gbphy_dev;
+	gb_connection_set_data(connection, gb_tty);
+	gb_gbphy_set_data(gbphy_dev, gb_tty);
+
+	retval = gb_connection_enable_tx(connection);
+	if (retval)
+		goto exit_release_minor;
+
+	send_control(gb_tty, gb_tty->ctrlout);
+
+	/* initialize the uart to be 9600n81 */
+	gb_tty->line_coding.rate = cpu_to_le32(9600);
+	gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
+	gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
+	gb_tty->line_coding.data_bits = 8;
+	send_line_coding(gb_tty);
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto exit_connection_disable;
+
+	tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
+					   &gbphy_dev->dev);
+	if (IS_ERR(tty_dev)) {
+		retval = PTR_ERR(tty_dev);
+		goto exit_connection_disable;
+	}
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_release_minor:
+	release_minor(gb_tty);
+exit_kfifo_free:
+	kfifo_free(&gb_tty->write_fifo);
+exit_buf_free:
+	kfree(gb_tty->buffer);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_tty_free:
+	kfree(gb_tty);
+
+	return retval;
+}
+
+static void gb_uart_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = gb_tty->connection;
+	struct tty_struct *tty;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	mutex_lock(&gb_tty->mutex);
+	gb_tty->disconnected = true;
+
+	wake_up_all(&gb_tty->wioctl);
+	mutex_unlock(&gb_tty->mutex);
+
+	tty = tty_port_tty_get(&gb_tty->port);
+	if (tty) {
+		tty_vhangup(tty);
+		tty_kref_put(tty);
+	}
+
+	gb_connection_disable_rx(connection);
+	tty_unregister_device(gb_tty_driver, gb_tty->minor);
+
+	/* FIXME - free transmit / receive buffers */
+
+	gb_connection_disable(connection);
+	tty_port_destroy(&gb_tty->port);
+	gb_connection_destroy(connection);
+	release_minor(gb_tty);
+	kfifo_free(&gb_tty->write_fifo);
+	kfree(gb_tty->buffer);
+	kfree(gb_tty);
+}
+
+static int gb_tty_init(void)
+{
+	int retval = 0;
+
+	gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
+	if (IS_ERR(gb_tty_driver)) {
+		pr_err("Can not allocate tty driver\n");
+		retval = -ENOMEM;
+		goto fail_unregister_dev;
+	}
+
+	gb_tty_driver->driver_name = "gb";
+	gb_tty_driver->name = GB_NAME;
+	gb_tty_driver->major = 0;
+	gb_tty_driver->minor_start = 0;
+	gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
+	gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
+	gb_tty_driver->init_termios = tty_std_termios;
+	gb_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	tty_set_operations(gb_tty_driver, &gb_ops);
+
+	retval = tty_register_driver(gb_tty_driver);
+	if (retval) {
+		pr_err("Can not register tty driver: %d\n", retval);
+		goto fail_put_gb_tty;
+	}
+
+	return 0;
+
+fail_put_gb_tty:
+	put_tty_driver(gb_tty_driver);
+fail_unregister_dev:
+	return retval;
+}
+
+static void gb_tty_exit(void)
+{
+	tty_unregister_driver(gb_tty_driver);
+	put_tty_driver(gb_tty_driver);
+	idr_destroy(&tty_minors);
+}
+
+static const struct gbphy_device_id gb_uart_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
+
+static struct gbphy_driver uart_driver = {
+	.name		= "uart",
+	.probe		= gb_uart_probe,
+	.remove		= gb_uart_remove,
+	.id_table	= gb_uart_id_table,
+};
+
+static int gb_uart_driver_init(void)
+{
+	int ret;
+
+	ret = gb_tty_init();
+	if (ret)
+		return ret;
+
+	ret = gb_gbphy_register(&uart_driver);
+	if (ret) {
+		gb_tty_exit();
+		return ret;
+	}
+
+	return 0;
+}
+module_init(gb_uart_driver_init);
+
+static void gb_uart_driver_exit(void)
+{
+	gb_gbphy_deregister(&uart_driver);
+	gb_tty_exit();
+}
+
+module_exit(gb_uart_driver_exit);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/usb.c b/drivers/staging/greybus/usb.c
new file mode 100644
index 000000000000..ccadda084b76
--- /dev/null
+++ b/drivers/staging/greybus/usb.c
@@ -0,0 +1,247 @@
+/*
+ * USB host driver for the Greybus "generic" USB module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+/* Greybus USB request types */
+#define GB_USB_TYPE_HCD_START		0x02
+#define GB_USB_TYPE_HCD_STOP		0x03
+#define GB_USB_TYPE_HUB_CONTROL		0x04
+
+struct gb_usb_hub_control_request {
+	__le16 typeReq;
+	__le16 wValue;
+	__le16 wIndex;
+	__le16 wLength;
+};
+
+struct gb_usb_hub_control_response {
+	u8 buf[0];
+};
+
+struct gb_usb_device {
+	struct gb_connection *connection;
+	struct gbphy_device *gbphy_dev;
+};
+
+static inline struct gb_usb_device *to_gb_usb_device(struct usb_hcd *hcd)
+{
+	return (struct gb_usb_device *)hcd->hcd_priv;
+}
+
+static inline struct usb_hcd *gb_usb_device_to_hcd(struct gb_usb_device *dev)
+{
+	return container_of((void *)dev, struct usb_hcd, hcd_priv);
+}
+
+static void hcd_stop(struct usb_hcd *hcd)
+{
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	int ret;
+
+	ret = gb_operation_sync(dev->connection, GB_USB_TYPE_HCD_STOP,
+				NULL, 0, NULL, 0);
+	if (ret)
+		dev_err(&dev->gbphy_dev->dev, "HCD stop failed '%d'\n", ret);
+}
+
+static int hcd_start(struct usb_hcd *hcd)
+{
+	struct usb_bus *bus = hcd_to_bus(hcd);
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	int ret;
+
+	ret = gb_operation_sync(dev->connection, GB_USB_TYPE_HCD_START,
+				NULL, 0, NULL, 0);
+	if (ret) {
+		dev_err(&dev->gbphy_dev->dev, "HCD start failed '%d'\n", ret);
+		return ret;
+	}
+
+	hcd->state = HC_STATE_RUNNING;
+	if (bus->root_hub)
+		usb_hcd_resume_root_hub(hcd);
+	return 0;
+}
+
+static int urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
+{
+	return -ENXIO;
+}
+
+static int urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
+{
+	return -ENXIO;
+}
+
+static int get_frame_number(struct usb_hcd *hcd)
+{
+	return 0;
+}
+
+static int hub_status_data(struct usb_hcd *hcd, char *buf)
+{
+	return 0;
+}
+
+static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
+		       char *buf, u16 wLength)
+{
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	struct gb_operation *operation;
+	struct gb_usb_hub_control_request *request;
+	struct gb_usb_hub_control_response *response;
+	size_t response_size;
+	int ret;
+
+	/* FIXME: handle unspecified lengths */
+	response_size = sizeof(*response) + wLength;
+
+	operation = gb_operation_create(dev->connection,
+					GB_USB_TYPE_HUB_CONTROL,
+					sizeof(*request),
+					response_size,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	request = operation->request->payload;
+	request->typeReq = cpu_to_le16(typeReq);
+	request->wValue = cpu_to_le16(wValue);
+	request->wIndex = cpu_to_le16(wIndex);
+	request->wLength = cpu_to_le16(wLength);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret)
+		goto out;
+
+	if (wLength) {
+		/* Greybus core has verified response size */
+		response = operation->response->payload;
+		memcpy(buf, response->buf, wLength);
+	}
+out:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static struct hc_driver usb_gb_hc_driver = {
+	.description = "greybus-hcd",
+	.product_desc = "Greybus USB Host Controller",
+	.hcd_priv_size = sizeof(struct gb_usb_device),
+
+	.flags = HCD_USB2,
+
+	.start = hcd_start,
+	.stop = hcd_stop,
+
+	.urb_enqueue = urb_enqueue,
+	.urb_dequeue = urb_dequeue,
+
+	.get_frame_number = get_frame_number,
+	.hub_status_data = hub_status_data,
+	.hub_control = hub_control,
+};
+
+static int gb_usb_probe(struct gbphy_device *gbphy_dev,
+			const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct device *dev = &gbphy_dev->dev;
+	struct gb_usb_device *gb_usb_dev;
+	struct usb_hcd *hcd;
+	int retval;
+
+	hcd = usb_create_hcd(&usb_gb_hc_driver, dev, dev_name(dev));
+	if (!hcd)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  NULL);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto exit_usb_put;
+	}
+
+	gb_usb_dev = to_gb_usb_device(hcd);
+	gb_usb_dev->connection = connection;
+	gb_connection_set_data(connection, gb_usb_dev);
+	gb_usb_dev->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, gb_usb_dev);
+
+	hcd->has_tt = 1;
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto exit_connection_destroy;
+
+	/*
+	 * FIXME: The USB bridged-PHY protocol driver depends on changes to
+	 *        USB core which are not yet upstream.
+	 *
+	 *        Disable for now.
+	 */
+	if (1) {
+		dev_warn(dev, "USB protocol disabled\n");
+		retval = -EPROTONOSUPPORT;
+		goto exit_connection_disable;
+	}
+
+	retval = usb_add_hcd(hcd, 0, 0);
+	if (retval)
+		goto exit_connection_disable;
+
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_usb_put:
+	usb_put_hcd(hcd);
+
+	return retval;
+}
+
+static void gb_usb_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_usb_device *gb_usb_dev = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = gb_usb_dev->connection;
+	struct usb_hcd *hcd = gb_usb_device_to_hcd(gb_usb_dev);
+
+	usb_remove_hcd(hcd);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	usb_put_hcd(hcd);
+}
+
+static const struct gbphy_device_id gb_usb_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_USB) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_usb_id_table);
+
+static struct gbphy_driver usb_driver = {
+	.name		= "usb",
+	.probe		= gb_usb_probe,
+	.remove		= gb_usb_remove,
+	.id_table	= gb_usb_id_table,
+};
+
+module_gbphy_driver(usb_driver);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/greybus/vibrator.c b/drivers/staging/greybus/vibrator.c
new file mode 100644
index 000000000000..4ba0e168930f
--- /dev/null
+++ b/drivers/staging/greybus/vibrator.c
@@ -0,0 +1,249 @@
+/*
+ * Greybus Vibrator protocol driver.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/kdev_t.h>
+#include <linux/idr.h>
+#include <linux/pm_runtime.h>
+
+#include "greybus.h"
+
+struct gb_vibrator_device {
+	struct gb_connection	*connection;
+	struct device		*dev;
+	int			minor;		/* vibrator minor number */
+	struct delayed_work     delayed_work;
+};
+
+/* Greybus Vibrator operation types */
+#define	GB_VIBRATOR_TYPE_ON			0x02
+#define	GB_VIBRATOR_TYPE_OFF			0x03
+
+static int turn_off(struct gb_vibrator_device *vib)
+{
+	struct gb_bundle *bundle = vib->connection->bundle;
+	int ret;
+
+	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_OFF,
+			NULL, 0, NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return ret;
+}
+
+static int turn_on(struct gb_vibrator_device *vib, u16 timeout_ms)
+{
+	struct gb_bundle *bundle = vib->connection->bundle;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	/* Vibrator was switched ON earlier */
+	if (cancel_delayed_work_sync(&vib->delayed_work))
+		turn_off(vib);
+
+	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_ON,
+			NULL, 0, NULL, 0);
+	if (ret) {
+		gb_pm_runtime_put_autosuspend(bundle);
+		return ret;
+	}
+
+	schedule_delayed_work(&vib->delayed_work, msecs_to_jiffies(timeout_ms));
+
+	return 0;
+}
+
+static void gb_vibrator_worker(struct work_struct *work)
+{
+	struct delayed_work *delayed_work = to_delayed_work(work);
+	struct gb_vibrator_device *vib =
+		container_of(delayed_work, struct gb_vibrator_device, delayed_work);
+
+	turn_off(vib);
+}
+
+static ssize_t timeout_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct gb_vibrator_device *vib = dev_get_drvdata(dev);
+	unsigned long val;
+	int retval;
+
+	retval = kstrtoul(buf, 10, &val);
+	if (retval < 0) {
+		dev_err(dev, "could not parse timeout value %d\n", retval);
+		return retval;
+	}
+
+	if (val)
+		retval = turn_on(vib, (u16)val);
+	else
+		retval = turn_off(vib);
+	if (retval)
+		return retval;
+
+	return count;
+}
+static DEVICE_ATTR_WO(timeout);
+
+static struct attribute *vibrator_attrs[] = {
+	&dev_attr_timeout.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(vibrator);
+
+static struct class vibrator_class = {
+	.name		= "vibrator",
+	.owner		= THIS_MODULE,
+	.dev_groups	= vibrator_groups,
+};
+
+static DEFINE_IDA(minors);
+
+static int gb_vibrator_probe(struct gb_bundle *bundle,
+					const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct gb_vibrator_device *vib;
+	struct device *dev;
+	int retval;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_VIBRATOR)
+		return -ENODEV;
+
+	vib = kzalloc(sizeof(*vib), GFP_KERNEL);
+	if (!vib)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+						NULL);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto err_free_vib;
+	}
+	gb_connection_set_data(connection, vib);
+
+	vib->connection = connection;
+
+	greybus_set_drvdata(bundle, vib);
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto err_connection_destroy;
+
+	/*
+	 * For now we create a device in sysfs for the vibrator, but odds are
+	 * there is a "real" device somewhere in the kernel for this, but I
+	 * can't find it at the moment...
+	 */
+	vib->minor = ida_simple_get(&minors, 0, 0, GFP_KERNEL);
+	if (vib->minor < 0) {
+		retval = vib->minor;
+		goto err_connection_disable;
+	}
+	dev = device_create(&vibrator_class, &bundle->dev,
+			    MKDEV(0, 0), vib, "vibrator%d", vib->minor);
+	if (IS_ERR(dev)) {
+		retval = -EINVAL;
+		goto err_ida_remove;
+	}
+	vib->dev = dev;
+
+	INIT_DELAYED_WORK(&vib->delayed_work, gb_vibrator_worker);
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+err_ida_remove:
+	ida_simple_remove(&minors, vib->minor);
+err_connection_disable:
+	gb_connection_disable(connection);
+err_connection_destroy:
+	gb_connection_destroy(connection);
+err_free_vib:
+	kfree(vib);
+
+	return retval;
+}
+
+static void gb_vibrator_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_vibrator_device *vib = greybus_get_drvdata(bundle);
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		gb_pm_runtime_get_noresume(bundle);
+
+	if (cancel_delayed_work_sync(&vib->delayed_work))
+		turn_off(vib);
+
+	device_unregister(vib->dev);
+	ida_simple_remove(&minors, vib->minor);
+	gb_connection_disable(vib->connection);
+	gb_connection_destroy(vib->connection);
+	kfree(vib);
+}
+
+static const struct greybus_bundle_id gb_vibrator_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_VIBRATOR) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_vibrator_id_table);
+
+static struct greybus_driver gb_vibrator_driver = {
+	.name		= "vibrator",
+	.probe		= gb_vibrator_probe,
+	.disconnect	= gb_vibrator_disconnect,
+	.id_table	= gb_vibrator_id_table,
+};
+
+static __init int gb_vibrator_init(void)
+{
+	int retval;
+
+	retval = class_register(&vibrator_class);
+	if (retval)
+		return retval;
+
+	retval = greybus_register(&gb_vibrator_driver);
+	if (retval)
+		goto err_class_unregister;
+
+	return 0;
+
+err_class_unregister:
+	class_unregister(&vibrator_class);
+
+	return retval;
+}
+module_init(gb_vibrator_init);
+
+static __exit void gb_vibrator_exit(void)
+{
+	greybus_deregister(&gb_vibrator_driver);
+	class_unregister(&vibrator_class);
+	ida_destroy(&minors);
+}
+module_exit(gb_vibrator_exit);
+
+MODULE_LICENSE("GPL v2");