phy: cpcap-usb: Add CPCAP PMIC USB support

Some Motorola phones like droid 4 use a custom CPCAP PMIC that has a
multiplexing USB PHY.

This USB PHY can operate at least in four modes using pin multiplexing
and two control GPIOS:

- Pass through companion PHY for the SoC USB PHY
- ULPI PHY for the SoC
- Pass through USB for the modem
- UART debug console for the SoC

This patch adds support for droid 4 USB PHY and debug UART modes,
support for other modes can be added later on as needed.

Both peripheral and host mode are working for the USB. The
host mode depends on the cpcap-charger driver for VBUS.

VBUS and ID pin detection are done using cpcap-adc IIO ADC
driver.

Cc: devicetree@vger.kernel.org
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

3 files changed, 690 insertions, 0 deletions

diff --git a/drivers/phy/motorola/Kconfig b/drivers/phy/motorola/Kconfig
new file mode 100644
index 000000000000..91a46cffd639
--- /dev/null
+++ b/drivers/phy/motorola/Kconfig
@@ -0,0 +1,11 @@
+#
+# Phy drivers for Motorola devices
+#
+config PHY_CPCAP_USB
+	tristate "CPCAP PMIC USB PHY driver"
+	depends on USB_SUPPORT && IIO
+	select GENERIC_PHY
+	select USB_PHY
+	help
+	  Enable this for USB to work on Motorola phones and tablets
+	  such as Droid 4.
diff --git a/drivers/phy/motorola/Makefile b/drivers/phy/motorola/Makefile
new file mode 100644
index 000000000000..b6cd618d671a
--- /dev/null
+++ b/drivers/phy/motorola/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the phy drivers.
+#
+
+obj-$(CONFIG_PHY_CPCAP_USB)		+= phy-cpcap-usb.o
diff --git a/drivers/phy/motorola/phy-cpcap-usb.c b/drivers/phy/motorola/phy-cpcap-usb.c
new file mode 100644
index 000000000000..082a48bd4d89
--- /dev/null
+++ b/drivers/phy/motorola/phy-cpcap-usb.c
@@ -0,0 +1,674 @@
+/*
+ * Motorola CPCAP PMIC USB PHY driver
+ * Copyright (C) 2017 Tony Lindgren <tony@atomide.com>
+ *
+ * Some parts based on earlier Motorola Linux kernel tree code in
+ * board-mapphone-usb.c and cpcap-usb-det.c:
+ * Copyright (C) 2007 - 2011 Motorola, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/atomic.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/iio/consumer.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/mfd/motorola-cpcap.h>
+#include <linux/phy/omap_usb.h>
+#include <linux/phy/phy.h>
+#include <linux/regulator/consumer.h>
+#include <linux/usb/musb.h>
+
+/* CPCAP_REG_USBC1 register bits */
+#define CPCAP_BIT_IDPULSE		BIT(15)
+#define CPCAP_BIT_ID100KPU		BIT(14)
+#define CPCAP_BIT_IDPUCNTRL		BIT(13)
+#define CPCAP_BIT_IDPU			BIT(12)
+#define CPCAP_BIT_IDPD			BIT(11)
+#define CPCAP_BIT_VBUSCHRGTMR3		BIT(10)
+#define CPCAP_BIT_VBUSCHRGTMR2		BIT(9)
+#define CPCAP_BIT_VBUSCHRGTMR1		BIT(8)
+#define CPCAP_BIT_VBUSCHRGTMR0		BIT(7)
+#define CPCAP_BIT_VBUSPU		BIT(6)
+#define CPCAP_BIT_VBUSPD		BIT(5)
+#define CPCAP_BIT_DMPD			BIT(4)
+#define CPCAP_BIT_DPPD			BIT(3)
+#define CPCAP_BIT_DM1K5PU		BIT(2)
+#define CPCAP_BIT_DP1K5PU		BIT(1)
+#define CPCAP_BIT_DP150KPU		BIT(0)
+
+/* CPCAP_REG_USBC2 register bits */
+#define CPCAP_BIT_ZHSDRV1		BIT(15)
+#define CPCAP_BIT_ZHSDRV0		BIT(14)
+#define CPCAP_BIT_DPLLCLKREQ		BIT(13)
+#define CPCAP_BIT_SE0CONN		BIT(12)
+#define CPCAP_BIT_UARTTXTRI		BIT(11)
+#define CPCAP_BIT_UARTSWAP		BIT(10)
+#define CPCAP_BIT_UARTMUX1		BIT(9)
+#define CPCAP_BIT_UARTMUX0		BIT(8)
+#define CPCAP_BIT_ULPISTPLOW		BIT(7)
+#define CPCAP_BIT_TXENPOL		BIT(6)
+#define CPCAP_BIT_USBXCVREN		BIT(5)
+#define CPCAP_BIT_USBCNTRL		BIT(4)
+#define CPCAP_BIT_USBSUSPEND		BIT(3)
+#define CPCAP_BIT_EMUMODE2		BIT(2)
+#define CPCAP_BIT_EMUMODE1		BIT(1)
+#define CPCAP_BIT_EMUMODE0		BIT(0)
+
+/* CPCAP_REG_USBC3 register bits */
+#define CPCAP_BIT_SPARE_898_15		BIT(15)
+#define CPCAP_BIT_IHSTX03		BIT(14)
+#define CPCAP_BIT_IHSTX02		BIT(13)
+#define CPCAP_BIT_IHSTX01		BIT(12)
+#define CPCAP_BIT_IHSTX0		BIT(11)
+#define CPCAP_BIT_IDPU_SPI		BIT(10)
+#define CPCAP_BIT_UNUSED_898_9		BIT(9)
+#define CPCAP_BIT_VBUSSTBY_EN		BIT(8)
+#define CPCAP_BIT_VBUSEN_SPI		BIT(7)
+#define CPCAP_BIT_VBUSPU_SPI		BIT(6)
+#define CPCAP_BIT_VBUSPD_SPI		BIT(5)
+#define CPCAP_BIT_DMPD_SPI		BIT(4)
+#define CPCAP_BIT_DPPD_SPI		BIT(3)
+#define CPCAP_BIT_SUSPEND_SPI		BIT(2)
+#define CPCAP_BIT_PU_SPI		BIT(1)
+#define CPCAP_BIT_ULPI_SPI_SEL		BIT(0)
+
+struct cpcap_usb_ints_state {
+	bool id_ground;
+	bool id_float;
+	bool chrg_det;
+	bool rvrs_chrg;
+	bool vbusov;
+
+	bool chrg_se1b;
+	bool se0conn;
+	bool rvrs_mode;
+	bool chrgcurr1;
+	bool vbusvld;
+	bool sessvld;
+	bool sessend;
+	bool se1;
+
+	bool battdetb;
+	bool dm;
+	bool dp;
+};
+
+enum cpcap_gpio_mode {
+	CPCAP_DM_DP,
+	CPCAP_MDM_RX_TX,
+	CPCAP_UNKNOWN,
+	CPCAP_OTG_DM_DP,
+};
+
+struct cpcap_phy_ddata {
+	struct regmap *reg;
+	struct device *dev;
+	struct clk *refclk;
+	struct usb_phy phy;
+	struct delayed_work detect_work;
+	struct pinctrl *pins;
+	struct pinctrl_state *pins_ulpi;
+	struct pinctrl_state *pins_utmi;
+	struct pinctrl_state *pins_uart;
+	struct gpio_desc *gpio[2];
+	struct iio_channel *vbus;
+	struct iio_channel *id;
+	struct regulator *vusb;
+	atomic_t active;
+};
+
+static bool cpcap_usb_vbus_valid(struct cpcap_phy_ddata *ddata)
+{
+	int error, value = 0;
+
+	error = iio_read_channel_processed(ddata->vbus, &value);
+	if (error >= 0)
+		return value > 3900 ? true : false;
+
+	dev_err(ddata->dev, "error reading VBUS: %i\n", error);
+
+	return false;
+}
+
+static int cpcap_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
+{
+	otg->host = host;
+	if (!host)
+		otg->state = OTG_STATE_UNDEFINED;
+
+	return 0;
+}
+
+static int cpcap_usb_phy_set_peripheral(struct usb_otg *otg,
+					struct usb_gadget *gadget)
+{
+	otg->gadget = gadget;
+	if (!gadget)
+		otg->state = OTG_STATE_UNDEFINED;
+
+	return 0;
+}
+
+static const struct phy_ops ops = {
+	.owner		= THIS_MODULE,
+};
+
+static int cpcap_phy_get_ints_state(struct cpcap_phy_ddata *ddata,
+				    struct cpcap_usb_ints_state *s)
+{
+	int val, error;
+
+	error = regmap_read(ddata->reg, CPCAP_REG_INTS1, &val);
+	if (error)
+		return error;
+
+	s->id_ground = val & BIT(15);
+	s->id_float = val & BIT(14);
+	s->vbusov = val & BIT(11);
+
+	error = regmap_read(ddata->reg, CPCAP_REG_INTS2, &val);
+	if (error)
+		return error;
+
+	s->vbusvld = val & BIT(3);
+	s->sessvld = val & BIT(2);
+	s->sessend = val & BIT(1);
+	s->se1 = val & BIT(0);
+
+	error = regmap_read(ddata->reg, CPCAP_REG_INTS4, &val);
+	if (error)
+		return error;
+
+	s->dm = val & BIT(1);
+	s->dp = val & BIT(0);
+
+	return 0;
+}
+
+static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata);
+static int cpcap_usb_set_usb_mode(struct cpcap_phy_ddata *ddata);
+
+static void cpcap_usb_detect(struct work_struct *work)
+{
+	struct cpcap_phy_ddata *ddata;
+	struct cpcap_usb_ints_state s;
+	bool vbus = false;
+	int error;
+
+	ddata = container_of(work, struct cpcap_phy_ddata, detect_work.work);
+
+	error = cpcap_phy_get_ints_state(ddata, &s);
+	if (error)
+		return;
+
+	if (s.id_ground) {
+		dev_dbg(ddata->dev, "id ground, USB host mode\n");
+		error = cpcap_usb_set_usb_mode(ddata);
+		if (error)
+			goto out_err;
+
+		error = musb_mailbox(MUSB_ID_GROUND);
+		if (error)
+			goto out_err;
+
+		error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
+					   CPCAP_BIT_VBUSSTBY_EN,
+					   CPCAP_BIT_VBUSSTBY_EN);
+		if (error)
+			goto out_err;
+
+		return;
+	}
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
+				   CPCAP_BIT_VBUSSTBY_EN, 0);
+	if (error)
+		goto out_err;
+
+	vbus = cpcap_usb_vbus_valid(ddata);
+
+	if (vbus) {
+		/* Are we connected to a docking station with vbus? */
+		if (s.id_ground) {
+			dev_dbg(ddata->dev, "connected to a dock\n");
+
+			/* No VBUS needed with docks */
+			error = cpcap_usb_set_usb_mode(ddata);
+			if (error)
+				goto out_err;
+			error = musb_mailbox(MUSB_ID_GROUND);
+			if (error)
+				goto out_err;
+
+			return;
+		}
+
+		/* Otherwise assume we're connected to a USB host */
+		dev_dbg(ddata->dev, "connected to USB host\n");
+		error = cpcap_usb_set_usb_mode(ddata);
+		if (error)
+			goto out_err;
+		error = musb_mailbox(MUSB_VBUS_VALID);
+		if (error)
+			goto out_err;
+
+		return;
+	}
+
+	/* Default to debug UART mode */
+	error = cpcap_usb_set_uart_mode(ddata);
+	if (error)
+		goto out_err;
+
+	error = musb_mailbox(MUSB_VBUS_OFF);
+	if (error)
+		goto out_err;
+
+	dev_dbg(ddata->dev, "set UART mode\n");
+
+	return;
+
+out_err:
+	dev_err(ddata->dev, "error setting cable state: %i\n", error);
+}
+
+static irqreturn_t cpcap_phy_irq_thread(int irq, void *data)
+{
+	struct cpcap_phy_ddata *ddata = data;
+
+	if (!atomic_read(&ddata->active))
+		return IRQ_NONE;
+
+	schedule_delayed_work(&ddata->detect_work, msecs_to_jiffies(1));
+
+	return IRQ_HANDLED;
+}
+
+static int cpcap_usb_init_irq(struct platform_device *pdev,
+			      struct cpcap_phy_ddata *ddata,
+			      const char *name)
+{
+	int irq, error;
+
+	irq = platform_get_irq_byname(pdev, name);
+	if (!irq)
+		return -ENODEV;
+
+	error = devm_request_threaded_irq(ddata->dev, irq, NULL,
+					  cpcap_phy_irq_thread,
+					  IRQF_SHARED,
+					  name, ddata);
+	if (error) {
+		dev_err(ddata->dev, "could not get irq %s: %i\n",
+			name, error);
+
+		return error;
+	}
+
+	return 0;
+}
+
+static const char * const cpcap_phy_irqs[] = {
+	/* REG_INT_0 */
+	"id_ground", "id_float",
+
+	/* REG_INT1 */
+	"se0conn", "vbusvld", "sessvld", "sessend", "se1",
+
+	/* REG_INT_3 */
+	"dm", "dp",
+};
+
+static int cpcap_usb_init_interrupts(struct platform_device *pdev,
+				     struct cpcap_phy_ddata *ddata)
+{
+	int i, error;
+
+	for (i = 0; i < ARRAY_SIZE(cpcap_phy_irqs); i++) {
+		error = cpcap_usb_init_irq(pdev, ddata, cpcap_phy_irqs[i]);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+/*
+ * Optional pins and modes. At least Motorola mapphone devices
+ * are using two GPIOs and dynamic pinctrl to multiplex PHY pins
+ * to UART, ULPI or UTMI mode.
+ */
+
+static int cpcap_usb_gpio_set_mode(struct cpcap_phy_ddata *ddata,
+				   enum cpcap_gpio_mode mode)
+{
+	if (!ddata->gpio[0] || !ddata->gpio[1])
+		return 0;
+
+	gpiod_set_value(ddata->gpio[0], mode & 1);
+	gpiod_set_value(ddata->gpio[1], mode >> 1);
+
+	return 0;
+}
+
+static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata)
+{
+	int error;
+
+	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_DM_DP);
+	if (error)
+		goto out_err;
+
+	if (ddata->pins_uart) {
+		error = pinctrl_select_state(ddata->pins, ddata->pins_uart);
+		if (error)
+			goto out_err;
+	}
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC1,
+				   CPCAP_BIT_VBUSPD,
+				   CPCAP_BIT_VBUSPD);
+	if (error)
+		goto out_err;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC2,
+				   0xffff, CPCAP_BIT_UARTMUX0 |
+				   CPCAP_BIT_EMUMODE0);
+	if (error)
+		goto out_err;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3, 0x7fff,
+				   CPCAP_BIT_IDPU_SPI);
+	if (error)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	dev_err(ddata->dev, "%s failed with %i\n", __func__, error);
+
+	return error;
+}
+
+static int cpcap_usb_set_usb_mode(struct cpcap_phy_ddata *ddata)
+{
+	int error;
+
+	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_OTG_DM_DP);
+	if (error)
+		return error;
+
+	if (ddata->pins_utmi) {
+		error = pinctrl_select_state(ddata->pins, ddata->pins_utmi);
+		if (error) {
+			dev_err(ddata->dev, "could not set usb mode: %i\n",
+				error);
+
+			return error;
+		}
+	}
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC1,
+				   CPCAP_BIT_VBUSPD, 0);
+	if (error)
+		goto out_err;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC2,
+				   CPCAP_BIT_USBXCVREN,
+				   CPCAP_BIT_USBXCVREN);
+	if (error)
+		goto out_err;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
+				   CPCAP_BIT_PU_SPI |
+				   CPCAP_BIT_DMPD_SPI |
+				   CPCAP_BIT_DPPD_SPI |
+				   CPCAP_BIT_SUSPEND_SPI |
+				   CPCAP_BIT_ULPI_SPI_SEL, 0);
+	if (error)
+		goto out_err;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC2,
+				   CPCAP_BIT_USBXCVREN,
+				   CPCAP_BIT_USBXCVREN);
+	if (error)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	dev_err(ddata->dev, "%s failed with %i\n", __func__, error);
+
+	return error;
+}
+
+static int cpcap_usb_init_optional_pins(struct cpcap_phy_ddata *ddata)
+{
+	ddata->pins = devm_pinctrl_get(ddata->dev);
+	if (IS_ERR(ddata->pins)) {
+		dev_info(ddata->dev, "default pins not configured: %ld\n",
+			 PTR_ERR(ddata->pins));
+		ddata->pins = NULL;
+	}
+
+	ddata->pins_ulpi = pinctrl_lookup_state(ddata->pins, "ulpi");
+	if (IS_ERR(ddata->pins_ulpi)) {
+		dev_info(ddata->dev, "ulpi pins not configured\n");
+		ddata->pins_ulpi = NULL;
+	}
+
+	ddata->pins_utmi = pinctrl_lookup_state(ddata->pins, "utmi");
+	if (IS_ERR(ddata->pins_utmi)) {
+		dev_info(ddata->dev, "utmi pins not configured\n");
+		ddata->pins_utmi = NULL;
+	}
+
+	ddata->pins_uart = pinctrl_lookup_state(ddata->pins, "uart");
+	if (IS_ERR(ddata->pins_uart)) {
+		dev_info(ddata->dev, "uart pins not configured\n");
+		ddata->pins_uart = NULL;
+	}
+
+	if (ddata->pins_uart)
+		return pinctrl_select_state(ddata->pins, ddata->pins_uart);
+
+	return 0;
+}
+
+static void cpcap_usb_init_optional_gpios(struct cpcap_phy_ddata *ddata)
+{
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		ddata->gpio[i] = devm_gpiod_get_index(ddata->dev, "mode",
+						      i, GPIOD_OUT_HIGH);
+		if (IS_ERR(ddata->gpio[i])) {
+			dev_info(ddata->dev, "no mode change GPIO%i: %li\n",
+				 i, PTR_ERR(ddata->gpio[i]));
+				 ddata->gpio[i] = NULL;
+		}
+	}
+}
+
+static int cpcap_usb_init_iio(struct cpcap_phy_ddata *ddata)
+{
+	enum iio_chan_type type;
+	int error;
+
+	ddata->vbus = devm_iio_channel_get(ddata->dev, "vbus");
+	if (IS_ERR(ddata->vbus)) {
+		error = PTR_ERR(ddata->vbus);
+		goto out_err;
+	}
+
+	if (!ddata->vbus->indio_dev) {
+		error = -ENXIO;
+		goto out_err;
+	}
+
+	error = iio_get_channel_type(ddata->vbus, &type);
+	if (error < 0)
+		goto out_err;
+
+	if (type != IIO_VOLTAGE) {
+		error = -EINVAL;
+		goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	dev_err(ddata->dev, "could not initialize VBUS or ID IIO: %i\n",
+		error);
+
+	return error;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cpcap_usb_phy_id_table[] = {
+	{
+		.compatible = "motorola,cpcap-usb-phy",
+	},
+	{
+		.compatible = "motorola,mapphone-cpcap-usb-phy",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, cpcap_usb_phy_id_table);
+#endif
+
+static int cpcap_usb_phy_probe(struct platform_device *pdev)
+{
+	struct cpcap_phy_ddata *ddata;
+	struct phy *generic_phy;
+	struct phy_provider *phy_provider;
+	struct usb_otg *otg;
+	const struct of_device_id *of_id;
+	int error;
+
+	of_id = of_match_device(of_match_ptr(cpcap_usb_phy_id_table),
+				&pdev->dev);
+	if (!of_id)
+		return -EINVAL;
+
+	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	ddata->reg = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!ddata->reg)
+		return -ENODEV;
+
+	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
+	if (!otg)
+		return -ENOMEM;
+
+	ddata->dev = &pdev->dev;
+	ddata->phy.dev = ddata->dev;
+	ddata->phy.label = "cpcap_usb_phy";
+	ddata->phy.otg = otg;
+	ddata->phy.type = USB_PHY_TYPE_USB2;
+	otg->set_host = cpcap_usb_phy_set_host;
+	otg->set_peripheral = cpcap_usb_phy_set_peripheral;
+	otg->usb_phy = &ddata->phy;
+	INIT_DELAYED_WORK(&ddata->detect_work, cpcap_usb_detect);
+	platform_set_drvdata(pdev, ddata);
+
+	ddata->vusb = devm_regulator_get(&pdev->dev, "vusb");
+	if (IS_ERR(ddata->vusb))
+		return PTR_ERR(ddata->vusb);
+
+	error = regulator_enable(ddata->vusb);
+	if (error)
+		return error;
+
+	generic_phy = devm_phy_create(ddata->dev, NULL, &ops);
+	if (IS_ERR(generic_phy)) {
+		error = PTR_ERR(generic_phy);
+		return PTR_ERR(generic_phy);
+	}
+
+	phy_set_drvdata(generic_phy, ddata);
+
+	phy_provider = devm_of_phy_provider_register(ddata->dev,
+						     of_phy_simple_xlate);
+	if (IS_ERR(phy_provider))
+		return PTR_ERR(phy_provider);
+
+	error = cpcap_usb_init_optional_pins(ddata);
+	if (error)
+		return error;
+
+	cpcap_usb_init_optional_gpios(ddata);
+
+	error = cpcap_usb_init_iio(ddata);
+	if (error)
+		return error;
+
+	error = cpcap_usb_init_interrupts(pdev, ddata);
+	if (error)
+		return error;
+
+	usb_add_phy_dev(&ddata->phy);
+	atomic_set(&ddata->active, 1);
+	schedule_delayed_work(&ddata->detect_work, msecs_to_jiffies(1));
+
+	return 0;
+}
+
+static int cpcap_usb_phy_remove(struct platform_device *pdev)
+{
+	struct cpcap_phy_ddata *ddata = platform_get_drvdata(pdev);
+	int error;
+
+	atomic_set(&ddata->active, 0);
+	error = cpcap_usb_set_uart_mode(ddata);
+	if (error)
+		dev_err(ddata->dev, "could not set UART mode\n");
+
+	error = musb_mailbox(MUSB_VBUS_OFF);
+	if (error)
+		dev_err(ddata->dev, "could not set mailbox\n");
+
+	usb_remove_phy(&ddata->phy);
+	cancel_delayed_work_sync(&ddata->detect_work);
+	clk_unprepare(ddata->refclk);
+	regulator_disable(ddata->vusb);
+
+	return 0;
+}
+
+static struct platform_driver cpcap_usb_phy_driver = {
+	.probe		= cpcap_usb_phy_probe,
+	.remove		= cpcap_usb_phy_remove,
+	.driver		= {
+		.name	= "cpcap-usb-phy",
+		.of_match_table = of_match_ptr(cpcap_usb_phy_id_table),
+	},
+};
+
+module_platform_driver(cpcap_usb_phy_driver);
+
+MODULE_ALIAS("platform:cpcap_usb");
+MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
+MODULE_DESCRIPTION("CPCAP usb phy driver");
+MODULE_LICENSE("GPL v2");