1 files changed, 429 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
new file mode 100644
index 000000000000..11f11086a68f
--- /dev/null
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -0,0 +1,429 @@
+/*
+ * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
+ * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
+
+ * Copyright (c) 2017, Collabora Ltd.
+ * Copyright (c) 2017, General Electric Company
+
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+
+ * This program is distributed in the hope 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 for
+ * more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+ * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
+ * display bridge of the GE B850v3. There are two physical bridges on the video
+ * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
+ * physical bridges are automatically configured by the input video signal, and
+ * the driver has no access to the video processing pipeline. The driver is
+ * only needed to read EDID from the STDP2690 and to handle HPD events from the
+ * STDP4028. The driver communicates with both bridges over i2c. The video
+ * signal pipeline is as follows:
+ *
+ *   Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_edid.h>
+#include <drm/drmP.h>
+
+#define EDID_EXT_BLOCK_CNT 0x7E
+
+#define STDP4028_IRQ_OUT_CONF_REG 0x02
+#define STDP4028_DPTX_IRQ_EN_REG 0x3C
+#define STDP4028_DPTX_IRQ_STS_REG 0x3D
+#define STDP4028_DPTX_STS_REG 0x3E
+
+#define STDP4028_DPTX_DP_IRQ_EN 0x1000
+
+#define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
+#define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
+#define STDP4028_DPTX_IRQ_CONFIG \
+		(STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
+
+#define STDP4028_DPTX_HOTPLUG_STS 0x0200
+#define STDP4028_DPTX_LINK_STS 0x1000
+#define STDP4028_CON_STATE_CONNECTED \
+		(STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
+
+#define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
+#define STDP4028_DPTX_LINK_CH_STS 0x2000
+#define STDP4028_DPTX_IRQ_CLEAR \
+		(STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
+
+static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
+
+struct ge_b850v3_lvds {
+	struct drm_connector connector;
+	struct drm_bridge bridge;
+	struct i2c_client *stdp4028_i2c;
+	struct i2c_client *stdp2690_i2c;
+	struct edid *edid;
+};
+
+static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
+
+static u8 *stdp2690_get_edid(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	unsigned char start = 0x00;
+	unsigned int total_size;
+	u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
+
+	struct i2c_msg msgs[] = {
+		{
+			.addr	= client->addr,
+			.flags	= 0,
+			.len	= 1,
+			.buf	= &start,
+		}, {
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= EDID_LENGTH,
+			.buf	= block,
+		}
+	};
+
+	if (!block)
+		return NULL;
+
+	if (i2c_transfer(adapter, msgs, 2) != 2) {
+		DRM_ERROR("Unable to read EDID.\n");
+		goto err;
+	}
+
+	if (!drm_edid_block_valid(block, 0, false, NULL)) {
+		DRM_ERROR("Invalid EDID data\n");
+		goto err;
+	}
+
+	total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
+	if (total_size > EDID_LENGTH) {
+		kfree(block);
+		block = kmalloc(total_size, GFP_KERNEL);
+		if (!block)
+			return NULL;
+
+		/* Yes, read the entire buffer, and do not skip the first
+		 * EDID_LENGTH bytes.
+		 */
+		start = 0x00;
+		msgs[1].len = total_size;
+		msgs[1].buf = block;
+
+		if (i2c_transfer(adapter, msgs, 2) != 2) {
+			DRM_ERROR("Unable to read EDID extension blocks.\n");
+			goto err;
+		}
+		if (!drm_edid_block_valid(block, 1, false, NULL)) {
+			DRM_ERROR("Invalid EDID data\n");
+			goto err;
+		}
+	}
+
+	return block;
+
+err:
+	kfree(block);
+	return NULL;
+}
+
+static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
+{
+	struct i2c_client *client;
+	int num_modes = 0;
+
+	client = ge_b850v3_lvds_ptr->stdp2690_i2c;
+
+	kfree(ge_b850v3_lvds_ptr->edid);
+	ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
+
+	if (ge_b850v3_lvds_ptr->edid) {
+		drm_mode_connector_update_edid_property(connector,
+						      ge_b850v3_lvds_ptr->edid);
+		num_modes = drm_add_edid_modes(connector,
+					       ge_b850v3_lvds_ptr->edid);
+	}
+
+	return num_modes;
+}
+
+static enum drm_mode_status ge_b850v3_lvds_mode_valid(
+		struct drm_connector *connector, struct drm_display_mode *mode)
+{
+	return MODE_OK;
+}
+
+static const struct
+drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
+	.get_modes = ge_b850v3_lvds_get_modes,
+	.mode_valid = ge_b850v3_lvds_mode_valid,
+};
+
+static enum drm_connector_status ge_b850v3_lvds_detect(
+		struct drm_connector *connector, bool force)
+{
+	struct i2c_client *stdp4028_i2c =
+			ge_b850v3_lvds_ptr->stdp4028_i2c;
+	s32 link_state;
+
+	link_state = i2c_smbus_read_word_data(stdp4028_i2c,
+					      STDP4028_DPTX_STS_REG);
+
+	if (link_state == STDP4028_CON_STATE_CONNECTED)
+		return connector_status_connected;
+
+	if (link_state == 0)
+		return connector_status_disconnected;
+
+	return connector_status_unknown;
+}
+
+static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.detect = ge_b850v3_lvds_detect,
+	.destroy = drm_connector_cleanup,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
+{
+	struct i2c_client *stdp4028_i2c
+			= ge_b850v3_lvds_ptr->stdp4028_i2c;
+
+	i2c_smbus_write_word_data(stdp4028_i2c,
+				  STDP4028_DPTX_IRQ_STS_REG,
+				  STDP4028_DPTX_IRQ_CLEAR);
+
+	if (ge_b850v3_lvds_ptr->connector.dev)
+		drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev);
+
+	return IRQ_HANDLED;
+}
+
+static int ge_b850v3_lvds_attach(struct drm_bridge *bridge)
+{
+	struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
+	struct i2c_client *stdp4028_i2c
+			= ge_b850v3_lvds_ptr->stdp4028_i2c;
+	int ret;
+
+	if (!bridge->encoder) {
+		DRM_ERROR("Parent encoder object not found");
+		return -ENODEV;
+	}
+
+	connector->polled = DRM_CONNECTOR_POLL_HPD;
+
+	drm_connector_helper_add(connector,
+				 &ge_b850v3_lvds_connector_helper_funcs);
+
+	ret = drm_connector_init(bridge->dev, connector,
+				 &ge_b850v3_lvds_connector_funcs,
+				 DRM_MODE_CONNECTOR_DisplayPort);
+	if (ret) {
+		DRM_ERROR("Failed to initialize connector with drm\n");
+		return ret;
+	}
+
+	ret = drm_mode_connector_attach_encoder(connector, bridge->encoder);
+	if (ret)
+		return ret;
+
+	/* Configures the bridge to re-enable interrupts after each ack. */
+	i2c_smbus_write_word_data(stdp4028_i2c,
+				  STDP4028_IRQ_OUT_CONF_REG,
+				  STDP4028_DPTX_DP_IRQ_EN);
+
+	/* Enable interrupts */
+	i2c_smbus_write_word_data(stdp4028_i2c,
+				  STDP4028_DPTX_IRQ_EN_REG,
+				  STDP4028_DPTX_IRQ_CONFIG);
+
+	return 0;
+}
+
+static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
+	.attach = ge_b850v3_lvds_attach,
+};
+
+static int ge_b850v3_lvds_init(struct device *dev)
+{
+	mutex_lock(&ge_b850v3_lvds_dev_mutex);
+
+	if (ge_b850v3_lvds_ptr)
+		goto success;
+
+	ge_b850v3_lvds_ptr = devm_kzalloc(dev,
+					  sizeof(*ge_b850v3_lvds_ptr),
+					  GFP_KERNEL);
+
+	if (!ge_b850v3_lvds_ptr) {
+		mutex_unlock(&ge_b850v3_lvds_dev_mutex);
+		return -ENOMEM;
+	}
+
+success:
+	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
+	return 0;
+}
+
+static void ge_b850v3_lvds_remove(void)
+{
+	mutex_lock(&ge_b850v3_lvds_dev_mutex);
+	/*
+	 * This check is to avoid both the drivers
+	 * removing the bridge in their remove() function
+	 */
+	if (!ge_b850v3_lvds_ptr)
+		goto out;
+
+	drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
+
+	kfree(ge_b850v3_lvds_ptr->edid);
+
+	ge_b850v3_lvds_ptr = NULL;
+out:
+	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
+}
+
+static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
+				       const struct i2c_device_id *id)
+{
+	struct device *dev = &stdp4028_i2c->dev;
+
+	ge_b850v3_lvds_init(dev);
+
+	ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
+	i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
+
+	/* drm bridge initialization */
+	ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
+	ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
+	drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
+
+	/* Clear pending interrupts since power up. */
+	i2c_smbus_write_word_data(stdp4028_i2c,
+				  STDP4028_DPTX_IRQ_STS_REG,
+				  STDP4028_DPTX_IRQ_CLEAR);
+
+	if (!stdp4028_i2c->irq)
+		return 0;
+
+	return devm_request_threaded_irq(&stdp4028_i2c->dev,
+			stdp4028_i2c->irq, NULL,
+			ge_b850v3_lvds_irq_handler,
+			IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+			"ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
+}
+
+static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
+{
+	ge_b850v3_lvds_remove();
+
+	return 0;
+}
+
+static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
+	{"stdp4028_ge_fw", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
+
+static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
+	{ .compatible = "megachips,stdp4028-ge-b850v3-fw" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
+
+static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
+	.id_table	= stdp4028_ge_b850v3_fw_i2c_table,
+	.probe		= stdp4028_ge_b850v3_fw_probe,
+	.remove		= stdp4028_ge_b850v3_fw_remove,
+	.driver		= {
+		.name		= "stdp4028-ge-b850v3-fw",
+		.of_match_table = stdp4028_ge_b850v3_fw_match,
+	},
+};
+
+static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
+				       const struct i2c_device_id *id)
+{
+	struct device *dev = &stdp2690_i2c->dev;
+
+	ge_b850v3_lvds_init(dev);
+
+	ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
+	i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
+
+	return 0;
+}
+
+static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
+{
+	ge_b850v3_lvds_remove();
+
+	return 0;
+}
+
+static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
+	{"stdp2690_ge_fw", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
+
+static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
+	{ .compatible = "megachips,stdp2690-ge-b850v3-fw" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
+
+static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
+	.id_table	= stdp2690_ge_b850v3_fw_i2c_table,
+	.probe		= stdp2690_ge_b850v3_fw_probe,
+	.remove		= stdp2690_ge_b850v3_fw_remove,
+	.driver		= {
+		.name		= "stdp2690-ge-b850v3-fw",
+		.of_match_table = stdp2690_ge_b850v3_fw_match,
+	},
+};
+
+static int __init stdpxxxx_ge_b850v3_init(void)
+{
+	int ret;
+
+	ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
+	if (ret)
+		return ret;
+
+	return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
+}
+module_init(stdpxxxx_ge_b850v3_init);
+
+static void __exit stdpxxxx_ge_b850v3_exit(void)
+{
+	i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
+	i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
+}
+module_exit(stdpxxxx_ge_b850v3_exit);
+
+MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
+MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
+MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
+MODULE_LICENSE("GPL v2");