[PATCH V6 8/8] drm/bridge: Add i2c based driver for ps8622/ps8625 bridge

[Ajay Kumar <ajaykumar.rs@samsung.com>]

From: Vincent Palatin <vpalatin@chromium.org>

This patch adds drm_bridge driver for parade DisplayPort
to LVDS bridge chip.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
---
 .../devicetree/bindings/vendor-prefixes.txt        |    1 +
 .../devicetree/bindings/video/bridge/ps8622.txt    |   19 +
 drivers/gpu/drm/bridge/Kconfig                     |   10 +
 drivers/gpu/drm/bridge/Makefile                    |    1 +
 drivers/gpu/drm/bridge/ps8622.c                    |  602 ++++++++++++++++++++
 5 files changed, 633 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/bridge/ps8622.txt
 create mode 100644 drivers/gpu/drm/bridge/ps8622.c

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 46a311e..b4a99cc 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -96,6 +96,7 @@ nxp	NXP Semiconductors
 onnn	ON Semiconductor Corp.
 opencores	OpenCores.org
 panasonic	Panasonic Corporation
+parade	Parade Technologies Inc.
 phytec	PHYTEC Messtechnik GmbH
 picochip	Picochip Ltd
 plathome	Plat'Home Co., Ltd.
diff --git a/Documentation/devicetree/bindings/video/bridge/ps8622.txt b/Documentation/devicetree/bindings/video/bridge/ps8622.txt
new file mode 100644
index 0000000..fdeafb2
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/bridge/ps8622.txt
@@ -0,0 +1,19 @@
+ps8622-bridge bindings
+
+Required properties:
+	- compatible: "parade,ps8622" or "parade,ps8625"
+	- reg: first i2c address of the bridge
+	- sleep-gpios: OF device-tree gpio specification
+	- reset-gpios: OF device-tree gpio specification
+
+Optional properties:
+	- lane-count: number of DP lanes to use
+
+Example:
+	ps8622-bridge@48 {
+		compatible = "parade,ps8622";
+		reg = <0x48>;
+		sleep-gpios = <&gpc3 6 1 0 0>;
+		reset-gpios = <&gpc3 1 1 0 0>;
+		lane-count = <1>
+	};
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 0b12d16..d73e474 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -16,4 +16,14 @@ config DRM_PTN3460
 	help
 	  ptn3460 eDP-LVDS bridge chip driver.
 
+config DRM_PS8622
+	tristate "Parade eDP/LVDS bridge"
+	depends on DRM && DRM_BRIDGE
+	depends on OF
+	depends on I2C
+	select DRM_PANEL
+	select BACKLIGHT_LCD_SUPPORT
+	select BACKLIGHT_CLASS_DEVICE
+	help
+	  parade eDP-LVDS bridge chip driver.
 endmenu
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index b4733e1..d1b5daa 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -1,3 +1,4 @@
 ccflags-y := -Iinclude/drm
 
 obj-$(CONFIG_DRM_PTN3460) += ptn3460.o
+obj-$(CONFIG_DRM_PS8622) += ps8622.o
diff --git a/drivers/gpu/drm/bridge/ps8622.c b/drivers/gpu/drm/bridge/ps8622.c
new file mode 100644
index 0000000..ec60fcf
--- /dev/null
+++ b/drivers/gpu/drm/bridge/ps8622.c
@@ -0,0 +1,602 @@
+/*
+ * Parade PS8622 eDP/LVDS bridge driver
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_panel.h>
+
+#include "drmP.h"
+#include "drm_crtc.h"
+#include "drm_crtc_helper.h"
+
+struct ps8622_bridge {
+	struct drm_connector connector;
+	struct i2c_client *client;
+	struct drm_bridge *bridge;
+	struct drm_panel *panel;
+	struct regulator *v12;
+	struct backlight_device *bl;
+	struct mutex enable_mutex;
+
+	struct gpio_desc *gpio_slp_n;
+	struct gpio_desc *gpio_rst_n;
+
+	u8 max_lane_count;
+	u8 lane_count;
+
+	bool enabled;
+};
+
+struct ps8622_device_data {
+	u8 max_lane_count;
+};
+
+static const struct ps8622_device_data ps8622_data = {
+	.max_lane_count = 1,
+};
+
+static const struct ps8622_device_data ps8625_data = {
+	.max_lane_count = 2,
+};
+
+/* Brightness scale on the Parade chip */
+#define PS8622_MAX_BRIGHTNESS 0xff
+
+/* Timings taken from the version 1.7 datasheet for the PS8622/PS8625 */
+#define PS8622_POWER_RISE_T1_MIN_US 10
+#define PS8622_POWER_RISE_T1_MAX_US 10000
+#define PS8622_RST_HIGH_T2_MIN_US 3000
+#define PS8622_RST_HIGH_T2_MAX_US 30000
+#define PS8622_PWMO_END_T12_MS 200
+#define PS8622_POWER_FALL_T16_MAX_US 10000
+#define PS8622_POWER_OFF_T17_MS 500
+
+#if ((PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US) > \
+	(PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US))
+#error "T2.min + T1.max must be less than T2.max + T1.min"
+#endif
+
+static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
+{
+	int ret;
+	struct i2c_adapter *adap = client->adapter;
+	struct i2c_msg msg;
+	u8 data[] = {reg, val};
+
+	msg.addr = client->addr + page;
+	msg.flags = 0;
+	msg.len = sizeof(data);
+	msg.buf = data;
+
+	ret = i2c_transfer(adap, &msg, 1);
+	if (ret != 1)
+		pr_warn("PS8622 I2C write (0x%02x,0x%02x,0x%02x) failed: %d\n",
+			client->addr + page, reg, val, ret);
+	return !(ret == 1);
+}
+
+static int ps8622_send_config(struct ps8622_bridge *ps_bridge)
+{
+	struct i2c_client *cl = ps_bridge->client;
+	int err = 0;
+
+	/* wait 20ms after power ON */
+	usleep_range(20000, 30000);
+
+	err |= ps8622_set(cl, 0x02, 0xa1, 0x01); /* HPD low */
+	/* SW setting */
+	err |= ps8622_set(cl, 0x04, 0x14, 0x01); /* [1:0] SW output 1.2V voltage
+						  * is lower to 96% */
+	/* RCO SS setting */
+	err |= ps8622_set(cl, 0x04, 0xe3, 0x20); /* [5:4] = b01 0.5%, b10 1%,
+						  * b11 1.5% */
+	err |= ps8622_set(cl, 0x04, 0xe2, 0x80); /* [7] RCO SS enable */
+	/* RPHY Setting */
+	err |= ps8622_set(cl, 0x04, 0x8a, 0x0c); /* [3:2] CDR tune wait cycle
+						  * before measure for fine tune
+						  * b00: 1us b01: 0.5us b10:2us
+						  * b11: 4us */
+	err |= ps8622_set(cl, 0x04, 0x89, 0x08); /* [3] RFD always on */
+	err |= ps8622_set(cl, 0x04, 0x71, 0x2d); /* CTN lock in/out:
+						  * 20000ppm/80000ppm.
+						  * Lock out 2 times. */
+	/* 2.7G CDR settings */
+	err |= ps8622_set(cl, 0x04, 0x7d, 0x07); /* NOF=40LSB for HBR CDR
+						  * setting */
+	err |= ps8622_set(cl, 0x04, 0x7b, 0x00); /* [1:0] Fmin=+4bands */
+	err |= ps8622_set(cl, 0x04, 0x7a, 0xfd); /* [7:5] DCO_FTRNG=+-40% */
+	/* 1.62G CDR settings */
+	err |= ps8622_set(cl, 0x04, 0xc0, 0x12); /* [5:2]NOF=64LSB [1:0]DCO
+						  * scale is 2/5 */
+	err |= ps8622_set(cl, 0x04, 0xc1, 0x92); /* Gitune=-37% */
+	err |= ps8622_set(cl, 0x04, 0xc2, 0x1c); /* Fbstep=100% */
+	err |= ps8622_set(cl, 0x04, 0x32, 0x80); /* [7] LOS signal disable */
+	/* RPIO Setting */
+	err |= ps8622_set(cl, 0x04, 0x00, 0xb0); /* [7:4] LVDS driver bias
+						  * current : 75% (250mV swing)
+						  * */
+	err |= ps8622_set(cl, 0x04, 0x15, 0x40); /* [7:6] Right-bar GPIO output
+						  * strength is 8mA */
+	/* EQ Training State Machine Setting */
+	err |= ps8622_set(cl, 0x04, 0x54, 0x10); /* RCO calibration start */
+	/* Logic, needs more than 10 I2C command */
+	err |= ps8622_set(cl, 0x01, 0x02, 0x80 | ps_bridge->max_lane_count);
+						 /* [4:0] MAX_LANE_COUNT set to
+						  * max supported lanes */
+	err |= ps8622_set(cl, 0x01, 0x21, 0x80 | ps_bridge->lane_count);
+						 /* [4:0] LANE_COUNT_SET set to
+						  * chosen lane count */
+	err |= ps8622_set(cl, 0x00, 0x52, 0x20);
+	err |= ps8622_set(cl, 0x00, 0xf1, 0x03); /* HPD CP toggle enable */
+	err |= ps8622_set(cl, 0x00, 0x62, 0x41);
+	err |= ps8622_set(cl, 0x00, 0xf6, 0x01); /* Counter number, add 1ms
+						  * counter delay */
+	err |= ps8622_set(cl, 0x00, 0x77, 0x06); /* [6]PWM function control by
+						  * DPCD0040f[7], default is PWM
+						  * block always works. */
+	err |= ps8622_set(cl, 0x00, 0x4c, 0x04); /* 04h Adjust VTotal tolerance
+						  * to fix the 30Hz no display
+						  * issue */
+	err |= ps8622_set(cl, 0x01, 0xc0, 0x00); /* DPCD00400='h00, Parade OUI =
+						  * 'h001cf8 */
+	err |= ps8622_set(cl, 0x01, 0xc1, 0x1c); /* DPCD00401='h1c */
+	err |= ps8622_set(cl, 0x01, 0xc2, 0xf8); /* DPCD00402='hf8 */
+	err |= ps8622_set(cl, 0x01, 0xc3, 0x44); /* DPCD403~408 = ASCII code
+						  * D2SLV5='h4432534c5635 */
+	err |= ps8622_set(cl, 0x01, 0xc4, 0x32); /* DPCD404 */
+	err |= ps8622_set(cl, 0x01, 0xc5, 0x53); /* DPCD405 */
+	err |= ps8622_set(cl, 0x01, 0xc6, 0x4c); /* DPCD406 */
+	err |= ps8622_set(cl, 0x01, 0xc7, 0x56); /* DPCD407 */
+	err |= ps8622_set(cl, 0x01, 0xc8, 0x35); /* DPCD408 */
+	err |= ps8622_set(cl, 0x01, 0xca, 0x01); /* DPCD40A, Initial Code major
+						  * revision '01' */
+	err |= ps8622_set(cl, 0x01, 0xcb, 0x05); /* DPCD40B, Initial Code minor
+						  * revision '05' */
+	if (ps_bridge->bl) {
+		err |= ps8622_set(cl, 0x01, 0xa5, 0xa0);
+						/* DPCD720, internal PWM */
+		err |= ps8622_set(cl, 0x01, 0xa7,
+				ps_bridge->bl->props.brightness);
+						 /* FFh for 100% brightness,
+						  *  0h for 0% brightness */
+	} else {
+		err |= ps8622_set(cl, 0x01, 0xa5, 0x80);
+						/* DPCD720, external PWM */
+	}
+	err |= ps8622_set(cl, 0x01, 0xcc, 0x13); /* Set LVDS output as 6bit-VESA
+						  * mapping, single LVDS channel
+						  * */
+	err |= ps8622_set(cl, 0x02, 0xb1, 0x20); /* Enable SSC set by register
+						  * */
+	err |= ps8622_set(cl, 0x04, 0x10, 0x16); /* Set SSC enabled and +/-1%
+						  * central spreading */
+	/* Logic end */
+	err |= ps8622_set(cl, 0x04, 0x59, 0x60); /* MPU Clock source: LC => RCO
+						  * */
+	err |= ps8622_set(cl, 0x04, 0x54, 0x14); /* LC -> RCO */
+	err |= ps8622_set(cl, 0x02, 0xa1, 0x91); /* HPD high */
+
+	return err ? -EIO : 0;
+}
+
+static int ps8622_backlight_update(struct backlight_device *bl)
+{
+	struct ps8622_bridge *ps_bridge = dev_get_drvdata(&bl->dev);
+	int ret, brightness = bl->props.brightness;
+
+	if (bl->props.power != FB_BLANK_UNBLANK ||
+	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+		brightness = 0;
+
+	mutex_lock(&ps_bridge->enable_mutex);
+
+	if (!ps_bridge->enabled) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = ps8622_set(ps_bridge->client, 0x01, 0xa7, brightness);
+
+out:
+	mutex_unlock(&ps_bridge->enable_mutex);
+	return ret;
+}
+
+static int ps8622_backlight_get(struct backlight_device *bl)
+{
+	return bl->props.brightness;
+}
+
+static const struct backlight_ops ps8622_backlight_ops = {
+	.update_status	= ps8622_backlight_update,
+	.get_brightness	= ps8622_backlight_get,
+};
+
+static void ps8622_pre_enable(struct drm_bridge *bridge)
+{
+	struct ps8622_bridge *ps_bridge = bridge->driver_private;
+	int ret;
+
+	mutex_lock(&ps_bridge->enable_mutex);
+	if (ps_bridge->enabled)
+		goto out;
+
+	gpiod_set_value(ps_bridge->gpio_rst_n, 0);
+
+	if (ps_bridge->v12) {
+		ret = regulator_enable(ps_bridge->v12);
+		if (ret)
+			DRM_ERROR("fails to enable ps_bridge->v12");
+	}
+
+	drm_panel_prepare(ps_bridge->panel);
+
+	gpiod_set_value(ps_bridge->gpio_slp_n, 1);
+
+	/*
+	 * T1 is the range of time that it takes for the power to rise after we
+	 * enable the lcd fet. T2 is the range of time in which the data sheet
+	 * specifies we should deassert the reset pin.
+	 *
+	 * If it takes T1.max for the power to rise, we need to wait atleast
+	 * T2.min before deasserting the reset pin. If it takes T1.min for the
+	 * power to rise, we need to wait at most T2.max before deasserting the
+	 * reset pin.
+	 */
+	usleep_range(PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US,
+		     PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US);
+
+	gpiod_set_value(ps_bridge->gpio_rst_n, 1);
+
+	ret = ps8622_send_config(ps_bridge);
+	if (ret)
+		DRM_ERROR("Failed to send config to bridge (%d)\n", ret);
+
+	ps_bridge->enabled = true;
+
+out:
+	mutex_unlock(&ps_bridge->enable_mutex);
+}
+
+static void ps8622_enable(struct drm_bridge *bridge)
+{
+	struct ps8622_bridge *ps_bridge = bridge->driver_private;
+
+	mutex_lock(&ps_bridge->enable_mutex);
+	drm_panel_enable(ps_bridge->panel);
+	mutex_unlock(&ps_bridge->enable_mutex);
+}
+
+static void ps8622_disable(struct drm_bridge *bridge)
+{
+	struct ps8622_bridge *ps_bridge = bridge->driver_private;
+
+	mutex_lock(&ps_bridge->enable_mutex);
+
+	if (!ps_bridge->enabled)
+		goto out;
+
+	ps_bridge->enabled = false;
+
+	drm_panel_disable(ps_bridge->panel);
+	msleep(PS8622_PWMO_END_T12_MS);
+
+	/*
+	 * This doesn't matter if the regulators are turned off, but something
+	 * else might keep them on. In that case, we want to assert the slp gpio
+	 * to lower power.
+	 */
+	gpiod_set_value(ps_bridge->gpio_slp_n, 0);
+
+	if (ps_bridge->v12)
+		regulator_disable(ps_bridge->v12);
+
+	/*
+	 * Sleep for at least the amount of time that it takes the power rail to
+	 * fall to prevent asserting the rst gpio from doing anything.
+	 */
+	usleep_range(PS8622_POWER_FALL_T16_MAX_US,
+		     2 * PS8622_POWER_FALL_T16_MAX_US);
+	gpiod_set_value(ps_bridge->gpio_rst_n, 0);
+
+	msleep(PS8622_POWER_OFF_T17_MS);
+
+out:
+	mutex_unlock(&ps_bridge->enable_mutex);
+}
+
+static void ps8622_post_disable(struct drm_bridge *bridge)
+{
+	struct ps8622_bridge *ps_bridge = bridge->driver_private;
+
+	drm_panel_unprepare(ps_bridge->panel);
+}
+
+static void ps8622_destroy(struct drm_bridge *bridge)
+{
+	drm_bridge_cleanup(bridge);
+}
+
+static int ps8622_get_modes(struct drm_connector *connector)
+{
+	struct ps8622_bridge *ps_bridge;
+
+	ps_bridge = container_of(connector, struct ps8622_bridge, connector);
+
+	return drm_panel_get_modes(ps_bridge->panel);
+}
+
+static struct drm_encoder *ps8622_best_encoder(struct drm_connector *connector)
+{
+	struct ps8622_bridge *ps_bridge;
+
+	ps_bridge = container_of(connector, struct ps8622_bridge, connector);
+
+	return ps_bridge->bridge->encoder;
+}
+
+static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
+	.get_modes = ps8622_get_modes,
+	.best_encoder = ps8622_best_encoder,
+};
+
+static enum drm_connector_status ps8622_detect(struct drm_connector *connector,
+		bool force)
+{
+	return connector_status_connected;
+}
+
+static void ps8622_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs ps8622_connector_funcs = {
+	.dpms = drm_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.detect = ps8622_detect,
+	.destroy = ps8622_connector_destroy,
+};
+
+int ps8622_post_encoder_init(struct drm_bridge *bridge)
+{
+	struct ps8622_bridge *ps_bridge = bridge->driver_private;
+	int ret;
+
+	/* bridge is attached to encoder.
+	 * safe to remove it from the bridge_lookup table.
+	 */
+	drm_bridge_remove_from_lookup(bridge);
+
+	ret = drm_bridge_init(bridge->drm_dev, bridge);
+	if (ret) {
+		DRM_ERROR("Failed to initialize bridge with drm\n");
+		return ret;
+	}
+
+	/* connector implementation */
+	ps_bridge->connector.polled = bridge->connector_polled;
+
+	ret = drm_connector_init(bridge->drm_dev, &ps_bridge->connector,
+			&ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
+	if (ret) {
+		DRM_ERROR("Failed to initialize connector with drm\n");
+		return ret;
+	}
+	drm_connector_helper_add(&ps_bridge->connector,
+					&ps8622_connector_helper_funcs);
+	drm_connector_register(&ps_bridge->connector);
+	drm_mode_connector_attach_encoder(&ps_bridge->connector,
+							bridge->encoder);
+
+	if (ps_bridge->panel)
+		drm_panel_attach(ps_bridge->panel, &ps_bridge->connector);
+
+	return ret;
+}
+
+static const struct drm_bridge_funcs ps8622_bridge_funcs = {
+	.post_encoder_init = ps8622_post_encoder_init,
+	.pre_enable = ps8622_pre_enable,
+	.enable = ps8622_enable,
+	.disable = ps8622_disable,
+	.post_disable = ps8622_post_disable,
+	.destroy = ps8622_destroy,
+};
+
+static const struct of_device_id ps8622_devices[] = {
+	{
+		.compatible = "parade,ps8622",
+		.data	= &ps8622_data,
+	}, {
+		.compatible = "parade,ps8625",
+		.data	= &ps8625_data,
+	}, {
+		/* end node */
+	}
+};
+MODULE_DEVICE_TABLE(of, ps8622_devices);
+
+static inline struct ps8622_device_data *get_device_data(struct device *dev)
+{
+	const struct of_device_id *match =
+			of_match_device(ps8622_devices, dev);
+
+	return (struct ps8622_device_data *)match->data;
+}
+
+static int ps8622_probe(struct i2c_client *client,
+					const struct i2c_device_id *id)
+{
+	struct device *dev = &(client->dev);
+	struct device_node *panel_node, *backlight_node;
+	struct drm_bridge *bridge;
+	struct backlight_device *backlight_dev;
+	struct ps8622_bridge *ps_bridge;
+	const struct ps8622_device_data *device_data;
+	int ret;
+
+	bridge = devm_kzalloc(dev, sizeof(*bridge), GFP_KERNEL);
+	if (!bridge) {
+		DRM_ERROR("Failed to allocate drm bridge\n");
+		return -ENOMEM;
+	}
+
+	ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
+	if (!ps_bridge) {
+		DRM_ERROR("could not allocate ps bridge\n");
+		return -ENOMEM;
+	}
+
+	panel_node = of_parse_phandle(dev->of_node, "panel", 0);
+	if (panel_node) {
+		ps_bridge->panel = of_drm_find_panel(panel_node);
+		of_node_put(panel_node);
+		if (!ps_bridge->panel)
+			return -EPROBE_DEFER;
+	}
+
+	backlight_dev = NULL;
+	backlight_node = of_parse_phandle(dev->of_node, "backlight", 0);
+	if (backlight_node) {
+		backlight_dev = of_find_backlight_by_node(backlight_node);
+		of_node_put(backlight_node);
+		if (!backlight_dev)
+			return -EPROBE_DEFER;
+	}
+
+	mutex_init(&ps_bridge->enable_mutex);
+
+	bridge->dev = dev;
+	bridge->driver_private = ps_bridge;
+	bridge->funcs = &ps8622_bridge_funcs;
+
+	ps_bridge->client = client;
+	ps_bridge->bridge = bridge;
+
+	device_data = get_device_data(dev);
+
+	ps_bridge->v12 = devm_regulator_get(&client->dev, "vdd_bridge");
+	if (IS_ERR(ps_bridge->v12)) {
+		DRM_INFO("no 1.2v regulator found for PS8622\n");
+		ps_bridge->v12 = NULL;
+	}
+
+	ps_bridge->gpio_slp_n = devm_gpiod_get(&client->dev, "sleep");
+	if (IS_ERR(ps_bridge->gpio_slp_n)) {
+		ret = PTR_ERR(ps_bridge->gpio_slp_n);
+		DRM_ERROR("cannot get gpio_slp_n %d\n", ret);
+		goto err_client;
+	} else {
+		ret = gpiod_direction_output(ps_bridge->gpio_slp_n, 1);
+		if (ret) {
+			DRM_ERROR("cannot configure gpio_slp_n\n");
+			goto err_client;
+		}
+	}
+
+	ps_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset");
+	if (IS_ERR(ps_bridge->gpio_rst_n)) {
+		ret = PTR_ERR(ps_bridge->gpio_rst_n);
+		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
+		goto err_client;
+	} else {
+		/*
+		 * Assert the reset pin high to avoid the bridge being
+		 * initialized prematurely
+		 */
+		ret = gpiod_direction_output(ps_bridge->gpio_rst_n, 1);
+		if (ret) {
+			DRM_ERROR("cannot configure gpio_slp_n\n");
+			goto err_client;
+		}
+	}
+
+	ps_bridge->max_lane_count = device_data->max_lane_count;
+
+	if (of_property_read_u8(dev->of_node, "lane-count",
+						&ps_bridge->lane_count))
+		ps_bridge->lane_count = ps_bridge->max_lane_count;
+	else if (ps_bridge->lane_count > ps_bridge->max_lane_count) {
+		DRM_INFO("lane-count property is too high for DP bridge\n");
+		ps_bridge->lane_count = ps_bridge->max_lane_count;
+	}
+
+	if (!backlight_dev) {
+		ps_bridge->bl = backlight_device_register("ps8622-backlight",
+				dev, ps_bridge, &ps8622_backlight_ops,
+				NULL);
+		if (IS_ERR(ps_bridge->bl)) {
+			DRM_ERROR("failed to register backlight\n");
+			ret = PTR_ERR(ps_bridge->bl);
+			ps_bridge->bl = NULL;
+			goto err_client;
+		}
+		ps_bridge->bl->props.max_brightness = PS8622_MAX_BRIGHTNESS;
+		ps_bridge->bl->props.brightness = PS8622_MAX_BRIGHTNESS;
+	}
+
+	i2c_set_clientdata(client, ps_bridge);
+
+	drm_bridge_add_for_lookup(bridge);
+
+	return 0;
+
+err_client:
+	DRM_ERROR("device probe failed : %d\n", ret);
+	return ret;
+}
+
+static int ps8622_remove(struct i2c_client *client)
+{
+	struct ps8622_bridge *ps_bridge = i2c_get_clientdata(client);
+
+	if (ps_bridge->bl)
+		backlight_device_unregister(ps_bridge->bl);
+
+	return 0;
+}
+
+static const struct i2c_device_id ps8622_i2c_table[] = {
+	{"parade", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, ps8622_i2c_table);
+
+struct i2c_driver ps8622_driver = {
+	.id_table	= ps8622_i2c_table,
+	.probe		= ps8622_probe,
+	.remove		= ps8622_remove,
+	.driver		= {
+		.name	= "parade",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ps8622_devices),
+	},
+};
+module_i2c_driver(ps8622_driver);
+
+MODULE_AUTHOR("Vincent Palatin <vpalatin@chromium.org>");
+MODULE_DESCRIPTION("Parade ps8622 eDP-LVDS converter driver");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5