4 files changed, 178 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/video/bridge/ps8622.txt b/doc/device-tree-bindings/video/bridge/ps8622.txt
new file mode 100644
index 0000000000..66d5d07ebb
--- /dev/null
+++ b/doc/device-tree-bindings/video/bridge/ps8622.txt
@@ -0,0 +1,33 @@
+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 for PD_ pin.
+	- reset-gpios: OF device-tree gpio specification for RST_ pin.
+	- parade,regs: List of 3-byte registers tuples to write:
+		<I2C chip address offset> <register> <value>
+
+Optional properties:
+	- lane-count: number of DP lanes to use
+	- use-external-pwm: backlight will be controlled by an external PWM
+	- video interfaces: Device node can contain video interface port
+			    nodes for panel according to [1].
+
+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Example:
+	lvds-bridge@48 {
+		compatible = "parade,ps8622";
+		reg = <0x48>;
+		sleep-gpios = <&gpc3 6 1 0 0>;
+		reset-gpios = <&gpc3 1 1 0 0>;
+		lane-count = <1>;
+		ports {
+			port@0 {
+				bridge_out: endpoint {
+					remote-endpoint = <&panel_in>;
+				};
+			};
+		};
+	};
diff --git a/drivers/video/bridge/Kconfig b/drivers/video/bridge/Kconfig
index 7ba6b17426..589795df9f 100644
--- a/drivers/video/bridge/Kconfig
+++ b/drivers/video/bridge/Kconfig
@@ -6,3 +6,13 @@ config VIDEO_BRIDGE
 	  another. For example, where the SoC only supports eDP and the LCD
 	  requires LVDS, an eDP->LVDS bridge chip can be used to provide the
 	  necessary conversion. This option enables support for these devices.
+
+config VIDEO_BRIDGE_PARADE_PS862X
+	bool "Support Parade PS862X DP->LVDS bridge"
+	depends on VIDEO_BRIDGE
+	help
+	  The Parade PS8622 and PS8625 are DisplayPort-to-LVDS (Low voltage
+	  differential signalling) converters. They enable an LVDS LCD panel
+	  to be connected to an eDP output device such as an SoC that lacks
+	  LVDS capability, or where LVDS requires too many signals to route
+	  on the PCB. Setup parameters are provided in the device tree.
diff --git a/drivers/video/bridge/Makefile b/drivers/video/bridge/Makefile
index f4bf087a18..c7cc563729 100644
--- a/drivers/video/bridge/Makefile
+++ b/drivers/video/bridge/Makefile
@@ -5,3 +5,4 @@
 #  SPDX-License-Identifier:	GPL-2.0+
 
 obj-$(CONFIG_VIDEO_BRIDGE) += video-bridge-uclass.o
+obj-$(CONFIG_VIDEO_BRIDGE_PARADE_PS862X) += ps862x.o
diff --git a/drivers/video/bridge/ps862x.c b/drivers/video/bridge/ps862x.c
new file mode 100644
index 0000000000..80f63e3eb5
--- /dev/null
+++ b/drivers/video/bridge/ps862x.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <i2c.h>
+#include <video_bridge.h>
+#include <power/regulator.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Initialisation of the chip is a process of writing certain values into
+ * certain registers over i2c bus. The chip in fact responds to a range of
+ * addresses on the i2c bus, so for each written value three parameters are
+ * required: i2c address, register address and the actual value.
+ *
+ * The base address is derived from the device tree, but oddly the chip
+ * responds on several addresses with different register sets for each.
+ */
+
+/**
+ * ps8622_write() Write a PS8622 eDP bridge i2c register
+ *
+ * @param dev		I2C device
+ * @param addr_off	offset from the i2c base address for ps8622
+ * @param reg_addr	register address to write
+ * @param value		value to be written
+ * @return 0 on success, non-0 on failure
+ */
+static int ps8622_write(struct udevice *dev, unsigned addr_off,
+			unsigned char reg_addr, unsigned char value)
+{
+	struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
+	uint8_t buf[2];
+	struct i2c_msg msg;
+	int ret;
+
+	msg.addr = chip->chip_addr + addr_off;
+	msg.flags = 0;
+	buf[0] = reg_addr;
+	buf[1] = value;
+	msg.buf = buf;
+	msg.len = 2;
+	ret = dm_i2c_xfer(dev, &msg, 1);
+	if (ret) {
+		debug("%s: write failed, reg=%#x, value=%#x, ret=%d\n",
+		      __func__, reg_addr, value, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ps8622_set_backlight(struct udevice *dev, int percent)
+{
+	int level = percent * 255 / 100;
+
+	debug("%s: level=%d\n", __func__, level);
+	return ps8622_write(dev, 0x01, 0xa7, level);
+}
+
+static int ps8622_attach(struct udevice *dev)
+{
+	const uint8_t *params;
+	struct udevice *reg;
+	int ret, i, len;
+
+	debug("%s: %s\n", __func__, dev->name);
+	/* set the LDO providing the 1.2V rail to the Parade bridge */
+	ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
+					   "power-supply", &reg);
+	if (!ret) {
+		ret = regulator_autoset(reg);
+	} else if (ret != -ENOENT) {
+		debug("%s: Failed to enable power: ret=%d\n", __func__, ret);
+		return ret;
+	}
+
+	ret = video_bridge_set_active(dev, true);
+	if (ret)
+		return ret;
+
+	params = fdt_getprop(gd->fdt_blob, dev->of_offset, "parade,regs", &len);
+	if (!params || len % 3) {
+		debug("%s: missing/invalid params=%p, len=%x\n", __func__,
+		      params, len);
+		return -EINVAL;
+	}
+
+	/* need to wait 20ms after power on before doing I2C writes */
+	mdelay(20);
+	for (i = 0; i < len; i += 3) {
+		ret = ps8622_write(dev, params[i + 0], params[i + 1],
+				   params[i + 2]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ps8622_probe(struct udevice *dev)
+{
+	debug("%s\n", __func__);
+	if (device_get_uclass_id(dev->parent) != UCLASS_I2C)
+		return -EPROTONOSUPPORT;
+
+	return 0;
+}
+
+struct video_bridge_ops ps8622_ops = {
+	.attach = ps8622_attach,
+	.set_backlight = ps8622_set_backlight,
+};
+
+static const struct udevice_id ps8622_ids[] = {
+	{ .compatible = "parade,ps8622", },
+	{ .compatible = "parade,ps8625", },
+	{ }
+};
+
+U_BOOT_DRIVER(parade_ps8622) = {
+	.name	= "parade_ps8622",
+	.id	= UCLASS_VIDEO_BRIDGE,
+	.of_match = ps8622_ids,
+	.probe	= ps8622_probe,
+	.ops	= &ps8622_ops,
+};