[PATCH V4 04/10] drm/panel: Add driver for lvds/edp based panels

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

This patch adds a simple driver to handle all the LCD and LED
powerup/down routines needed to support eDP/LVDS panels.

The LCD and LED units are usually powered up via regulators,
and almost on all boards, we will have a BACKLIGHT_EN pin to
enable/ disable the backlight.
Sometimes, we can have LCD_EN switches as well.

The routines in this driver can be used to control
panel power sequence on such boards.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
---
 .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
 drivers/gpu/drm/panel/Kconfig                      |   10 +
 drivers/gpu/drm/panel/Makefile                     |    1 +
 drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
 4 files changed, 323 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
 create mode 100644 drivers/gpu/drm/panel/panel-lvds.c

diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
new file mode 100644
index 0000000..7cb6084
--- /dev/null
+++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
@@ -0,0 +1,50 @@
+panel interface for eDP/lvds panels
+
+Required properties:
+  - compatible: "panel-lvds"
+
+Optional properties:
+	-lcd-en-gpio:
+		panel LCD poweron GPIO.
+			Indicates which GPIO needs to be powered up as output
+			to powerup/enable the switch to the LCD panel.
+	-led-en-gpio:
+		panel LED enable GPIO.
+			Indicates which GPIO needs to be powered up as output
+			to enable the backlight.
+	-panel-prepare-delay:
+		delay value in ms required for panel_prepare process
+			Delay in ms needed for the panel LCD unit to
+			powerup completely.
+			ex: delay needed till eDP panel throws HPD.
+			    delay needed so that we cans tart reading edid.
+	-panel-enable-delay:
+		delay value in ms required for panel_enable process
+			Delay in ms needed for the panel backlight/LED unit
+			to powerup, and delay needed between video_enable and
+			backlight_enable.
+	-panel-disable-delay:
+		delay value in ms required for panel_disable process
+			Delay in ms needed for the panel backlight/LED unit
+			powerdown, and delay needed between backlight_disable
+			and video_disable.
+	-panel-unprepare-delay:
+		delay value in ms required for panel_post_disable process
+			Delay in ms needed for the panel LCD unit to
+			to powerdown completely, and the minimum delay needed
+			before powering it on again.
+	-panel-width-mm: physical panel width [mm]
+	-panel-height-mm: physical panel height [mm]
+
+Example:
+
+	panel-lvds {
+		compatible = "panel-lvds";
+		led-en-gpio = <&gpx3 0 1>;
+		panel-prepare-delay = <40>;
+		panel-enable-delay = <20>;
+		panel-disable-delay = <20>;
+		panel-unprepare-delay = <30>;
+		panel-width-mm = <256>;
+		panel-height-mm = <144>;
+	};
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 4ec874d..8fe7ee5 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -30,4 +30,14 @@ config DRM_PANEL_S6E8AA0
 	select DRM_MIPI_DSI
 	select VIDEOMODE_HELPERS
 
+config DRM_PANEL_EDP_LVDS
+	tristate "support for eDP/LVDS panels"
+	depends on OF && DRM_PANEL
+	select VIDEOMODE_HELPERS
+	help
+	  DRM panel driver for direct eDP panels or LVDS connected
+	  via DP bridges, that need at most a regulator for LCD unit,
+	  a regulator for LED unit and/or enable GPIOs for LCD or LED units.
+	  Delay values can also be specified to support powerup and
+	  powerdown process.
 endmenu
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 8b92921..eaafa01 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
 obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
 obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
+obj-$(CONFIG_DRM_PANEL_EDP_LVDS) += panel-lvds.o
diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
new file mode 100644
index 0000000..2124fcb
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-lvds.c
@@ -0,0 +1,262 @@
+/*
+ * panel driver for lvds and eDP panels
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd
+ *
+ * Ajay Kumar <ajaykumar.rs@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_panel.h>
+
+struct panel_lvds {
+	struct drm_panel	base;
+	struct regulator	*backlight_fet;
+	struct regulator	*lcd_fet;
+	struct videomode	vm;
+	int			width_mm;
+	int			height_mm;
+	bool			backlight_fet_enabled;
+	bool			lcd_fet_enabled;
+	int			led_en_gpio;
+	int			lcd_en_gpio;
+	int			panel_prepare_delay;
+	int			panel_enable_delay;
+	int			panel_disable_delay;
+	int			panel_unprepare_delay;
+};
+
+static inline struct panel_lvds *to_panel(struct drm_panel *panel)
+{
+	return container_of(panel, struct panel_lvds, base);
+}
+
+static int panel_lvds_prepare(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
+		if (!lvds_panel->lcd_fet_enabled) {
+			if (regulator_enable(lvds_panel->lcd_fet))
+				DRM_ERROR("failed to enable LCD fet\n");
+			lvds_panel->lcd_fet_enabled = true;
+		}
+
+	if (gpio_is_valid(lvds_panel->lcd_en_gpio))
+		gpio_set_value(lvds_panel->lcd_en_gpio, 1);
+
+	msleep(lvds_panel->panel_prepare_delay);
+
+	return 0;
+}
+
+static int panel_lvds_enable(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
+		if (!lvds_panel->backlight_fet_enabled) {
+			if (regulator_enable(lvds_panel->backlight_fet))
+				DRM_ERROR("failed to enable LED fet\n");
+			lvds_panel->backlight_fet_enabled = true;
+		}
+
+	msleep(lvds_panel->panel_enable_delay);
+
+	if (gpio_is_valid(lvds_panel->led_en_gpio))
+		gpio_set_value(lvds_panel->led_en_gpio, 1);
+
+	return 0;
+}
+
+static int panel_lvds_disable(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (gpio_is_valid(lvds_panel->led_en_gpio))
+		gpio_set_value(lvds_panel->led_en_gpio, 0);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
+		if (lvds_panel->backlight_fet_enabled) {
+			regulator_disable(lvds_panel->backlight_fet);
+			lvds_panel->backlight_fet_enabled = false;
+		}
+
+	msleep(lvds_panel->panel_disable_delay);
+
+	return 0;
+}
+
+static int panel_lvds_unprepare(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (gpio_is_valid(lvds_panel->lcd_en_gpio))
+		gpio_set_value(lvds_panel->lcd_en_gpio, 0);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
+		if (lvds_panel->lcd_fet_enabled) {
+			regulator_disable(lvds_panel->lcd_fet);
+			lvds_panel->lcd_fet_enabled = false;
+		}
+
+	msleep(lvds_panel->panel_unprepare_delay);
+
+	return 0;
+}
+
+static int panel_lvds_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct panel_lvds *lvds_panel = to_panel(panel);
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_create(connector->dev);
+	if (!mode) {
+		DRM_ERROR("failed to create a new display mode.\n");
+		return 0;
+	}
+
+	drm_display_mode_from_videomode(&lvds_panel->vm, mode);
+	mode->width_mm = lvds_panel->width_mm;
+	mode->height_mm = lvds_panel->height_mm;
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	return 1;
+}
+
+static const struct drm_panel_funcs panel_lvds_funcs = {
+	.unprepare = panel_lvds_unprepare,
+	.disable = panel_lvds_disable,
+	.prepare = panel_lvds_prepare,
+	.enable = panel_lvds_enable,
+	.get_modes = panel_lvds_get_modes,
+};
+
+static int panel_lvds_probe(struct platform_device *pdev)
+{
+	struct panel_lvds *panel;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+
+	panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
+	if (!panel)
+		return -ENOMEM;
+
+	ret = of_get_videomode(node, &panel->vm, 0);
+	if (ret) {
+		DRM_ERROR("failed: of_get_videomode() : %d\n", ret);
+		return ret;
+	}
+
+	panel->lcd_fet = devm_regulator_get_optional(dev, "lcd_vdd");
+	if (IS_ERR(panel->lcd_fet))
+		return -EPROBE_DEFER;
+
+	panel->backlight_fet = devm_regulator_get_optional(dev, "vcd_led");
+	if (IS_ERR(panel->backlight_fet))
+		return -EPROBE_DEFER;
+
+	panel->lcd_en_gpio = of_get_named_gpio(node, "lcd-en-gpio", 0);
+	panel->led_en_gpio = of_get_named_gpio(node, "led-en-gpio", 0);
+
+	of_property_read_u32(node, "panel-width-mm", &panel->width_mm);
+	of_property_read_u32(node, "panel-height-mm", &panel->height_mm);
+
+	of_property_read_u32(node, "panel-prepare-delay",
+					&panel->panel_prepare_delay);
+	of_property_read_u32(node, "panel-enable-delay",
+					&panel->panel_enable_delay);
+	of_property_read_u32(node, "panel-disable-delay",
+					&panel->panel_disable_delay);
+	of_property_read_u32(node, "panel-unprepare-delay",
+					&panel->panel_unprepare_delay);
+
+	if (gpio_is_valid(panel->lcd_en_gpio)) {
+		ret = devm_gpio_request_one(dev, panel->lcd_en_gpio,
+					GPIOF_OUT_INIT_LOW, "lcd_en_gpio");
+		if (ret) {
+			DRM_ERROR("failed to get lcd-en gpio [%d]\n", ret);
+			return 0;
+		}
+	} else {
+		panel->lcd_en_gpio = -ENODEV;
+	}
+
+	if (gpio_is_valid(panel->led_en_gpio)) {
+		ret = devm_gpio_request_one(dev, panel->led_en_gpio,
+					GPIOF_OUT_INIT_LOW, "led_en_gpio");
+		if (ret) {
+			DRM_ERROR("failed to get led-en gpio [%d]\n", ret);
+			return 0;
+		}
+	} else {
+		panel->led_en_gpio = -ENODEV;
+	}
+
+	drm_panel_init(&panel->base);
+	panel->base.dev = dev;
+	panel->base.funcs = &panel_lvds_funcs;
+
+	ret = drm_panel_add(&panel->base);
+	if (ret < 0)
+		return ret;
+
+	dev_set_drvdata(dev, panel);
+
+	return 0;
+}
+
+static int panel_lvds_remove(struct platform_device *pdev)
+{
+	struct panel_lvds *panel = dev_get_drvdata(&pdev->dev);
+
+	panel_lvds_disable(&panel->base);
+	panel_lvds_unprepare(&panel->base);
+
+	drm_panel_remove(&panel->base);
+
+	return 0;
+}
+
+static const struct of_device_id lvds_panel_dt_match[] = {
+	{ .compatible = "panel-lvds" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, lvds_panel_dt_match);
+
+struct platform_driver lvds_panel_driver = {
+	.driver = {
+		.name = "panel_lvds",
+		.owner = THIS_MODULE,
+		.of_match_table = lvds_panel_dt_match,
+	},
+	.probe = panel_lvds_probe,
+	.remove = panel_lvds_remove,
+};
+module_platform_driver(lvds_panel_driver);
+
+MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
+MODULE_DESCRIPTION("lvds/eDP panel driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5