[RFC 2/3] drm/panel: Add simple panel support

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Add a driver for simple panels. Such panels can have a regulator that
provides the supply voltage and a separate GPIO to enable the panel.
Optionally the panels can have a backlight associated with them so it
can be enabled or disabled according to the panel's power management
mode.

Support is added for three panels: An AU Optronics 10.1" WSVGA, a
Chunghwa Picture Tubes 10.1" WXGA and a Panasonic 10.1 WUXGA TFT LCD
panel.

Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 .../devicetree/bindings/panel/panel-simple.txt     |  25 ++
 drivers/gpu/drm/Makefile                           |   1 +
 drivers/gpu/drm/panel/Kconfig                      |  13 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 drivers/gpu/drm/panel/panel-simple.c               | 335 +++++++++++++++++++++
 5 files changed, 375 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/panel/panel-simple.txt
 create mode 100644 drivers/gpu/drm/panel/Makefile
 create mode 100644 drivers/gpu/drm/panel/panel-simple.c

diff --git a/Documentation/devicetree/bindings/panel/panel-simple.txt b/Documentation/devicetree/bindings/panel/panel-simple.txt
new file mode 100644
index 0000000..dfd4b76
--- /dev/null
+++ b/Documentation/devicetree/bindings/panel/panel-simple.txt
@@ -0,0 +1,25 @@
+Simple display panel
+
+Required properties:
+- compatible: should be one of:
+  - "auo,b101aw03": AU Optronics Corporation 10.1" WSVGA TFT LCD panel
+  - "cptt,claa101wb03": Chunghwa Picture Tubes Ltd. 10.1" WXGA TFT LCD panel
+  - "pc,vvx10f004b00": Panasonic Corporation 10.1" WUXGA TFT LCD panel
+
+Optional properties:
+- ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
+- power-supply: regulator to provide the supply voltage
+- enable-gpios: GPIO pin to enable or disable the panel
+- backlight: phandle of the backlight device attached to the panel
+
+Example:
+
+	panel: panel {
+		compatible = "cptt,claa101wb01";
+		ddc-i2c-bus = <&panelddc>;
+
+		power-supply = <&vdd_pnl_reg>;
+		enable-gpios = <&gpio 90 0>;
+
+		backlight = <&backlight>;
+	};
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 9b009c7..764a5ec 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_DRM_TILCDC)	+= tilcdc/
 obj-$(CONFIG_DRM_QXL) += qxl/
 obj-$(CONFIG_DRM_MSM) += msm/
 obj-y			+= i2c/
+obj-y			+= panel/
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 2ddd5bd..843087b 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -2,3 +2,16 @@ menuconfig DRM_PANEL
 	bool "DRM panel support"
 	help
 	  Panel registration and lookup framework.
+
+if DRM_PANEL
+
+config DRM_PANEL_SIMPLE
+	bool "support for simple panels"
+	depends on OF
+	help
+	  DRM panel driver for dumb panels that need at most a regulator and
+	  a GPIO to be powered up. Optionally a backlight can be attached so
+	  that it can be automatically turned off when the panel goes into a
+	  low power state.
+
+endif
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
new file mode 100644
index 0000000..af9dfa2
--- /dev/null
+++ b/drivers/gpu/drm/panel/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
new file mode 100644
index 0000000..e38cd6f
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/backlight.h>
+#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 <drm/drm_crtc.h>
+#include <drm/drm_panel.h>
+
+struct panel_desc {
+	const struct drm_display_mode *modes;
+	unsigned int num_modes;
+
+	struct {
+		unsigned int width;
+		unsigned int height;
+	} size;
+};
+
+struct panel_simple {
+	struct drm_panel base;
+
+	const struct panel_desc *desc;
+
+	struct backlight_device *backlight;
+	struct regulator *supply;
+
+	unsigned long enable_gpio_flags;
+	int enable_gpio;
+};
+
+static inline struct panel_simple *to_panel_simple(struct drm_panel *panel)
+{
+	return container_of(panel, struct panel_simple, base);
+}
+
+static void panel_simple_dpms(struct drm_panel *panel, int mode)
+{
+	struct panel_simple *p = to_panel_simple(panel);
+	int err;
+
+	if (mode == DRM_MODE_DPMS_ON) {
+		if (p->supply) {
+			err = regulator_enable(p->supply);
+			if (err < 0)
+				dev_err(panel->dev,
+					"failed to enable supply: %d\n",
+					err);
+		}
+
+		if (gpio_is_valid(p->enable_gpio)) {
+			if (p->enable_gpio_flags & GPIO_ACTIVE_LOW)
+				gpio_set_value(p->enable_gpio, 0);
+			else
+				gpio_set_value(p->enable_gpio, 1);
+		}
+	}
+
+	if (p->backlight) {
+		if (mode != DRM_MODE_DPMS_ON)
+			p->backlight->props.power = FB_BLANK_POWERDOWN;
+		else
+			p->backlight->props.power = FB_BLANK_UNBLANK;
+
+		backlight_update_status(p->backlight);
+	}
+
+	if (mode == DRM_MODE_DPMS_OFF) {
+		if (gpio_is_valid(p->enable_gpio)) {
+			if (p->enable_gpio_flags & GPIO_ACTIVE_LOW)
+				gpio_set_value(p->enable_gpio, 1);
+			else
+				gpio_set_value(p->enable_gpio, 0);
+		}
+
+		if (p->supply)
+			regulator_disable(p->supply);
+	}
+}
+
+static int panel_simple_get_modes(struct drm_panel *panel)
+{
+	struct panel_simple *p = to_panel_simple(panel);
+	struct drm_display_mode *mode;
+	unsigned int i;
+
+	for (i = 0; i < p->desc->num_modes; i++) {
+		mode = drm_mode_duplicate(panel->drm, &p->desc->modes[i]);
+		if (!mode)
+			return -ENOMEM;
+
+		drm_mode_set_name(mode);
+
+		drm_mode_probed_add(panel->connector, mode);
+	}
+
+	return p->desc->num_modes;
+}
+
+static const struct drm_panel_funcs panel_simple_funcs = {
+	.dpms = panel_simple_dpms,
+	.get_modes = panel_simple_get_modes,
+};
+
+static const struct drm_display_mode auo_b101aw03_mode = {
+	.clock = 51450,
+	.hdisplay = 1024,
+	.hsync_start = 1024 + 156,
+	.hsync_end = 1024 + 156 + 8,
+	.htotal = 1024 + 156 + 8 + 156,
+	.vdisplay = 600,
+	.vsync_start = 600 + 16,
+	.vsync_end = 600 + 16 + 6,
+	.vtotal = 600 + 16 + 6 + 16,
+	.vrefresh = 60,
+};
+
+static const struct panel_desc auo_b101aw03 = {
+	.modes = &auo_b101aw03_mode,
+	.num_modes = 1,
+	.size = {
+		.width = 223,
+		.height = 125,
+	},
+};
+
+static const struct drm_display_mode chunghwa_claa101wb01_mode = {
+	.clock = 69300,
+	.hdisplay = 1366,
+	.hsync_start = 1366 + 48,
+	.hsync_end = 1366 + 48 + 32,
+	.htotal = 1366 + 48 + 32 + 20,
+	.vdisplay = 768,
+	.vsync_start = 768 + 16,
+	.vsync_end = 768 + 16 + 8,
+	.vtotal = 768 + 16 + 8 + 16,
+	.vrefresh = 60,
+};
+
+static const struct panel_desc chunghwa_claa101wb01 = {
+	.modes = &chunghwa_claa101wb01_mode,
+	.num_modes = 1,
+	.size = {
+		.width = 223,
+		.height = 125,
+	},
+};
+
+static const struct drm_display_mode panasonic_vvx10f004b00_mode = {
+	.clock = 154700,
+	.hdisplay = 1920,
+	.hsync_start = 1920 + 154,
+	.hsync_end = 1920 + 154 + 16,
+	.htotal = 1920 + 154 + 16 + 32,
+	.vdisplay = 1200,
+	.vsync_start = 1200 + 17,
+	.vsync_end = 1200 + 17 + 2,
+	.vtotal = 1200 + 17 + 2 + 16,
+	.vrefresh = 60,
+};
+
+static const struct panel_desc panasonic_vvx10f004b00 = {
+	.modes = &panasonic_vvx10f004b00_mode,
+	.num_modes = 1,
+	.size = {
+		.width = 217,
+		.height = 136,
+	},
+};
+
+static const struct of_device_id panel_simple_of_match[] = {
+	{
+		.compatible = "auo,b101aw03",
+		.data = &auo_b101aw03,
+	}, {
+		.compatible = "cptt,claa101wb01",
+		.data = &chunghwa_claa101wb01
+	}, {
+		.compatible = "pc,vvx10f004b00",
+		.data = &panasonic_vvx10f004b00
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, panel_simple_of_match);
+
+static int panel_simple_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *id;
+	struct device_node *backlight;
+	struct panel_simple *panel;
+	enum of_gpio_flags flags;
+	int err;
+
+	panel = devm_kzalloc(&pdev->dev, sizeof(*panel), GFP_KERNEL);
+	if (!panel)
+		return -ENOMEM;
+
+	id = of_match_node(panel_simple_of_match, pdev->dev.of_node);
+	if (!id)
+		return -ENODEV;
+
+	panel->desc = id->data;
+
+	panel->supply = devm_regulator_get_optional(&pdev->dev, "power");
+	if (IS_ERR(panel->supply)) {
+		if (PTR_ERR(panel->supply) != -ENODEV) {
+			dev_err(&pdev->dev, "failed to get regulator: %ld\n",
+				PTR_ERR(panel->supply));
+			return PTR_ERR(panel->supply);
+		}
+
+		panel->supply = NULL;
+	}
+
+	panel->enable_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
+						     "enable-gpios", 0,
+						     &flags);
+	if (gpio_is_valid(panel->enable_gpio)) {
+		unsigned int value;
+
+		if (flags & OF_GPIO_ACTIVE_LOW)
+			panel->enable_gpio_flags |= GPIO_ACTIVE_LOW;
+
+		err = gpio_request(panel->enable_gpio, "enable");
+		if (err < 0) {
+			dev_err(&pdev->dev, "failed to request GPIO#%u: %d\n",
+				panel->enable_gpio, err);
+			return err;
+		}
+
+		value = (panel->enable_gpio_flags & GPIO_ACTIVE_LOW) != 0;
+
+		err = gpio_direction_output(panel->enable_gpio, value);
+		if (err < 0) {
+			dev_err(&pdev->dev, "failed to setup GPIO%u: %d\n",
+				panel->enable_gpio, err);
+			goto free_gpio;
+		}
+	}
+
+	backlight = of_parse_phandle(pdev->dev.of_node, "backlight", 0);
+	if (backlight) {
+		panel->backlight = of_find_backlight_by_node(backlight);
+		if (!panel->backlight) {
+			err = -EPROBE_DEFER;
+			goto free_gpio;
+		}
+
+		of_node_put(backlight);
+	}
+
+	drm_panel_init(&panel->base);
+	panel->base.dev = &pdev->dev;
+	panel->base.funcs = &panel_simple_funcs;
+
+	err = drm_panel_add(&panel->base);
+	if (err < 0)
+		goto free_gpio;
+
+	platform_set_drvdata(pdev, panel);
+
+	return 0;
+
+free_gpio:
+	if (gpio_is_valid(panel->enable_gpio))
+		gpio_free(panel->enable_gpio);
+
+	return err;
+}
+
+static int panel_simple_remove(struct platform_device *pdev)
+{
+	struct panel_simple *panel = platform_get_drvdata(pdev);
+
+	if (gpio_is_valid(panel->enable_gpio)) {
+		if (panel->enable_gpio_flags & GPIO_ACTIVE_LOW)
+			gpio_set_value(panel->enable_gpio, 1);
+		else
+			gpio_set_value(panel->enable_gpio, 0);
+
+		gpio_free(panel->enable_gpio);
+	}
+
+	if (panel->supply)
+		regulator_disable(panel->supply);
+
+	if (panel->backlight)
+		put_device(&panel->backlight->dev);
+
+	drm_panel_detach(&panel->base);
+	drm_panel_remove(&panel->base);
+
+	return 0;
+}
+
+static struct platform_driver panel_simple_driver = {
+	.driver = {
+		.name = "panel-simple",
+		.owner = THIS_MODULE,
+		.of_match_table = panel_simple_of_match,
+	},
+	.probe = panel_simple_probe,
+	.remove = panel_simple_remove,
+};
+module_platform_driver(panel_simple_driver);
+
+MODULE_DESCRIPTION("DRM Driver for Simple Panels");
+MODULE_AUTHOR("Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>");
+MODULE_LICENSE("GPL v2");
-- 
1.8.4