[PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha BN]

Provide a small convenience wrapper that set/get the
display brightness value

Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>

---
v1:
 *tested in nexus7 2nd gen.

v2:
 * implemented jani review comments
   -functions name mapped accordingly
   -bl value increased from 0xff to 0xffff
   -backlight interface will be handled in panel driver,
    so it is moved from the mipi_dsi helper function
---
 drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  4 ++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 49311fc..2c03784 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1041,6 +1041,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
 
+/**
+ * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+				brightness, sizeof(*brightness));
+	if (err < 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+
+/**
+ * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
+ * the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness)
+{
+	ssize_t err;
+	u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
+
+	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 bl_value, sizeof(bl_value));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
+
 static int mipi_dsi_drv_probe(struct device *dev)
 {
 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 72f5b15..4d77bb0 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -270,6 +270,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
 			     enum mipi_dsi_dcs_tear_mode mode);
 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness);
 
 /**
  * struct mipi_dsi_driver - DSI driver
-- 
1.9.1

[PATCH v6 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Vinay Simha BN]

Add support for the JDI LT070ME05000 WUXGA DSI panel used in
Nexus 7 2013 devices.

Programming sequence for the panel is was originally found in the
android-msm-flo-3.4-lollipop-release branch from:
    https://android.googlesource.com/kernel/msm.git

And video mode setting is from dsi-panel-jdi-dualmipi1-video.dtsi
file in:
    git://codeaurora.org/kernel/msm-3.10.git  LNX.LA.3.6_rb1.27

Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>

---
v1:
 * sumit ported to drm/panel framework, john cherry-picked to mainline,
   folded down other fixes from Vinay and Archit, vinay removed interface
   setting cmd mode, video mode panel selected
v2:
 * incorporated code reviews from theiry, archit
   code style, alphabetical soring in Makefile, Kconfig, regulator_bulk,
   arrays of u8, generic helper function, documentation bindings,

v3:
 * dcs backlight support added
 * tested this panel driver in nexus7 2013 device

v4:
 * backlight interface added in the panel driver
 * incorporated width_mm and height_mm suggested by rob herring

v5:
 * theirry review comments incorporated
   panel model naming consistent, alphabetical soring in Kconfig
   Makefile, MAX_BRIGHTNESS dropped, regulator_names, parameterize
   panel width and height, descprition for control display, cabc
   and interface setting, temporary variable removed, consistent
   error reporting and commit message
 * removed tear on/off, scanline, since these are required only
   for command mode panels

v6:
 * emil review comments incorporated
   PANEL_NUM_REGULATORS dropped, return ret added at necessary
   places, if checks dropped for backlight and gpios
---
 drivers/gpu/drm/panel/Kconfig                  |  11 +
 drivers/gpu/drm/panel/Makefile                 |   1 +
 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c | 494 +++++++++++++++++++++++++
 3 files changed, 506 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 1500ab9..62aba97 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -18,6 +18,17 @@ config DRM_PANEL_SIMPLE
 	  that it can be automatically turned off when the panel goes into a
 	  low power state.
 
+config DRM_PANEL_JDI_LT070ME05000
+	tristate "JDI LT070ME05000 WUXGA DSI panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for JDI DSI video mode
+	  panel as found in Google Nexus 7 (2013) devices.
+	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
+	  24 bit per pixel.
+
 config DRM_PANEL_SAMSUNG_LD9040
 	tristate "Samsung LD9040 RGB/SPI panel"
 	depends on OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index f277eed..a5c7ec0 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
+obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
diff --git a/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c b/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c
new file mode 100644
index 0000000..3213025
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c
@@ -0,0 +1,494 @@
+/*
+ * Copyright (C) 2016 InforceComputing
+ * Author: Vinay Simha BN <simhavcs@gmail.com>
+ *
+ * Copyright (C) 2016 Linaro Ltd
+ * Author: Sumit Semwal <sumit.semwal@linaro.org>
+ *
+ * From internet archives, the panel for Nexus 7 2nd Gen, 2013 model is a
+ * JDI model LT070ME05000, and its data sheet is at:
+ * http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+
+#include <video/mipi_display.h>
+
+static const char * const regulator_names[] = {
+	"vddp",
+	"dcdc_en",
+	"vcc"
+};
+
+struct jdi_panel {
+	struct drm_panel base;
+	struct mipi_dsi_device *dsi;
+
+	struct regulator_bulk_data supplies[3];
+
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *enable_gpio;
+	struct backlight_device *backlight;
+
+	bool prepared;
+	bool enabled;
+
+	const struct drm_display_mode *mode;
+};
+
+static inline struct jdi_panel *to_jdi_panel(struct drm_panel *panel)
+{
+	return container_of(panel, struct jdi_panel, base);
+}
+
+static int jdi_panel_init(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	int ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_soft_reset(dsi);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(10000, 20000);
+
+	ret = mipi_dsi_dcs_set_pixel_format(dsi, MIPI_DCS_PIXEL_FMT_24BIT << 4);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_set_column_address(dsi, 0, jdi->mode->hdisplay - 1);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_set_page_address(dsi, 0, jdi->mode->vdisplay - 1);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * BIT(5) BCTRL = 1 Backlight Control Block On, Brightness registers
+	 *                  are active
+	 * BIT(3) BL = 1    Backlight Control On
+	 * BIT(2) DD = 0    Display Dimming is Off
+	 */
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+				 (u8[]){ 0x24 }, 1);
+	if (ret < 0)
+		return ret;
+
+	/* CABC off */
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_POWER_SAVE,
+				 (u8[]){ 0x00 }, 1);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+	if (ret < 0)
+		return ret;
+
+	msleep(120);
+
+	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x00}, 2);
+	if (ret < 0)
+		return ret;
+
+	mdelay(10);
+
+	/* Interface setting, video mode */
+	ret = mipi_dsi_generic_write(dsi, (u8[])
+				     {0xB3, 0x26, 0x08, 0x00, 0x20, 0x00}, 6);
+	if (ret < 0)
+		return ret;
+
+	mdelay(20);
+
+	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x03}, 2);
+
+	return ret;
+}
+
+static int jdi_panel_on(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	int ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_on(dsi);
+
+	return ret;
+}
+
+static int jdi_panel_off(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_off(dsi);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+
+	msleep(100);
+
+	return ret;
+}
+
+static int jdi_panel_disable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+
+	if (!jdi->enabled)
+		return 0;
+
+	jdi->backlight->props.power = FB_BLANK_POWERDOWN;
+	backlight_update_status(jdi->backlight);
+
+	jdi->enabled = false;
+
+	return 0;
+}
+
+static int jdi_panel_unprepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	if (!jdi->prepared)
+		return 0;
+
+	ret = jdi_panel_off(jdi);
+	if (ret) {
+		dev_err(panel->dev, "failed to set panel off: %d\n", ret);
+		return ret;
+	}
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
+	if (ret < 0)
+		dev_err(dev, "regulator disable failed, %d\n", ret);
+
+	gpiod_set_value(jdi->reset_gpio, 0);
+
+	gpiod_set_value(jdi->enable_gpio, 0);
+
+	jdi->prepared = false;
+
+	return ret;
+}
+
+static int jdi_panel_prepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	if (jdi->prepared)
+		return 0;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
+	if (ret < 0) {
+		dev_err(dev, "regulator enable failed, %d\n", ret);
+		return ret;
+	}
+
+	msleep(20);
+
+	if (jdi->reset_gpio) {
+		gpiod_set_value(jdi->reset_gpio, 1);
+		usleep_range(10, 20);
+	}
+
+	if (jdi->enable_gpio) {
+		gpiod_set_value(jdi->enable_gpio, 1);
+		usleep_range(10, 20);
+	}
+
+	ret = jdi_panel_init(jdi);
+	if (ret < 0) {
+		dev_err(panel->dev, "failed to init panel: %d\n", ret);
+		goto poweroff;
+	}
+
+	ret = jdi_panel_on(jdi);
+	if (ret < 0) {
+		dev_err(panel->dev, "failed to set panel on: %d\n", ret);
+		goto poweroff;
+	}
+
+	jdi->prepared = true;
+
+	return 0;
+
+poweroff:
+	gpiod_set_value(jdi->enable_gpio, 0);
+	gpiod_set_value(jdi->reset_gpio, 0);
+
+	return ret;
+}
+
+static int jdi_panel_enable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+
+	if (jdi->enabled)
+		return 0;
+
+	jdi->backlight->props.power = FB_BLANK_UNBLANK;
+	backlight_update_status(jdi->backlight);
+
+	jdi->enabled = true;
+
+	return 0;
+}
+
+static const struct drm_display_mode default_mode = {
+		.clock = 155493,
+		.hdisplay = 1200,
+		.hsync_start = 1200 + 48,
+		.hsync_end = 1200 + 48 + 32,
+		.htotal = 1200 + 48 + 32 + 60,
+		.vdisplay = 1920,
+		.vsync_start = 1920 + 3,
+		.vsync_end = 1920 + 3 + 5,
+		.vtotal = 1920 + 3 + 5 + 6,
+		.vrefresh = 60,
+		.flags = 0,
+};
+
+static int jdi_panel_get_modes(struct drm_panel *panel)
+{
+	struct drm_display_mode *mode;
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+
+	mode = drm_mode_duplicate(panel->drm, &default_mode);
+	if (!mode) {
+		dev_err(dev, "failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			default_mode.vrefresh);
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	drm_mode_probed_add(panel->connector, mode);
+
+	panel->connector->display_info.width_mm = 95;
+	panel->connector->display_info.height_mm = 151;
+
+	return 1;
+}
+
+static int dsi_dcs_bl_get_brightness(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	int ret;
+	u16 brightness = bl->props.brightness;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_get_display_brightness(dsi, &brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return brightness & 0xff;
+}
+
+static int dsi_dcs_bl_update_status(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_brightness(dsi, bl->props.brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct backlight_ops dsi_bl_ops = {
+	.update_status = dsi_dcs_bl_update_status,
+	.get_brightness = dsi_dcs_bl_get_brightness,
+};
+
+struct backlight_device *
+drm_panel_create_dsi_backlight(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct backlight_properties props;
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.brightness = 255;
+	props.max_brightness = 255;
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+					      &dsi_bl_ops, &props);
+}
+
+static const struct drm_panel_funcs jdi_panel_funcs = {
+	.disable = jdi_panel_disable,
+	.unprepare = jdi_panel_unprepare,
+	.prepare = jdi_panel_prepare,
+	.enable = jdi_panel_enable,
+	.get_modes = jdi_panel_get_modes,
+};
+
+static const struct of_device_id jdi_of_match[] = {
+	{ .compatible = "jdi,lt070me05000", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, jdi_of_match);
+
+static int jdi_panel_add(struct jdi_panel *jdi)
+{
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+	unsigned int i;
+
+	jdi->mode = &default_mode;
+
+	for (i = 0; i < ARRAY_SIZE(jdi->supplies); i++)
+		jdi->supplies[i].supply = regulator_names[i];
+
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(jdi->supplies),
+				      jdi->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to init regulator, ret=%d\n", ret);
+		return ret;
+	}
+
+	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->reset_gpio)) {
+		ret = PTR_ERR(jdi->reset_gpio);
+		dev_err(dev, "cannot get reset-gpios %d\n", ret);
+		return ret;
+	}
+
+	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->enable_gpio)) {
+		ret = PTR_ERR(jdi->enable_gpio);
+		dev_err(dev, "cannot get enable-gpio %d\n", ret);
+		return ret;
+	}
+
+	jdi->backlight = drm_panel_create_dsi_backlight(jdi->dsi);
+	if (IS_ERR(jdi->backlight)) {
+		ret = PTR_ERR(jdi->backlight);
+		dev_err(dev, "failed to register backlight %d\n", ret);
+		return ret;
+	}
+
+	drm_panel_init(&jdi->base);
+	jdi->base.funcs = &jdi_panel_funcs;
+	jdi->base.dev = &jdi->dsi->dev;
+
+	ret = drm_panel_add(&jdi->base);
+
+	return ret;
+}
+
+static void jdi_panel_del(struct jdi_panel *jdi)
+{
+	if (jdi->base.dev)
+		drm_panel_remove(&jdi->base);
+}
+
+static int jdi_panel_probe(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi;
+	int ret;
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags =  MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
+			   MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+	jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
+	if (!jdi)
+		return -ENOMEM;
+
+	mipi_dsi_set_drvdata(dsi, jdi);
+
+	jdi->dsi = dsi;
+
+	ret = jdi_panel_add(jdi);
+	if (ret < 0)
+		return ret;
+
+	return mipi_dsi_attach(dsi);
+}
+
+static int jdi_panel_remove(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+	int ret;
+
+	ret = jdi_panel_disable(&jdi->base);
+	if (ret < 0)
+		dev_err(&dsi->dev, "failed to disable panel: %d\n", ret);
+
+	ret = mipi_dsi_detach(dsi);
+	if (ret < 0)
+		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n",
+			ret);
+
+	drm_panel_detach(&jdi->base);
+	jdi_panel_del(jdi);
+
+	return 0;
+}
+
+static void jdi_panel_shutdown(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+
+	jdi_panel_disable(&jdi->base);
+}
+
+static struct mipi_dsi_driver jdi_panel_driver = {
+	.driver = {
+		.name = "panel-jdi-lt070me05000",
+		.of_match_table = jdi_of_match,
+	},
+	.probe = jdi_panel_probe,
+	.remove = jdi_panel_remove,
+	.shutdown = jdi_panel_shutdown,
+};
+module_mipi_dsi_driver(jdi_panel_driver);
+
+MODULE_AUTHOR("Sumit Semwal <sumit.semwal@linaro.org>");
+MODULE_AUTHOR("Vinay Simha BN <simhavcs@gmail.com>");
+MODULE_DESCRIPTION("JDI LT070ME05000 WUXGA");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

Re: [PATCH v6 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Emil Velikov]

Hi Vinay,

On 17 June 2016 at 19:23, Vinay Simha BN <simhavcs@gmail.com> wrote:

> v6:
>  * emil review comments incorporated
>    PANEL_NUM_REGULATORS dropped, return ret added at necessary
>    places, if checks dropped for backlight and gpios

Looks like some of my suggestions went below the radar. Did you miss
them or I've I lost the plot somewhere ? In case of the latter don't
be shy to point out :-)


> +struct jdi_panel {
> +       struct drm_panel base;
> +       struct mipi_dsi_device *dsi;
> +
> +       struct regulator_bulk_data supplies[3];
> +
struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];


> +static int jdi_panel_off(struct jdi_panel *jdi)
> +{
> +       struct mipi_dsi_device *dsi = jdi->dsi;
> +       int ret;
> +
> +       dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +       ret = mipi_dsi_dcs_set_display_off(dsi);
> +       if (ret < 0)
> +               return ret;
> +
IMHO neither this function nor its caller jdi_panel_unprepare() should
stop in the middle/return prematurely.

Or in other words - one should change the function return type to void
and drop the returns.


> +static int jdi_panel_unprepare(struct drm_panel *panel)
> +{
> +       struct jdi_panel *jdi = to_jdi_panel(panel);
> +       struct device *dev = &jdi->dsi->dev;
> +       int ret;
> +
> +       if (!jdi->prepared)
> +               return 0;
> +
> +       ret = jdi_panel_off(jdi);
> +       if (ret) {
> +               dev_err(panel->dev, "failed to set panel off: %d\n", ret);
> +               return ret;
As suggested above, drop this return.



> +static int jdi_panel_prepare(struct drm_panel *panel)
> +{
> +       struct jdi_panel *jdi = to_jdi_panel(panel);
> +       struct device *dev = &jdi->dsi->dev;
> +       int ret;
> +
> +       if (jdi->prepared)
> +               return 0;
> +
> +       ret = regulator_bulk_enable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
> +       if (ret < 0) {
> +               dev_err(dev, "regulator enable failed, %d\n", ret);
> +               return ret;
> +       }
> +
> +       msleep(20);
> +
> +       if (jdi->reset_gpio) {
You can drop the check.

> +               gpiod_set_value(jdi->reset_gpio, 1);
> +               usleep_range(10, 20);
> +       }
> +
> +       if (jdi->enable_gpio) {
Ditto.


> +
> +poweroff:
> +       gpiod_set_value(jdi->enable_gpio, 0);
> +       gpiod_set_value(jdi->reset_gpio, 0);
> +
Just noticed that you're missing regulator_bulk_disable() here.


Regards,
Emil

Re: [PATCH v6 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Vinay Simha]

On Sat, Jun 18, 2016 at 5:58 AM, Emil Velikov <emil.l.velikov@gmail.com> wrote:
> Hi Vinay,
>
> On 17 June 2016 at 19:23, Vinay Simha BN <simhavcs@gmail.com> wrote:
>
>> v6:
>>  * emil review comments incorporated
>>    PANEL_NUM_REGULATORS dropped, return ret added at necessary
>>    places, if checks dropped for backlight and gpios
>
> Looks like some of my suggestions went below the radar. Did you miss
> them or I've I lost the plot somewhere ? In case of the latter don't
> be shy to point out :-)
>
>
>> +struct jdi_panel {
>> +       struct drm_panel base;
>> +       struct mipi_dsi_device *dsi;
>> +
>> +       struct regulator_bulk_data supplies[3];
>> +
> struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];
>
>
>> +static int jdi_panel_off(struct jdi_panel *jdi)
>> +{
>> +       struct mipi_dsi_device *dsi = jdi->dsi;
>> +       int ret;
>> +
>> +       dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>> +
>> +       ret = mipi_dsi_dcs_set_display_off(dsi);
>> +       if (ret < 0)
>> +               return ret;
>> +
> IMHO neither this function nor its caller jdi_panel_unprepare() should
> stop in the middle/return prematurely.
>
> Or in other words - one should change the function return type to void
> and drop the returns.
>
>
>> +static int jdi_panel_unprepare(struct drm_panel *panel)
>> +{
>> +       struct jdi_panel *jdi = to_jdi_panel(panel);
>> +       struct device *dev = &jdi->dsi->dev;
>> +       int ret;
>> +
>> +       if (!jdi->prepared)
>> +               return 0;
>> +
>> +       ret = jdi_panel_off(jdi);
>> +       if (ret) {
>> +               dev_err(panel->dev, "failed to set panel off: %d\n", ret);
>> +               return ret;
> As suggested above, drop this return.
>
i can make the function void for jdi_panel_off  and drop the return,
but i cannot make void for jdi_panel_unprepare,
since drm_panel_prepare requires 0 or negative value.


* call to drm_panel_prepare().
 *
 * Return: 0 on success or a negative error code on failure.
 */
static inline int drm_panel_unprepare(struct drm_panel *panel)
{
        if (panel && panel->funcs && panel->funcs->unprepare)
                return panel->funcs->unprepare(panel);

        return panel ? -ENOSYS : -EINVAL;
}

>
>
>> +static int jdi_panel_prepare(struct drm_panel *panel)
>> +{
>> +       struct jdi_panel *jdi = to_jdi_panel(panel);
>> +       struct device *dev = &jdi->dsi->dev;
>> +       int ret;
>> +
>> +       if (jdi->prepared)
>> +               return 0;
>> +
>> +       ret = regulator_bulk_enable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
>> +       if (ret < 0) {
>> +               dev_err(dev, "regulator enable failed, %d\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       msleep(20);
>> +
>> +       if (jdi->reset_gpio) {
> You can drop the check.
>
>> +               gpiod_set_value(jdi->reset_gpio, 1);
>> +               usleep_range(10, 20);
>> +       }
>> +
>> +       if (jdi->enable_gpio) {
> Ditto.
>
>
>> +
>> +poweroff:
>> +       gpiod_set_value(jdi->enable_gpio, 0);
>> +       gpiod_set_value(jdi->reset_gpio, 0);
>> +
> Just noticed that you're missing regulator_bulk_disable() here.
>
>
> Regards,
> Emil



-- 
Regards,

Vinay Simha.B.N.

Re: [PATCH v6 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Emil Velikov]

On 18 June 2016 at 07:59, Vinay Simha <simhavcs@gmail.com> wrote:
> On Sat, Jun 18, 2016 at 5:58 AM, Emil Velikov <emil.l.velikov@gmail.com> wrote:
>> Hi Vinay,
>>
>> On 17 June 2016 at 19:23, Vinay Simha BN <simhavcs@gmail.com> wrote:
>>
>>> v6:
>>>  * emil review comments incorporated
>>>    PANEL_NUM_REGULATORS dropped, return ret added at necessary
>>>    places, if checks dropped for backlight and gpios
>>
>> Looks like some of my suggestions went below the radar. Did you miss
>> them or I've I lost the plot somewhere ? In case of the latter don't
>> be shy to point out :-)
>>
>>
>>> +struct jdi_panel {
>>> +       struct drm_panel base;
>>> +       struct mipi_dsi_device *dsi;
>>> +
>>> +       struct regulator_bulk_data supplies[3];
>>> +
>> struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];
>>
>>
>>> +static int jdi_panel_off(struct jdi_panel *jdi)
>>> +{
>>> +       struct mipi_dsi_device *dsi = jdi->dsi;
>>> +       int ret;
>>> +
>>> +       dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>>> +
>>> +       ret = mipi_dsi_dcs_set_display_off(dsi);
>>> +       if (ret < 0)
>>> +               return ret;
>>> +
>> IMHO neither this function nor its caller jdi_panel_unprepare() should
>> stop in the middle/return prematurely.
>>
>> Or in other words - one should change the function return type to void
>> and drop the returns.
>>
>>
>>> +static int jdi_panel_unprepare(struct drm_panel *panel)
>>> +{
>>> +       struct jdi_panel *jdi = to_jdi_panel(panel);
>>> +       struct device *dev = &jdi->dsi->dev;
>>> +       int ret;
>>> +
>>> +       if (!jdi->prepared)
>>> +               return 0;
>>> +
>>> +       ret = jdi_panel_off(jdi);
>>> +       if (ret) {
>>> +               dev_err(panel->dev, "failed to set panel off: %d\n", ret);
>>> +               return ret;
>> As suggested above, drop this return.
>>
> i can make the function void for jdi_panel_off  and drop the return,
> but i cannot make void for jdi_panel_unprepare,
> since drm_panel_prepare requires 0 or negative value.
>
Seems like I wasn't clear enough - all you want here is to drop the
spurious return.

Regards,
Emil

Re: [PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha]

hi,

Any further comments or reviews?

On Mon, Jun 20, 2016 at 11:23 AM, Vinay Simha BN <simhavcs@gmail.com> wrote:
> Provide a small convenience wrapper that set/get the
> display brightness value
>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Archit Taneja <archit.taneja@gmail.com>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
> ---
> v1:
>  *tested in nexus7 2nd gen.
>
> v2:
>  * implemented jani review comments
>    -functions name mapped accordingly
>    -bl value increased from 0xff to 0xffff
>    -backlight interface will be handled in panel driver,
>     so it is moved from the mipi_dsi helper function
> ---
>  drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_mipi_dsi.h     |  4 ++++
>  2 files changed, 53 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> index 49311fc..2c03784 100644
> --- a/drivers/gpu/drm/drm_mipi_dsi.c
> +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> @@ -1041,6 +1041,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
>  }
>  EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
>
> +/**
> + * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
> + * of the display
> + * @dsi: DSI peripheral device
> + * @brightness: brightness value
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
> +                                       u16 *brightness)
> +{
> +       ssize_t err;
> +
> +       err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
> +                               brightness, sizeof(*brightness));
> +       if (err < 0) {
> +               if (err == 0)
> +                       err = -ENODATA;
> +
> +               return err;
> +       }
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
> +
> +/**
> + * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
> + * the display
> + * @dsi: DSI peripheral device
> + * @brightness: brightness value
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
> +                                       u16 brightness)
> +{
> +       ssize_t err;
> +       u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
> +
> +       err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
> +                                bl_value, sizeof(bl_value));
> +       if (err < 0)
> +               return err;
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
> +
>  static int mipi_dsi_drv_probe(struct device *dev)
>  {
>         struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index 72f5b15..4d77bb0 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -270,6 +270,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
>  int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
>                              enum mipi_dsi_dcs_tear_mode mode);
>  int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
> +int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
> +                                       u16 *brightness);
> +int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
> +                                       u16 brightness);
>
>  /**
>   * struct mipi_dsi_driver - DSI driver
> --
> 2.1.2
>



-- 
Regards,

Vinay Simha.B.N.

[PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha BN]

Provide a small convenience wrapper that set/get the
display brightness value

Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
---
v1:
 *tested in nexus7 2nd gen.

v2:
 * implemented jani review comments
   -functions name mapped accordingly
   -bl value increased from 0xff to 0xffff
   -backlight interface will be handled in panel driver,
    so it is moved from the mipi_dsi helper function
---
 drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  4 ++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 49311fc..2c03784 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1041,6 +1041,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
 
+/**
+ * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+				brightness, sizeof(*brightness));
+	if (err < 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+
+/**
+ * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
+ * the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness)
+{
+	ssize_t err;
+	u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
+
+	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 bl_value, sizeof(bl_value));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
+
 static int mipi_dsi_drv_probe(struct device *dev)
 {
 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 72f5b15..4d77bb0 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -270,6 +270,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
 			     enum mipi_dsi_dcs_tear_mode mode);
 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness);
 
 /**
  * struct mipi_dsi_driver - DSI driver
-- 
2.1.2

[PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha BN]

Provide a small convenience wrapper that set/get the
display brightness value

Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>

---
v1:
 *tested in nexus7 2nd gen.

v2:
 * implemented jani review comments
   -functions name mapped accordingly
   -bl value increased from 0xff to 0xffff
   -backlight interface will be handled in panel driver,
    so it is moved from the mipi_dsi helper function
---
 drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  4 ++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 49311fc..2c03784 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1041,6 +1041,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
 
+/**
+ * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+				brightness, sizeof(*brightness));
+	if (err < 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+
+/**
+ * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
+ * the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness)
+{
+	ssize_t err;
+	u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
+
+	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 bl_value, sizeof(bl_value));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
+
 static int mipi_dsi_drv_probe(struct device *dev)
 {
 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 72f5b15..4d77bb0 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -270,6 +270,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
 			     enum mipi_dsi_dcs_tear_mode mode);
 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness);
 
 /**
  * struct mipi_dsi_driver - DSI driver
-- 
1.9.1

[PATCH v2 1/2] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha BN]

Provide a small convenience wrapper that set/get the
display brightness value

Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>

--
v1:
 *tested in nexus7 2nd gen.

v2:
 * implemented jani review comments
   -functions name mapped accordingly
   -bl value increased from 0xff to 0xffff
   -backlight interface will be handled in panel driver,
    so it is moved from the mipi_dsi helper function
---
 drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  4 ++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 7938ce7..5661a00 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1025,6 +1025,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
 
+/**
+ * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+				brightness, sizeof(*brightness));
+	if (err < 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+
+/**
+ * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
+ * the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness)
+{
+	ssize_t err;
+	u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
+
+	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 bl_value, sizeof(bl_value));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
+
 static int mipi_dsi_drv_probe(struct device *dev)
 {
 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index ec55285..4494641 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -268,6 +268,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
 			     enum mipi_dsi_dcs_tear_mode mode);
 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness);
 
 /**
  * struct mipi_dsi_driver - DSI driver
-- 
2.1.2