[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 v5 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>
[sumit.semwal: Ported to the drm/panel framework]
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
[jstultz: Cherry-picked to mainline, folded down other fixes
 from Vinay and Archit]
Signed-off-by: John Stultz <john.stultz@linaro.org>
[vinay simha bn: removed interface setting cmd mode, video
mode panel setting selection]
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>

---
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
---
 drivers/gpu/drm/panel/Kconfig                  |  11 +
 drivers/gpu/drm/panel/Makefile                 |   1 +
 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c | 515 +++++++++++++++++++++++++
 3 files changed, 527 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..e935a63
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c
@@ -0,0 +1,515 @@
+/*
+ * 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>
+
+#define PANEL_NUM_REGULATORS   3
+
+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[PANEL_NUM_REGULATORS];
+
+	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);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+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);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+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);
+	if (ret < 0)
+		return ret;
+
+	msleep(100);
+
+	return 0;
+}
+
+static int jdi_panel_disable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+
+	if (!jdi->enabled)
+		return 0;
+
+	if (jdi->backlight) {
+		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);
+		return ret;
+	}
+
+	if (jdi->reset_gpio)
+		gpiod_set_value(jdi->reset_gpio, 0);
+
+	if (jdi->enable_gpio)
+		gpiod_set_value(jdi->enable_gpio, 0);
+
+	jdi->prepared = false;
+
+	return 0;
+}
+
+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) {
+		dev_err(panel->dev, "failed to init panel: %d\n", ret);
+		goto poweroff;
+	}
+
+	ret = jdi_panel_on(jdi);
+	if (ret) {
+		dev_err(panel->dev, "failed to set panel on: %d\n", ret);
+		goto poweroff;
+	}
+
+	jdi->prepared = true;
+
+	return 0;
+
+poweroff:
+	if (jdi->reset_gpio)
+		gpiod_set_value(jdi->reset_gpio, 0);
+	if (jdi->enable_gpio)
+		gpiod_set_value(jdi->enable_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;
+
+	if (jdi->backlight) {
+		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 < PANEL_NUM_REGULATORS; 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)) {
+		dev_err(dev, "cannot get reset-gpios %ld\n",
+			PTR_ERR(jdi->reset_gpio));
+		jdi->reset_gpio = NULL;
+	} else {
+		gpiod_direction_output(jdi->reset_gpio, 0);
+	}
+
+	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->enable_gpio)) {
+		dev_err(dev, "cannot get enable-gpio %ld\n",
+			PTR_ERR(jdi->enable_gpio));
+		jdi->enable_gpio = NULL;
+	} else {
+		gpiod_direction_output(jdi->enable_gpio, 0);
+	}
+
+	jdi->backlight = drm_panel_create_dsi_backlight(jdi->dsi);
+	if (!jdi->backlight)
+		return -EPROBE_DEFER;
+
+	drm_panel_init(&jdi->base);
+	jdi->base.funcs = &jdi_panel_funcs;
+	jdi->base.dev = &jdi->dsi->dev;
+
+	ret = drm_panel_add(&jdi->base);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+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 v5 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Emil Velikov]

Hi Vinay,

I belive I've spotted a few issues. If my understanding is correct,
then I'll defer to Thierry if he'd like them fixed here, or as
follow-ups.

On 16 June 2016 at 04:00, Vinay Simha BN <simhavcs@gmail.com> wrote:


> +#define PANEL_NUM_REGULATORS   3
> +
Nit: #define PANEL_NUM_REGULATORS ARRAY_SIZE(regulator_names) or just
drop the extra define and use the latter directly ?


> +static int jdi_panel_init(struct jdi_panel *jdi)
> +{


> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
Nit: The above three lines can become one - "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);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
Ditto.


> +static int jdi_panel_disable(struct drm_panel *panel)
> +{
> +       struct jdi_panel *jdi = to_jdi_panel(panel);
> +
> +       if (!jdi->enabled)
> +               return 0;
> +
Thinking out loud:

Thierry,
Shouldn't we fold 'enabled' and 'prepared' in struct drm_panel and
tweak the helpers respectively ? Is there any specific reason for
keeping these in the drivers ?


> +       if (jdi->backlight) {
We seems to be bailing out of jdi_panel_add() when this is NULL. Thus
we can omit the check.



> +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);
> +               return ret;
> +       }
> +
Since we cannot recover from most/all of the above I'm thinking if one
shouldn't drop the "return ret" lines. Same goes for jdi_panel_off().


> +       if (jdi->reset_gpio)
> +               gpiod_set_value(jdi->reset_gpio, 0);
> +
> +       if (jdi->enable_gpio)
Drop these two checks. The gpios are required, thus one should bail
out in jdi_panel_add()



> +static int jdi_panel_prepare(struct drm_panel *panel)
> +{

> +       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);
> +       }
> +


> +poweroff:
> +       if (jdi->reset_gpio)
> +               gpiod_set_value(jdi->reset_gpio, 0);
> +       if (jdi->enable_gpio)
> +               gpiod_set_value(jdi->enable_gpio, 0);
> +
Generic suggestion/nitpick: Please keep the teardown order the inverse
of the setup one. In here one could/should handle enable_gpio first
and then reset_gpio.

> +       return ret;
> +}
> +
> +static int jdi_panel_enable(struct drm_panel *panel)
> +{
> +       struct jdi_panel *jdi = to_jdi_panel(panel);
> +
> +       if (jdi->enabled)
> +               return 0;
> +
> +       if (jdi->backlight) {
Analogous to jdi_panel_disable - drop the check ?



> +static int jdi_panel_add(struct jdi_panel *jdi)
> +{


> +       jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +       if (IS_ERR(jdi->reset_gpio)) {
> +               dev_err(dev, "cannot get reset-gpios %ld\n",
> +                       PTR_ERR(jdi->reset_gpio));
> +               jdi->reset_gpio = NULL;
> +       } else {
> +               gpiod_direction_output(jdi->reset_gpio, 0);
> +       }
> +
> +       jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
> +       if (IS_ERR(jdi->enable_gpio)) {
> +               dev_err(dev, "cannot get enable-gpio %ld\n",
> +                       PTR_ERR(jdi->enable_gpio));
> +               jdi->enable_gpio = NULL;
> +       } else {
> +               gpiod_direction_output(jdi->enable_gpio, 0);
> +       }
> +
As mentioned above - since these two are required, thus we should
error out of this function. Right ?

> +       jdi->backlight = drm_panel_create_dsi_backlight(jdi->dsi);
> +       if (!jdi->backlight)
> +               return -EPROBE_DEFER;
> +
> +       drm_panel_init(&jdi->base);
> +       jdi->base.funcs = &jdi_panel_funcs;
> +       jdi->base.dev = &jdi->dsi->dev;
> +
> +       ret = drm_panel_add(&jdi->base);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
return ret;

Regards,
Emil

Re: [PATCH v5 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Thierry Reding]

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On Thu, Jun 16, 2016 at 06:02:53PM +0100, Emil Velikov wrote:
> On 16 June 2016 at 04:00, Vinay Simha BN <simhavcs@gmail.com> wrote:
[...]
> > +static int jdi_panel_disable(struct drm_panel *panel)
> > +{
> > +       struct jdi_panel *jdi = to_jdi_panel(panel);
> > +
> > +       if (!jdi->enabled)
> > +               return 0;
> > +
> Thinking out loud:
> 
> Thierry,
> Shouldn't we fold 'enabled' and 'prepared' in struct drm_panel and
> tweak the helpers respectively ? Is there any specific reason for
> keeping these in the drivers ?

Yes, I think that would make sense eventually. It's clearly a recurring
pattern. Ideally nothing would be calling these functions more than once
and thereby making the checks unnecessary. In practice that may mean
that we need to put the variables and checks into the drm/panel core
because display drivers (as opposed to a sane core implementation) call
these. I suppose we could encourage proper usage by adding a couple of
WARNs here and there if expectations aren't met.

I don't think doing this is terribly urgent because it's easy to rip out
of drivers once the drm/panel core supports it. And it's something that
we could even leave within drivers when the core supports it, so trivial
to remove one by one after the core patches have landed.

Thierry

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Re: [PATCH v5 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Daniel Vetter]

On Mon, Jul 11, 2016 at 02:29:37PM +0200, Thierry Reding wrote:
> On Thu, Jun 16, 2016 at 06:02:53PM +0100, Emil Velikov wrote:
> > On 16 June 2016 at 04:00, Vinay Simha BN <simhavcs@gmail.com> wrote:
> [...]
> > > +static int jdi_panel_disable(struct drm_panel *panel)
> > > +{
> > > +       struct jdi_panel *jdi = to_jdi_panel(panel);
> > > +
> > > +       if (!jdi->enabled)
> > > +               return 0;
> > > +
> > Thinking out loud:
> > 
> > Thierry,
> > Shouldn't we fold 'enabled' and 'prepared' in struct drm_panel and
> > tweak the helpers respectively ? Is there any specific reason for
> > keeping these in the drivers ?
> 
> Yes, I think that would make sense eventually. It's clearly a recurring
> pattern. Ideally nothing would be calling these functions more than once
> and thereby making the checks unnecessary. In practice that may mean
> that we need to put the variables and checks into the drm/panel core
> because display drivers (as opposed to a sane core implementation) call
> these. I suppose we could encourage proper usage by adding a couple of
> WARNs here and there if expectations aren't met.
> 
> I don't think doing this is terribly urgent because it's easy to rip out
> of drivers once the drm/panel core supports it. And it's something that
> we could even leave within drivers when the core supports it, so trivial
> to remove one by one after the core patches have landed.

As long as we have non-atomic drm drivers using this multiple
enable/disable calls can happen. Atomic drivers should screw this up
(ignoring a few misguided ones that mix atomic and legacy helpers in bad
ways, but those are getting fixed).

I think a good plan would be:
1. Move this tracking into drm panel helpers, ditch it from all drivers.
2. Add WARN_ON for multiple enables/disables, but only for DRIVER_ATOMIC.

Makes sure we can remove this boilerplate, makes sure that atomic drivers
are consistent, leaves existing drivers unharmed.

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v5 2/2] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Thierry Reding]

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On Tue, Jul 12, 2016 at 12:34:02PM +0200, Daniel Vetter wrote:
> On Mon, Jul 11, 2016 at 02:29:37PM +0200, Thierry Reding wrote:
> > On Thu, Jun 16, 2016 at 06:02:53PM +0100, Emil Velikov wrote:
> > > On 16 June 2016 at 04:00, Vinay Simha BN <simhavcs@gmail.com> wrote:
> > [...]
> > > > +static int jdi_panel_disable(struct drm_panel *panel)
> > > > +{
> > > > +       struct jdi_panel *jdi = to_jdi_panel(panel);
> > > > +
> > > > +       if (!jdi->enabled)
> > > > +               return 0;
> > > > +
> > > Thinking out loud:
> > > 
> > > Thierry,
> > > Shouldn't we fold 'enabled' and 'prepared' in struct drm_panel and
> > > tweak the helpers respectively ? Is there any specific reason for
> > > keeping these in the drivers ?
> > 
> > Yes, I think that would make sense eventually. It's clearly a recurring
> > pattern. Ideally nothing would be calling these functions more than once
> > and thereby making the checks unnecessary. In practice that may mean
> > that we need to put the variables and checks into the drm/panel core
> > because display drivers (as opposed to a sane core implementation) call
> > these. I suppose we could encourage proper usage by adding a couple of
> > WARNs here and there if expectations aren't met.
> > 
> > I don't think doing this is terribly urgent because it's easy to rip out
> > of drivers once the drm/panel core supports it. And it's something that
> > we could even leave within drivers when the core supports it, so trivial
> > to remove one by one after the core patches have landed.
> 
> As long as we have non-atomic drm drivers using this multiple
> enable/disable calls can happen. Atomic drivers should screw this up
> (ignoring a few misguided ones that mix atomic and legacy helpers in bad
> ways, but those are getting fixed).
> 
> I think a good plan would be:
> 1. Move this tracking into drm panel helpers, ditch it from all drivers.
> 2. Add WARN_ON for multiple enables/disables, but only for DRIVER_ATOMIC.
> 
> Makes sure we can remove this boilerplate, makes sure that atomic drivers
> are consistent, leaves existing drivers unharmed.

Yeah, that sounds like a reasonable plan.

Thierry

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