[PATCH v4 0/2] drm/panel: add support for Ilitek ILI7807S DSI panels

[PATCH v4 0/2] drm/panel: add support for Ilitek ILI7807S DSI panels

[Arpit Saini]

Add DT bindings and a DRM panel driver for panels based on the Ilitek
ILI7807S display controller. The first supported panel is the DLC
DLC0697 1080x1920@60Hz MIPI DSI panel.

Changes in v4:
- Use active-low reset GPIO semantics: define reset-gpios as active-low
  in DT and use hold=1/drop=0 in the driver (Dmitry Baryshkov)
- Replace raw DCS writes with proper helpers: mipi_dsi_dcs_set_tear_on_multi(),
  MIPI_DCS_SET_CABC_MIN_BRIGHTNESS, MIPI_DCS_WRITE_CONTROL_DISPLAY,
  MIPI_DCS_WRITE_POWER_SAVE (Dmitry Baryshkov)
- Use mipi_dsi_dcs_set_display_brightness_multi() with 0x1fff initial
  brightness (Dmitry Baryshkov)
- Move MIPI_DSI_MODE_LPM to probe(), drop toggling in on()/off()
  (Dmitry Baryshkov)
- Express .clock as arithmetic expression for clarity (Dmitry Baryshkov)
- Update panel physical dimensions width_mm/height_mm (Dmitry Baryshkov)
- Link to v3: https://lore.kernel.org/r/20260624-ili7807s-v3-0-ddf37052a289@oss.qualcomm.com

Changes in v3:
- Return devm_mipi_dsi_attach() directly (Neil Armstrong)
- Link to v2: https://lore.kernel.org/all/20260618-ili7807s-v2-0-b3f0c109b102@oss.qualcomm.com/

Changes in v2:
- Drop MAINTAINERS entry (Dmitry Baryshkov)
- Use devm_drm_panel_add() instead of drm_panel_add() to avoid
  manual drm_panel_remove() in the error path (Dmitry Baryshkov)
- Rework backlight: call drm_panel_of_backlight() first and fall back
  to creating a DCS backlight device if panel->backlight is still NULL
  (Dmitry Baryshkov)
- Remove backlight-en-gpios from the binding (Dmitry Baryshkov)
- Fix mode_flags LPM not restored on backlight update error path
- Link to v1 : https://lore.kernel.org/all/20260518-ili7807s-panel-v1-0-d7b048163b1c@oss.qualcomm.com/

---
Arpit Saini (2):
      dt-bindings: display: panel: add Ilitek ILI7807S panel controller
      drm/panel: add Ilitek ILI7807S panel driver

 .../bindings/display/panel/ilitek,ili7807s.yaml    |  71 +++++
 drivers/gpu/drm/panel/Kconfig                      |  12 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 drivers/gpu/drm/panel/panel-ilitek-ili7807s.c      | 285 +++++++++++++++++++++
 4 files changed, 369 insertions(+)
---
base-commit: 4e5dfb7c84012007c3c7061126491bbc92d71bf1
change-id: 20260615-ili7807s-panel

Best regards,
-- 
Arpit Saini <arpit.saini@oss.qualcomm.com>

[PATCH v4 1/2] dt-bindings: display: panel: add Ilitek ILI7807S panel controller

[Arpit Saini]

ILI7807S is a DSI display controller used to drive MIPI-DSI panels.
The DLC DLC0697 1080x1920 LCD panel is based on this controller.

The panel requires a reset GPIO, I/O voltage supply (vddi), positive
LCD bias supply (avdd) and negative LCD bias supply (avee). The panel
operates in video burst mode with four data lanes using RGB888 pixel
format.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Arpit Saini <arpit.saini@oss.qualcomm.com>
---
 .../bindings/display/panel/ilitek,ili7807s.yaml    | 71 ++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml b/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml
new file mode 100644
index 000000000000..ba8c5bbf8ffc
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/ilitek,ili7807s.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Ilitek ILI7807S-based DSI panels
+
+maintainers:
+  - Arpit Saini <arpit.saini@oss.qualcomm.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - dlc,dlc0697
+      - const: ilitek,ili7807s
+
+  reg:
+    maxItems: 1
+    description: DSI virtual channel
+
+  vddi-supply:
+    description: I/O voltage supply (1.8V)
+
+  avdd-supply:
+    description: Positive LCD bias supply (AVDD), typically +5.5V
+      (range 4.5V to 6.3V)
+
+  avee-supply:
+    description: Negative LCD bias supply (AVEE), typically -5.5V
+      (range -6.3V to -4.5V)
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - vddi-supply
+  - avdd-supply
+  - avee-supply
+  - port
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "dlc,dlc0697", "ilitek,ili7807s";
+            reg = <0>;
+
+            reset-gpios = <&tlmm 3 GPIO_ACTIVE_LOW>;
+            vddi-supply = <&pm4125_l15>;
+            avdd-supply = <&avdd>;
+            avee-supply = <&avee>;
+
+            port {
+                panel_in: endpoint {
+                    remote-endpoint = <&dsi0_out>;
+                };
+            };
+        };
+    };

-- 
2.34.1

[PATCH v4 2/2] drm/panel: add Ilitek ILI7807S panel driver

[Arpit Saini]

Add a DRM panel driver for the DLC DLC0697 1080x1920@60Hz MIPI DSI
panel based on the Ilitek ILI7807S display controller.

The panel operates in video burst mode with four data lanes using
RGB888 pixel format.

Signed-off-by: Arpit Saini <arpit.saini@oss.qualcomm.com>
---
 drivers/gpu/drm/panel/Kconfig                 |  12 ++
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-ilitek-ili7807s.c | 285 ++++++++++++++++++++++++++
 3 files changed, 298 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 7450b27622a2..1cbaac1bf545 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -264,6 +264,18 @@ config DRM_PANEL_HYDIS_HV101HD1
 
 	  If M is selected the module will be called panel-hydis-hv101hd1
 
+config DRM_PANEL_ILITEK_ILI7807S
+	tristate "Ilitek ILI7807S-based panels"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y if you want to enable support for panels based on the
+	  Ilitek ILI7807S display controller, such as the DLC DLC0697
+	  1080x1920 MIPI DSI panel.
+
+	  If M is selected the module will be called panel-ilitek-ili7807s.
+
 config DRM_PANEL_ILITEK_IL9322
 	tristate "Ilitek ILI9322 320x240 QVGA panels"
 	depends on OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index c2c5cf817116..c3002b351cb8 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_HIMAX_HX83112B) += panel-himax-hx83112b.o
 obj-$(CONFIG_DRM_PANEL_HIMAX_HX83121A) += panel-himax-hx83121a.o
 obj-$(CONFIG_DRM_PANEL_HIMAX_HX8394) += panel-himax-hx8394.o
 obj-$(CONFIG_DRM_PANEL_HYDIS_HV101HD1) += panel-hydis-hv101hd1.o
+obj-$(CONFIG_DRM_PANEL_ILITEK_ILI7807S) += panel-ilitek-ili7807s.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_IL9322) += panel-ilitek-ili9322.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9341) += panel-ilitek-ili9341.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9805) += panel-ilitek-ili9805.o
diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
new file mode 100644
index 000000000000..12b491b0bca4
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+struct panel_desc {
+	const struct drm_display_mode *mode;
+	unsigned int lanes;
+	enum mipi_dsi_pixel_format format;
+	unsigned long mode_flags;
+	void (*init)(struct mipi_dsi_multi_context *dsi_ctx);
+};
+
+struct ili7807s {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	const struct panel_desc *desc;
+
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+};
+
+static const struct regulator_bulk_data ili7807s_supplies[] = {
+	{ .supply = "vddi" },
+	{ .supply = "avdd" },
+	{ .supply = "avee" },
+};
+
+static inline struct ili7807s *to_ili7807s(struct drm_panel *panel)
+{
+	return container_of(panel, struct ili7807s, panel);
+}
+
+static void ili7807s_reset(struct ili7807s *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(10000, 11000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+}
+
+static void dlc0697_init_sequence(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_soft_reset_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 120);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x78, 0x07, 0x00);
+	mipi_dsi_dcs_set_tear_on_multi(dsi_ctx, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_SET_CABC_MIN_BRIGHTNESS, 0x09, 0x99);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
+	mipi_dsi_dcs_set_display_brightness_multi(dsi_ctx, 0x1fff);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 120);
+
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 20);
+}
+
+static int ili7807s_on(struct ili7807s *ctx)
+{
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	ctx->desc->init(&dsi_ctx);
+
+	return dsi_ctx.accum_err;
+}
+
+static int ili7807s_off(struct ili7807s *ctx)
+{
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
+	mipi_dsi_msleep(&dsi_ctx, 20);
+
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
+	mipi_dsi_msleep(&dsi_ctx, 120);
+
+	return dsi_ctx.accum_err;
+}
+
+static int ili7807s_prepare(struct drm_panel *panel)
+{
+	struct ili7807s *ctx = to_ili7807s(panel);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
+	if (ret < 0) {
+		dev_err(ctx->panel.dev, "failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	msleep(20);
+
+	ili7807s_reset(ctx);
+
+	ret = ili7807s_on(ctx);
+	if (ret < 0) {
+		dev_err(ctx->panel.dev, "failed to initialise panel: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+
+	regulator_bulk_disable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
+	return ret;
+}
+
+static int ili7807s_unprepare(struct drm_panel *panel)
+{
+	struct ili7807s *ctx = to_ili7807s(panel);
+	int ret;
+
+	ret = ili7807s_off(ctx);
+	if (ret < 0)
+		dev_err(ctx->panel.dev, "failed to disable panel: %d\n", ret);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+
+	regulator_bulk_disable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static int ili7807s_get_modes(struct drm_panel *panel,
+			      struct drm_connector *connector)
+{
+	struct ili7807s *ctx = to_ili7807s(panel);
+
+	return drm_connector_helper_get_modes_fixed(connector, ctx->desc->mode);
+}
+
+static const struct drm_panel_funcs ili7807s_panel_funcs = {
+	.prepare = ili7807s_prepare,
+	.unprepare = ili7807s_unprepare,
+	.get_modes = ili7807s_get_modes,
+};
+
+static int ili7807s_bl_update_status(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	u16 brightness = backlight_get_brightness(bl);
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return ret;
+}
+
+static const struct backlight_ops ili7807s_bl_ops = {
+	.update_status = ili7807s_bl_update_status,
+};
+
+static struct backlight_device *ili7807s_create_backlight(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	const struct backlight_properties props = {
+		.type           = BACKLIGHT_RAW,
+		.brightness     = 0x3fff,
+		.max_brightness = 0x3fff,
+	};
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+					      &ili7807s_bl_ops, &props);
+}
+
+static const struct drm_display_mode dlc0697_mode = {
+	.clock = (1080 + 18 + 2 + 16) * (1920 + 26 + 4 + 20) * 60 / 1000,
+
+	.hdisplay    = 1080,
+	.hsync_start = 1080 + 18,
+	.hsync_end   = 1080 + 18 + 2,
+	.htotal      = 1080 + 18 + 2 + 16,
+
+	.vdisplay    = 1920,
+	.vsync_start = 1920 + 26,
+	.vsync_end   = 1920 + 26 + 4,
+	.vtotal      = 1920 + 26 + 4 + 20,
+
+	.width_mm  = 87,
+	.height_mm = 154,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+};
+
+static const struct panel_desc dlc0697_desc = {
+	.mode       = &dlc0697_mode,
+	.lanes      = 4,
+	.format     = MIPI_DSI_FMT_RGB888,
+	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST,
+	.init       = dlc0697_init_sequence,
+};
+
+static int ili7807s_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	const struct panel_desc *desc;
+	struct ili7807s *ctx;
+	int ret;
+
+	ctx = devm_drm_panel_alloc(dev, struct ili7807s, panel,
+				   &ili7807s_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	desc = of_device_get_match_data(dev);
+	ctx->desc = desc;
+
+	ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(ili7807s_supplies),
+					    ili7807s_supplies, &ctx->supplies);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get regulators\n");
+
+	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ctx->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
+				     "failed to get reset gpio\n");
+
+	ctx->dsi = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	dsi->lanes      = desc->lanes;
+	dsi->format     = desc->format;
+	dsi->mode_flags = desc->mode_flags | MIPI_DSI_MODE_LPM;
+
+	ctx->panel.prepare_prev_first = true;
+
+	ret = drm_panel_of_backlight(&ctx->panel);
+	if (ret)
+		return ret;
+
+	if (!ctx->panel.backlight) {
+		ctx->panel.backlight = ili7807s_create_backlight(dsi);
+		if (IS_ERR(ctx->panel.backlight))
+			return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
+					     "failed to create backlight\n");
+	}
+
+	ret = devm_drm_panel_add(dev, &ctx->panel);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to add panel\n");
+
+	return devm_mipi_dsi_attach(dev, dsi);
+}
+
+static const struct of_device_id ili7807s_of_match[] = {
+	{ .compatible = "dlc,dlc0697", .data = &dlc0697_desc },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ili7807s_of_match);
+
+static struct mipi_dsi_driver ili7807s_dsi_driver = {
+	.probe  = ili7807s_probe,
+	.driver = {
+		.name           = "panel-ilitek-ili7807s",
+		.of_match_table = ili7807s_of_match,
+	},
+};
+module_mipi_dsi_driver(ili7807s_dsi_driver);
+
+MODULE_AUTHOR("Arpit Saini <arpit.saini@oss.qualcomm.com>");
+MODULE_DESCRIPTION("Panel driver for Ilitek ILI7807S LCD DSI panel");
+MODULE_LICENSE("GPL");

-- 
2.34.1

Re: [PATCH v4 2/2] drm/panel: add Ilitek ILI7807S panel driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] Conflicting MIPI DCS brightness functions send payload with mismatched endianness
- [High] Incorrect devres registration order causes DSI to detach before panel teardown
- [High] Unconditional DSI hardware access in backlight update callback while panel is unpowered
- [Medium] Hardcoded brightness in initialization sequence desynchronizes physical and logical state
--

commit 225e11adf3557eed6e400ee38411cadcbb543985
Author: Arpit Saini <arpit.saini@oss.qualcomm.com>
Subject: drm/panel: add Ilitek ILI7807S panel driver

Add a DRM panel driver for the DLC DLC0697 1080x1920@60Hz MIPI DSI panel based
on the Ilitek ILI7807S display controller.

> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
[ ... ]
> +static void dlc0697_init_sequence(struct mipi_dsi_multi_context *dsi_ctx)
> +{
[ ... ]
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x78, 0x07, 0x00);
> +	mipi_dsi_dcs_set_tear_on_multi(dsi_ctx, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_SET_CABC_MIN_BRIGHTNESS, 0x09, 0x99);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
> +	mipi_dsi_dcs_set_display_brightness_multi(dsi_ctx, 0x1fff);

[Severity: Medium]
Will hardcoding the brightness to 0x1fff during initialization cause the
screen to flash at maximum brightness on system resume?

The brightness will remain maxed out until the subsequent enable path triggers
a backlight update. Does it make sense to restore the user's configured
brightness level from the backlight device here instead?

[Severity: High]
Does the panel hardware expect the 16-bit brightness payload in Little Endian
or Big Endian byte order?

This initialization sequence uses mipi_dsi_dcs_set_display_brightness_multi(),
which sends a Little Endian payload. However, the backlight update callback
ili7807s_bl_update_status() uses mipi_dsi_dcs_set_display_brightness_large(),
which sends a Big Endian payload:

ili7807s_bl_update_status() {
    ...
    ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
}

Since these serialize the value with opposite endianness, one of these paths
might send a corrupted value to the hardware, potentially causing incorrect
backlight levels or initialization failures.

[ ... ]
> +static int ili7807s_bl_update_status(struct backlight_device *bl)
> +{
> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);

[Severity: High]
Can a userspace process writing to the backlight sysfs brightness attribute
cause a DSI host timeout if the panel is currently asleep?

The backlight device is registered in ili7807s_probe() and exposed to userspace
asynchronously from the display pipeline state. Because ili7807s_bl_update_status()
transmits DCS commands without checking if the panel is actually powered on
(for example, by checking a prepared flag), attempting to communicate over the
DSI bus while unpowered can cause the host controller to wait indefinitely.

[ ... ]
> +static int ili7807s_probe(struct mipi_dsi_device *dsi)
> +{
[ ... ]
> +	ret = devm_drm_panel_add(dev, &ctx->panel);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to add panel\n");
> +
> +	return devm_mipi_dsi_attach(dev, dsi);
> +}

[Severity: High]
Could the devres registration order here cause DSI transmission errors during
driver unbind?

Since devres actions execute in LIFO order, devm_mipi_dsi_attach() will be
undone (detaching the DSI device) before devm_drm_panel_add() is undone.
When the DRM subsystem subsequently tears down the display pipeline and
invokes the panel's unprepare callback, the DCS commands sent to power down
the panel will fail because the DSI device is no longer attached to the host.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260701-ili7807s-v4-0-c7d76d4780a5@oss.qualcomm.com?part=2

Re: [PATCH v4 2/2] drm/panel: add Ilitek ILI7807S panel driver

[Neil Armstrong]

On 7/1/26 13:12, Arpit Saini wrote:
> Add a DRM panel driver for the DLC DLC0697 1080x1920@60Hz MIPI DSI
> panel based on the Ilitek ILI7807S display controller.
> 
> The panel operates in video burst mode with four data lanes using
> RGB888 pixel format.
> 
> Signed-off-by: Arpit Saini <arpit.saini@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/panel/Kconfig                 |  12 ++
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   drivers/gpu/drm/panel/panel-ilitek-ili7807s.c | 285 ++++++++++++++++++++++++++
>   3 files changed, 298 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 7450b27622a2..1cbaac1bf545 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -264,6 +264,18 @@ config DRM_PANEL_HYDIS_HV101HD1
>   
>   	  If M is selected the module will be called panel-hydis-hv101hd1
>   
> +config DRM_PANEL_ILITEK_ILI7807S
> +	tristate "Ilitek ILI7807S-based panels"
> +	depends on OF
> +	depends on DRM_MIPI_DSI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	help
> +	  Say Y if you want to enable support for panels based on the
> +	  Ilitek ILI7807S display controller, such as the DLC DLC0697
> +	  1080x1920 MIPI DSI panel.
> +
> +	  If M is selected the module will be called panel-ilitek-ili7807s.
> +
>   config DRM_PANEL_ILITEK_IL9322
>   	tristate "Ilitek ILI9322 320x240 QVGA panels"
>   	depends on OF && SPI
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index c2c5cf817116..c3002b351cb8 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_HIMAX_HX83112B) += panel-himax-hx83112b.o
>   obj-$(CONFIG_DRM_PANEL_HIMAX_HX83121A) += panel-himax-hx83121a.o
>   obj-$(CONFIG_DRM_PANEL_HIMAX_HX8394) += panel-himax-hx8394.o
>   obj-$(CONFIG_DRM_PANEL_HYDIS_HV101HD1) += panel-hydis-hv101hd1.o
> +obj-$(CONFIG_DRM_PANEL_ILITEK_ILI7807S) += panel-ilitek-ili7807s.o
>   obj-$(CONFIG_DRM_PANEL_ILITEK_IL9322) += panel-ilitek-ili9322.o
>   obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9341) += panel-ilitek-ili9341.o
>   obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9805) += panel-ilitek-ili9805.o
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
> new file mode 100644
> index 000000000000..12b491b0bca4
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili7807s.c
> @@ -0,0 +1,285 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_probe_helper.h>
> +
> +struct panel_desc {
> +	const struct drm_display_mode *mode;
> +	unsigned int lanes;
> +	enum mipi_dsi_pixel_format format;
> +	unsigned long mode_flags;
> +	void (*init)(struct mipi_dsi_multi_context *dsi_ctx);
> +};
> +
> +struct ili7807s {
> +	struct drm_panel panel;
> +	struct mipi_dsi_device *dsi;
> +	const struct panel_desc *desc;
> +
> +	struct regulator_bulk_data *supplies;
> +	struct gpio_desc *reset_gpio;
> +};
> +
> +static const struct regulator_bulk_data ili7807s_supplies[] = {
> +	{ .supply = "vddi" },
> +	{ .supply = "avdd" },
> +	{ .supply = "avee" },
> +};
> +
> +static inline struct ili7807s *to_ili7807s(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct ili7807s, panel);
> +}
> +
> +static void ili7807s_reset(struct ili7807s *ctx)
> +{
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	usleep_range(10000, 11000);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	usleep_range(10000, 11000);
> +}
> +
> +static void dlc0697_init_sequence(struct mipi_dsi_multi_context *dsi_ctx)
> +{
> +	mipi_dsi_dcs_soft_reset_multi(dsi_ctx);
> +	mipi_dsi_msleep(dsi_ctx, 120);
> +
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x78, 0x07, 0x00);
> +	mipi_dsi_dcs_set_tear_on_multi(dsi_ctx, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_SET_CABC_MIN_BRIGHTNESS, 0x09, 0x99);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
> +	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
> +	mipi_dsi_dcs_set_display_brightness_multi(dsi_ctx, 0x1fff);
> +
> +	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
> +	mipi_dsi_msleep(dsi_ctx, 120);
> +
> +	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
> +	mipi_dsi_msleep(dsi_ctx, 20);
> +}
> +
> +static int ili7807s_on(struct ili7807s *ctx)
> +{
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> +
> +	ctx->desc->init(&dsi_ctx);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int ili7807s_off(struct ili7807s *ctx)
> +{
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> +
> +	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 20);
> +
> +	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int ili7807s_prepare(struct drm_panel *panel)
> +{
> +	struct ili7807s *ctx = to_ili7807s(panel);
> +	int ret;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
> +	if (ret < 0) {
> +		dev_err(ctx->panel.dev, "failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	msleep(20);
> +
> +	ili7807s_reset(ctx);
> +
> +	ret = ili7807s_on(ctx);
> +	if (ret < 0) {
> +		dev_err(ctx->panel.dev, "failed to initialise panel: %d\n", ret);
> +		goto err;
> +	}
> +
> +	return 0;
> +
> +err:
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +
> +	regulator_bulk_disable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
> +	return ret;
> +}
> +
> +static int ili7807s_unprepare(struct drm_panel *panel)
> +{
> +	struct ili7807s *ctx = to_ili7807s(panel);
> +	int ret;
> +
> +	ret = ili7807s_off(ctx);
> +	if (ret < 0)
> +		dev_err(ctx->panel.dev, "failed to disable panel: %d\n", ret);
> +
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +
> +	regulator_bulk_disable(ARRAY_SIZE(ili7807s_supplies), ctx->supplies);
> +
> +	return 0;
> +}
> +
> +static int ili7807s_get_modes(struct drm_panel *panel,
> +			      struct drm_connector *connector)
> +{
> +	struct ili7807s *ctx = to_ili7807s(panel);
> +
> +	return drm_connector_helper_get_modes_fixed(connector, ctx->desc->mode);
> +}
> +
> +static const struct drm_panel_funcs ili7807s_panel_funcs = {
> +	.prepare = ili7807s_prepare,
> +	.unprepare = ili7807s_unprepare,
> +	.get_modes = ili7807s_get_modes,
> +};
> +
> +static int ili7807s_bl_update_status(struct backlight_device *bl)
> +{
> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	return ret;
> +}
> +
> +static const struct backlight_ops ili7807s_bl_ops = {
> +	.update_status = ili7807s_bl_update_status,
> +};
> +
> +static struct backlight_device *ili7807s_create_backlight(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	const struct backlight_properties props = {
> +		.type           = BACKLIGHT_RAW,
> +		.brightness     = 0x3fff,
> +		.max_brightness = 0x3fff,
> +	};
> +
> +	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
> +					      &ili7807s_bl_ops, &props);
> +}
> +
> +static const struct drm_display_mode dlc0697_mode = {
> +	.clock = (1080 + 18 + 2 + 16) * (1920 + 26 + 4 + 20) * 60 / 1000,
> +
> +	.hdisplay    = 1080,
> +	.hsync_start = 1080 + 18,
> +	.hsync_end   = 1080 + 18 + 2,
> +	.htotal      = 1080 + 18 + 2 + 16,
> +
> +	.vdisplay    = 1920,
> +	.vsync_start = 1920 + 26,
> +	.vsync_end   = 1920 + 26 + 4,
> +	.vtotal      = 1920 + 26 + 4 + 20,
> +
> +	.width_mm  = 87,
> +	.height_mm = 154,
> +	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
> +};
> +
> +static const struct panel_desc dlc0697_desc = {
> +	.mode       = &dlc0697_mode,
> +	.lanes      = 4,
> +	.format     = MIPI_DSI_FMT_RGB888,
> +	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST,
> +	.init       = dlc0697_init_sequence,
> +};
> +
> +static int ili7807s_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	const struct panel_desc *desc;
> +	struct ili7807s *ctx;
> +	int ret;
> +
> +	ctx = devm_drm_panel_alloc(dev, struct ili7807s, panel,
> +				   &ili7807s_panel_funcs,
> +				   DRM_MODE_CONNECTOR_DSI);
> +	if (IS_ERR(ctx))
> +		return PTR_ERR(ctx);
> +
> +	desc = of_device_get_match_data(dev);
> +	ctx->desc = desc;
> +
> +	ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(ili7807s_supplies),
> +					    ili7807s_supplies, &ctx->supplies);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to get regulators\n");
> +
> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ctx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +				     "failed to get reset gpio\n");
> +
> +	ctx->dsi = dsi;
> +	mipi_dsi_set_drvdata(dsi, ctx);
> +
> +	dsi->lanes      = desc->lanes;
> +	dsi->format     = desc->format;
> +	dsi->mode_flags = desc->mode_flags | MIPI_DSI_MODE_LPM;
> +
> +	ctx->panel.prepare_prev_first = true;
> +
> +	ret = drm_panel_of_backlight(&ctx->panel);
> +	if (ret)
> +		return ret;
> +
> +	if (!ctx->panel.backlight) {
> +		ctx->panel.backlight = ili7807s_create_backlight(dsi);
> +		if (IS_ERR(ctx->panel.backlight))
> +			return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
> +					     "failed to create backlight\n");
> +	}
> +
> +	ret = devm_drm_panel_add(dev, &ctx->panel);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to add panel\n");
> +
> +	return devm_mipi_dsi_attach(dev, dsi);
> +}
> +
> +static const struct of_device_id ili7807s_of_match[] = {
> +	{ .compatible = "dlc,dlc0697", .data = &dlc0697_desc },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, ili7807s_of_match);
> +
> +static struct mipi_dsi_driver ili7807s_dsi_driver = {
> +	.probe  = ili7807s_probe,
> +	.driver = {
> +		.name           = "panel-ilitek-ili7807s",
> +		.of_match_table = ili7807s_of_match,
> +	},
> +};
> +module_mipi_dsi_driver(ili7807s_dsi_driver);
> +
> +MODULE_AUTHOR("Arpit Saini <arpit.saini@oss.qualcomm.com>");
> +MODULE_DESCRIPTION("Panel driver for Ilitek ILI7807S LCD DSI panel");
> +MODULE_LICENSE("GPL");
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil

Re: [PATCH v4 0/2] drm/panel: add support for Ilitek ILI7807S DSI panels

[Neil Armstrong]

Hi,

On Wed, 01 Jul 2026 16:42:48 +0530, Arpit Saini wrote:
> Add DT bindings and a DRM panel driver for panels based on the Ilitek
> ILI7807S display controller. The first supported panel is the DLC
> DLC0697 1080x1920@60Hz MIPI DSI panel.
> 
> Changes in v4:
> - Use active-low reset GPIO semantics: define reset-gpios as active-low
>   in DT and use hold=1/drop=0 in the driver (Dmitry Baryshkov)
> - Replace raw DCS writes with proper helpers: mipi_dsi_dcs_set_tear_on_multi(),
>   MIPI_DCS_SET_CABC_MIN_BRIGHTNESS, MIPI_DCS_WRITE_CONTROL_DISPLAY,
>   MIPI_DCS_WRITE_POWER_SAVE (Dmitry Baryshkov)
> - Use mipi_dsi_dcs_set_display_brightness_multi() with 0x1fff initial
>   brightness (Dmitry Baryshkov)
> - Move MIPI_DSI_MODE_LPM to probe(), drop toggling in on()/off()
>   (Dmitry Baryshkov)
> - Express .clock as arithmetic expression for clarity (Dmitry Baryshkov)
> - Update panel physical dimensions width_mm/height_mm (Dmitry Baryshkov)
> - Link to v3: https://lore.kernel.org/r/20260624-ili7807s-v3-0-ddf37052a289@oss.qualcomm.com
> 
> [...]

Thanks, Applied to https://gitlab.freedesktop.org/drm/misc/kernel.git (drm-misc-next)

[1/2] dt-bindings: display: panel: add Ilitek ILI7807S panel controller
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/447a76a99e242fd04eaea33ecd9a6d73992e49a0
[2/2] drm/panel: add Ilitek ILI7807S panel driver
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/dd7ec83f456734de8efc115eac671e5add82777a

-- 
Neil