[PATCH v7 0/2] drm/panel: Add panel driver for ChipWealth CH13726A based panels

[PATCH v7 0/2] drm/panel: Add panel driver for ChipWealth CH13726A based panels

[Aaron Kling via B4 Relay]

This driver is based on the one by Teguh Sobirin [0], cut down to only
support the AYN Thor bottom panel.

Due to [1], the AYN vendor description patch has been folded into the
AYN QCS8550 dt series. Which means this series now depends on said
series and it must be picked up before this.

[0] https://github.com/AYNTechnologies/linux/commit/d0ff75b09e66023c5f88992706dee4601aa7a437
[1] https://lore.kernel.org/linux-arm-msm/c7fb3f89-6574-4761-9ef2-2fdf6d4801b5@kernel.org

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
Changes in v7:
- Invert reset gpio logic and instead expect the correct active high or
  low setting in kernel dt.
- Link to v6: https://lore.kernel.org/r/20260422-ch13726a-v6-0-03680d6673ff@gmail.com

Changes in v6:
- Add trailers from v4
- Link to v5: https://lore.kernel.org/r/20260421-ch13726a-v5-0-f7f6f4f30e05@gmail.com

Changes in v5:
- Don't duplicate prepared tracking
- Use devm_regulator_bulk_get_const() instead of setting names in probe
- Use devm_drm_panel_alloc() instead of drm_panel_init()
- Link to v4: https://lore.kernel.org/r/20260408-ch13726a-v4-0-9bb1a9b8f329@gmail.com

Changes in v4:
- Add fallback compatible to bindings doc in patch 1
- Link to v3: https://lore.kernel.org/r/20260323-ch13726a-v3-0-e28b6f97fe80@gmail.com

Changes in v3:
- Reword patch 1 commit message for clarity
- Order properties properly in patch 1
- Track vendor description dependency series change
- Link to v2: https://lore.kernel.org/r/20260317-ch13726a-v2-0-28aa46bcd6d0@gmail.com

Changes in v2:
- Add Neil Armstrong to binding maintainer list
- Add 120hz mode, which required a minor restructure of the driver
- Link to v1: https://lore.kernel.org/r/20260222-ch13726a-v1-0-e501d78e105a@gmail.com

---
Aaron Kling (1):
      dt-bindings: display: panel: Add ChipWealth CH13726A AMOLED driver

Teguh Sobirin (1):
      drm/panel: Add panel driver for ChipWealth CH13726A based panels

 .../display/panel/chipwealth,ch13726a.yaml         |  67 +++++
 drivers/gpu/drm/panel/Kconfig                      |  11 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c  | 333 +++++++++++++++++++++
 4 files changed, 412 insertions(+)
---
base-commit: 7080e32d3f09d8688c4a87d81bdcc71f7f606b16
change-id: 20260220-ch13726a-59c6678d53d8
prerequisite-change-id: 20260217-ayn-qcs8550-16c07b63de26:v5
prerequisite-patch-id: 2b010637c46f5ea0e19a2fa87cc5ccb19bfd9204
prerequisite-patch-id: d0c633dc17f0aba726a8e8d21fee52b944bf67ff
prerequisite-patch-id: 76ac126273870a96f05e1bd87f4f31bdc3746440
prerequisite-patch-id: 76b61799dba520fc7fa3ff39b044e24103337af3
prerequisite-patch-id: 3844bef2eda3cf59031b1d131eb6ba9295629bb4
prerequisite-patch-id: 3331648bc6f4ac3bb156f0525aa1ede92bfc57f1

Best regards,
-- 
Aaron Kling <webgeek1234@gmail.com>

[PATCH v7 1/2] dt-bindings: display: panel: Add ChipWealth CH13726A AMOLED driver

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

The Chip Wealth Technology CH13726A AMOLED driver is a single chip
solution for MIPI-DSI. This is used for the AYN Thor bottom panel.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 .../display/panel/chipwealth,ch13726a.yaml         | 67 ++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/chipwealth,ch13726a.yaml b/Documentation/devicetree/bindings/display/panel/chipwealth,ch13726a.yaml
new file mode 100644
index 00000000000000..c8d7b61037e622
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/chipwealth,ch13726a.yaml
@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/chipwealth,ch13726a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Chip Wealth Technology CH13726A AMOLED driver
+
+maintainers:
+  - Neil Armstrong <neil.armstrong@linaro.org>
+
+description:
+  Chip Wealth Technology CH13726A is a single-chip solution
+  for AMOLED connected using a MIPI-DSI video interface.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    items:
+      - const: ayntec,thor-panel-bottom
+      - const: chipwealth,ch13726a
+
+  reg:
+    maxItems: 1
+    description: DSI virtual channel
+
+  vdd-supply: true
+  vddio-supply: true
+  vdd1v2-supply: true
+  avdd-supply: true
+
+  port: true
+  reset-gpios: true
+  rotation: true
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+  - vddio-supply
+  - vdd1v2-supply
+  - avdd-supply
+  - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        panel@0 {
+            compatible = "ayntec,thor-panel-bottom", "chipwealth,ch13726a";
+            reg = <0>;
+            vdd1v2-supply = <&vreg_l11b_1p2>;
+            vddio-supply = <&vdd_disp_1v8>;
+            vdd-supply = <&vreg_l13b_3p0>;
+            avdd-supply = <&vdd_disp2_2v8>;
+            reset-gpios = <&tlmm 133 GPIO_ACTIVE_HIGH>;
+        };
+    };
+
+...

-- 
2.53.0

Claude review: dt-bindings: display: panel: Add ChipWealth CH13726A AMOLED driver

[Claude Code Review Bot]

Patch Review

**Status: Looks good.** Already has `Reviewed-by: Krzysztof Kozlowski`.

The binding is well-structured — it properly references `panel-common.yaml`, uses a two-entry compatible with a device-specific and chip-level fallback, lists all four supply properties, and the example is valid. No issues found.

---

---
Generated by Claude Code Patch Reviewer

[PATCH v7 2/2] drm/panel: Add panel driver for ChipWealth CH13726A based panels

[Aaron Kling via B4 Relay]

From: Teguh Sobirin <teguh@sobir.in>

This is used by the AYN Thor for the bottom panel.

Signed-off-by: Teguh Sobirin <teguh@sobir.in>
Co-developed-by: Aaron Kling <webgeek1234@gmail.com>
Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/panel/Kconfig                     |  11 +
 drivers/gpu/drm/panel/Makefile                    |   1 +
 drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c | 333 ++++++++++++++++++++++
 3 files changed, 345 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index d6863b28ddc559..e2c00f08f4507d 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -105,6 +105,17 @@ config DRM_PANEL_BOE_TV101WUM_LL2
 	  Say Y here if you want to support for BOE TV101WUM-LL2
 	  WUXGA PANEL DSI Video Mode panel
 
+config DRM_PANEL_CHIPWEALTH_CH13726A
+	tristate "CHIPWEALTH CH13726A-based DSI panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
+	help
+	  Say Y here if you want to enable support for ChipWealth
+	  CH13726A-based display panels.
+
 config DRM_PANEL_EBBG_FT8719
 	tristate "EBBG FT8719 panel driver"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index a4291dc3905bed..343d283d1620fb 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_DRM_PANEL_BOE_TD4320) += panel-boe-td4320.o
 obj-$(CONFIG_DRM_PANEL_BOE_TH101MB31UIG002_28A) += panel-boe-th101mb31ig002-28a.o
 obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_LL2) += panel-boe-tv101wum-ll2.o
 obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_NL6) += panel-boe-tv101wum-nl6.o
+obj-$(CONFIG_DRM_PANEL_CHIPWEALTH_CH13726A) += panel-chipwealth-ch13726a.o
 obj-$(CONFIG_DRM_PANEL_DSI_CM) += panel-dsi-cm.o
 obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
diff --git a/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c b/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c
new file mode 100644
index 00000000000000..be76bc825c3fd2
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ChipWealth CH13726A MIPI-DSI panel driver
+ * Copyright (c) 2024, Teguh Sobirin <teguh@sobir.in>.
+ */
+
+#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 <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#include <video/mipi_display.h>
+
+static const struct regulator_bulk_data ch13726a_supplies[] = {
+	{ .supply = "vdd1v2", },
+	{ .supply = "vddio", },
+	{ .supply = "vdd", },
+	{ .supply = "avdd", },
+};
+
+struct ch13726a_panel {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+	struct ch13726a_desc *desc;
+	enum drm_panel_orientation orientation;
+};
+
+struct ch13726a_desc {
+	unsigned int width_mm;
+	unsigned int height_mm;
+	unsigned int bpc;
+
+	const struct drm_display_mode *modes;
+	unsigned int num_modes;
+};
+
+static inline struct ch13726a_panel *to_ch13726a_panel(struct drm_panel *panel)
+{
+	return container_of(panel, struct ch13726a_panel, panel);
+}
+
+static void ch13726a_reset(struct ch13726a_panel *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+	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 int ch13726a_on(struct ch13726a_panel *ctx)
+{
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	ctx->dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_generic_write_seq_multi(&dsi_ctx, 0xf0, 0x50);
+	mipi_dsi_generic_write_seq_multi(&dsi_ctx, 0xb9, 0x00);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
+
+	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
+
+	return dsi_ctx.accum_err;
+}
+
+static int ch13726a_disable(struct drm_panel *panel)
+{
+	struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
+	mipi_dsi_msleep(&dsi_ctx, 50);
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
+
+	return dsi_ctx.accum_err;
+}
+
+static int ch13726a_prepare(struct drm_panel *panel)
+{
+	struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+	struct device *dev = &ctx->dsi->dev;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ch13726a_supplies), ctx->supplies);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	ch13726a_reset(ctx);
+
+	ret = ch13726a_on(ctx);
+	if (ret < 0) {
+		dev_err(dev, "Failed to initialize panel: %d\n", ret);
+		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+		regulator_bulk_disable(ARRAY_SIZE(ch13726a_supplies), ctx->supplies);
+		return ret;
+	}
+
+	msleep(28);
+
+	return 0;
+}
+
+static int ch13726a_unprepare(struct drm_panel *panel)
+{
+	struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(ch13726a_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static const struct drm_display_mode thor_bottom_modes[] = {
+	{
+		/* 120Hz */
+		.clock = (1080 + 28 + 4 + 36) * (1240 + 16 + 4 + 8) * 120 / 1000,
+		.hdisplay = 1080,
+		.hsync_start = 1080 + 28,
+		.hsync_end = 1080 + 28 + 4,
+		.htotal = 1080 + 28 + 4 + 36,
+		.vdisplay = 1240,
+		.vsync_start = 1240 + 16,
+		.vsync_end = 1240 + 16 + 4,
+		.vtotal = 1240 + 16 + 4 + 8,
+	},
+	{
+		/* 60Hz */
+		.clock = (1080 + 28 + 4 + 36) * (1240 + 16 + 4 + 8) * 60 / 1000,
+		.hdisplay = 1080,
+		.hsync_start = 1080 + 28,
+		.hsync_end = 1080 + 28 + 4,
+		.htotal = 1080 + 28 + 4 + 36,
+		.vdisplay = 1240,
+		.vsync_start = 1240 + 16,
+		.vsync_end = 1240 + 16 + 4,
+		.vtotal = 1240 + 16 + 4 + 8,
+	}
+};
+
+static struct ch13726a_desc thor_bottom_desc = {
+	.modes = thor_bottom_modes,
+	.num_modes = ARRAY_SIZE(thor_bottom_modes),
+	.width_mm = 65,
+	.height_mm = 75,
+	.bpc = 8,
+};
+
+static int ch13726a_get_modes(struct drm_panel *panel,
+					struct drm_connector *connector)
+{
+	struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+	for (uint8_t i = 0; i < ctx->desc->num_modes; i++) {
+		const struct drm_display_mode *m = &ctx->desc->modes[i];
+		struct drm_display_mode *mode;
+
+		mode = drm_mode_duplicate(connector->dev, m);
+		if (!mode) {
+			dev_err(&ctx->dsi->dev, "failed to add mode %ux%u@%u\n",
+				m->hdisplay, m->vdisplay, drm_mode_vrefresh(m));
+			return -ENOMEM;
+		}
+
+		mode->type = DRM_MODE_TYPE_DRIVER;
+		if (i == 0)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+		drm_mode_set_name(mode);
+		drm_mode_probed_add(connector, mode);
+	}
+
+	connector->display_info.width_mm = ctx->desc->width_mm;
+	connector->display_info.height_mm = ctx->desc->height_mm;
+	connector->display_info.bpc = ctx->desc->bpc;
+
+	return ctx->desc->num_modes;
+}
+
+static enum drm_panel_orientation ch13726a_get_orientation(struct drm_panel *panel)
+{
+	struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+	return ctx->orientation;
+}
+
+static const struct drm_panel_funcs ch13726a_panel_funcs = {
+	.prepare = ch13726a_prepare,
+	.unprepare = ch13726a_unprepare,
+	.disable = ch13726a_disable,
+	.get_modes = ch13726a_get_modes,
+	.get_orientation = ch13726a_get_orientation,
+};
+
+static int ch13726a_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(dsi, brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct backlight_ops ch13726a_bl_ops = {
+	.update_status = ch13726a_bl_update_status,
+};
+
+static struct backlight_device *
+ch13726a_create_backlight(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	const struct backlight_properties props = {
+		.type = BACKLIGHT_RAW,
+		.brightness = 255,
+		.max_brightness = 255,
+	};
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+					      &ch13726a_bl_ops, &props);
+}
+
+static int ch13726a_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct ch13726a_panel *ctx;
+	int ret;
+
+	ctx = devm_drm_panel_alloc(dev, __typeof(*ctx), panel,
+				   &ch13726a_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ctx->desc = (struct ch13726a_desc *)of_device_get_match_data(dev);
+	if (!ctx->desc)
+		return -ENODEV;
+
+	ret = devm_regulator_bulk_get_const(dev,
+					    ARRAY_SIZE(ch13726a_supplies),
+					    ch13726a_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-gpios\n");
+
+	ret = of_drm_get_panel_orientation(dev->of_node, &ctx->orientation);
+	if (ret < 0) {
+		dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
+		return ret;
+	}
+
+	ctx->dsi = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
+			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+	ctx->panel.prepare_prev_first = true;
+
+	ctx->panel.backlight = ch13726a_create_backlight(dsi);
+	if (IS_ERR(ctx->panel.backlight))
+		return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
+				     "Failed to create backlight\n");
+
+	drm_panel_add(&ctx->panel);
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0) {
+		dev_err(dev, "Failed to attach to DSI host: %d\n", ret);
+		drm_panel_remove(&ctx->panel);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ch13726a_remove(struct mipi_dsi_device *dsi)
+{
+	struct ch13726a_panel *ctx = mipi_dsi_get_drvdata(dsi);
+	int ret;
+
+	ret = mipi_dsi_detach(dsi);
+	if (ret < 0)
+		dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
+
+	drm_panel_remove(&ctx->panel);
+}
+
+static const struct of_device_id ch13726a_of_match[] = {
+	{ .compatible = "ayntec,thor-panel-bottom", .data = &thor_bottom_desc },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ch13726a_of_match);
+
+static struct mipi_dsi_driver ch13726a_driver = {
+	.probe = ch13726a_probe,
+	.remove = ch13726a_remove,
+	.driver = {
+		.name = "panel-ch13726a-amoled",
+		.of_match_table = ch13726a_of_match,
+	},
+};
+module_mipi_dsi_driver(ch13726a_driver);
+
+MODULE_DESCRIPTION("DRM driver for CH13726A DSI panels");
+MODULE_LICENSE("GPL");

-- 
2.53.0

Claude review: drm/panel: Add panel driver for ChipWealth CH13726A based panels

[Claude Code Review Bot]

Patch Review

**Issue 1 (Kconfig): Unnecessary DP helper selections**

```c
select DRM_DISPLAY_DP_HELPER
select DRM_DISPLAY_HELPER
```

This is a pure MIPI-DSI panel. The only other panel drivers that `select DRM_DISPLAY_DP_HELPER` are eDP panels (Samsung ATNA33XC20, simple eDP). Comparable MIPI-DSI panel drivers like `DRM_PANEL_BOE_TD4320` select neither of these. Both `select` lines should be removed — the driver doesn't use any display helper or DP helper APIs.

**Issue 2 (const-correctness): `desc` pointer and `thor_bottom_desc` should be const**

The descriptor struct is declared as:

```c
struct ch13726a_desc *desc;
```

and `thor_bottom_desc` is:

```c
static struct ch13726a_desc thor_bottom_desc = {
```

Since `of_device_get_match_data()` returns `const void *`, the current cast discards const:

```c
ctx->desc = (struct ch13726a_desc *)of_device_get_match_data(dev);
```

The field should be `const struct ch13726a_desc *desc`, the variable should be `static const struct ch13726a_desc thor_bottom_desc`, and the cast should be `(const struct ch13726a_desc *)` (or better, dropped entirely since C allows implicit conversion from `const void *` to `const T *`).

**Issue 3 (style): `uint8_t` loop variable in `get_modes`**

```c
for (uint8_t i = 0; i < ctx->desc->num_modes; i++) {
```

Kernel convention is to use `unsigned int` or `int` for loop counters, not fixed-width types. `unsigned int` would match the type of `num_modes`.

**Issue 4 (style): `__typeof(*ctx)` in `devm_drm_panel_alloc`**

```c
ctx = devm_drm_panel_alloc(dev, __typeof(*ctx), panel,
                           &ch13726a_panel_funcs,
                           DRM_MODE_CONNECTOR_DSI);
```

While functionally correct, all other panel drivers pass the struct name directly:

```c
ctx = devm_drm_panel_alloc(dev, struct ch13726a_panel, panel,
                           &ch13726a_panel_funcs,
                           DRM_MODE_CONNECTOR_DSI);
```

**Observation (not a blocker): `of_drm_get_panel_orientation` error path**

```c
ret = of_drm_get_panel_orientation(dev->of_node, &ctx->orientation);
if (ret < 0) {
    dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
    return ret;
}
```

This could use `dev_err_probe()` for consistency with the other error paths in `probe()`, which would also handle `-EPROBE_DEFER` cleanly:

```c
return dev_err_probe(dev, ret, "Failed to get orientation\n");
```

**Overall for patch 2:** The driver logic itself is solid — the reset sequence, init commands, backlight handling, and multi-rate mode support all look correct. The `mipi_dsi_multi_context` usage is clean, `prepare_prev_first = true` is properly set, and the remove path correctly detaches DSI before removing the panel. The issues above are all minor fixups.

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Generated by Claude Code Patch Reviewer

Claude review: drm/panel: Add panel driver for ChipWealth CH13726A based panels

[Claude Code Review Bot]

Overall Series Review

Subject: drm/panel: Add panel driver for ChipWealth CH13726A based panels
Author: Aaron Kling via B4 Relay <devnull+webgeek1234.gmail.com@kernel.org>
Patches: 3
Reviewed: 2026-04-28T15:10:45.632908

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This is a clean, well-structured v7 series adding a MIPI-DSI panel driver for the ChipWealth CH13726A AMOLED controller, used as the bottom panel in the AYN Thor handheld. The series is at a good level of maturity — it already carries Reviewed-by tags from DT and DRM reviewers, and uses modern APIs (`devm_drm_panel_alloc`, `devm_regulator_bulk_get_const`, `mipi_dsi_multi_context`). The issues found are minor.

The main substantive issue is the Kconfig selecting DP helpers that a MIPI-DSI panel doesn't need. The remaining items are const-correctness and minor style.

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Generated by Claude Code Patch Reviewer