[PATCH v3 0/2] drm/panel: Add Novatek NT36536 panel driver

[PATCH v3 0/2] drm/panel: Add Novatek NT36536 panel driver

[Pengyu Luo]

Add a driver for panels using the Novatek NT36536 Display Driver IC,
including support for the CSOT PP8807HB1-1, a dual-link 10-bit panel
found in LENOVO Legion Y700 Gen4.

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
Changes in v3:
- Only include needed device-id headers (Uwe)
- Link to v2: https://lore.kernel.org/dri-devel/20260705153515.46147-1-mitltlatltl@gmail.com
Changes in v2:
- Collect tags
- Mention the CSOT PP8807HB1-1 is a dual-link panel (Krzysztof)
- Use devm_drm_panel_add() (Neil)
- Link to v1: https://lore.kernel.org/dri-devel/20260630023439.248861-1-mitltlatltl@gmail.com

Pengyu Luo (2):
  dt-bindings: display: panel: Add Novatek NT36536
  drm/panel: Add Novatek NT36536 panel driver

 .../display/panel/novatek,nt36536.yaml        |  91 ++++
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-novatek-nt36536.c | 488 ++++++++++++++++++
 4 files changed, 591 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/novatek,nt36536.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-novatek-nt36536.c

-- 
2.54.0

[PATCH v3 1/2] dt-bindings: display: panel: Add Novatek NT36536

[Pengyu Luo]

NT36536 is a driver IC used to drive MIPI-DSI panels. It is found in
LENOVO Legion Y700 Gen4 with a dual-link 10-bit CSOT panel.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
v3:
No changes.
v2:
- Collect tags
- Mention the CSOT PP8807HB1-1 is a dual-link panel (Krzysztof)
---
 .../display/panel/novatek,nt36536.yaml        | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/novatek,nt36536.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/novatek,nt36536.yaml b/Documentation/devicetree/bindings/display/panel/novatek,nt36536.yaml
new file mode 100644
index 000000000000..0862998cc6ef
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/novatek,nt36536.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/novatek,nt36536.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Novatek NT36536 based DSI display Panels
+
+maintainers:
+  - Pengyu Luo <mitltlatltl@gmail.com>
+
+description:
+  The Novatek NT36536 is a generic DSI Panel IC used to drive dsi
+  panels. Support video mode panels from China Star Optoelectronics
+  Technology (CSOT), such as PP8807HB1-1 which is a dual-link 10-bit
+  panel.
+
+allOf:
+  - $ref: panel-common-dual.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - csot,pp8807hb1-1
+      - const: novatek,nt36536
+
+  reg:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  vddio-supply:
+    description: I/O source voltage rail
+
+  vsp-supply:
+    description: Positive source voltage rail
+
+  vsn-supply:
+    description: Negative source voltage rail
+
+  backlight: true
+  ports: true
+
+required:
+  - compatible
+  - reg
+  - vddio-supply
+  - reset-gpios
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "csot,pp8807hb1-1", "novatek,nt36536";
+            reg = <0>;
+
+            vddio-supply = <&vreg_iovdd_1p8>;
+            reset-gpios = <&tlmm 98 GPIO_ACTIVE_LOW>;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+                    panel_in_0: endpoint {
+                        remote-endpoint = <&dsi0_out>;
+                    };
+                };
+
+                port@1{
+                    reg = <1>;
+                    panel_in_1: endpoint {
+                        remote-endpoint = <&dsi1_out>;
+                    };
+                };
+            };
+        };
+    };
+
+...
-- 
2.54.0

[PATCH v3 2/2] drm/panel: Add Novatek NT36536 panel driver

[Pengyu Luo]

Add a driver for panels using the Novatek NT36536 Display Driver IC,
including support for the CSOT PP8807HB1-1, a dual-link 10-bit panel
found in LENOVO Legion Y700 Gen4.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
v3:
- Only include needed device-id headers (Uwe)
v2:
- Collect tags
- Use devm_drm_panel_add() (Neil)
---
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-novatek-nt36536.c | 488 ++++++++++++++++++
 3 files changed, 500 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-novatek-nt36536.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index cfbfb371bc67..53c0b95c26ca 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -662,6 +662,17 @@ config DRM_PANEL_NOVATEK_NT36523
 	  around the Novatek NT36523 display controller, such as some
 	  Boe panels used in Xiaomi Mi Pad 5 and 5 Pro tablets.
 
+config DRM_PANEL_NOVATEK_NT36536
+	tristate "Novatek NT36536 panel driver"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_KMS_HELPER
+	help
+	  Say Y here if you want to enable support for Novatek NT36536-based
+	  display panels, such as the one found in the LENOVO Legion Y700
+	  Gen4.
+
 config DRM_PANEL_NOVATEK_NT36672A
 	tristate "Novatek NT36672A DSI panel"
 	depends on GPIOLIB
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 0f29f22f589e..3b523cf37833 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35532) += panel-novatek-nt35532.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36523) += panel-novatek-nt36523.o
+obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36536) += panel-novatek-nt36536.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672A) += panel-novatek-nt36672a.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672E) += panel-novatek-nt36672e.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37700F) += panel-novatek-nt37700f.o
diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36536.c b/drivers/gpu/drm/panel/panel-novatek-nt36536.c
new file mode 100644
index 000000000000..961bfc605b1a
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-novatek-nt36536.c
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Novatek NT36536 DriverIC panels driver
+ * Copyright (c) 2026 Pengyu Luo <mitltlatltl@gmail.com>
+ *
+ * Based on the sample code which is generated with
+ * linux-mdss-dsi-panel-driver-generator
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/device-id/of.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/display/drm_dsc.h>
+#include <drm/display/drm_dsc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+#include <video/mipi_display.h>
+
+struct novatek {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi[2];
+	const struct panel_desc *desc;
+	struct drm_dsc_config dsc;
+	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data *supplies;
+	struct backlight_device *backlight;
+};
+
+struct panel_desc {
+	unsigned int width_mm;
+	unsigned int height_mm;
+	unsigned int bpc;
+	unsigned int lanes;
+	enum mipi_dsi_pixel_format format;
+	unsigned long mode_flags;
+	const struct drm_dsc_config *dsc_cfg;
+	const struct drm_display_mode *modes;
+	unsigned int num_modes;
+
+	int (*init_sequence)(struct mipi_dsi_multi_context *dsi_ctx);
+
+	bool is_dual_dsi;
+	bool has_dcs_backlight;
+};
+
+static const struct regulator_bulk_data novatek_supplies[] = {
+	{ .supply = "vddio" },
+	{ .supply = "vsp" },
+	{ .supply = "vsn" },
+};
+
+static inline struct novatek *to_novatek(struct drm_panel *panel)
+{
+	return container_of(panel, struct novatek, panel);
+}
+
+static inline struct mipi_dsi_device *to_primary_dsi(struct novatek *ctx)
+{
+	/* Sync on DSI1 for dual dsi */
+	return ctx->desc->is_dual_dsi ? ctx->dsi[1] : ctx->dsi[0];
+}
+
+static void novatek_reset(struct novatek *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(11000, 12000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(1000, 2000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(3000, 4000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+}
+
+static int novatek_prepare(struct drm_panel *panel)
+{
+	struct novatek *ctx = to_novatek(panel);
+	struct mipi_dsi_device *dsi = to_primary_dsi(ctx);
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
+	struct drm_dsc_picture_parameter_set pps;
+	struct device *dev = &dsi->dev;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(novatek_supplies),
+				    ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	novatek_reset(ctx);
+
+	ret = ctx->desc->init_sequence(&dsi_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(novatek_supplies),
+				       ctx->supplies);
+		return ret;
+	}
+
+	drm_dsc_pps_payload_pack(&pps, &ctx->dsc);
+	mipi_dsi_picture_parameter_set_multi(&dsi_ctx, &pps);
+	mipi_dsi_compression_mode_multi(&dsi_ctx, true);
+	mipi_dsi_msleep(&dsi_ctx, 28);
+
+	return backlight_enable(ctx->backlight);
+}
+
+static int novatek_off(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_set_display_off_multi(dsi_ctx);
+	mipi_dsi_dcs_enter_sleep_mode_multi(dsi_ctx);
+
+	return dsi_ctx->accum_err;
+}
+
+static int novatek_unprepare(struct drm_panel *panel)
+{
+	struct novatek *ctx = to_novatek(panel);
+	struct mipi_dsi_device *dsi = to_primary_dsi(ctx);
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
+	struct device *dev = &dsi->dev;
+	int ret;
+
+	backlight_disable(ctx->backlight);
+
+	ret = novatek_off(&dsi_ctx);
+	if (ret < 0)
+		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(novatek_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static int novatek_get_modes(struct drm_panel *panel,
+			     struct drm_connector *connector)
+{
+	struct novatek *ctx = to_novatek(panel);
+	const struct panel_desc *desc = ctx->desc;
+	int i;
+
+	for (i = 0; i < desc->num_modes; i++) {
+		const struct drm_display_mode *m = &desc->modes[i];
+		struct drm_display_mode *mode;
+
+		mode = drm_mode_duplicate(connector->dev, m);
+		if (!mode) {
+			dev_err(panel->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 = desc->width_mm;
+	connector->display_info.height_mm = desc->height_mm;
+	connector->display_info.bpc = desc->bpc;
+
+	return desc->num_modes;
+}
+
+static const struct drm_panel_funcs novatek_panel_funcs = {
+	.prepare = novatek_prepare,
+	.unprepare = novatek_unprepare,
+	.get_modes = novatek_get_modes,
+};
+
+static int novatek_bl_update_status(struct backlight_device *bl)
+{
+	struct novatek *ctx = bl_get_data(bl);
+	u16 brightness = backlight_get_brightness(bl);
+
+	return mipi_dsi_dcs_set_display_brightness_large(to_primary_dsi(ctx),
+							 brightness);
+}
+
+static const struct backlight_ops novatek_bl_ops = {
+	.update_status = novatek_bl_update_status,
+};
+
+static struct backlight_device *novatek_create_backlight(struct novatek *ctx)
+{
+	struct mipi_dsi_device *dsi = to_primary_dsi(ctx);
+	struct device *dev = &dsi->dev;
+	const struct backlight_properties props = {
+		.type = BACKLIGHT_RAW,
+		.brightness = 512,
+		.max_brightness = 4095,
+		.scale = BACKLIGHT_SCALE_NON_LINEAR,
+	};
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, ctx,
+					      &novatek_bl_ops, &props);
+}
+
+static int csot_pp8807hb1_1_init_seq(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x20);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_SET_PARTIAL_ROWS, 0x50);
+
+	/* cabc */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x23);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x89, 0xa4);
+
+	/* pen code */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x26);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xcd, 0x8f, 0xa9, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xce, 0x8c, 0xa9, 0x00);
+
+	/* esd init */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x27);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x79, 0x22);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd0, 0x31);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd1, 0x08, 0x08);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd2, 0x08);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0xd0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x00, 0x31);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x09, 0xee);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x1c, 0x77);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x1d, 0x07);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0xe0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbb, 0x00);
+
+	/* IC transfer */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0xf0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe6, 0x02);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x10);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x3b,
+				     0x03, 0x4e, 0x1a, 0x04, 0x04, 0x01, 0x80,
+				     0x36, 0x36);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x60, 0x00);
+	/* enable DSC */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x90, 0x03, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x91,
+				     0xab, 0xa8, 0x00, 0x14, 0xd2, 0x00, 0x00,
+				     0x00, 0x01, 0xb9, 0x00, 0x06, 0x05, 0x7a,
+				     0x05, 0xb8);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x92, 0x10, 0xe0);
+	/* frame ctl */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0x91, 0x80);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb3, 0x40);
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 105);
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 40);
+
+	return dsi_ctx->accum_err;
+}
+
+static struct drm_dsc_config csot_pp8807hb1_1_dsc_cfg = {
+	.dsc_version_major = 1,
+	.dsc_version_minor = 2,
+	.slice_height = 20,
+	.slice_width = 476,
+	.slice_count = 2,
+	.bits_per_component = 10,
+	.bits_per_pixel = 8 << 4,
+	.block_pred_enable = true,
+};
+
+static const struct drm_display_mode csot_pp8807hb1_1_modes[] = {
+	/* 915552 KHz */
+	{
+		.clock = (952 + 138 + 16 + 16) * 2 * (3040 + 26 + 4 + 330) * 120 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 138) * 2,
+		.hsync_end = (952 + 138 + 16) * 2,
+		.htotal = (952 + 138 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 26,
+		.vsync_end = 3040 + 26 + 4,
+		.vtotal = 3040 + 26 + 4 + 330,
+	},
+	{
+		.clock = (952 + 138 + 16 + 16) * 2 * (3040 + 3426 + 4 + 330) * 60 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 138) * 2,
+		.hsync_end = (952 + 138 + 16) * 2,
+		.htotal = (952 + 138 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 3426,
+		.vsync_end = 3040 + 3426 + 4,
+		.vtotal = 3040 + 3426 + 4 + 330,
+	},
+	{
+		.clock = (952 + 138 + 16 + 16) * 2 * (3040 + 10226 + 4 + 330) * 30 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 138) * 2,
+		.hsync_end = (952 + 138 + 16) * 2,
+		.htotal = (952 + 138 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 10226,
+		.vsync_end = 3040 + 10226 + 4,
+		.vtotal = 3040 + 10226 + 4 + 330,
+	},
+	/* 1064606.4 KHz */
+	{
+		.clock = (952 + 50 + 16 + 16) * 2 * (3040 + 26 + 4 + 50) * 165 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 50) * 2,
+		.hsync_end = (952 + 50 + 16) * 2,
+		.htotal = (952 + 50 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 26,
+		.vsync_end = 3040 + 26 + 4,
+		.vtotal = 3040 + 26 + 4 + 50,
+	},
+	{
+		.clock = (952 + 50 + 16 + 16) * 2 * (3040 + 481 + 4 + 50) * 144 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 50) * 2,
+		.hsync_end = (952 + 50 + 16) * 2,
+		.htotal = (952 + 50 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 481,
+		.vsync_end = 3040 + 481 + 4,
+		.vtotal = 3040 + 481 + 4 + 50,
+	},
+	/* 737942.4 KHz */
+	{
+		.clock = (952 + 330 + 16 + 16) * 2 * (3040 + 26 + 4 + 50) * 90 / 1000,
+		.hdisplay = 952 * 2,
+		.hsync_start = (952 + 330) * 2,
+		.hsync_end = (952 + 330 + 16) * 2,
+		.htotal = (952 + 330 + 16 + 16) * 2,
+		.vdisplay = 3040,
+		.vsync_start = 3040 + 26,
+		.vsync_end = 3040 + 26 + 4,
+		.vtotal = 3040 + 26 + 4 + 50,
+	},
+};
+
+static int novatek_probe(struct mipi_dsi_device *dsi)
+{
+	struct mipi_dsi_device_info dsi_info = {"dsi-secondary", 0, NULL};
+	struct mipi_dsi_host *dsi1_host;
+	struct device *dev = &dsi->dev;
+	const struct panel_desc *desc;
+	struct device_node *dsi1;
+	struct novatek *ctx;
+	int num_dsi = 1;
+	int ret, i;
+
+	ctx = devm_drm_panel_alloc(dev, struct novatek, panel,
+				   &novatek_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(novatek_supplies),
+					    novatek_supplies, &ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	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");
+
+	desc = of_device_get_match_data(dev);
+	if (!desc)
+		return -ENODEV;
+	ctx->desc = desc;
+	ctx->dsc = *desc->dsc_cfg;
+
+	if (desc->is_dual_dsi) {
+		num_dsi = 2;
+		dsi1 = of_graph_get_remote_node(dsi->dev.of_node, 1, -1);
+		if (!dsi1) {
+			dev_err(dev, "cannot get secondary DSI node.\n");
+			return -ENODEV;
+		}
+
+		dsi1_host = of_find_mipi_dsi_host_by_node(dsi1);
+		of_node_put(dsi1);
+		if (!dsi1_host)
+			return dev_err_probe(dev, -EPROBE_DEFER,
+					     "cannot get secondary DSI host\n");
+
+		ctx->dsi[1] = devm_mipi_dsi_device_register_full(dev, dsi1_host,
+								 &dsi_info);
+		if (IS_ERR(ctx->dsi[1])) {
+			dev_err(dev, "cannot get secondary DSI device\n");
+			return PTR_ERR(ctx->dsi[1]);
+		}
+
+		mipi_dsi_set_drvdata(ctx->dsi[1], ctx);
+	}
+
+	ctx->dsi[0] = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	ctx->panel.prepare_prev_first = true;
+
+	ret = devm_drm_panel_add(dev, &ctx->panel);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to add panel\n");
+
+	for (i = 0; i < num_dsi; i++) {
+		ctx->dsi[i]->lanes = desc->lanes;
+		ctx->dsi[i]->format = desc->format;
+		ctx->dsi[i]->mode_flags = desc->mode_flags;
+		ctx->dsi[i]->dsc = &ctx->dsc;
+		ret = devm_mipi_dsi_attach(dev, ctx->dsi[i]);
+		if (ret < 0) {
+			drm_panel_remove(&ctx->panel);
+			return dev_err_probe(dev, ret,
+					     "Failed to attach to DSI host\n");
+		}
+	}
+
+	if (desc->has_dcs_backlight) {
+		ctx->backlight = novatek_create_backlight(ctx);
+		if (IS_ERR(ctx->backlight))
+			return dev_err_probe(dev, PTR_ERR(ctx->backlight),
+					     "Failed to create backlight\n");
+	} else {
+		ret = drm_panel_of_backlight(&ctx->panel);
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to get backlight\n");
+	}
+
+	return 0;
+}
+
+/* Model name: CSOT PP8807HB1-1 */
+static const struct panel_desc csot_pp8807hb1_1_desc = {
+	.width_mm = 118,
+	.height_mm = 190,
+	.bpc = 10, /* set this to 8 with RGB888 format to support 8-bit mode */
+	.lanes = 3,
+	.format = MIPI_DSI_FMT_RGB101010,
+	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS |
+		      MIPI_DSI_MODE_NO_EOT_PACKET | MIPI_DSI_MODE_VIDEO_BURST |
+		      MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_DSC_ALL_SLICES_IN_PKT,
+	.dsc_cfg = &csot_pp8807hb1_1_dsc_cfg,
+	.modes = csot_pp8807hb1_1_modes,
+	.num_modes = ARRAY_SIZE(csot_pp8807hb1_1_modes),
+	.init_sequence = csot_pp8807hb1_1_init_seq,
+	.is_dual_dsi = true,
+	.has_dcs_backlight = false,
+};
+
+static const struct of_device_id novatek_of_match[] = {
+	{ .compatible = "csot,pp8807hb1-1", .data = &csot_pp8807hb1_1_desc },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, novatek_of_match);
+
+static struct mipi_dsi_driver novatek_driver = {
+	.probe = novatek_probe,
+	.driver = {
+		.name = "panel-novatek-nt36536",
+		.of_match_table = novatek_of_match,
+	},
+};
+module_mipi_dsi_driver(novatek_driver);
+
+MODULE_AUTHOR("Pengyu Luo <mitltlatltl@gmail.com>");
+MODULE_DESCRIPTION("Novatek NT36536 DriverIC panels driver");
+MODULE_LICENSE("GPL");
-- 
2.54.0

Re: [PATCH v3 2/2] drm/panel: Add Novatek NT36536 panel driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] Unrolled resource leak and ignored DSI errors in `novatek_prepare()`.
- [Medium] DCS commands are sent unconditionally in backlight update handler.
- [Low] Missing Kconfig dependency for DSC helpers causes build failures.
- [Low] Manual call to `drm_panel_remove()` circumvents devres cleanup contract.
--

--- Patch [2]: [PATCH v3 2/2] drm/panel: Add Novatek NT36536 panel driver ---
commit c0321dc5c18b4a1a33b6415a4883e16993cea388
Author: Pengyu Luo <mitltlatltl@gmail.com>
drm/panel: Add Novatek NT36536 panel driver

This commit adds support for Novatek NT36536-based display panels,
specifically enabling the CSOT PP8807HB1-1 dual-link 10-bit panel found
in the LENOVO Legion Y700 Gen4.

> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index c0cc2bb4a3eb7..37b0938615673 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -650,6 +650,17 @@ config DRM_PANEL_NOVATEK_NT36523
>  	  around the Novatek NT36523 display controller, such as some
>  	  Boe panels used in Xiaomi Mi Pad 5 and 5 Pro tablets.
>  
> +config DRM_PANEL_NOVATEK_NT36536
> +	tristate "Novatek NT36536 panel driver"
> +	depends on OF
> +	depends on DRM_MIPI_DSI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	select DRM_KMS_HELPER

[Severity: Low]
Does this Kconfig entry need to select DRM_DISPLAY_DSC_HELPER?

Because the driver unconditionally uses drm_dsc_pps_payload_pack(), compiling
the driver without DSC helpers enabled globally will result in undefined
reference linker errors. It seems this should also select DRM_DISPLAY_HELPER.

> +	help
> +	  Say Y here if you want to enable support for Novatek NT36536-based
> +	  display panels, such as the one found in the LENOVO Legion Y700
> +	  Gen4.

[ ... ]

> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36536.c b/drivers/gpu/drm/panel/panel-novatek-nt36536.c
> new file mode 100644
> index 0000000000000..2a82b54880c30
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt36536.c

[ ... ]

> +static int novatek_prepare(struct drm_panel *panel)
> +{
> +	struct novatek *ctx = to_novatek(panel);
> +	struct mipi_dsi_device *dsi = to_primary_dsi(ctx);
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
> +	struct drm_dsc_picture_parameter_set pps;
> +	struct device *dev = &dsi->dev;
> +	int ret;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(novatek_supplies),
> +				    ctx->supplies);
> +	if (ret < 0)
> +		return ret;
> +
> +	novatek_reset(ctx);
> +
> +	ret = ctx->desc->init_sequence(&dsi_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(novatek_supplies),
> +				       ctx->supplies);
> +		return ret;
> +	}
> +
> +	drm_dsc_pps_payload_pack(&pps, &ctx->dsc);
> +	mipi_dsi_picture_parameter_set_multi(&dsi_ctx, &pps);
> +	mipi_dsi_compression_mode_multi(&dsi_ctx, true);
> +	mipi_dsi_msleep(&dsi_ctx, 28);
> +
> +	return backlight_enable(ctx->backlight);

[Severity: High]
Does this error path leak resources and ignore DSI errors?

If backlight_enable() fails, it returns an error code directly. At this point,
the panel regulators are still enabled and the reset GPIO is asserted.
Returning an error causes the DRM core to consider the prepare phase failed,
meaning novatek_unprepare() will never be called. This results in a permanent
power leak.

Additionally, dsi_ctx.accum_err is completely ignored after sending DSC
configuration commands, silently masking DSI transmission failures.

> +}

[ ... ]

> +static int novatek_bl_update_status(struct backlight_device *bl)
> +{
> +	struct novatek *ctx = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +
> +	return mipi_dsi_dcs_set_display_brightness_large(to_primary_dsi(ctx),
> +							 brightness);

[Severity: Medium]
Can this send DCS commands unconditionally while the panel is unpowered?

Because the backlight brightness can be modified via sysfs at any time, this
can execute when the panel is suspended, unpowered, and regulators are
disabled. Sending DSI commands in this state typically results in DSI host
controller timeouts and kernel error logs. Should the driver verify the panel
is prepared before sending DCS commands?

> +}

[ ... ]

> +static int novatek_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");
> +
> +	for (i = 0; i < num_dsi; i++) {
> +		ctx->dsi[i]->lanes = desc->lanes;
> +		ctx->dsi[i]->format = desc->format;
> +		ctx->dsi[i]->mode_flags = desc->mode_flags;
> +		ctx->dsi[i]->dsc = &ctx->dsc;
> +		ret = devm_mipi_dsi_attach(dev, ctx->dsi[i]);
> +		if (ret < 0) {
> +			drm_panel_remove(&ctx->panel);

[Severity: Low]
Is this manual call to drm_panel_remove() redundant?

The panel is registered via devm_drm_panel_add(), which schedules
drm_panel_remove() to run automatically via devres on failure. Manually
calling drm_panel_remove() in the devm_mipi_dsi_attach() error path
circumvents the devres cleanup contract and leads to duplicate removal
attempts by the driver core.

> +			return dev_err_probe(dev, ret,
> +					     "Failed to attach to DSI host\n");
> +		}
> +	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709142846.12463-1-mitltlatltl@gmail.com?part=2