[PATCH v2 0/2] drm/panel: Add Himax HX83121A panel driver

[PATCH v2 0/2] drm/panel: Add Himax HX83121A panel driver

[Pengyu Luo]

Add a driver for panels using the Himax HX83121A Display Driver IC,
including support for the BOE/CSOT PPC357DB1-4, found in HUAWEI
Matebook E Go series (Gaokun2/3).

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
base-commit: d517cb8cea012f43b069617fc8179b45404f8018
---
Changes in v3:
- remove '|' from description (Krzysztof)
- drop description for reset-gpios (Krzysztof)
- use backlight_enable instead of backlight_update_status to avoid NULL ptr
- Link to v2: https://lore.kernel.org/dri-devel/20260305084810.370024-1-mitltlatltl@gmail.com

Changes in v2:
- fix dt_binding_check (Rob)
- use devm_drm_panel_alloc (Neil)
- move panels specific chunks before module probe function. (Neil)
- fix supply in .c file
- do not initialise statics to false
- Link to v1: https://lore.kernel.org/dri-devel/20260303115730.9580-1-mitltlatltl@gmail.com

Pengyu Luo (2):
  dt-bindings: display: panel: Add Himax HX83121A
  drm/panel: Add Himax HX83121A panel driver

 .../display/panel/himax,hx83121a.yaml         |  86 ++
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-himax-hx83121a.c  | 750 ++++++++++++++++++
 4 files changed, 848 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-himax-hx83121a.c

-- 
2.53.0

[PATCH v3 1/2] dt-bindings: display: panel: Add Himax HX83121A

[Pengyu Luo]

HX83121A is a driver IC used to drive MIPI-DSI panels. It is found
in HUAWEI Matebook E Go series (Gaokun2/3) with BOE or CSOT panels.

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
v3:
- remove '|' from description (Krzysztof)
- drop description for reset-gpios (Krzysztof)
---
 .../display/panel/himax,hx83121a.yaml         | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml
new file mode 100644
index 0000000000..603e3ad85b
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/himax,hx83121a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Himax HX83121A based DSI display Panels
+
+maintainers:
+  - Pengyu Luo <mitltlatltl@gmail.com>
+
+description:
+  The Himax HX83121A is a generic DSI Panel IC used to drive dsi
+  panels. Support video mode panels from China Star Optoelectronics
+  Technology (CSOT) and BOE Technology.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - boe,ppc357db1-4
+          - csot,ppc357db1-4
+      - const: himax,hx83121a
+
+  reg:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  avdd-supply:
+    description: analog positive supply for IC
+
+  avee-supply:
+    description: analog negative supply for IC
+
+  vddi-supply:
+    description: power supply for IC
+
+  backlight: true
+
+required:
+  - compatible
+  - reg
+  - vddi-supply
+  - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "csot,ppc357db1-4", "himax,hx83121a";
+            reg = <0>;
+
+            vddi-supply = <&vreg_l2b>;
+            reset-gpios = <&tlmm 38 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>;
+                    };
+                };
+            };
+        };
+    };
+
+...
-- 
2.53.0

[PATCH v3 2/2] drm/panel: Add Himax HX83121A panel driver

[Pengyu Luo]

Add a driver for panels using the Himax HX83121A Display Driver IC,
including support for the BOE/CSOT PPC357DB1-4, found in HUAWEI
Matebook E Go series (Gaokun2/3).

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
v3:
- use backlight_enable instead of backlight_update_status to avoid NULL ptr
---
 drivers/gpu/drm/panel/Kconfig                |  11 +
 drivers/gpu/drm/panel/Makefile               |   1 +
 drivers/gpu/drm/panel/panel-himax-hx83121a.c | 749 +++++++++++++++++++
 3 files changed, 761 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-himax-hx83121a.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a99f2e2a49..c18ff46e2e 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -203,6 +203,17 @@ config DRM_PANEL_HIMAX_HX83112B
 	  Say Y here if you want to enable support for Himax HX83112B-based
 	  display panels, such as the one found in the Fairphone 3 smartphone.
 
+config DRM_PANEL_HIMAX_HX83121A
+	tristate "Himax HX83121A-based DSI panel"
+	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 Himax HX83121A-based
+	  display panels, such as the one found in the HUAWEI Matebook E Go
+          series.
+
 config DRM_PANEL_HIMAX_HX8394
 	tristate "HIMAX HX8394 MIPI-DSI LCD panels"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 3336a2c0cd..372d67b8cc 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_DRM_PANEL_HIMAX_HX8279) += panel-himax-hx8279.o
 obj-$(CONFIG_DRM_PANEL_HIMAX_HX83102) += panel-himax-hx83102.o
 obj-$(CONFIG_DRM_PANEL_HIMAX_HX83112A) += panel-himax-hx83112a.o
 obj-$(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_IL9322) += panel-ilitek-ili9322.o
diff --git a/drivers/gpu/drm/panel/panel-himax-hx83121a.c b/drivers/gpu/drm/panel/panel-himax-hx83121a.c
new file mode 100644
index 0000000000..ebe643ba41
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-himax-hx83121a.c
@@ -0,0 +1,749 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Himax HX83121A DriverIC panels driver
+ * Copyright (c) 2024-2026 Pengyu Luo <mitltlatltl@gmail.com>
+ *
+ * Multiple panels handling based on panel-novatek-nt36523.c
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/mod_devicetable.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 <video/mipi_display.h>
+
+static bool enable_dsc;
+module_param(enable_dsc, bool, 0);
+MODULE_PARM_DESC(enable_dsc, "enable DSC on the panel (default: false)");
+
+struct himax {
+	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 *dsc_modes;
+	unsigned int num_dsc_modes;
+
+	const struct drm_display_mode *modes;
+	unsigned int num_modes;
+
+	int (*init_sequence_dsc)(struct mipi_dsi_multi_context *dsi_ctx);
+	int (*init_sequence)(struct mipi_dsi_multi_context *dsi_ctx);
+
+	bool is_dual_dsi;
+	bool has_dcs_backlight;
+};
+
+static const struct regulator_bulk_data himax_supplies[] = {
+	{ .supply = "vddi" },
+	{ .supply = "avdd" },
+	{ .supply = "avee" },
+};
+
+static inline struct himax *to_himax(struct drm_panel *panel)
+{
+	return container_of(panel, struct himax, panel);
+}
+
+static inline struct mipi_dsi_device *to_primary_dsi(struct himax *ctx)
+{
+	/* Sync on DSI1 for dual dsi */
+	return ctx->desc->is_dual_dsi ? ctx->dsi[1] : ctx->dsi[0];
+}
+
+static void himax_reset(struct himax *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(4000, 4100);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	msleep(20);
+}
+
+static int himax_prepare(struct drm_panel *panel)
+{
+	struct himax *ctx = to_himax(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;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(himax_supplies),
+				    ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	himax_reset(ctx);
+
+	if (enable_dsc && ctx->desc->init_sequence_dsc)
+		ret = ctx->desc->init_sequence_dsc(&dsi_ctx);
+	else if (ctx->desc->init_sequence)
+		ret = ctx->desc->init_sequence(&dsi_ctx);
+	else
+		ret = -EOPNOTSUPP;
+
+	if (ret < 0) {
+		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+		regulator_bulk_disable(ARRAY_SIZE(himax_supplies),
+				       ctx->supplies);
+		return ret;
+	}
+
+	if (enable_dsc) {
+		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);
+	}
+
+	return backlight_enable(ctx->backlight);
+}
+
+static int himax_off(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_enter_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 120);
+
+	return dsi_ctx->accum_err;
+}
+
+static int himax_unprepare(struct drm_panel *panel)
+{
+	struct himax *ctx = to_himax(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;
+
+	ret = himax_off(&dsi_ctx);
+	if (ret < 0)
+		dev_err(dev, "panel failed to off: %d\n", ret);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(himax_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static int himax_get_modes(struct drm_panel *panel,
+			   struct drm_connector *connector)
+{
+	struct himax *ctx = to_himax(panel);
+	const struct panel_desc *desc = ctx->desc;
+	const struct drm_display_mode *modes;
+	int num_modes;
+	int i;
+
+	modes = enable_dsc ? desc->dsc_modes : desc->modes;
+	num_modes = enable_dsc ? desc->num_dsc_modes : desc->num_modes;
+
+	for (i = 0; i < num_modes; i++) {
+		const struct drm_display_mode *m = &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 num_modes;
+}
+
+static const struct drm_panel_funcs himax_panel_funcs = {
+	.prepare = himax_prepare,
+	.unprepare = himax_unprepare,
+	.get_modes = himax_get_modes,
+};
+
+static int himax_bl_update_status(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	u16 brightness = backlight_get_brightness(bl);
+	/* TODO: brightness to raw map table */
+	return mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
+}
+
+static const struct backlight_ops himax_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = himax_bl_update_status,
+};
+
+static struct backlight_device *
+himax_create_backlight(struct mipi_dsi_device *dsi)
+{
+	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, dsi,
+					      &himax_bl_ops, &props);
+}
+
+static int boe_ppc357db1_4_dsc_init_seq(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x83, 0x12, 0x1a, 0x55, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe1, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc7);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0x98);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x02);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x01, 0x07, 0x01, 0x07, 0x01, 0x07, 0x06, 0x06,
+				     0x06, 0x16, 0x00, 0x16, 0x81, 0x02, 0x40, 0x00,
+				     0x1a, 0x4a, 0x05, 0x04, 0x03, 0x02, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc6);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd2, 0x00, 0x30);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc9);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd3, 0x04);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc6);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2, 0x42);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xd0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0xf5);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xcd,
+				     0x81, 0x00, 0x80, 0x77, 0x00, 0x01, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1,
+				     0xc7, 0xb2, 0xa0, 0x90, 0x81, 0x75, 0x69, 0x5f,
+				     0x55, 0x4c, 0x44, 0x3d, 0x36, 0x2f, 0x2a, 0x24,
+				     0x1e, 0x19, 0x14, 0x10, 0x09, 0x08, 0x07, 0x54,
+				     0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xaa, 0xd4, 0xff, 0x2a, 0x55, 0x7f, 0xaa, 0xd4,
+				     0xff, 0xea, 0xff, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc8);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb1, 0x25);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbe, 0x01, 0x35, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd9, 0x5f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x00, 0x00, 0x00);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 140);
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_msleep(dsi_ctx, 20);
+
+	return dsi_ctx->accum_err;
+}
+
+static int boe_ppc357db1_4_init_seq(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x83, 0x12, 0x1a, 0x55, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd1, 0x37, 0x03, 0x0c, 0xfd);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2, 0x20);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe1, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc7);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0xa6);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x02);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x01, 0x07, 0x01, 0x07, 0x01, 0x07, 0x06, 0x06,
+				     0x06, 0x16, 0x00, 0x16, 0x81, 0x02, 0x40, 0x00,
+				     0x1a, 0x4a, 0x05, 0x04, 0x03, 0x02, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2,
+				     0x02, 0x68, 0x02, 0x68, 0x02, 0x68, 0x02, 0x68,
+				     0x02, 0x6f, 0x03, 0x04, 0x2d, 0x09, 0x09, 0x00,
+				     0x00, 0x0f, 0x0f, 0x0f, 0x0f, 0x00, 0x00, 0x00,
+				     0x01, 0x10, 0x10, 0x1c, 0x25, 0x3c, 0x00, 0x23,
+				     0x5d, 0x02, 0x02, 0x00, 0x00, 0x58, 0x01, 0xac,
+				     0x0f, 0xa9, 0x10, 0x00, 0x2d, 0x6f, 0x00, 0x70,
+				     0x00, 0x0a, 0xcb, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc6);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd2, 0x09, 0x85);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc9);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd3, 0x04);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xd0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0xf5);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1,
+				     0xc7, 0xb2, 0xa0, 0x90, 0x81, 0x75, 0x69, 0x5f,
+				     0x55, 0x4c, 0x44, 0x3d, 0x36, 0x2f, 0x2a, 0x24,
+				     0x1e, 0x19, 0x14, 0x10, 0x09, 0x08, 0x07, 0x54,
+				     0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xaa, 0xd4, 0xff, 0x2a, 0x55, 0x7f, 0xaa, 0xd4,
+				     0xff, 0xea, 0xff, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc8);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb1, 0x25);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbe, 0x01, 0x35, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd9, 0x5f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x00, 0x00, 0x00);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 140);
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_msleep(dsi_ctx, 31);
+
+	return dsi_ctx->accum_err;
+}
+
+static int csot_ppc357db1_4_dsc_init_seq(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x83, 0x12, 0x1a, 0x55, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb1,
+				     0x1c, 0x6b, 0x6b, 0x27, 0xe7, 0x00, 0x1b, 0x25,
+				     0x21, 0x21, 0x2d, 0x2d, 0x17, 0x33, 0x31, 0x40,
+				     0xcd, 0xff, 0x1a, 0x05, 0x15, 0x98, 0x00, 0x88,
+				     0x7f, 0xff, 0xff, 0xcf, 0x1a, 0xcc, 0x02, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd1, 0x37, 0x03, 0x0c, 0xfd);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2,
+				     0x00, 0x6a, 0x40, 0x00, 0x00, 0x14, 0x98, 0x60,
+				     0x3c, 0x02, 0x80, 0x21, 0x21, 0x00, 0x00, 0xf0,
+				     0x27);
+	/*
+	 * NOTE: Register 0xE2 configuration (based on downstream reference):
+	 * - 0x00: 120Hz with DSC enabled
+	 * - 0x10: 60Hz with DSC enabled
+	 * - 0x20: 60Hz with DSC disabled
+	 *
+	 * Both 0x00 and 0x10 are compatible with 60Hz/120Hz when DSC is active.
+	 * We use a fixed DSC-on value to remain refresh-rate agnostic.
+	 */
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xc0, 0x23, 0x23, 0xcc, 0x22, 0x99, 0xd8);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb4,
+				     0x46, 0x06, 0x0c, 0xbe, 0x0c, 0xbe, 0x09, 0x46,
+				     0x0f, 0x57, 0x0f, 0x57, 0x03, 0x4a, 0x00, 0x00,
+				     0x04, 0x0c, 0x00, 0x18, 0x01, 0x06, 0x08, 0x00,
+				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				     0x00, 0x00, 0xff, 0x00, 0xff, 0x10, 0x00, 0x02,
+				     0x14, 0x14, 0x14, 0x14);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe1, 0x01, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xe2);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7, 0x49);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd3,
+				     0x00, 0xc0, 0x08, 0x08, 0x08, 0x04, 0x04, 0x04,
+				     0x16, 0x02, 0x07, 0x07, 0x07, 0x31, 0x13, 0x19,
+				     0x12, 0x12, 0x03, 0x03, 0x03, 0x32, 0x10, 0x18,
+				     0x00, 0x11, 0x32, 0x10, 0x03, 0x00, 0x03, 0x32,
+				     0x10, 0x03, 0x00, 0x03, 0x00, 0x00, 0xff, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe1,
+				     0x11, 0x00, 0x00, 0x89, 0x30, 0x80, 0x0a, 0x00,
+				     0x03, 0x20, 0x00, 0x14, 0x03, 0x20, 0x03, 0x20,
+				     0x02, 0x00, 0x02, 0x91, 0x00, 0x20, 0x02, 0x47,
+				     0x00, 0x0b, 0x00, 0x0c, 0x05, 0x0e, 0x03, 0x68,
+				     0x18, 0x00, 0x10, 0xe0, 0x03, 0x0c, 0x20, 0x00,
+				     0x06, 0x0b, 0x0b, 0x33, 0x0e, 0x1c, 0x2a, 0x38,
+				     0x46, 0x54, 0x62, 0x69, 0x70, 0x77, 0x79, 0x7b,
+				     0x7d, 0x7e, 0x01, 0x02, 0x01, 0x00, 0x09);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x17, 0x08, 0x08, 0x2c, 0x46, 0x1e, 0x02, 0x23,
+				     0x5d, 0x02, 0xc9, 0x00, 0x00, 0x00, 0x00, 0x12,
+				     0x05, 0x02, 0x02, 0x07, 0x10, 0x10, 0x00, 0x1d,
+				     0xb9, 0x23, 0xb9, 0x00, 0x33, 0x02, 0x88);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x02, 0x00, 0xb2, 0x01, 0x56, 0x07, 0x56, 0x08,
+				     0x48, 0x14, 0xfd, 0x26);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x02);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x08, 0x08, 0x01, 0x03, 0x01, 0x03, 0x07, 0x02,
+				     0x02, 0x47, 0x00, 0x47, 0x81, 0x02, 0x40, 0x00,
+				     0x18, 0x4a, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01,
+				     0x00, 0x00, 0x03, 0x02, 0x01, 0x00, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbf,
+				     0xfd, 0x00, 0x80, 0x9c, 0x36, 0x00, 0x81, 0x0c);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xcd,
+				     0x81, 0x00, 0x80, 0x77, 0x00, 0x01, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1,
+				     0xc7, 0xb2, 0xa0, 0x90, 0x81, 0x75, 0x69, 0x5f,
+				     0x55, 0x4c, 0x44, 0x3d, 0x36, 0x2f, 0x2a, 0x24,
+				     0x1e, 0x19, 0x14, 0x10, 0x09, 0x08, 0x07, 0x54,
+				     0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xaa, 0xd4, 0xff, 0x2a, 0x55, 0x7f, 0xaa, 0xd4,
+				     0xff, 0xea, 0xff, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbe, 0x01, 0x35, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd9, 0x5f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x00, 0x00, 0x00);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 140);
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_msleep(dsi_ctx, 20);
+
+	return dsi_ctx->accum_err;
+}
+
+static int csot_ppc357db1_4_init_seq(struct mipi_dsi_multi_context *dsi_ctx)
+{
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x83, 0x12, 0x1a, 0x55, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb1,
+				     0x1c, 0x6b, 0x6b, 0x27, 0xe7, 0x00, 0x1b, 0x11,
+				     0x21, 0x21, 0x2d, 0x2d, 0x17, 0x33, 0x31, 0x40,
+				     0xcd, 0xff, 0x1a, 0x05, 0x15, 0x98, 0x00, 0x88,
+				     0x7f, 0xff, 0xff, 0xcf, 0x1a, 0xcc, 0x02, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd1, 0x37, 0x03, 0x0c, 0xfd);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2, 0x20);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2,
+				     0x00, 0x6a, 0x40, 0x00, 0x00, 0x14, 0x98, 0x60,
+				     0x3c, 0x02, 0x80, 0x21, 0x21, 0x00, 0x00, 0x10,
+				     0x27);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe1, 0x00, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xe2);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7, 0x49);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd3,
+				     0x00, 0xc0, 0x08, 0x08, 0x08, 0x04, 0x04, 0x04,
+				     0x16, 0x02, 0x07, 0x07, 0x07, 0x31, 0x13, 0x16,
+				     0x12, 0x12, 0x03, 0x03, 0x03, 0x32, 0x10, 0x15,
+				     0x00, 0x11, 0x32, 0x10, 0x03, 0x00, 0x03, 0x32,
+				     0x10, 0x03, 0x00, 0x03, 0x00, 0x00, 0xff, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x02);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe2,
+				     0x80, 0x05, 0x1c, 0xbe, 0x09, 0x8d, 0x0f, 0x57,
+				     0x03, 0x87, 0x06, 0x10, 0x32, 0x06, 0x15, 0x00,
+				     0x00, 0x14, 0x14, 0x14, 0x14, 0x00, 0x00, 0x00,
+				     0x01, 0x10, 0x10, 0x16, 0x28, 0x3c, 0x03, 0x23,
+				     0x5d, 0x02, 0x02, 0x00, 0x00, 0x48, 0x01, 0xac,
+				     0x0f, 0xab, 0x10, 0x00, 0x32, 0x87, 0x00, 0xa1,
+				     0x00, 0x0a, 0xcb, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x02, 0x00, 0xb2, 0x01, 0x56, 0x07, 0x56, 0x08,
+				     0x48, 0x14, 0x00, 0x26);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x02);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe7,
+				     0x05, 0x05, 0x01, 0x05, 0x01, 0x05, 0x04, 0x04,
+				     0x04, 0x24, 0x00, 0x24, 0x81, 0x02, 0x40, 0x00,
+				     0x32, 0x87, 0x03, 0x02, 0x01, 0x00, 0x00, 0x00,
+				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xd0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb2, 0xf0);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbf,
+				     0xfd, 0x00, 0x80, 0x9c, 0x10, 0x00, 0x81, 0x0c);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1, 0xe1,
+				     0xc7, 0xb2, 0xa0, 0x90, 0x81, 0x75, 0x69, 0x5f,
+				     0x55, 0x4c, 0x44, 0x3d, 0x36, 0x2f, 0x2a, 0x24,
+				     0x1e, 0x19, 0x14, 0x10, 0x09, 0x08, 0x07, 0x54,
+				     0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe4,
+				     0xaa, 0xd4, 0xff, 0x2a, 0x55, 0x7f, 0xaa, 0xd4,
+				     0xff, 0xea, 0xff, 0x03);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbd, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0xc8);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb1, 0x25);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xe9, 0x3f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xbe, 0x01, 0x35, 0x00);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xd9, 0x5f);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb9, 0x00, 0x00, 0x00);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(dsi_ctx);
+	mipi_dsi_msleep(dsi_ctx, 140);
+	mipi_dsi_dcs_set_display_on_multi(dsi_ctx);
+
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_POWER_SAVE, 0x01);
+	mipi_dsi_dcs_write_seq_multi(dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x24);
+	mipi_dsi_msleep(dsi_ctx, 31);
+
+	return dsi_ctx->accum_err;
+}
+
+static struct drm_dsc_config ppc357db1_4_dsc_cfg = {
+	.dsc_version_major = 1,
+	.dsc_version_minor = 1,
+	.slice_height = 20,
+	.slice_width = 800,
+	.slice_count = 1,
+	.bits_per_component = 8,
+	.bits_per_pixel = 8 << 4,
+	.block_pred_enable = true,
+};
+
+static const struct drm_display_mode ppc357db1_4_dsc_modes[] = {
+	{
+		.clock = (800 + 60 + 40 + 40) * 2 * (2560 + 154 + 4 + 18) * 120 / 1000,
+		.hdisplay = 800 * 2,
+		.hsync_start = (800 + 60) * 2,
+		.hsync_end = (800 + 60 + 40) * 2,
+		.htotal = (800 + 60 + 40 + 40) * 2,
+		.vdisplay = 2560,
+		.vsync_start = 2560 + 154,
+		.vsync_end = 2560 + 154 + 4,
+		.vtotal = 2560 + 154 + 4 + 18,
+	},
+	{
+		.clock = (800 + 60 + 40 + 40) * 2 * (2560 + 2890 + 4 + 18) * 60 / 1000,
+		.hdisplay = 800 * 2,
+		.hsync_start = (800 + 60) * 2,
+		.hsync_end = (800 + 60 + 40) * 2,
+		.htotal = (800 + 60 + 40 + 40) * 2,
+		.vdisplay = 2560,
+		.vsync_start = 2560 + 2890,
+		.vsync_end = 2560 + 2890 + 4,
+		.vtotal = 2560 + 2890 + 4 + 18,
+	},
+};
+
+static const struct drm_display_mode ppc357db1_4_modes[] = {
+	{
+		.clock = (800 + 60 + 20 + 40) * 2 * (2560 + 154 + 4 + 18) * 60 / 1000,
+		.hdisplay = 800 * 2,
+		.hsync_start = (800 + 60) * 2,
+		.hsync_end = (800 + 60 + 20) * 2,
+		.htotal = (800 + 60 + 20 + 40) * 2,
+		.vdisplay = 2560,
+		.vsync_start = 2560 + 168,
+		.vsync_end = 2560 + 168 + 4,
+		.vtotal = 2560 + 168 + 4 + 18,
+	},
+};
+
+static int himax_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 himax *ctx;
+	int num_dsi = 1;
+	int ret, i;
+
+	ctx = devm_drm_panel_alloc(dev, struct himax, panel, &himax_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (!ctx)
+		return -ENOMEM;
+
+	ret = devm_regulator_bulk_get_const(&dsi->dev,
+					    ARRAY_SIZE(himax_supplies),
+					    himax_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;
+
+	if (desc->has_dcs_backlight) {
+		ctx->backlight = himax_create_backlight(to_primary_dsi(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");
+	}
+
+	drm_panel_add(&ctx->panel);
+
+	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 = enable_dsc ? &ctx->dsc : NULL;
+		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");
+		}
+	}
+
+	return 0;
+}
+
+static void himax_remove(struct mipi_dsi_device *dsi)
+{
+	struct himax *ctx = mipi_dsi_get_drvdata(dsi);
+
+	drm_panel_remove(&ctx->panel);
+}
+
+/* Model name: BOE PPC357DB1-4 */
+static const struct panel_desc boe_ppc357db1_4_desc = {
+	.width_mm = 266,
+	.height_mm = 166,
+	.lanes = 4,
+	.format = MIPI_DSI_FMT_RGB888,
+	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS |
+		      MIPI_DSI_MODE_LPM,
+	.dsc_cfg = &ppc357db1_4_dsc_cfg,
+	.dsc_modes = ppc357db1_4_dsc_modes,
+	.num_dsc_modes = ARRAY_SIZE(ppc357db1_4_dsc_modes),
+	.modes = ppc357db1_4_modes,
+	.num_modes = ARRAY_SIZE(ppc357db1_4_modes),
+	.init_sequence_dsc = boe_ppc357db1_4_dsc_init_seq,
+	.init_sequence = boe_ppc357db1_4_init_seq,
+	.is_dual_dsi = true,
+	.has_dcs_backlight = true,
+};
+
+/* Model name: CSOT PPC357DB1-4 */
+static const struct panel_desc csot_ppc357db1_4_desc = {
+	.width_mm = 266,
+	.height_mm = 166,
+	.lanes = 4,
+	.format = MIPI_DSI_FMT_RGB888,
+	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS |
+		      MIPI_DSI_MODE_LPM,
+	.dsc_cfg = &ppc357db1_4_dsc_cfg,
+	.dsc_modes = ppc357db1_4_dsc_modes,
+	.num_dsc_modes = ARRAY_SIZE(ppc357db1_4_dsc_modes),
+	.modes = ppc357db1_4_modes,
+	.num_modes = ARRAY_SIZE(ppc357db1_4_modes),
+	.init_sequence_dsc = csot_ppc357db1_4_dsc_init_seq,
+	.init_sequence = csot_ppc357db1_4_init_seq,
+	.is_dual_dsi = true,
+	.has_dcs_backlight = true,
+};
+
+/*
+ * Known panels with HX83121A:
+ * CSOT PNC357DB1-4: on MI Book S 12.4
+ * CSOT PPC357DB1-1: on SAMSUNG Galaxy Tab S7 FE
+ * BOE/CSOT PPC357DB1-4: on HUAWEI Matebook E Go
+ * CSOT PPC357DB1-5: on MI Pad 5 Pro 12.4
+ */
+
+static const struct of_device_id himax_of_match[] = {
+	{ .compatible = "boe,ppc357db1-4", .data = &boe_ppc357db1_4_desc },
+	{ .compatible = "csot,ppc357db1-4", .data = &csot_ppc357db1_4_desc },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, himax_of_match);
+
+static struct mipi_dsi_driver himax_driver = {
+	.probe = himax_probe,
+	.remove = himax_remove,
+	.driver = {
+		.name = "panel-himax-hx83121a",
+		.of_match_table = himax_of_match,
+	},
+};
+module_mipi_dsi_driver(himax_driver);
+
+MODULE_AUTHOR("Pengyu Luo <mitltlatltl0@gmail.com>");
+MODULE_DESCRIPTION("Himax HX83121A DriverIC panels driver");
+MODULE_LICENSE("GPL");
-- 
2.53.0

Re: [PATCH v3 1/2] dt-bindings: display: panel: Add Himax HX83121A

[Rob Herring (Arm)]

On Sun, 15 Mar 2026 22:45:35 +0800, Pengyu Luo wrote:
> HX83121A is a driver IC used to drive MIPI-DSI panels. It is found
> in HUAWEI Matebook E Go series (Gaokun2/3) with BOE or CSOT panels.
> 
> Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> ---
> v3:
> - remove '|' from description (Krzysztof)
> - drop description for reset-gpios (Krzysztof)
> ---
>  .../display/panel/himax,hx83121a.yaml         | 86 +++++++++++++++++++
>  1 file changed, 86 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/himax,hx83121a.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/panel/himax,hx83121a.example.dtb: panel@0 (csot,ppc357db1-4): 'ports' does not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/display/panel/himax,hx83121a.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260315144536.515032-2-mitltlatltl@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Claude review: drm/panel: Add Himax HX83121A panel driver

[Claude Code Review Bot]

Overall Series Review

Subject: drm/panel: Add Himax HX83121A panel driver
Author: Pengyu Luo <mitltlatltl@gmail.com>
Patches: 4
Reviewed: 2026-03-16T11:51:07.003523

---

This is a v3 patch series adding a new DRM panel driver for the Himax HX83121A Display Driver IC, supporting BOE and CSOT panel variants (PPC357DB1-4) found in HUAWEI Matebook E Go devices. The series is structured cleanly: patch 1 adds DT bindings, patch 2 adds the driver. The driver follows the existing `panel-novatek-nt36523.c` dual-DSI pattern. The code is generally well-structured, but there are several issues worth addressing, ranging from binding correctness (missing dual-DSI port schema), error-handling bugs, a questionable module parameter, and minor style issues.

---
Generated by Claude Code Patch Reviewer

Claude review: dt-bindings: display: panel: Add Himax HX83121A

[Claude Code Review Bot]

Patch Review

**Missing dual-DSI port schema.** This is a dual-DSI panel (as the example and driver show), yet the binding doesn't reference `panel-common-dual.yaml` or define a `ports` schema at all. Compare with `novatek,nt36523.yaml` which uses:
```yaml
allOf:
  - $ref: panel-common-dual.yaml#
```
Without this, `dt_binding_check` likely won't validate the `ports` node in the example, and the `port@1` in the example is undocumented. The `additionalProperties: false` should probably become `unevaluatedProperties: false` when using the `$ref`.

**Missing `port` property.** The example has a `ports` node with two ports, but there is no `port` or `ports` property declared in the schema. This is handled by the `panel-common-dual.yaml` ref, but since it's not referenced, this is an omission.

**`avdd-supply` and `avee-supply` not required.** They are listed as optional in the binding but the driver always requests them via `regulator_bulk_get`. If the hardware always needs them, consider making them required, or at minimum document that they are optional (which they currently are, as regulators can be dummy). This is minor - the current approach is acceptable if dummy regulators suffice.

**Minor style in example:** `port@1{` is missing a space before `{` (line 326 of the binding yaml). Should be `port@1 {`. This exists in the nt36523 binding too, but it's still poor style.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/panel: Add Himax HX83121A panel driver

[Claude Code Review Bot]

Patch Review

**`devm_drm_panel_alloc` error handling is wrong.** The function returns an ERR_PTR on failure, not NULL. The current code:
```c
ctx = devm_drm_panel_alloc(dev, struct himax, panel, &himax_panel_funcs,
			   DRM_MODE_CONNECTOR_DSI);
if (!ctx)
	return -ENOMEM;
```
Should be:
```c
if (IS_ERR(ctx))
	return PTR_ERR(ctx);
```
Compare with `panel-novatek-nt36523.c:1169` which does it correctly. This is a **bug** — on allocation failure the driver would dereference an ERR_PTR.

**`dsc` field unconditionally copied from `desc->dsc_cfg`.** At line `ctx->dsc = *desc->dsc_cfg;` — this is fine as long as all panel descriptors have a non-NULL `dsc_cfg`, which they currently do. But if a future panel variant doesn't support DSC at all, this would NULL-deref. A guard would be prudent:
```c
if (desc->dsc_cfg)
	ctx->dsc = *desc->dsc_cfg;
```

**`enable_dsc` module parameter is global and not per-panel.** Using a `module_param` bool to toggle DSC at load time is a fragile design. It affects all panel instances simultaneously and cannot be changed at runtime in a meaningful way (the DSI attach already happened). The `dsc` pointer on the DSI device is set once at probe:
```c
ctx->dsi[i]->dsc = enable_dsc ? &ctx->dsc : NULL;
```
If DSC mode is changed after probe, the modes and DSI config won't match. This is likely acceptable for the initial bring-up use case described, but should be documented as a limitation or replaced with a proper DT property or panel mode selection mechanism.

**`ppc357db1_4_dsc_cfg` should be `const`.** The struct is declared as:
```c
static struct drm_dsc_config ppc357db1_4_dsc_cfg = {
```
Since it's used only to initialize `ctx->dsc` by copy, it should be `static const`.

**Missing `backlight_disable` in `himax_unprepare`.** The `himax_prepare` function calls `backlight_enable(ctx->backlight)` at the end, but `himax_unprepare` never calls `backlight_disable`. This means the backlight won't be properly turned off on unprepare. The panel will send sleep-enter but the DCS backlight remains logically enabled. Should add:
```c
backlight_disable(ctx->backlight);
```
at the beginning of `himax_unprepare`.

**Missing `set_display_off` in `himax_off`.** The `himax_off` function only sends `enter_sleep_mode` but does not send `set_display_off` first. The MIPI DCS spec recommends sending Display Off before entering sleep. Many other panel drivers do:
```c
mipi_dsi_dcs_set_display_off_multi(dsi_ctx);
mipi_dsi_msleep(dsi_ctx, 20);
mipi_dsi_dcs_enter_sleep_mode_multi(dsi_ctx);
```

**Kconfig `select DRM_KMS_HELPER` is likely unnecessary.** Only 4 other panel drivers select it and the trend has been to avoid selecting it for new MIPI DSI panel drivers. The driver doesn't appear to use anything from KMS helper directly. Consider dropping it.

**Kconfig help text indentation mismatch.** The last line of the help text uses spaces instead of a tab:
```
+	  Say Y here if you want to enable support for Himax HX83121A-based
+	  display panels, such as the one found in the HUAWEI Matebook E Go
+          series.
```
The `series.` line uses spaces for indentation instead of a tab+spaces, breaking the indentation pattern.

**`to_himax` helper is unnecessary with `devm_drm_panel_alloc`.** With `devm_drm_panel_alloc`, the idiomatic way to get the container is `to_drm_panel()` already returning the right pointer, but since `container_of` works fine here it's not a real issue — just a style observation.

**Non-standard mode clock calculation.** The mode definitions use inline arithmetic like:
```c
.clock = (800 + 60 + 40 + 40) * 2 * (2560 + 154 + 4 + 18) * 120 / 1000,
```
This is actually a nice pattern for readability. However, for the non-DSC mode, the vfront_porch differs between the mode struct and the clock calculation:
```c
.clock = (800 + 60 + 20 + 40) * 2 * (2560 + 154 + 4 + 18) * 60 / 1000,
...
.vsync_start = 2560 + 168,
```
The clock uses vfp=154 but `vsync_start` uses vfp=168. These should match — either the clock or the vsync_start is wrong. This is a **potential bug** that would cause the actual refresh rate to differ from the intended 60Hz.

**`of_device_get_match_data` vs `device_get_match_data`.** The newer preferred API is `device_get_match_data(dev)` which works with both OF and ACPI. Minor, but worth updating for consistency with modern kernel style.

---
Generated by Claude Code Patch Reviewer