[PATCH v3 0/2] Support for Synaptics TDDI series panels

[PATCH v3 0/2] Support for Synaptics TDDI series panels

[Kaustabh Chakraborty]

Synaptics' Touch and Display Driver Integration (TDDI) technology [1]
employs a single chip for both touchscreen and display capabilities.
Such designs reportedly help reducing costs and power consumption.

Although the touchscreens, which are powered by Synaptics'
Register-Mapped Interface 4 (RMI4) touch protocol via I2C or SPI have
driver support in the kernel, the MIPI DSI display panels don't.

This series introduces a rudimentary driver for controlling said display
panels, which supports TD4101 and TD4300 panels.

[1] https://www.synaptics.com/technology/display-integration

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
Changes in v3:
- fixed various dt_binding_check errors (robh's bot)
- adjusted commit description of [v2 1/2] (robh)
- utilized devm_drm_panel_alloc() and devm_regulator_bulk_get_const()
- Link to v2: https://lore.kernel.org/r/20250625-panel-synaptics-tddi-v2-0-7a62ab1d13c7@disroot.org

Changes in v2:
- fixed various dt_binding_check errors (conor)
- did s/tddi_update_brightness/tddi_update_status
- added check for panel enable in tddi_update_status()
- used backlight_get_brightness() in appropriate places
- Link to v1: https://lore.kernel.org/r/20250612-panel-synaptics-tddi-v1-0-dfb8a425f76c@disroot.org

---
Kaustabh Chakraborty (2):
      dt-bindings: display: panel: document Synaptics TDDI panel
      drm: panel: add support for Synaptics TDDI series DSI panels

 .../display/panel/synaptics,td4300-panel.yaml      |  89 +++++++
 drivers/gpu/drm/panel/Kconfig                      |  11 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 drivers/gpu/drm/panel/panel-synaptics-tddi.c       | 289 +++++++++++++++++++++
 4 files changed, 390 insertions(+)
---
base-commit: d086c886ceb9f59dea6c3a9dae7eb89e780a20c9
change-id: 20250523-panel-synaptics-tddi-0b0b3f07f814

Best regards,
-- 
Kaustabh Chakraborty <kauschluss@disroot.org>

[PATCH v3 1/2] dt-bindings: display: panel: document Synaptics TDDI panel

[Kaustabh Chakraborty]

Document the Synaptics TDDI (Touch/Display Integration) panel hardware.
Along with the MIPI-DSI panel, these devices also have an in-built LED
backlight device and a touchscreen, all packed together in a single chip.

Also, add compatibles for supported panels - TD4101 and TD4300. Both
have the '-panel' suffix so as to remove any ambiguity between the panel
and touchscreen chips.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
 .../display/panel/synaptics,td4300-panel.yaml      | 89 ++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..152d94367130e9d80a885fe87a2da53db88e3393
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/synaptics,td4300-panel.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Synaptics TDDI Display Panel Controller
+
+maintainers:
+  - Kaustabh Chakraborty <kauschluss@disroot.org>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    enum:
+      - syna,td4101-panel
+      - syna,td4300-panel
+
+  reg:
+    maxItems: 1
+
+  vio-supply:
+    description: core I/O voltage supply
+
+  vsn-supply:
+    description: negative voltage supply for analog circuits
+
+  vsp-supply:
+    description: positive voltage supply for analog circuits
+
+  backlight-gpios:
+    maxItems: 1
+    description: backlight enable GPIO
+
+  reset-gpios: true
+  width-mm: true
+  height-mm: true
+  panel-timing: true
+
+required:
+  - compatible
+  - reg
+  - width-mm
+  - height-mm
+  - panel-timing
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "syna,td4300-panel";
+            reg = <0>;
+
+            vio-supply = <&panel_vio_reg>;
+            vsn-supply = <&panel_vsn_reg>;
+            vsp-supply = <&panel_vsp_reg>;
+
+            backlight-gpios = <&gpd3 5 GPIO_ACTIVE_LOW>;
+            reset-gpios = <&gpd3 4 GPIO_ACTIVE_LOW>;
+
+            width-mm = <68>;
+            height-mm = <121>;
+
+            panel-timing {
+                clock-frequency = <144389520>;
+
+                hactive = <1080>;
+                hsync-len = <4>;
+                hfront-porch = <120>;
+                hback-porch = <32>;
+
+                vactive = <1920>;
+                vsync-len = <2>;
+                vfront-porch = <21>;
+                vback-porch = <4>;
+            };
+        };
+    };
+
+...

-- 
2.50.0

[PATCH v3 2/2] drm: panel: add support for Synaptics TDDI series DSI panels

[Kaustabh Chakraborty]

Synaptics TDDI (Touch/Display Integration) panels utilize a single chip
for display and touch controllers. Implement a simple device driver for
such panels, along with its built-in LED backlight controller, and add
support for TD4101 and TD4300 panels in the driver.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
 drivers/gpu/drm/panel/Kconfig                |  11 +
 drivers/gpu/drm/panel/Makefile               |   1 +
 drivers/gpu/drm/panel/panel-synaptics-tddi.c | 289 +++++++++++++++++++++++++++
 3 files changed, 301 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 09b9f7ff9340abb708a503f7564acc46b2faaf7d..b080da939f5e3d11bf4c437ae167480d2721b41f 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -1021,6 +1021,17 @@ config DRM_PANEL_SYNAPTICS_R63353
 	  Say Y if you want to enable support for panels based on the
 	  Synaptics R63353 controller.
 
+config DRM_PANEL_SYNAPTICS_TDDI
+	tristate "Synaptics TDDI display panels"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y if you want to enable support for the Synaptics TDDI display
+	  panels. There are multiple MIPI DSI panels manufactured under the TDDI
+	  namesake, with varying resolutions and data lanes. They also have a
+	  built-in LED backlight and a touch controller.
+
 config DRM_PANEL_TDO_TL070WSH30
 	tristate "TDO TL070WSH30 DSI panel"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 957555b499968ebbfb55c87d2729ce88b5d48a57..a6e786e2b578e09d95de5b6430eba94c668ee4bc 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -98,6 +98,7 @@ obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7703) += panel-sitronix-st7703.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
 obj-$(CONFIG_DRM_PANEL_SUMMIT) += panel-summit.o
 obj-$(CONFIG_DRM_PANEL_SYNAPTICS_R63353) += panel-synaptics-r63353.o
+obj-$(CONFIG_DRM_PANEL_SYNAPTICS_TDDI) += panel-synaptics-tddi.o
 obj-$(CONFIG_DRM_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
 obj-$(CONFIG_DRM_PANEL_SONY_TD4353_JDI) += panel-sony-td4353-jdi.o
 obj-$(CONFIG_DRM_PANEL_SONY_TULIP_TRULY_NT35521) += panel-sony-tulip-truly-nt35521.o
diff --git a/drivers/gpu/drm/panel/panel-synaptics-tddi.c b/drivers/gpu/drm/panel/panel-synaptics-tddi.c
new file mode 100644
index 0000000000000000000000000000000000000000..1e99be8791770437ce22c482320a7c475f50019e
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-synaptics-tddi.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Synaptics TDDI display panel driver.
+ *
+ * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
+ */
+
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+struct tddi_panel_data {
+	u8 lanes;
+	/* wait timings for panel enable */
+	u8 delay_ms_sleep_exit;
+	u8 delay_ms_display_on;
+	/* wait timings for panel disable */
+	u8 delay_ms_display_off;
+	u8 delay_ms_sleep_enter;
+};
+
+struct tddi_ctx {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	struct drm_display_mode mode;
+	struct backlight_device *backlight;
+	const struct tddi_panel_data *data;
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *backlight_gpio;
+	u32 bus_flags;
+	u32 width;
+	u32 height;
+};
+
+static const struct regulator_bulk_data tddi_supplies[] = {
+	{ .supply = "vio" },
+	{ .supply = "vsn" },
+	{ .supply = "vsp" },
+};
+
+static inline struct tddi_ctx *to_tddi_ctx(struct drm_panel *panel)
+{
+	return container_of(panel, struct tddi_ctx, panel);
+}
+
+static int tddi_update_status(struct backlight_device *backlight)
+{
+	struct tddi_ctx *ctx = bl_get_data(backlight);
+	struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };
+	u8 brightness = backlight_get_brightness(backlight);
+
+	if (!ctx->panel.enabled)
+		return 0;
+
+	mipi_dsi_dcs_set_display_brightness_multi(&dsi, brightness);
+
+	return dsi.accum_err;
+}
+
+static int tddi_prepare(struct drm_panel *panel)
+{
+	struct tddi_ctx *ctx = to_tddi_ctx(panel);
+	struct device *dev = &ctx->dsi->dev;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(tddi_supplies), ctx->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(5000, 6000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(5000, 6000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+
+	gpiod_set_value_cansleep(ctx->backlight_gpio, 0);
+	usleep_range(5000, 6000);
+
+	return 0;
+}
+
+static int tddi_unprepare(struct drm_panel *panel)
+{
+	struct tddi_ctx *ctx = to_tddi_ctx(panel);
+
+	gpiod_set_value_cansleep(ctx->backlight_gpio, 1);
+	usleep_range(5000, 6000);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(5000, 6000);
+
+	regulator_bulk_disable(ARRAY_SIZE(tddi_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static int tddi_enable(struct drm_panel *panel)
+{
+	struct tddi_ctx *ctx = to_tddi_ctx(panel);
+	struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };
+	u8 brightness = ctx->backlight->props.brightness;
+
+	mipi_dsi_dcs_write_seq_multi(&dsi, MIPI_DCS_WRITE_POWER_SAVE, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x0c);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi);
+	mipi_dsi_msleep(&dsi, ctx->data->delay_ms_sleep_exit);
+
+	/* sync the panel with the backlight's brightness level */
+	mipi_dsi_dcs_set_display_brightness_multi(&dsi, brightness);
+
+	mipi_dsi_dcs_set_display_on_multi(&dsi);
+	mipi_dsi_msleep(&dsi, ctx->data->delay_ms_display_on);
+
+	return dsi.accum_err;
+};
+
+static int tddi_disable(struct drm_panel *panel)
+{
+	struct tddi_ctx *ctx = to_tddi_ctx(panel);
+	struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };
+
+	mipi_dsi_dcs_set_display_off_multi(&dsi);
+	mipi_dsi_msleep(&dsi, ctx->data->delay_ms_display_off);
+
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi);
+	mipi_dsi_msleep(&dsi, ctx->data->delay_ms_sleep_enter);
+
+	return dsi.accum_err;
+}
+
+static int tddi_get_modes(struct drm_panel *panel,
+			  struct drm_connector *connector)
+{
+	struct tddi_ctx *ctx = to_tddi_ctx(panel);
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(connector->dev, &ctx->mode);
+	if (!mode)
+		return -ENOMEM;
+
+	mode->type |= DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+	drm_mode_probed_add(connector, mode);
+	drm_mode_set_name(mode);
+
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+	connector->display_info.bus_flags = ctx->bus_flags;
+
+	return 1;
+}
+
+static const struct backlight_ops tddi_bl_ops = {
+	.update_status = tddi_update_status,
+};
+
+static const struct drm_panel_funcs tddi_drm_panel_funcs = {
+	.prepare = tddi_prepare,
+	.unprepare = tddi_unprepare,
+	.enable = tddi_enable,
+	.disable = tddi_disable,
+	.get_modes = tddi_get_modes,
+};
+
+static int tddi_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct tddi_ctx *ctx;
+	int ret;
+
+	ctx = devm_drm_panel_alloc(dev, struct tddi_ctx, panel,
+				   &tddi_drm_panel_funcs, DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ctx->data = of_device_get_match_data(dev);
+
+	ctx->dsi = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(tddi_supplies),
+					    tddi_supplies, &ctx->supplies);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get regulators\n");
+
+	ctx->backlight_gpio = devm_gpiod_get_optional(dev, "backlight", GPIOD_ASIS);
+	if (IS_ERR(ctx->backlight_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->backlight_gpio),
+				     "failed to get backlight-gpios\n");
+
+	ctx->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_ASIS);
+	if (IS_ERR(ctx->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
+				     "failed to get reset-gpios\n");
+
+	ret = of_get_drm_panel_display_mode(dev->of_node, &ctx->mode,
+					    &ctx->bus_flags);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get panel timings\n");
+
+	ctx->backlight = devm_backlight_device_register(dev, dev_name(dev), dev,
+							ctx, &tddi_bl_ops, NULL);
+	if (IS_ERR(ctx->backlight))
+		return dev_err_probe(dev, PTR_ERR(ctx->backlight),
+				     "failed to register backlight device");
+
+	ctx->backlight->props.type = BACKLIGHT_PLATFORM;
+	ctx->backlight->props.brightness = 255;
+	ctx->backlight->props.max_brightness = 255;
+
+	dsi->lanes = ctx->data->lanes;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
+			  MIPI_DSI_MODE_VIDEO_NO_HFP;
+
+	ctx->panel.prepare_prev_first = true;
+	drm_panel_add(&ctx->panel);
+
+	ret = devm_mipi_dsi_attach(dev, dsi);
+	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 tddi_remove(struct mipi_dsi_device *dsi)
+{
+	struct tddi_ctx *ctx = mipi_dsi_get_drvdata(dsi);
+
+	drm_panel_remove(&ctx->panel);
+}
+
+static const struct tddi_panel_data td4101_panel_data = {
+	.lanes = 2,
+	/* wait timings for panel enable */
+	.delay_ms_sleep_exit = 100,
+	.delay_ms_display_on = 0,
+	/* wait timings for panel disable */
+	.delay_ms_display_off = 20,
+	.delay_ms_sleep_enter = 90,
+};
+
+static const struct tddi_panel_data td4300_panel_data = {
+	.lanes = 4,
+	/* wait timings for panel enable */
+	.delay_ms_sleep_exit = 100,
+	.delay_ms_display_on = 0,
+	/* wait timings for panel disable */
+	.delay_ms_display_off = 0,
+	.delay_ms_sleep_enter = 0,
+};
+
+static const struct of_device_id tddi_of_device_id[] = {
+	{
+		.compatible = "syna,td4101-panel",
+		.data = &td4101_panel_data,
+	}, {
+		.compatible = "syna,td4300-panel",
+		.data = &td4300_panel_data,
+	}, { }
+};
+MODULE_DEVICE_TABLE(of, tddi_of_device_id);
+
+static struct mipi_dsi_driver tddi_dsi_driver = {
+	.probe = tddi_probe,
+	.remove = tddi_remove,
+	.driver = {
+		.name = "panel-synaptics-tddi",
+		.of_match_table = tddi_of_device_id,
+	},
+};
+module_mipi_dsi_driver(tddi_dsi_driver);
+
+MODULE_AUTHOR("Kaustabh Chakraborty <kauschluss@disroot.org>");
+MODULE_DESCRIPTION("Synaptics TDDI Display Panel Driver");
+MODULE_LICENSE("GPL");

-- 
2.50.0

Re: [PATCH v3 1/2] dt-bindings: display: panel: document Synaptics TDDI panel

[Krzysztof Kozlowski]

On Sun, Jul 20, 2025 at 05:31:54PM +0530, Kaustabh Chakraborty wrote:
> Document the Synaptics TDDI (Touch/Display Integration) panel hardware.
> Along with the MIPI-DSI panel, these devices also have an in-built LED
> backlight device and a touchscreen, all packed together in a single chip.
> 
> Also, add compatibles for supported panels - TD4101 and TD4300. Both
> have the '-panel' suffix so as to remove any ambiguity between the panel
> and touchscreen chips.
> 
> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
>  .../display/panel/synaptics,td4300-panel.yaml      | 89 ++++++++++++++++++++++
>  1 file changed, 89 insertions(+)

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: display: panel: document Synaptics TDDI panel

[Dmitry Baryshkov]

On Sun, Jul 20, 2025 at 05:31:54PM +0530, Kaustabh Chakraborty wrote:
> Document the Synaptics TDDI (Touch/Display Integration) panel hardware.
> Along with the MIPI-DSI panel, these devices also have an in-built LED
> backlight device and a touchscreen, all packed together in a single chip.
> 
> Also, add compatibles for supported panels - TD4101 and TD4300. Both
> have the '-panel' suffix so as to remove any ambiguity between the panel
> and touchscreen chips.
> 
> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
>  .../display/panel/synaptics,td4300-panel.yaml      | 89 ++++++++++++++++++++++
>  1 file changed, 89 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..152d94367130e9d80a885fe87a2da53db88e3393
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/synaptics,td4300-panel.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Synaptics TDDI Display Panel Controller
> +
> +maintainers:
> +  - Kaustabh Chakraborty <kauschluss@disroot.org>
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - syna,td4101-panel
> +      - syna,td4300-panel
> +
> +  reg:
> +    maxItems: 1
> +
> +  vio-supply:
> +    description: core I/O voltage supply
> +
> +  vsn-supply:
> +    description: negative voltage supply for analog circuits
> +
> +  vsp-supply:
> +    description: positive voltage supply for analog circuits
> +
> +  backlight-gpios:
> +    maxItems: 1
> +    description: backlight enable GPIO
> +
> +  reset-gpios: true
> +  width-mm: true
> +  height-mm: true
> +  panel-timing: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - width-mm
> +  - height-mm
> +  - panel-timing
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    dsi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        panel@0 {
> +            compatible = "syna,td4300-panel";
> +            reg = <0>;
> +
> +            vio-supply = <&panel_vio_reg>;
> +            vsn-supply = <&panel_vsn_reg>;
> +            vsp-supply = <&panel_vsp_reg>;
> +
> +            backlight-gpios = <&gpd3 5 GPIO_ACTIVE_LOW>;
> +            reset-gpios = <&gpd3 4 GPIO_ACTIVE_LOW>;
> +
> +            width-mm = <68>;
> +            height-mm = <121>;
> +
> +            panel-timing {

Are the timings defined by the 'TD4300' name or might there be different
panels with the same name but different timings?

> +                clock-frequency = <144389520>;
> +
> +                hactive = <1080>;
> +                hsync-len = <4>;
> +                hfront-porch = <120>;
> +                hback-porch = <32>;
> +
> +                vactive = <1920>;
> +                vsync-len = <2>;
> +                vfront-porch = <21>;
> +                vback-porch = <4>;
> +            };
> +        };
> +    };
> +
> +...
> 
> -- 
> 2.50.0
> 

-- 
With best wishes
Dmitry

Re: [PATCH v3 2/2] drm: panel: add support for Synaptics TDDI series DSI panels

[Dmitry Baryshkov]

On Sun, Jul 20, 2025 at 05:31:55PM +0530, Kaustabh Chakraborty wrote:
> Synaptics TDDI (Touch/Display Integration) panels utilize a single chip
> for display and touch controllers. Implement a simple device driver for
> such panels, along with its built-in LED backlight controller, and add
> support for TD4101 and TD4300 panels in the driver.
> 
> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
>  drivers/gpu/drm/panel/Kconfig                |  11 +
>  drivers/gpu/drm/panel/Makefile               |   1 +
>  drivers/gpu/drm/panel/panel-synaptics-tddi.c | 289 +++++++++++++++++++++++++++
>  3 files changed, 301 insertions(+)
> 
> +
> +static int tddi_get_modes(struct drm_panel *panel,
> +			  struct drm_connector *connector)
> +{
> +	struct tddi_ctx *ctx = to_tddi_ctx(panel);
> +	struct drm_display_mode *mode;
> +
> +	mode = drm_mode_duplicate(connector->dev, &ctx->mode);
> +	if (!mode)
> +		return -ENOMEM;
> +
> +	mode->type |= DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +	drm_mode_probed_add(connector, mode);
> +	drm_mode_set_name(mode);
> +
> +	connector->display_info.width_mm = mode->width_mm;
> +	connector->display_info.height_mm = mode->height_mm;

Please use drm_connector_helper_get_modes_fixed()

> +	connector->display_info.bus_flags = ctx->bus_flags;
> +
> +	return 1;
> +}
> +
> +static const struct backlight_ops tddi_bl_ops = {
> +	.update_status = tddi_update_status,
> +};
> +
> +static const struct drm_panel_funcs tddi_drm_panel_funcs = {
> +	.prepare = tddi_prepare,
> +	.unprepare = tddi_unprepare,
> +	.enable = tddi_enable,
> +	.disable = tddi_disable,
> +	.get_modes = tddi_get_modes,
> +};
> +
> +static int tddi_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct tddi_ctx *ctx;
> +	int ret;
> +
> +	ctx = devm_drm_panel_alloc(dev, struct tddi_ctx, panel,
> +				   &tddi_drm_panel_funcs, DRM_MODE_CONNECTOR_DSI);
> +	if (IS_ERR(ctx))
> +		return PTR_ERR(ctx);
> +
> +	ctx->data = of_device_get_match_data(dev);
> +
> +	ctx->dsi = dsi;
> +	mipi_dsi_set_drvdata(dsi, ctx);
> +
> +	ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(tddi_supplies),
> +					    tddi_supplies, &ctx->supplies);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to get regulators\n");
> +
> +	ctx->backlight_gpio = devm_gpiod_get_optional(dev, "backlight", GPIOD_ASIS);
> +	if (IS_ERR(ctx->backlight_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->backlight_gpio),
> +				     "failed to get backlight-gpios\n");
> +
> +	ctx->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_ASIS);
> +	if (IS_ERR(ctx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +				     "failed to get reset-gpios\n");
> +
> +	ret = of_get_drm_panel_display_mode(dev->of_node, &ctx->mode,
> +					    &ctx->bus_flags);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to get panel timings\n");
> +
> +	ctx->backlight = devm_backlight_device_register(dev, dev_name(dev), dev,
> +							ctx, &tddi_bl_ops, NULL);
> +	if (IS_ERR(ctx->backlight))
> +		return dev_err_probe(dev, PTR_ERR(ctx->backlight),
> +				     "failed to register backlight device");
> +
> +	ctx->backlight->props.type = BACKLIGHT_PLATFORM;
> +	ctx->backlight->props.brightness = 255;
> +	ctx->backlight->props.max_brightness = 255;

Props should be set before registering the backlight

> +
> +	dsi->lanes = ctx->data->lanes;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> +			  MIPI_DSI_MODE_VIDEO_NO_HFP;
> +
> +	ctx->panel.prepare_prev_first = true;
> +	drm_panel_add(&ctx->panel);
> +
> +	ret = devm_mipi_dsi_attach(dev, dsi);
> +	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 tddi_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct tddi_ctx *ctx = mipi_dsi_get_drvdata(dsi);
> +
> +	drm_panel_remove(&ctx->panel);
> +}
> +
> +static const struct tddi_panel_data td4101_panel_data = {
> +	.lanes = 2,
> +	/* wait timings for panel enable */
> +	.delay_ms_sleep_exit = 100,
> +	.delay_ms_display_on = 0,
> +	/* wait timings for panel disable */
> +	.delay_ms_display_off = 20,
> +	.delay_ms_sleep_enter = 90,
> +};
> +
> +static const struct tddi_panel_data td4300_panel_data = {
> +	.lanes = 4,
> +	/* wait timings for panel enable */
> +	.delay_ms_sleep_exit = 100,
> +	.delay_ms_display_on = 0,
> +	/* wait timings for panel disable */
> +	.delay_ms_display_off = 0,
> +	.delay_ms_sleep_enter = 0,
> +};
> +
> +static const struct of_device_id tddi_of_device_id[] = {
> +	{
> +		.compatible = "syna,td4101-panel",
> +		.data = &td4101_panel_data,
> +	}, {
> +		.compatible = "syna,td4300-panel",
> +		.data = &td4300_panel_data,
> +	}, { }
> +};
> +MODULE_DEVICE_TABLE(of, tddi_of_device_id);
> +
> +static struct mipi_dsi_driver tddi_dsi_driver = {
> +	.probe = tddi_probe,
> +	.remove = tddi_remove,
> +	.driver = {
> +		.name = "panel-synaptics-tddi",
> +		.of_match_table = tddi_of_device_id,
> +	},
> +};
> +module_mipi_dsi_driver(tddi_dsi_driver);
> +
> +MODULE_AUTHOR("Kaustabh Chakraborty <kauschluss@disroot.org>");
> +MODULE_DESCRIPTION("Synaptics TDDI Display Panel Driver");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.50.0
> 

-- 
With best wishes
Dmitry

Re: [PATCH v3 1/2] dt-bindings: display: panel: document Synaptics TDDI panel

[Kaustabh Chakraborty]

On 2025-08-03 12:02, Dmitry Baryshkov wrote:
> On Sun, Jul 20, 2025 at 05:31:54PM +0530, Kaustabh Chakraborty wrote:
>> Document the Synaptics TDDI (Touch/Display Integration) panel 
>> hardware.
>> Along with the MIPI-DSI panel, these devices also have an in-built LED
>> backlight device and a touchscreen, all packed together in a single 
>> chip.
>> 
>> Also, add compatibles for supported panels - TD4101 and TD4300. Both
>> have the '-panel' suffix so as to remove any ambiguity between the 
>> panel
>> and touchscreen chips.
>> 
>> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
>> ---
>>  .../display/panel/synaptics,td4300-panel.yaml      | 89 
>> ++++++++++++++++++++++
>>  1 file changed, 89 insertions(+)
>> 
>> diff --git 
>> a/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml 
>> b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
>> new file mode 100644
>> index 
>> 0000000000000000000000000000000000000000..152d94367130e9d80a885fe87a2da53db88e3393
>> --- /dev/null
>> +++ 
>> b/Documentation/devicetree/bindings/display/panel/synaptics,td4300-panel.yaml
>> @@ -0,0 +1,89 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: 
>> http://devicetree.org/schemas/display/panel/synaptics,td4300-panel.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Synaptics TDDI Display Panel Controller
>> +
>> +maintainers:
>> +  - Kaustabh Chakraborty <kauschluss@disroot.org>
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - syna,td4101-panel
>> +      - syna,td4300-panel
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  vio-supply:
>> +    description: core I/O voltage supply
>> +
>> +  vsn-supply:
>> +    description: negative voltage supply for analog circuits
>> +
>> +  vsp-supply:
>> +    description: positive voltage supply for analog circuits
>> +
>> +  backlight-gpios:
>> +    maxItems: 1
>> +    description: backlight enable GPIO
>> +
>> +  reset-gpios: true
>> +  width-mm: true
>> +  height-mm: true
>> +  panel-timing: true
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - width-mm
>> +  - height-mm
>> +  - panel-timing
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +
>> +    dsi {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        panel@0 {
>> +            compatible = "syna,td4300-panel";
>> +            reg = <0>;
>> +
>> +            vio-supply = <&panel_vio_reg>;
>> +            vsn-supply = <&panel_vsn_reg>;
>> +            vsp-supply = <&panel_vsp_reg>;
>> +
>> +            backlight-gpios = <&gpd3 5 GPIO_ACTIVE_LOW>;
>> +            reset-gpios = <&gpd3 4 GPIO_ACTIVE_LOW>;
>> +
>> +            width-mm = <68>;
>> +            height-mm = <121>;
>> +
>> +            panel-timing {
> 
> Are the timings defined by the 'TD4300' name or might there be 
> different
> panels with the same name but different timings?

Yes, if I recall correctly, the same panel was used by some Huawei 
phones
with different panel timings. So this is just future-proofing.

> 
>> +                clock-frequency = <144389520>;
>> +
>> +                hactive = <1080>;
>> +                hsync-len = <4>;
>> +                hfront-porch = <120>;
>> +                hback-porch = <32>;
>> +
>> +                vactive = <1920>;
>> +                vsync-len = <2>;
>> +                vfront-porch = <21>;
>> +                vback-porch = <4>;
>> +            };
>> +        };
>> +    };
>> +
>> +...
>> 
>> --
>> 2.50.0
>> 
> 
> --
> With best wishes
> Dmitry