[PATCH RESEND v5 0/2] Support for Synaptics TDDI series panels

[PATCH RESEND v5 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 v5:
- added missing Reviewed-by tag from Krzysztof in [v3 1/2]
- Link to v4: https://lore.kernel.org/r/20250819-panel-synaptics-tddi-v4-0-448f466d16a6@disroot.org

Changes in v4:
- utilized drm_connector_helper_get_modes_fixed() (dmitry.baryshkov)
- constified backlight properties (dmitry.baryshkov)
- Link to v3: https://lore.kernel.org/r/20250720-panel-synaptics-tddi-v3-0-43a5957f4b24@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       | 276 +++++++++++++++++++++
 4 files changed, 377 insertions(+)
---
base-commit: 5303936d609e09665deda94eaedf26a0e5c3a087
change-id: 20250523-panel-synaptics-tddi-0b0b3f07f814

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

[PATCH RESEND v5 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.

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

-- 
2.51.0

[PATCH RESEND v5 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 | 276 +++++++++++++++++++++++++++
 3 files changed, 288 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 407c5f6a268b2ec66e5d0eddae26b3368e4cb2cb..98708979ab45281628620bbe803fe8b597eb812d 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -1045,6 +1045,17 @@ 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 3615a761b44f9de0b4a653be157d8e0bcbc8f6b7..2535e1c9df76451d1c66d7d211ac9bfbf18dc80e 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -100,6 +100,7 @@ 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..a4b3cbdebb6ca4062c02c6e7ac184f3ec245926a
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-synaptics-tddi.c
@@ -0,0 +1,276 @@
+// 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>
+#include <drm/drm_probe_helper.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;
+};
+
+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);
+
+	return drm_connector_helper_get_modes_fixed(connector, &ctx->mode);
+}
+
+static const struct backlight_ops tddi_bl_ops = {
+	.update_status = tddi_update_status,
+};
+
+static const struct backlight_properties tddi_bl_props = {
+	.type = BACKLIGHT_PLATFORM,
+	.brightness = 255,
+	.max_brightness = 255,
+};
+
+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, NULL);
+	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,
+							&tddi_bl_props);
+	if (IS_ERR(ctx->backlight))
+		return dev_err_probe(dev, PTR_ERR(ctx->backlight),
+				     "failed to register backlight device");
+
+	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");

-- 
2.51.0

Re: [PATCH RESEND v5 2/2] drm: panel: add support for Synaptics TDDI series DSI panels

[Neil Armstrong]

On 10/9/25 18:22, 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 | 276 +++++++++++++++++++++++++++
>   3 files changed, 288 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 407c5f6a268b2ec66e5d0eddae26b3368e4cb2cb..98708979ab45281628620bbe803fe8b597eb812d 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -1045,6 +1045,17 @@ 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 3615a761b44f9de0b4a653be157d8e0bcbc8f6b7..2535e1c9df76451d1c66d7d211ac9bfbf18dc80e 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -100,6 +100,7 @@ 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..a4b3cbdebb6ca4062c02c6e7ac184f3ec245926a
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-synaptics-tddi.c
> @@ -0,0 +1,276 @@
> +// 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>
> +#include <drm/drm_probe_helper.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;
> +};
> +
> +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);
> +
> +	return drm_connector_helper_get_modes_fixed(connector, &ctx->mode);
> +}
> +
> +static const struct backlight_ops tddi_bl_ops = {
> +	.update_status = tddi_update_status,
> +};
> +
> +static const struct backlight_properties tddi_bl_props = {
> +	.type = BACKLIGHT_PLATFORM,
> +	.brightness = 255,
> +	.max_brightness = 255,
> +};
> +
> +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, NULL);
> +	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,
> +							&tddi_bl_props);
> +	if (IS_ERR(ctx->backlight))
> +		return dev_err_probe(dev, PTR_ERR(ctx->backlight),
> +				     "failed to register backlight device");
> +
> +	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");
> 

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

Re: [PATCH RESEND v5 0/2] Support for Synaptics TDDI series panels

[Kaustabh Chakraborty]

Hi,

I've been trying to get this driver accepted. If panel maintainers have
haven't looked into it yet, this is a gentle reminder.

Thank you.

On 2025-10-09 16:22, Kaustabh Chakraborty wrote:
> 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 v5:
> - added missing Reviewed-by tag from Krzysztof in [v3 1/2]
> - Link to v4: https://lore.kernel.org/r/20250819-panel-synaptics-tddi-v4-0-448f466d16a6@disroot.org
> 
> Changes in v4:
> - utilized drm_connector_helper_get_modes_fixed() (dmitry.baryshkov)
> - constified backlight properties (dmitry.baryshkov)
> - Link to v3: https://lore.kernel.org/r/20250720-panel-synaptics-tddi-v3-0-43a5957f4b24@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       | 276 +++++++++++++++++++++
>  4 files changed, 377 insertions(+)
> ---
> base-commit: 5303936d609e09665deda94eaedf26a0e5c3a087
> change-id: 20250523-panel-synaptics-tddi-0b0b3f07f814
> 
> Best regards,
> -- 
> Kaustabh Chakraborty <kauschluss@disroot.org>

Re: [PATCH RESEND v5 0/2] Support for Synaptics TDDI series panels

[Neil Armstrong]

Hi,

On Thu, 09 Oct 2025 21:52:09 +0530, Kaustabh Chakraborty wrote:
> 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.
> 
> [...]

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

[1/2] dt-bindings: display: panel: document Synaptics TDDI panel
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/5c42579b0705ea372ed7e6f158c880618850b409
[2/2] drm: panel: add support for Synaptics TDDI series DSI panels
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/3eae82503f4fb24e36fc06f6827b8360678c2555

-- 
Neil