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 <[email protected]>
---
 drivers/gpu/drm/panel/Kconfig                |  11 ++
 drivers/gpu/drm/panel/Makefile               |   1 +
 drivers/gpu/drm/panel/panel-synaptics-tddi.c | 284 +++++++++++++++++++++++++++
 3 files changed, 296 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 
d5aa1c95c6a45b2fea9b1d7a9e8a39fe617b860c..ad906d96ac5cbbbd6846d6c6a9043033660daf54
 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -1011,6 +1011,17 @@ 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 
73a39bc726045f3ce52fdeef8c0ec762a4a378c7..3cde8f27e7e6c1d12b08fd2f9e6252dd121a6b38
 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -97,6 +97,7 @@ 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..c081380c087a927634d1452c151dfa350149add5
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-synaptics-tddi.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Synaptics TDDI display panel driver.
+ *
+ * Copyright (C) 2025 Kaustabh Chakraborty <[email protected]>
+ */
+
+#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[3];
+       struct gpio_desc *reset_gpio;
+       struct gpio_desc *backlight_gpio;
+       u32 bus_flags;
+       u32 width;
+       u32 height;
+};
+
+static inline struct tddi_ctx *to_tddi_ctx(struct drm_panel *panel)
+{
+       return container_of(panel, struct tddi_ctx, panel);
+}
+
+static int tddi_update_brightness(struct backlight_device *backlight)
+{
+       struct mipi_dsi_multi_context dsi = { .dsi = bl_get_data(backlight) };
+       u8 brightness = backlight->props.brightness;
+
+       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(ctx->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(ctx->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_brightness,
+};
+
+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_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+       if (!ctx)
+               return -ENOMEM;
+
+       ctx->data = of_device_get_match_data(dev);
+
+       ctx->dsi = dsi;
+       mipi_dsi_set_drvdata(dsi, ctx);
+
+       ctx->supplies[0].supply = "vio";
+       ctx->supplies[1].supply = "vsn";
+       ctx->supplies[2].supply = "vsp";
+       ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->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,
+                                                       dsi, &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;
+
+       drm_panel_init(&ctx->panel, dev, &tddi_drm_panel_funcs,
+                      DRM_MODE_CONNECTOR_DSI);
+       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 <[email protected]>");
+MODULE_DESCRIPTION("Synaptics TDDI Display Panel Driver");
+MODULE_LICENSE("GPL");

-- 
2.49.0

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