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 <kauschl...@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 <kauschl...@disroot.org>");
> +MODULE_DESCRIPTION("Synaptics TDDI Display Panel Driver");
> +MODULE_LICENSE("GPL");
>
> --
> 2.50.0
>
--
With best wishes
Dmitry
