docs(uboot/splash): Add DPI display support section

source/linux/Foundational_Components/U-Boot/UG-Splash-Screen.rst

@@ -729,6 +729,103 @@
             CONFIG_DRM_TIDSS=y
             CONFIG_PHY_CADENCE_DPHY=y
 
+Enabling DPI splash
+-------------------
+The DPI display path should be enabled and recognized during U-Boot's display pipeline detection.
+
+**Enabling DPI output in tidss_drv.c**
+
+U-Boot's ``tidss`` driver detects and initializes display pipelines in
+``tidss_enable_pipeline_components()`` (:file:`drivers/video/tidss/tidss_drv.c`) by
+matching the device-tree node name of each port's remote endpoint against known
+patterns: ``"oldi"`` and ``"dsi"``/``"dsi_host"``. A DPI panel connected
+directly to the DSS video port does not match any of these patterns, so add a ``"dpi"`` branch alongside the
+existing interfaces:
+
+.. code-block:: c
+
+   } else if (strstr(ofnode_get_name(remote_port), "dpi")) {
+       priv->bridge_dev = NULL;
+       priv->active_hw_vps[active_pipelines++] = hw_videoport;
+       break;
+   }
+
+.. note::
+
+   The match is performed against the node name of the remote port's parent
+   (``ofnode_get_name(remote_port)``), not against the panel's ``compatible``
+   property. The panel node in the device tree must include ``dpi`` in its
+   node name/label for this branch to trigger.
+
+**Adding a DPI panel node in the device tree**
+
+Add a panel node whose name contains ``dpi`` and connect it to the DSS video port
+endpoint via ``remote-endpoint``, providing the panel's ``panel-timing`` properties.
+Below is an example device-tree snippet for adding a DPI panel node:
+
+.. code-block:: dts
+
+   / {
+       panel_dpi0: panel-dpi {
+           bootph-all;
+           compatible = "simple-panel";
+           status = "okay";
+
+           port {
+               bootph-all;
+               panel_dpi0_in: endpoint {
+                   bootph-all;
+                   remote-endpoint = <&dss_vp0_endpoint>;
+               };
+           };
+
+           panel-timing {
+               bootph-all;
+               clock-frequency = <9200000>;
+               hactive = <800>;
+               vactive = <480>;
+               hfront-porch = <8>;
+               hback-porch = <4>;
+               hsync-len = <41>;
+               vfront-porch = <4>;
+               vback-porch = <2>;
+               vsync-len = <10>;
+               hsync-active = <0>;
+               vsync-active = <0>;
+               de-active = <1>;
+               pixelclk-active = <1>;
+           };
+       };
+   };
+
+   &dss0 {
+       bootph-all;
+       status = "okay";
+
+       ports {
+           bootph-all;
+           #address-cells = <1>;
+           #size-cells = <0>;
+
+           port@0 {
+               bootph-all;
+               reg = <0>;
+               dss_vp0_endpoint: endpoint {
+                   bootph-all;
+                   remote-endpoint = <&panel_dpi0_in>;
+               };
+           };
+       };
+   };
+
+The ``panel-timing`` values must match the panel's datasheet, and should be kept
+consistent with the ``panel-timing`` values used in the Linux kernel device tree for
+the same panel so that U-Boot and Linux drive the panel with identical timings across
+the splash-to-kernel handoff.
+
+Once all of the pipeline detection and device-tree changes are in place, the rest of
+the splash screen flow is identical to the flow described in the previous sections.
+
 Disable splash screen
 ---------------------