dt-bindings: display: bridge: renesas,dsi-csi2-tx: Allow panel@ subnode

This controller can have both bridges and panels connected to it. In
order to describe panels properly in DT, pull in dsi-controller.yaml
and disallow only unevaluatedProperties, because the panel node is
optional. Include example binding with panel.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/r/20250904210147.186728-4-marek.vasut+renesas@mailbox.org

Documentation/devicetree/bindings/display/bridge/renesas,dsi-csi2-tx.yaml

@@ -14,6 +14,9 @@ description: |
   R-Car Gen4 SoCs. The encoder can operate in either DSI or CSI-2 mode, with up
   to four data lanes.
 
+allOf:
+  - $ref: /schemas/display/dsi-controller.yaml#
+
 properties:
   compatible:
     enum:
@@ -80,14 +83,14 @@ required:
   - resets
   - ports
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
     #include <dt-bindings/clock/r8a779a0-cpg-mssr.h>
     #include <dt-bindings/power/r8a779a0-sysc.h>
 
-    dsi0: dsi-encoder@fed80000 {
+    dsi@fed80000 {
         compatible = "renesas,r8a779a0-dsi-csi2-tx";
         reg = <0xfed80000 0x10000>;
         power-domains = <&sysc R8A779A0_PD_ALWAYS_ON>;
@@ -117,4 +120,50 @@ examples:
             };
         };
     };
+
+  - |
+    #include <dt-bindings/clock/r8a779g0-cpg-mssr.h>
+    #include <dt-bindings/power/r8a779g0-sysc.h>
+
+    dsi@fed80000 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "renesas,r8a779g0-dsi-csi2-tx";
+        reg = <0xfed80000 0x10000>;
+        clocks = <&cpg CPG_MOD 415>,
+                 <&cpg CPG_CORE R8A779G0_CLK_DSIEXT>,
+                 <&cpg CPG_CORE R8A779G0_CLK_DSIREF>;
+        clock-names = "fck", "dsi", "pll";
+        power-domains = <&sysc R8A779G0_PD_ALWAYS_ON>;
+        resets = <&cpg 415>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+            };
+
+            port@1 {
+                reg = <1>;
+
+                dsi0port1_out: endpoint {
+                    remote-endpoint = <&panel_in>;
+                    data-lanes = <1 2>;
+                };
+            };
+        };
+
+        panel@0 {
+            reg = <0>;
+            compatible = "raspberrypi,dsi-7inch";
+
+            port {
+                panel_in: endpoint {
+                    remote-endpoint = <&dsi0port1_out>;
+                };
+            };
+        };
+    };
 ...