dt-bindings: it6505: add properties to restrict output bandwidth

Currently there are no "upstream" users. So, no existing users to break.
Add properties to restrict dp output data-lanes and clock.

Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
Signed-off-by: allen Chen <allen.chen@ite.com.tw>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221103091243.96036-2-allen.chen@ite.com.tw

Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml

@@ -52,9 +52,49 @@ properties:
     maxItems: 1
     description: extcon specifier for the Power Delivery
 
-  port:
-    $ref: /schemas/graph.yaml#/properties/port
-    description: A port node pointing to DPI host port node
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: A port node pointing to DPI host port node
+
+        properties:
+          endpoint:
+            $ref: /schemas/graph.yaml#/$defs/endpoint-base
+            unevaluatedProperties: false
+
+            properties:
+              link-frequencies:
+                minItems: 1
+                maxItems: 1
+                description: Allowed max link frequencies in Hz
+
+      port@1:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: Video port for DP output
+
+        properties:
+          endpoint:
+            $ref: /schemas/graph.yaml#/$defs/endpoint-base
+            unevaluatedProperties: false
+
+            properties:
+              data-lanes:
+                minItems: 1
+                uniqueItems: true
+                items:
+                  - enum: [ 0, 1 ]
+                  - const: 1
+                  - const: 2
+                  - const: 3
+
+    required:
+      - port@0
+      - port@1
 
 required:
   - compatible
@@ -63,6 +103,7 @@ required:
   - interrupts
   - reset-gpios
   - extcon
+  - ports
 
 additionalProperties: false
 
@@ -85,9 +126,24 @@ examples:
             reset-gpios = <&pio 179 1>;
             extcon = <&usbc_extcon>;
 
-            port {
-                it6505_in: endpoint {
-                    remote-endpoint = <&dpi_out>;
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+                    it6505_in: endpoint {
+                        remote-endpoint = <&dpi_out>;
+                        link-frequencies = /bits/ 64 <150000000>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    it6505_out: endpoint {
+                        remote-endpoint = <&dp_in>;
+                        data-lanes = <0 1>;
+                    };
                 };
             };
         };