dt-bindings: usb: document aspeed vhub device ID/string properties

Update device tree binding document for aspeed vhub's device IDs and
string properties.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Documentation/devicetree/bindings/usb/aspeed,usb-vhub.yaml

@@ -52,6 +52,59 @@ properties:
         minimum: 1
         maximum: 21
 
+  vhub-vendor-id:
+    description: vhub Vendor ID
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - maximum: 65535
+
+  vhub-product-id:
+    description: vhub Product ID
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - maximum: 65535
+
+  vhub-device-revision:
+    description: vhub Device Revision in binary-coded decimal
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - maximum: 65535
+
+  vhub-strings:
+    type: object
+
+    properties:
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
+    patternProperties:
+      '^string@[0-9a-f]+$':
+        type: object
+        description: string descriptors of the specific language
+
+        properties:
+          reg:
+            maxItems: 1
+            description: 16-bit Language Identifier defined by USB-IF
+
+          manufacturer:
+            description: vhub manufacturer
+            allOf:
+              - $ref: /schemas/types.yaml#/definitions/string
+
+          product:
+            description: vhub product name
+            allOf:
+              - $ref: /schemas/types.yaml#/definitions/string
+
+          serial-number:
+            description: vhub device serial number
+            allOf:
+              - $ref: /schemas/types.yaml#/definitions/string
+
 required:
   - compatible
   - reg
@@ -74,4 +127,19 @@ examples:
             aspeed,vhub-generic-endpoints = <15>;
             pinctrl-names = "default";
             pinctrl-0 = <&pinctrl_usb2ad_default>;
+
+            vhub-vendor-id = <0x1d6b>;
+            vhub-product-id = <0x0107>;
+            vhub-device-revision = <0x0100>;
+            vhub-strings {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                string@0409 {
+                        reg = <0x0409>;
+                        manufacturer = "ASPEED";
+                        product = "USB Virtual Hub";
+                        serial-number = "0000";
+                };
+            };
     };