dt-bindings: usb: ti,keystone-dwc3.yaml: Improve schema

There were some review comments after the patch was integrated.
Address those.

Fixes: 1883a934e1 ("dt-bindings: usb: convert keystone-usb.txt to YAML")
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Documentation/devicetree/bindings/usb/ti,keystone-dwc3.yaml

@@ -11,22 +11,36 @@ maintainers:
 
 properties:
   compatible:
-    oneOf:
-      - const: "ti,keystone-dwc3"
-      - const: "ti,am654-dwc3"
+    items:
+      - enum:
+        - ti,keystone-dwc3
+        - ti,am654-dwc3
 
   reg:
     maxItems: 1
-    description: Address and length of the register set for the USB subsystem on
-      the SOC.
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  ranges: true
 
   interrupts:
     maxItems: 1
-    description: The irq number of this device that is used to interrupt the MPU.
-
 
   clocks:
-    description: Clock ID for USB functional clock.
+    minItems: 1
+    maxItems: 2
+
+  assigned-clocks:
+    minItems: 1
+    maxItems: 2
+
+  assigned-clock-parents:
+    minItems: 1
+    maxItems: 2
 
   power-domains:
     description: Should contain a phandle to a PM domain provider node
@@ -42,33 +56,42 @@ properties:
 
   phy-names:
     items:
-      - const: "usb3-phy"
+      - const: usb3-phy
 
-  dwc3:
+  dma-coherent: true
+
+  dma-ranges: true
+
+patternProperties:
+  "usb@[a-f0-9]+$":
+    type: object
     description: This is the node representing the DWC3 controller instance
       Documentation/devicetree/bindings/usb/dwc3.txt
 
 required:
   - compatible
   - reg
+  - "#address-cells"
+  - "#size-cells"
+  - ranges
   - interrupts
-  - clocks
+
+additionalProperties: false
 
 examples:
   - |
     #include <dt-bindings/interrupt-controller/arm-gic.h>
 
-    usb: usb@2680000 {
+    dwc3@2680000 {
       compatible = "ti,keystone-dwc3";
       #address-cells = <1>;
       #size-cells = <1>;
       reg = <0x2680000 0x10000>;
       clocks = <&clkusb>;
-      clock-names = "usb";
       interrupts = <GIC_SPI 393 IRQ_TYPE_EDGE_RISING>;
       ranges;
 
-      dwc3@2690000 {
+      usb@2690000 {
         compatible = "synopsys,dwc3";
         reg = <0x2690000 0x70000>;
         interrupts = <GIC_SPI 393 IRQ_TYPE_EDGE_RISING>;