dt-bindings: usb: amlogic,meson-g12a-usb-ctrl: add the Amlogic AXG Families USB Glue Bindings

The Amlogic AXG is close to the GXL Glue but with a single OTG PHY.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Documentation/devicetree/bindings/usb/amlogic,meson-g12a-usb-ctrl.yaml

@@ -25,13 +25,14 @@ description: |
   The Amlogic A1 embeds a DWC3 USB IP Core configured for USB2 in
   host-only mode.
 
-  The Amlogic GXL & GXM SoCs doesn't embed an USB3 PHY.
+  The Amlogic GXL, GXM & AXG SoCs doesn't embed an USB3 PHY.
 
 properties:
   compatible:
     enum:
       - amlogic,meson-gxl-usb-ctrl
       - amlogic,meson-gxm-usb-ctrl
+      - amlogic,meson-axg-usb-ctrl
       - amlogic,meson-g12a-usb-ctrl
       - amlogic,meson-a1-usb-ctrl
 
@@ -151,6 +152,25 @@ allOf:
 
       required:
         - clock-names
+  - if:
+      properties:
+        compatible:
+          enum:
+            - amlogic,meson-axg-usb-ctrl
+
+    then:
+      properties:
+        phy-names:
+          items:
+            - const: usb2-phy1 # USB2 PHY1 if USBOTG_B port is used
+        clocks:
+          minItems: 2
+        clock-names:
+          items:
+            - const: usb_ctrl
+            - const: ddr
+      required:
+        - clock-names
   - if:
       properties:
         compatible: