dt-bindings: net: sun4i-mdio: Convert the binding to a schemas

Switch our Allwinner A10 MDIO controller binding to a YAML schema to enable
the DT validation.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/net/allwinner,sun4i-a10-mdio.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/allwinner,sun4i-a10-mdio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A10 MDIO Controller Device Tree Bindings
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Maxime Ripard <maxime.ripard@bootlin.com>
+
+allOf:
+  - $ref: "mdio.yaml#"
+
+# Select every compatible, including the deprecated ones. This way, we
+# will be able to report a warning when we have that compatible, since
+# we will validate the node thanks to the select, but won't report it
+# as a valid value in the compatible property description
+select:
+  properties:
+    compatible:
+      enum:
+        - allwinner,sun4i-a10-mdio
+
+        # Deprecated
+        - allwinner,sun4i-mdio
+
+  required:
+    - compatible
+
+properties:
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  compatible:
+    const: allwinner,sun4i-a10-mdio
+
+  reg:
+    maxItems: 1
+
+  phy-supply:
+    description: PHY regulator
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    mdio@1c0b080 {
+        compatible = "allwinner,sun4i-a10-mdio";
+        reg = <0x01c0b080 0x14>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        phy-supply = <&reg_emac_3v3>;
+
+        phy0: ethernet-phy@0 {
+            reg = <0>;
+        };
+    };
+
+# FIXME: We should set it, but it would report all the generic
+# properties as additional properties.
+# additionalProperties: false
+
+...

Documentation/devicetree/bindings/net/allwinner,sun4i-mdio.txt

-* Allwinner A10 MDIO Ethernet Controller interface
-
-Required properties:
-- compatible: should be "allwinner,sun4i-a10-mdio"
-              (Deprecated: "allwinner,sun4i-mdio").
-- reg: address and length of the register set for the device.
-
-Optional properties:
-- phy-supply: phandle to a regulator if the PHY needs one
-
-Example at the SoC level:
-mdio@1c0b080 {
-	compatible = "allwinner,sun4i-a10-mdio";
-	reg = <0x01c0b080 0x14>;
-	#address-cells = <1>;
-	#size-cells = <0>;
-};
-
-And at the board level:
-
-mdio@1c0b080 {
-	phy-supply = <&reg_emac_3v3>;
-
-	phy0: ethernet-phy@0 {
-		reg = <0>;
-	};
-};