diff --git a/Documentation/devicetree/bindings/net/realtek,rtl9301-mdio.yaml b/Documentation/devicetree/bindings/net/realtek,rtl9301-mdio.yaml
new file mode 100644
index 000000000000..02e4e33e9969
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/realtek,rtl9301-mdio.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/realtek,rtl9301-mdio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek RTL9300 MDIO Controller
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - realtek,rtl9302b-mdio
+              - realtek,rtl9302c-mdio
+              - realtek,rtl9303-mdio
+          - const: realtek,rtl9301-mdio
+      - const: realtek,rtl9301-mdio
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  '^mdio-bus@[0-3]$':
+    $ref: mdio.yaml#
+
+    properties:
+      reg:
+        maxItems: 1
+
+    required:
+      - reg
+
+    patternProperties:
+      '^ethernet-phy@[a-f0-9]+$':
+        type: object
+        $ref: ethernet-phy.yaml#
+        unevaluatedProperties: false
+
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    mdio-controller@ca00 {
+      compatible = "realtek,rtl9301-mdio";
+      reg = <0xca00 0x200>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      mdio-bus@0 {
+        reg = <0>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ethernet-phy@0 {
+          compatible = "ethernet-phy-ieee802.3-c45";
+          reg = <0>;
+        };
+      };
+
+      mdio-bus@1 {
+        reg = <1>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ethernet-phy@0 {
+          compatible = "ethernet-phy-ieee802.3-c45";
+          reg = <0>;
+        };
+      };
+    };
diff --git a/Documentation/devicetree/bindings/net/realtek,rtl9301-switch.yaml b/Documentation/devicetree/bindings/net/realtek,rtl9301-switch.yaml
index 5d29647bea2d..80eabc170669 100644
--- a/Documentation/devicetree/bindings/net/realtek,rtl9301-switch.yaml
+++ b/Documentation/devicetree/bindings/net/realtek,rtl9301-switch.yaml
@@ -54,6 +54,9 @@ patternProperties:
   'i2c@[0-9a-f]+$':
     $ref: /schemas/i2c/realtek,rtl9301-i2c.yaml#
 
+  'mdio-controller@[0-9a-f]+$':
+    $ref: realtek,rtl9301-mdio.yaml#
+
 required:
   - compatible
   - reg
@@ -129,15 +132,43 @@ examples:
         };
       };
 
+      mdio-controller@ca00 {
+        compatible = "realtek,rtl9301-mdio";
+        reg = <0xca00 0x200>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        mdio-bus@0 {
+          reg = <0>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          phy1: ethernet-phy@0 {
+            reg = <0>;
+          };
+        };
+        mdio-bus@1 {
+          reg = <1>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          phy2: ethernet-phy@0 {
+            reg = <0>;
+          };
+        };
+      };
+
       ethernet-ports {
         #address-cells = <1>;
         #size-cells = <0>;
 
         port@0 {
           reg = <0>;
+          phy-handle = <&phy1>;
         };
         port@1 {
           reg = <1>;
+          phy-handle = <&phy2>;
         };
       };
     };