@@ -5,6 +5,7 @@ Required properties:
 
 - compatible: may be compatible = "mediatek,mt7530"
 	or compatible = "mediatek,mt7621"
+	or compatible = "mediatek,mt7531"
 - #address-cells: Must be 1.
 - #size-cells: Must be 0.
 - mediatek,mcm: Boolean; if defined, indicates that either MT7530 is the part

@@ -32,10 +33,13 @@ Required properties for the child nodes within ports container:
 
 - reg: Port address described must be 6 for CPU port and from 0 to 5 for
 	user ports.
-- phy-mode: String, must be either "trgmii" or "rgmii" for port labeled
-	 "cpu".
+- phy-mode: String, the follow value would be acceptable for port labeled "cpu"
+	If compatible mediatek,mt7530 or mediatek,mt7621 is set,
+	must be either "trgmii" or "rgmii"
+	If compatible mediatek,mt7531 is set,
+	must be either "sgmii", "1000base-x" or "2500base-x"
 
-Port 5 of the switch is muxed between:
+Port 5 of mt7530 and mt7621 switch is muxed between:
 1. GMAC5: GMAC5 can interface with another external MAC or PHY.
 2. PHY of port 0 or port 4: PHY interfaces with an external MAC like 2nd GMAC
    of the SOC. Used in many setups where port 0/4 becomes the WAN port.

@@ -308,3 +312,70 @@ Example 3: MT7621: Port 5 is connected to external PHY: Port 5 -> external PHY.
 		};
 	};
 };
+
+Example 4:
+
+&eth {
+	gmac0: mac@0 {
+		compatible = "mediatek,eth-mac";
+		reg = <0>;
+		phy-mode = "2500base-x";
+
+		fixed-link {
+			speed = <1000>;
+			full-duplex;
+			pause;
+		};
+	};
+
+	&mdio0 {
+		switch@0 {
+			compatible = "mediatek,mt7531";
+			reg = <0>;
+			reset-gpios = <&pio 54 0>;
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				reg = <0>;
+
+				port@0 {
+					reg = <0>;
+					label = "lan0";
+				};
+
+				port@1 {
+					reg = <1>;
+					label = "lan1";
+				};
+
+				port@2 {
+					reg = <2>;
+					label = "lan2";
+				};
+
+				port@3 {
+					reg = <3>;
+					label = "lan3";
+				};
+
+				port@4 {
+					reg = <4>;
+					label = "wan";
+				};
+
+				port@6 {
+					reg = <6>;
+					label = "cpu";
+					ethernet = <&gmac0>;
+					phy-mode = "2500base-x";
+
+					fixed-link {
+						speed = <1000>;
+						full-duplex;
+						pause;
+					};
+				};
+			};
+		};
+	};