Mediatek MT7530 Ethernet switch
================================

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
	on multi-chip module belong to MT7623A has or the remotely standalone
	chip as the function MT7623N reference board provided for.

If compatible mediatek,mt7530 is set then the following properties are required

- core-supply: Phandle to the regulator node necessary for the core power.
- io-supply: Phandle to the regulator node necessary for the I/O power.
	See Documentation/devicetree/bindings/regulator/mt6323-regulator.txt
	for details for the regulator setup on these boards.

If the property mediatek,mcm isn't defined, following property is required

- reset-gpios: Should be a gpio specifier for a reset line.

Else, following properties are required

- resets : Phandle pointing to the system reset controller with
	line index for the ethsys.
- reset-names : Should be set to "mcm".

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, the following values are 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 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.
   Note: On a MT7621 SOC with integrated switch: 2nd GMAC can only connected to
	 GMAC5 when the gpios for RGMII2 (GPIO 22-33) are not used and not
	 connected to external component!

Port 5 modes/configurations:
1. Port 5 is disabled and isolated: An external phy can interface to the 2nd
   GMAC of the SOC.
   In the case of a build-in MT7530 switch, port 5 shares the RGMII bus with 2nd
   GMAC and an optional external phy. Mind the GPIO/pinctl settings of the SOC!
2. Port 5 is muxed to PHY of port 0/4: Port 0/4 interfaces with 2nd GMAC.
   It is a simple MAC to PHY interface, port 5 needs to be setup for xMII mode
   and RGMII delay.
3. Port 5 is muxed to GMAC5 and can interface to an external phy.
   Port 5 becomes an extra switch port.
   Only works on platform where external phy TX<->RX lines are swapped.
   Like in the Ubiquiti ER-X-SFP.
4. Port 5 is muxed to GMAC5 and interfaces with the 2nd GAMC as 2nd CPU port.
   Currently a 2nd CPU port is not supported by DSA code.

Depending on how the external PHY is wired:
1. normal: The PHY can only connect to 2nd GMAC but not to the switch
2. swapped: RGMII TX, RX are swapped; external phy interface with the switch as
   a ethernet port. But can't interface to the 2nd GMAC.

Based on the DT the port 5 mode is configured.

Driver tries to lookup the phy-handle of the 2nd GMAC of the master device.
When phy-handle matches PHY of port 0 or 4 then port 5 set-up as mode 2.
phy-mode must be set, see also example 2 below!
 * mt7621: phy-mode = "rgmii-txid";
 * mt7623: phy-mode = "rgmii";

See Documentation/devicetree/bindings/net/dsa/dsa.txt for a list of additional
required, optional properties and how the integrated switch subnodes must
be specified.

Example:

	&mdio0 {
		switch@0 {
			compatible = "mediatek,mt7530";
			#address-cells = <1>;
			#size-cells = <0>;
			reg = <0>;

			core-supply = <&mt6323_vpa_reg>;
			io-supply = <&mt6323_vemc3v3_reg>;
			reset-gpios = <&pio 33 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 = "trgmii";
					fixed-link {
						speed = <1000>;
						full-duplex;
					};
				};
			};
		};
	};

Example 2: MT7621: Port 4 is WAN port: 2nd GMAC -> Port 5 -> PHY port 4.

&eth {
	gmac0: mac@0 {
		compatible = "mediatek,eth-mac";
		reg = <0>;
		phy-mode = "rgmii";

		fixed-link {
			speed = <1000>;
			full-duplex;
			pause;
		};
	};

	gmac1: mac@1 {
		compatible = "mediatek,eth-mac";
		reg = <1>;
		phy-mode = "rgmii-txid";
		phy-handle = <&phy4>;
	};

	mdio: mdio-bus {
		#address-cells = <1>;
		#size-cells = <0>;

		/* Internal phy */
		phy4: ethernet-phy@4 {
			reg = <4>;
		};

		mt7530: switch@1f {
			compatible = "mediatek,mt7621";
			#address-cells = <1>;
			#size-cells = <0>;
			reg = <0x1f>;
			pinctrl-names = "default";
			mediatek,mcm;

			resets = <&rstctrl 2>;
			reset-names = "mcm";

			ports {
				#address-cells = <1>;
				#size-cells = <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";
				};

/* Commented out. Port 4 is handled by 2nd GMAC.
				port@4 {
					reg = <4>;
					label = "lan4";
				};
*/

				cpu_port0: port@6 {
					reg = <6>;
					label = "cpu";
					ethernet = <&gmac0>;
					phy-mode = "rgmii";

					fixed-link {
						speed = <1000>;
						full-duplex;
						pause;
					};
				};
			};
		};
	};
};

Example 3: MT7621: Port 5 is connected to external PHY: Port 5 -> external PHY.

&eth {
	gmac0: mac@0 {
		compatible = "mediatek,eth-mac";
		reg = <0>;
		phy-mode = "rgmii";

		fixed-link {
			speed = <1000>;
			full-duplex;
			pause;
		};
	};

	mdio: mdio-bus {
		#address-cells = <1>;
		#size-cells = <0>;

		/* External phy */
		ephy5: ethernet-phy@7 {
			reg = <7>;
		};

		mt7530: switch@1f {
			compatible = "mediatek,mt7621";
			#address-cells = <1>;
			#size-cells = <0>;
			reg = <0x1f>;
			pinctrl-names = "default";
			mediatek,mcm;

			resets = <&rstctrl 2>;
			reset-names = "mcm";

			ports {
				#address-cells = <1>;
				#size-cells = <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 = "lan4";
				};

				port@5 {
					reg = <5>;
					label = "lan5";
					phy-mode = "rgmii";
					phy-handle = <&ephy5>;
				};

				cpu_port0: port@6 {
					reg = <6>;
					label = "cpu";
					ethernet = <&gmac0>;
					phy-mode = "rgmii";

					fixed-link {
						speed = <1000>;
						full-duplex;
						pause;
					};
				};
			};
		};
	};
};