* Allwinner sun8i GMAC ethernet controller

This device is a platform glue layer for stmmac.
Please see stmmac.txt for the other unchanged properties.

Required properties:
- compatible: should be one of the following string:
		"allwinner,sun8i-a83t-emac"
		"allwinner,sun8i-h3-emac"
		"allwinner,sun8i-v3s-emac"
		"allwinner,sun50i-a64-emac"
- reg: address and length of the register for the device.
- interrupts: interrupt for the device
- interrupt-names: should be "macirq"
- clocks: A phandle to the reference clock for this device
- clock-names: should be "stmmaceth"
- resets: A phandle to the reset control for this device
- reset-names: should be "stmmaceth"
- phy-mode: See ethernet.txt
- phy-handle: See ethernet.txt
- #address-cells: shall be 1
- #size-cells: shall be 0
- syscon: A phandle to the syscon of the SoC with one of the following
 compatible string:
  - allwinner,sun8i-h3-system-controller
  - allwinner,sun8i-v3s-system-controller
  - allwinner,sun50i-a64-system-controller
  - allwinner,sun8i-a83t-system-controller

Optional properties:
- allwinner,tx-delay-ps: TX clock delay chain value in ps. Range value is 0-700. Default is 0)
- allwinner,rx-delay-ps: RX clock delay chain value in ps. Range value is 0-3100. Default is 0)
Both delay properties need to be a multiple of 100. They control the delay for
external PHY.

Optional properties for the following compatibles:
  - "allwinner,sun8i-h3-emac",
  - "allwinner,sun8i-v3s-emac":
- allwinner,leds-active-low: EPHY LEDs are active low

Required child node of emac:
- mdio bus node: should be named mdio

Required properties of the mdio node:
- #address-cells: shall be 1
- #size-cells: shall be 0

The device node referenced by "phy" or "phy-handle" should be a child node
of the mdio node. See phy.txt for the generic PHY bindings.

Required properties of the phy node with the following compatibles:
  - "allwinner,sun8i-h3-emac",
  - "allwinner,sun8i-v3s-emac":
- clocks: a phandle to the reference clock for the EPHY
- resets: a phandle to the reset control for the EPHY

Example:

emac: ethernet@1c0b000 {
	compatible = "allwinner,sun8i-h3-emac";
	syscon = <&syscon>;
	reg = <0x01c0b000 0x104>;
	interrupts = <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>;
	interrupt-names = "macirq";
	resets = <&ccu RST_BUS_EMAC>;
	reset-names = "stmmaceth";
	clocks = <&ccu CLK_BUS_EMAC>;
	clock-names = "stmmaceth";
	#address-cells = <1>;
	#size-cells = <0>;

	phy-handle = <&int_mii_phy>;
	phy-mode = "mii";
	allwinner,leds-active-low;
	mdio: mdio {
		#address-cells = <1>;
		#size-cells = <0>;
		int_mii_phy: ethernet-phy@1 {
			reg = <1>;
			clocks = <&ccu CLK_BUS_EPHY>;
			resets = <&ccu RST_BUS_EPHY>;
		};
	};
};