Rockchip SoC RK3288 10/100/1000 Ethernet driver(GMAC)

The device node has following properties.

Required properties:
 - compatible: Can be one of "rockchip,rk3228-gmac", "rockchip,rk3288-gmac",
                             "rockchip,rk3368-gmac"
 - reg: addresses and length of the register sets for the device.
 - interrupts: Should contain the GMAC interrupts.
 - interrupt-names: Should contain the interrupt names "macirq".
 - rockchip,grf: phandle to the syscon grf used to control speed and mode.
 - clocks: <&cru SCLK_MAC>: clock selector for main clock, from PLL or PHY.
	   <&cru SCLK_MAC_PLL>: PLL clock for SCLK_MAC
	   <&cru SCLK_MAC_RX>: clock gate for RX
	   <&cru SCLK_MAC_TX>: clock gate for TX
	   <&cru SCLK_MACREF>: clock gate for RMII referce clock
	   <&cru SCLK_MACREF_OUT> clock gate for RMII reference clock output
	   <&cru ACLK_GMAC>: AXI clock gate for GMAC
	   <&cru PCLK_GMAC>: APB clock gate for GMAC
 - clock-names: One name for each entry in the clocks property.
 - phy-mode: See ethernet.txt file in the same directory.
 - pinctrl-names: Names corresponding to the numbered pinctrl states.
 - pinctrl-0: pin-control mode. can be <&rgmii_pins> or <&rmii_pins>.
 - clock_in_out: For RGMII, it must be "input", means main clock(125MHz)
   is not sourced from SoC's PLL, but input from PHY; For RMII, "input" means
   PHY provides the reference clock(50MHz), "output" means GMAC provides the
   reference clock.
 - snps,reset-gpio       gpio number for phy reset.
 - snps,reset-active-low boolean flag to indicate if phy reset is active low.
 - assigned-clocks: main clock, should be <&cru SCLK_MAC>;
 - assigned-clock-parents = parent of main clock.
   can be <&ext_gmac> or <&cru SCLK_MAC_PLL>.

Optional properties:
 - tx_delay: Delay value for TXD timing. Range value is 0~0x7F, 0x30 as default.
 - rx_delay: Delay value for RXD timing. Range value is 0~0x7F, 0x10 as default.
 - phy-supply: phandle to a regulator if the PHY needs one

Example:

gmac: ethernet@ff290000 {
	compatible = "rockchip,rk3288-gmac";
	reg = <0xff290000 0x10000>;
	interrupts = <GIC_SPI 27 IRQ_TYPE_LEVEL_HIGH>;
	interrupt-names = "macirq";
	rockchip,grf = <&grf>;
	clocks = <&cru SCLK_MAC>,
		<&cru SCLK_MAC_RX>, <&cru SCLK_MAC_TX>,
		<&cru SCLK_MACREF>, <&cru SCLK_MACREF_OUT>,
		<&cru ACLK_GMAC>, <&cru PCLK_GMAC>;
	clock-names = "stmmaceth",
		"mac_clk_rx", "mac_clk_tx",
		"clk_mac_ref", "clk_mac_refout",
		"aclk_mac", "pclk_mac";
	phy-mode = "rgmii";
	pinctrl-names = "default";
	pinctrl-0 = <&rgmii_pins /*&rmii_pins*/>;

	clock_in_out = "input";
	snps,reset-gpio = <&gpio4 7 0>;
	snps,reset-active-low;

	assigned-clocks = <&cru SCLK_MAC>;
	assigned-clock-parents = <&ext_gmac>;
	tx_delay = <0x30>;
	rx_delay = <0x10>;

	status = "ok";
};
