1Rockchip EMMC PHY
2-----------------------
3
4Required properties:
5 - compatible: rockchip,rk3399-emmc-phy
6 - #phy-cells: must be 0
7 - reg: PHY register address offset and length in "general
8   register files"
9
10Optional properties:
11 - clock-names: Should contain "emmcclk".  Although this is listed as optional
12		(because most boards can get basic functionality without having
13		access to it), it is strongly suggested.
14		See ../clock/clock-bindings.txt for details.
15 - clocks: Should have a phandle to the card clock exported by the SDHCI driver.
16 - drive-impedance-ohm: Specifies the drive impedance in Ohm.
17                        Possible values are 33, 40, 50, 66 and 100.
18                        If not set, the default value of 50 will be applied.
19 - rockchip,enable-strobe-pulldown: Enable internal pull-down for the strobe
20                                    line.  If not set, pull-down is not used.
21 - rockchip,output-tapdelay-select: Specifies the phyctrl_otapdlysec register.
22                                    If not set, the register defaults to 0x4.
23                                    Maximum value 0xf.
24
25Example:
26
27
28grf: syscon@ff770000 {
29	compatible = "rockchip,rk3399-grf", "syscon", "simple-mfd";
30	#address-cells = <1>;
31	#size-cells = <1>;
32
33...
34
35	emmcphy: phy@f780 {
36		compatible = "rockchip,rk3399-emmc-phy";
37		reg = <0xf780 0x20>;
38		clocks = <&sdhci>;
39		clock-names = "emmcclk";
40		drive-impedance-ohm = <50>;
41		#phy-cells = <0>;
42	};
43};
44