Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt

   1 Rockchip EMMC PHY
   2 -----------------------
   3
   4 Required 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
  10 Optional 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
  20 Example:
  21
  22
  23 grf: syscon@ff770000 {
  24         compatible = "rockchip,rk3399-grf", "syscon", "simple-mfd";
  25         #address-cells = <1>;
  26         #size-cells = <1>;
  27
  28 ...
  29
  30         emmcphy: phy@f780 {
  31                 compatible = "rockchip,rk3399-emmc-phy";
  32                 reg = <0xf780 0x20>;
  33                 clocks = <&sdhci>;
  34                 clock-names = "emmcclk";
  35                 drive-impedance-ohm = <50>;
  36                 #phy-cells = <0>;
  37         };
  38 };