dt-bindings: add MediaTek XS-PHY binding

MediaTek XS-PHY binding

--------------------------

The XS-PHY controller supports physical layer functionality for USB3.1

GEN2 controller on MediaTek SoCs.

Required properties (controller (parent) node):

 - compatible	: should be "mediatek,<soc-model>-xsphy", "mediatek,xsphy",

		  soc-model is the name of SoC, such as mt3611 etc;

		  when using "mediatek,xsphy" compatible string, you need SoC specific

		  ones in addition, one of:

		  - "mediatek,mt3611-xsphy"

 - #address-cells, #size-cells : should use the same values as the root node

 - ranges: must be present

Optional properties (controller (parent) node):

 - reg		: offset and length of register shared by multiple U3 ports,

		  exclude port's private register, if only U2 ports provided,

		  shouldn't use the property.

 - mediatek,src-ref-clk-mhz	: u32, frequency of reference clock for slew rate

		  calibrate

 - mediatek,src-coef	: u32, coefficient for slew rate calibrate, depends on

		  SoC process

Required nodes	: a sub-node is required for each port the controller

		  provides. Address range information including the usual

		  'reg' property is used inside these nodes to describe

		  the controller's topology.

Required properties (port (child) node):

- reg		: address and length of the register set for the port.

- clocks	: a list of phandle + clock-specifier pairs, one for each

		  entry in clock-names

- clock-names	: must contain

		  "ref": 48M reference clock for HighSpeed analog phy; and 26M

			reference clock for SuperSpeedPlus analog phy, sometimes is

			24M, 25M or 27M, depended on platform.

- #phy-cells	: should be 1

		  cell after port phandle is phy type from:

			- PHY_TYPE_USB2

			- PHY_TYPE_USB3

The following optional properties are only for debug or HQA test

Optional properties (PHY_TYPE_USB2 port (child) node):

- mediatek,eye-src	: u32, the value of slew rate calibrate

- mediatek,eye-vrt	: u32, the selection of VRT reference voltage

- mediatek,eye-term	: u32, the selection of HS_TX TERM reference voltage

- mediatek,efuse-intr	: u32, the selection of Internal Resistor

Optional properties (PHY_TYPE_USB3 port (child) node):

- mediatek,efuse-intr	: u32, the selection of Internal Resistor

- mediatek,efuse-tx-imp	: u32, the selection of TX Impedance

- mediatek,efuse-rx-imp	: u32, the selection of RX Impedance

Banks layout of xsphy

-------------------------------------------------------------

port        offset    bank

u2 port0    0x0000    MISC

            0x0100    FMREG

            0x0300    U2PHY_COM

u2 port1    0x1000    MISC

            0x1100    FMREG

            0x1300    U2PHY_COM

u2 port2    0x2000    MISC

            ...

u31 common  0x3000    DIG_GLB

            0x3100    PHYA_GLB

u31 port0   0x3400    DIG_LN_TOP

            0x3500    DIG_LN_TX0

            0x3600    DIG_LN_RX0

            0x3700    DIG_LN_DAIF

            0x3800    PHYA_LN

u31 port1   0x3a00    DIG_LN_TOP

            0x3b00    DIG_LN_TX0

            0x3c00    DIG_LN_RX0

            0x3d00    DIG_LN_DAIF

            0x3e00    PHYA_LN

            ...

DIG_GLB & PHYA_GLB are shared by U31 ports.

Example:

u3phy: usb-phy@11c40000 {

	compatible = "mediatek,mt3611-xsphy", "mediatek,xsphy";

	reg = <0 0x11c43000 0 0x0200>;

	mediatek,src-ref-clk-mhz = <26>;

	mediatek,src-coef = <17>;

	#address-cells = <2>;

	#size-cells = <2>;

	ranges;

	u2port0: usb-phy@11c40000 {

		reg = <0 0x11c40000 0 0x0400>;

		clocks = <&clk48m>;

		clock-names = "ref";

		mediatek,eye-src = <4>;

		#phy-cells = <1>;

	};

	u3port0: usb-phy@11c43000 {

		reg = <0 0x11c43400 0 0x0500>;

		clocks = <&clk26m>;

		clock-names = "ref";

		mediatek,efuse-intr = <28>;

		#phy-cells = <1>;

	};

};