ST STiH407 USB PHY controller

This file documents the dt bindings for the usb picoPHY driver which is the PHY for both USB2 and USB3
host controllers (when controlling usb2/1.1 devices) available on STiH407 SoC family from STMicroelectronics.

Required properties:
- compatible		: should be "st,stih407-usb2-phy"
- st,syscfg		: phandle of sysconfig bank plus integer array containing phyparam and phyctrl register offsets
- resets		: list of phandle and reset specifier pairs. There should be two entries, one
			  for the whole phy and one for the port
- reset-names		: list of reset signal names. Should be "global" and "port"
See: Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
See: Documentation/devicetree/bindings/reset/reset.txt

Example:

usb2_picophy0: usbpicophy {
	compatible	= "st,stih407-usb2-phy";
	#phy-cells	= <0>;
	st,syscfg	= <&syscfg_core 0x100 0xf4>;
	resets		= <&softreset STIH407_PICOPHY_SOFTRESET>,
			  <&picophyreset STIH407_PICOPHY0_RESET>;
	reset-names	= "global", "port";
};