R-Car/How-to-describe-device-tree-for-R-Car-Gen3-USB2-DRD-channel

Overview
When we would like to use a USB2.0 DRD channel of R-Car Gen3 SoCs, the following device nodes require "dr_mode" properties in your device tree. Otherwise, since phy-rcar-gen3-usb2.c driver doesn't initialize specific registers, the USB2.0 channel doesn't work correctly.


 * ehci0
 * ohci0
 * hsusb
 * ehci3 (if r8a77951)
 * ohci3 (if r8a77951)
 * hsusb3 (if r8a77951)

A "dr_mode" property can have "otg", "host" or "peripheral".

Optional property "renesas,no-otg-pins"
We can set "renesas,no-otg-pins" to the following device nodes to avoid checking of ID pins for "host" or "peripheral" mode.


 * usb2_phy0
 * usb3_phy3 (if r8a77951)