usb: Add driver to allow any GPIO to be used for 7211 USB signals

The Broadcom 7211 has new functionality that allows some USB low
speed side band signals, that go from the XHCI host controller to
pins on the chip, to be remapped to use any GPIO pin instead of the
limited set selectable by hardware. This can be done without changing
the standard driver for the host controller. There is currently
support for three USB signals, PWRON, VBUS_PRESENT and PWRFLT. This
driver will allow the remapping of any of these three signals based
on settings in the Device Tree node for the driver. The driver was
written so that it could handle additional signals added in the
future by just adding the correct properties to the DT node.

Below is an example of a DT node that would remap all three
signals:

usb_pinmap: usb-pinmap@22000d0 {
	compatible = "brcm,usb-pinmap";
	reg = <0x22000d0 0x4>;
	in-gpios = <&gpio 18 0>, <&gpio 19 0>;
	brcm,in-functions = "VBUS", "PWRFLT";
	brcm,in-masks = <0x8000 0x40000 0x10000 0x80000>;
	out-gpios = <&gpio 20 0>;
	brcm,out-functions = "PWRON";
	brcm,out-masks = <0x20000 0x800000 0x400000 0x200000>;
	interrupts = <0x0 0xb2 0x4>;
};

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Link: https://lore.kernel.org/r/20201012200007.8862-3-alcooperx@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>