rk3399: nanopc-t4 usb otg

[Jack Mitchell <ml-psbXN780rFT10XsdtD+oqA@public.gmane.org>]

Hi,

Can anyone confirm working operation of USB OTG over a type c phy on an
RK3399 at commit 8c2ffd9174779014c3fe1f96d9dc3641d9175f00 (tag: v5.1-rc2).

I've got a nanopc-t4 here and when I try to load the g_ether driver I
receive

[    6.359280] udc-core: couldn't find an available UDC - added
[g_ether] to list of pending drivers

I've had a look through the dts and all seems to be in order. USB
devices work fine in the host ports and I've confirmed otg mode.

root@rk3399:/sys/kernel/debug/fe800000.dwc3# cat mode
otg

The cable is being detected at plug/unplug as can be seen from

[ 1252.479273] phy phy-ff770000.syscon:usb2-phy@e450.2: charger =
USB_SDP_CHARGER

My defconfig is the standard arm64 as provided with the addition of
CONFIG_USB_ETH=m.

Any information would be helpful, especially if this is working on other
3399 based boards at the mentioned commit.

Regards,
Jack.