Quoting Peter Chen (2017-01-15 19:45:51)

So, you need to call phy_set_mode when switching between host and device.
Besides, you also need to toggle VBUSVLDEXT when the external vbus
is on or off at device mode (doesn't need for host mode), is it correct?

Correct.

At include/linux/usb/phy.h, we have .set_vbus interface, maybe you need
to port it to generic phy framework.

Ok. I'll look into that. Can the other patches in this series be picked
up? Otherwise I can resend them all again once I fix the phy_set_mode()
call location and introduce a new phy op.