Hi, Peter Chen writes: >> Peter Chen writes: >>> That's very strange, that means the SoC doesn't know VBUS fails down >>> after detaching from the host. >>> You could measure the VBUS value at the board, then read the VBUS >>> value at register to confirm it. >> >> I have put a scope on VBUS. With kernel 4.9 after detaching, it >> discharges all the way down to about 500 mV, with 4.19 this >> discharging stops after about 4 seconds at about 2.4V and remains there. >> > > I suspect it is not related to USB, would you please disable USB node at DTS > to measure again?
With USB disabled (&usbotg1 and &usbotg2), VBUS is available when I connect to the host and properly discharged when I disconnect. I also tried the OTG's host mode yesterday. When I attach a Micro-B plug to A-receptable adapter (and no actual gadget), the GPIO-controlled regulator is turned on and drives VBUS. When I detach it and the board switches back to gadget, the regulator is turned off and VBUS is properly drained. Cheers, Kai
