Hi Anand, On Mon, Feb 4, 2019 at 9:04 PM Anand Moon <linux.amoon@xxxxxxxxx> wrote: [...] > > > @@ -36,6 +43,8 @@ > > > regulator-min-microvolt = <5000000>; > > > regulator-max-microvolt = <5000000>; > > > > > > + vin-supply = <&p5v0>; > > did you find out why this patch fixes the USB_OTG_PWR regulator? > > based on just reading the patch I can't find an explanation myself > > > > As per the device tree binding we need this setting to enable power input source > [0] Documentation/devicetree/bindings/regulator/fixed-regulator.txt > > *I have observed few more place where this setting is missing* OK, I understand that we should describe the hierarchy of the regulators > > have you tested without this patch to rule out that you hit some bug > > in the regulator framework back when you wrote the patch? > > (I don't have an Odroid-C2 so I can't test this myself). > > > > Yes I have tested this patch.Some device like usb camera and usb hard drive > when connected to usb port will generate warning message. > which shows us that not enough power is being set to the port. I don't understand why adding "p5v0" as parent of "usb_otg_pwr" changes the output of "usb_otg_pwr": - "p5v0" is a fixed regulator which cannot be controlled at all (apart from removing power from it) - "usb_otg_pwr" does not have any current limits set inside the .dts - "usb_otg_pwr" has the same fixed voltage as the new "p5v0" regulator what are your steps-to-reproduce for your original issue ("reset high-speed USB device number 3 using dwc2")? Regards Martin