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SubjectRe: [PATCHv3 1/2] ARM64: dts: meson-gxbb-odroidc2: Fix usb phy reset warning
Hi Anand,

On Mon, Feb 4, 2019 at 9:04 PM Anand Moon <linux.amoon@gmail.com> 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

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