Hi Martin,
On Thu, 15 Jul 2021 at 05:00, Martin Blumenstingl
<martin.blumenstingl@xxxxxxxxxxxxxx> wrote:
>
> Hi Anand,
>
> On Wed, Jul 14, 2021 at 7:25 PM Anand Moon <linux.amoon@xxxxxxxxx> wrote:
> [...]
> > Can you give these small changes a try,
> > $ git diff
> > diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts
> > b/arch/arm/boot/dts/meson8b-odroidc1.dts
> > index 748f4c6a050a..066523f14074 100644
> > --- a/arch/arm/boot/dts/meson8b-odroidc1.dts
> > +++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
> > @@ -47,8 +47,9 @@ usb_pwr_en: regulator-usb-pwr-en {
> > /*
> > * signal name from schematics: PWREN
> > */
> > - gpio = <&gpio_ao GPIOAO_5 GPIO_ACTIVE_HIGH>;
> > + gpio = <&gpio_ao GPIOAO_5 GPIO_OPEN_DRAIN>;
> > enable-active-high;
> > + regulator-always-on;
> > };
> >
> > [alarm@archl-c1e ~]$ sudo cat /sys/kernel/debug/gpio | grep usb
> > gpio-1953 (USB_HUB_RST_N |usb-hub-reset ) out hi
> > gpio-1954 (USB_OTG_PWREN |regulator-usb-pwr-en) out lo
> I can reproduce the /sys/kernel/debug/gpio output with this patch
>
> Still USB works for me regardless of whether USB_OTG_PWREN is HIGH or LOW
> This is something that is not possible if the regulator is really
> connected on the board like you are describing in this patch.
> If this .dts change was correct then I would expect that USB is
> breaking when inverting the GPIO polarity.
>
> I am using the "inverted GPIO polarity" approach to find the Ethernet
> PHY reset GPIO when working on boards for which I don't have the
> schematics:
Thanks for the hint,
> 1) make an assumption of which GPIO to use
> 2) try with GPIO_ACTIVE_LOW -> PHY should be detected
> 3) change it to GPIO_ACTIVE_HIGH -> PHY should not be found anymore
> (because it's in reset)
> 4) before submitting the board.dts upstream I of course change it back
> to GPIO_ACTIVE_LOW
Yes I am going to changes this to GPIO_ACTIVE_LOW in the next version.
These dts changes just assist in power through PHY to USB ports.
After going through the previous email I got this working see below.
[alarm@archl-c1e linux-amlogic-5.y-devel]$ sudo cat
/sys/kernel/debug/gpio | grep usb
gpio-1953 (USB_HUB_RST_N |usb-hub-reset ) out hi
gpio-1954 (USB_OTG_PWREN |regulator-usb-pwr-en) out lo ACTIVE LOW
>
> If during step 3) the PHY is still found then I know that it's not the
> correct GPIO.
> I am seeing the same behavior with this USB regulator. My
> interpretation of this is: either you are not using the right GPIO or
> the GPIO is not related to &usb1 (or it's PHY).
>
With reference to the schematic odroid-c1+_rev0.4_20160226
section USB HOST POWER ---- MP62551DGT-LF-Z
Both USB POWER and PWREN help control the power to USB Ports.
>
> Best regards,
> Martin
Thanks
-Anand
