Re: [PATCH v4 7/7] phy: exynos5-usbdrd: allow DWC3 runtime suspend with UDC bound (E850+)

[Peter Griffin <peter.griffin@linaro.org>]

Hi André,

On Fri, 6 Dec 2024 at 16:31, André Draszik <andre.draszik@linaro.org> wrote:
>
> To make USB runtime suspend work when a UDC has been bound, the phy
> needs to inform the USBDRD controller (DWC3) that Vbus and bvalid are
> gone, so that it can in turn raise the respective gadget interrupt with
> event == DWC3_DEVICE_EVENT_DISCONNECT, which will cause the USB stack
> to clean up, allowing DWC3 to enter runtime suspend.
>
> On e850 and gs101 this isn't working, as the respective signals are not
> directly connected, and instead this driver uses override bits in the
> PHY IP to set those signals. It currently forcefully sets them to 'on',
> so the above mentioned interrupt will not be raised, preventing runtime
> suspend.
>
> To detect that state, update this driver to act on the TCPC's
> orientation signal - when orientation == NONE, Vbus is gone and we can
> clear the respective bits. Similarly, for other orientation values we
> re-enable them.
>
> This makes runtime suspend work on platforms with a TCPC (like Pixel6),
> while keeping compatibility with platforms without (e850-96).
>
> With runtime suspend working, USB-C cable orientation detection now
> also fully works on such platforms, and the link comes up as Superspeed
> as expected irrespective of the cable orientation and whether UDC /
> gadget are configured and active.
>
> Signed-off-by: André Draszik <andre.draszik@linaro.org>

As mentioned on the last patch, in my testing cable orientation
detection is working, but Pixel is detected as a superspeed device in
one orientation, and high speed device in the other orientation. So
you should either change the wording of the last paragraph in the
commit message (assuming you get the same results as me) or make it
detect as superspeed in both orientations.

Thanks,

Peter.