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

Hi André,

On Sat, 7 Dec 2024 at 22:03, Peter Griffin [off-list ref] wrote:

Hi André,

On Fri, 6 Dec 2024 at 16:31, André Draszik [off-list ref] wrote:

quoted

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.

You can disregard this point, I had a typo in my test setup :( I just
confirmed that it is detected as SuperSpeed in both orientations.

Thanks,

Peter