Re: [PATCH] arm64: dts: allwinner: properly connect USB PHY to port 0

[Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org>]

On Mon, 24 Jun 2019 16:25:47 +0800
Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org> wrote:

Hi,

> On Thu, Jun 20, 2019 at 9:02 AM Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org> wrote:
> >
> > In recent Allwinner SoCs the first USB host controller (HCI0) shares
> > the first PHY with the MUSB controller. Probably to make this sharing
> > work, we were avoiding to declare this in the DT. This has two
> > shortcomings:
> > - U-Boot (which uses the same .dts) cannot use this port without a PHY
> >   linked, so we were loosing one USB port there.
> > - It requires the MUSB driver to be enabled and loaded, although we
> >   don't actually use it.
> >
> > For those (64-bit) boards which use an USB-A socket for HCI0/MUSB, add
> > a "phys" property pointing to the USB PHY 0.
> >
> > This makes it work in U-Boot, also improves compatiblity when no MUSB
> > driver is loaded (for instance in distribution installers).
> >
> > Signed-off-by: Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org>
> > ---
> > Hi,
> >
> > I have the feeling this belongs into the .dtsi, but cant't tell for sure
> > how this interacts with the MUSB driver. If need be, we can always pull
> > this up later, I guess.  
> 
> Have you tried if gadget mode and switching between gadget/host mode on
> an otg port still works? AFAICT that would be the main thing to worry
> about.

I briefly tried gadget mode on a BPi-M64, and that still seemed to work,
but I couldn't switch it to host mode. IIRC that didn't even work without
this patch, but I didn't find the time to investigate yet.

Is it supposed to switch automatically when the ID pin changes state? Do
you know a board/kernel combination which is known to work?

Cheers,
Andre.