[PATCH V3] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Mon, Jan 17, 2022 at 7:46 PM Fabio Estevam <festevam at gmail.com> wrote:
>
> Hi Adam,
>
> On Mon, Jan 17, 2022 at 9:21 PM Adam Ford <aford173 at gmail.com> wrote:
> >
> > The imx8mm and imx8mn appear compatible with imx7d-usb
> > flags in the OTG driver.  If the dr_mode is defined as
> > host or peripheral, the device appears to operate correctly,
> > however the auto host/peripheral detection results in an error.
> >
> > The solution isn't just adding checks for imx8mm and imx8mn to
> > the check for imx7, because the USB clock needs to be running
> > to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> >
> > Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> > so I modified that function to return an unknown state if the
> > device tree does not explicitly state whether it is a host
> > or a peripheral.
> >
> > When the driver probes, it looks to see if it's in the unknown
> > state, and only then will it read the register to auto-detect.
> >
> > Signed-off-by: Adam Ford <aford173 at gmail.com>
> > ---
> > V3:  Keep ehci_usb_of_to_plat but add the ability to return
> >      and unknown state instead of reading the register.
> >      If the probe determines the states is unknown, it will
> >      query the register after the clocks have been enabled.
> >      Because of the slight behavior change, I removed any
> >      review or tested tags.
>
> Unfortunately, v3 breaks 'ums 0 mmc 0' on the imx7s-warp board.

Thanks for testing it.

I am not really sure what's significantly different between them.  Do
you get any errors when you run UMS?

>
> The eMMC is no longer mounted and the board hangs.