[PATCH 2/3] usb: ehci-mx6: add IMX8MM OTG support

[Patrick Wildt]

Am Tue, Apr 27, 2021 at 10:50:34AM -0700 schrieb Tim Harvey:
> On Tue, Apr 27, 2021 at 10:44 AM Marek Vasut <marex at denx.de> wrote:
> >
> > On 4/27/21 7:08 PM, Tim Harvey wrote:
> > > Add support for determining host vs peripheral mode for IMX8MM
> > > configured as OTG.
> > >
> > > Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> > > ---
> > >   drivers/usb/host/ehci-mx6.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> > > index c2dfe49012..d055d2b1fe 100644
> > > --- a/drivers/usb/host/ehci-mx6.c
> > > +++ b/drivers/usb/host/ehci-mx6.c
> > > @@ -523,7 +523,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> > >                       plat->init_type = USB_INIT_DEVICE;
> > >               else
> > >                       plat->init_type = USB_INIT_HOST;
> > > -     } else if (is_mx7()) {
> > > +     } else if (is_mx7() || is_imx8mm()) {
> >
> > This likely also applies to 8mq/mm/mn/mp , i.e. all of them.
> 
> Agreed. Perhaps Adam, Frieder, or Fabio have something to test with? I
> only have IMX8M Mini at the moment.

No, I don't think this applies to all of them, 8MM and 8MN should be
correct.

So from a historic point of view the first one that showed up is the
8MQ, which has a DesignWare xHCI controller.  There's no eHCI, so this
driver doesn't attach and there is neither the fsl,imx27-usb nor the
fsl,imx7d-usb compatible.  Hence not having imx8mq should be correct.

When the i.MX8MM showed up the biggest difference obviously was the
silicon technology, reducing temperature.  But it also replaced the
DesignWare xHCI with ... what was it, the cadence OTG controller?
This is basically a carbon copy of the fsl,imx7d-usb (which has the
i.MX6 as heritage).  Hence imx8mm is correct here.

Then the i.MX8MP showed up, which is builds on that, but it finally
gets the DesignWare xHCI back.  So in that regard it's more a better
version of i.MX8MQ.  The fsl,imx7d-usb compatible is not part of the
dts, hence not having imx8mp should be correct.

The i.MX8MN is new to me, but by grepping you can see that the MN also
has the fsl,imx7d-usb compatible.

Hence I think only 8MM and 8MN should be added, not 8MQ or 8MP.

Patrick