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

[Marek Vasut]

On 4/28/21 3:55 AM, Tim Harvey wrote:
> On Tue, Apr 27, 2021 at 12:52 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 4/27/21 9:24 PM, Patrick Wildt wrote:
>>> 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?
>>
>> chipidea
>>
>>> This is basically a carbon copy of the fsl,imx7d-usb (which has the
>>> i.MX6 as heritage).  Hence imx8mm is correct here.
>>
>> Not quite, the mx8mm/mn variant is a bit more complex due to the extra
>> power domain stuff. And the PHY/MISC bits changed from mx7 too.
>>
>>> 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.
>>
>> Seems there is always some sort of overlap between the Ms in terms of
>> IPs that are reused.
>>
>>> Hence I think only 8MM and 8MN should be added, not 8MQ or 8MP.
>>
>> I agree, 8MP also only lists xhci (likely dwc3), like original M(Q).
>> MN should work, I use these patches on a board with it, in host mode only.
> 
> I will re-submit and add is_imx8mn().... that's what the NXP
> downstream u-boot does as well.

Thanks