Re: [PATCH V4 21/22] ARM: dts: stm32: Add bindings for USB on AV96

[Marek Vasut <marex@denx.de>]

On 4/11/20 6:12 AM, Manivannan Sadhasivam wrote:
> On Fri, Apr 10, 2020 at 08:02:51PM +0200, Marek Vasut wrote:
>> On 4/10/20 1:34 PM, Manivannan Sadhasivam wrote:
>>> On Fri, Apr 10, 2020 at 11:16:53AM +0200, Marek Vasut wrote:
>>>> On 4/10/20 11:08 AM, Manivannan Sadhasivam wrote:
>>>>> Hi,
>>>>
>>>> Hi,
>>>>
>>>>> On Tue, Apr 07, 2020 at 08:37:50PM +0200, Marek Vasut wrote:
>>>>>> On 4/6/20 1:08 PM, Marek Vasut wrote:
>>>>>>> On 4/6/20 9:22 AM, Manivannan Sadhasivam wrote:
>>>>>>>> On Wed, Apr 01, 2020 at 03:22:36PM +0200, Marek Vasut wrote:
>>>>>>>>> Fill in the bindings for USB host and gadget on AV96.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Marek Vasut <marex@denx.de>
>>>>>>>>
>>>>>>>> I can't get the USB B-Micro OTG port to work with this patch. Do I need to
>>>>>>>> enable any configs other than PHY and USB DWC2 drivers?
>>>>>>>
>>>>>>> Only the DWC2 GADGET (and possibly host, for dual-role) and some gadget
>>>>>>> implementation (e.g. gadget zero).
>>>>>>
>>>>>> I think I see what doesn't work for you.
>>>>>>
>>>>>> It seems the following works on next:
>>>>>> power on -> plug in USB stick (or any other USB device) -> unplug ->
>>>>>> plug in usb host (e.g. PC)
>>>>>>
>>>>>> But this does not:
>>>>>> power on -> plug in usb host (e.g. PC)
>>>>>>  - the PC is not detected
>>>>>>
>>>>>
>>>>> Both doesn't work. I have the rndis gadget configured in userspace but plugging
>>>>> in the micro-b cable doesn't do anything.
>>>>>
>>>>>> Did that ^ ever work for you before ? I suspect this is a bug in the
>>>>>> DWC2 driver. The OTG operation there is known to be flaky at best.
>>>>>
>>>>> Not on this board. I don't recall what happended with vendor image. But I do
>>>>> have another STM32MP1 based 96Board (which will be submitted soon), there I can
>>>>> get OTG port working.
>>>>>
>>>>> But in that board a BG96 modem is connected to USB2 port on the board itself
>>>>> which gets enumerated during probe.
>>>>
>>>> But it's not configured as OTG on this other board, right ?
>>>
>>> It is configured as a OTG port. But that board has a different issue which
>>> resets the board when we connect any OTG cable to act as a host. That's not
>>> related to DWC2 or this issue btw.
>>
>> Do I misunderstand the part where you claim there is a modem connected
>> to the DWC2 ? That would mean it's in Host mode, no ?
>>
> 
> Let me make it clear. On that board, the USB connection is almost similar to
> Avenger96 except that there is only one host port used and it is connected to
> the BG96 modem onboard. The other OTG port is connected to micro-b connector.

So the BG96 modem is irrelevant, since it's connected to EHCI HCD,
different controller altogether.

> There I can _only_ get the OTG port to work in device mode. I haven't figured
> out what is the exact issue yet. So in the meantime, I may use
> 
> dr_mode = "peripheral"
> 
> to avoid it being used as host. But on Avenger96 board, the host ports are
> working but the OTG port is neither working as host nor as device.

Is there any difference in the DT between the AV96 and your custom board ?

In particular, look at
&pwr_regulators {
         vdd-supply = <&vdd_io>;
         vdd_3v3_usbfs-supply = <&vdd_usb>;
};

&usbotg_hs {} node and all the other usb* nodes.

>>> Anyway, I can't get OTG (device/host) to work on both old and new boards.
>>
>> Do you have 588-200 now too ?
>>
> 
> I have both 588-100 and 588-200 now. I told you that at the time of initial
> upstreaming I had only 588-100 but later Arrow sent me the new board.

OK good.

>> I think there is some fix in current linux-next which partly fixes the
>> DWC2 role switching, so rebase this patchset on current linux-next and
>> see what happens. But it's still not perfect. I also think that ST
>> managed to side-step this issue by using the STUSB1600 chip, but I might
>> be wrong.
> 
> Okay, I'll try for both Avenger96 and Stinger96 (yeah that's the name of the
> board I'm working on right now).

OK, so the OTG should be indeed almost identical.

Try the latest linux-next, the DWC2 behaves "better" in there. And try
plugging in some USB device first (like a USB stick), see if that's
detected.

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