linux-kernel - Re: [PATCH v2] usb: dwc2: drd: fix inconsistent mode if role-switch-default-mode="host"

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Date:   Wed, 1 Mar 2023 12:31:47 +0100
From:   Amelie Delaunay <amelie.delaunay@...s.st.com>
To:     Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
        Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
        Ziyang Huang <hzyitc@...look.com>
CC:     "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] usb: dwc2: drd: fix inconsistent mode if
 role-switch-default-mode="host"



On 3/1/23 12:26, Fabrice Gasnier wrote:
> On 2/22/23 08:00, Minas Harutyunyan wrote:
>> Hi Amelie,
>>
>> Could you please review and test this patch on your setup.
>> Doesn't broke anything.
>>
> 
> Hi Minas,
> 
> I tested at my end on behalf of Amelie.
> Of course I let her possibly comment.
> 
> This doesn't break anything on existing boards. I also tested the
> example described by Ziyang in the commit message.
> 
> You can add my:
> Tested-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>
> 

Thanks Fabrice for testing!

You can also add my:
Reviewed-by: Amelie Delaunay <amelie.delaunay@...s.st.com>

Regards,
Amelie

> Thanks & BR,
> Fabrice
> 
>> Thanks,
>> Minas
>>
>> On 2/21/2023 2:30 PM, Ziyang Huang <hzyitc@...look.com> wrote:
>>> From: Ziyang Huang <hzyitc@...look.com>
>>> Sent: Tuesday, February 21, 2023 2:30 PM
>>> To: Minas Harutyunyan <hminas@...opsys.com>
>>> Cc: gregkh@...uxfoundation.org; fabrice.gasnier@...s.st.com;
>>> amelie.delaunay@...s.st.com; linux-usb@...r.kernel.org; linux-
>>> kernel@...r.kernel.org; Ziyang Huang <hzyitc@...look.com>
>>> Subject: [PATCH v2] usb: dwc2: drd: fix inconsistent mode if role-switch-
>>> default-mode="host"
>>>
>>> Some boards might use USB-A female connector for USB ports, however, the
>>> port could be connected to a dual-mode USB controller, making it also
>>> behaves as a peripheral device if male-to-male cable is connected.
>>>
>>> In this case, the dts looks like this:
>>>
>>> 	&usb0 {
>>> 		status = "okay";
>>> 		dr_mode = "otg";
>>> 		usb-role-switch;
>>> 		role-switch-default-mode = "host";
>>> 	};
>>>
>>> After boot, dwc2_ovr_init() sets GOTGCTL to GOTGCTL_AVALOVAL and call
>>> dwc2_force_mode() with parameter host=false, which causes inconsistent mode
>>> - The hardware is in peripheral mode while the kernel status is in host
>>> mode.
>>>
>>> What we can do now is to call dwc2_drd_role_sw_set() to switch to device
>>> mode, and everything should work just fine now, even switching back to
>>> none(default) mode afterwards.
>>>
>>> Fixes: e14acb876985 ("usb: dwc2: drd: add role-switch-default-node support")
>>> Signed-off-by: Ziyang Huang <hzyitc@...look.com>
>>> ---
>>> Changes since v1
>>> - Use corrent name in Signed-off-by
>>>
>>> drivers/usb/dwc2/drd.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c index
>>> d8d6493bc457..a8605b02115b 100644
>>> --- a/drivers/usb/dwc2/drd.c
>>> +++ b/drivers/usb/dwc2/drd.c
>>> @@ -35,7 +35,8 @@ static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
>>>
>>> 	spin_unlock_irqrestore(&hsotg->lock, flags);
>>>
>>> -	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
>>> +	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST) ||
>>> +				(hsotg->role_sw_default_mode == USB_DR_MODE_HOST));
>>> }
>>>
>>> static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
>>> --
>>> 2.34.1
>>