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

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Message-ID: <0ffed85a-6bc9-b51e-c431-a23b9bf3919c@foss.st.com>
Date:   Wed, 1 Mar 2023 12:26:04 +0100
From:   Fabrice Gasnier <fabrice.gasnier@...s.st.com>
To:     Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
        Ziyang Huang <hzyitc@...look.com>,
        "amelie.delaunay@...s.st.com" <amelie.delaunay@...s.st.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 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 & 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
>