linux-kernel - Re: [PATCH] usb: dwc3: drd: Add support for extcon drd notifier even with usb role switch config enabled

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Message-ID: <3792f301-1d94-0c72-87ff-c0683870bea1@ti.com>
Date:   Wed, 23 Feb 2022 13:04:18 +0530
From:   Aswath Govindraju <a-govindraju@...com>
To:     Thinh Nguyen <Thinh.Nguyen@...opsys.com>
CC:     Kishon Vijay Abraham I <kishon@...com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrey Smirnov <andrew.smirnov@...il.com>
Subject: Re: [PATCH] usb: dwc3: drd: Add support for extcon drd notifier even
 with usb role switch config enabled

Hi Thinh,

On 23/02/22 6:33 am, Thinh Nguyen wrote:
> Hi,
> 
> Aswath Govindraju wrote:
>> In AM62x SoC, the USB controller supports USB role switching by using the
>> extcon drd notifiers. The current implementation does not accommodate this.
>> If usb role switching is enabled then drd notifiers are not added. If usb
>> role switching is not enabled then the dr_mode is forced to peripheral
>> (dwc3_get_dr_mode) and role switching will not be possible(dwc3_set_mode).
>>
>> Therefore, rearrange the "if else" logic such that extcon drd notifiers can
>> be added even with usb role switching enabled.
>>
>> Signed-off-by: Aswath Govindraju <a-govindraju@...com>
>> ---
>>  drivers/usb/dwc3/drd.c | 16 +++++++++-------
>>  1 file changed, 9 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
>> index b919ea3d87f2..0e86b1d8b50c 100644
>> --- a/drivers/usb/dwc3/drd.c
>> +++ b/drivers/usb/dwc3/drd.c
>> @@ -583,12 +583,7 @@ int dwc3_drd_init(struct dwc3 *dwc)
>>  	if (IS_ERR(dwc->edev))
>>  		return PTR_ERR(dwc->edev);
>>  
>> -	if (ROLE_SWITCH &&
>> -	    device_property_read_bool(dwc->dev, "usb-role-switch")) {
>> -		ret = dwc3_setup_role_switch(dwc);
>> -		if (ret < 0)
>> -			return ret;
>> -	} else if (dwc->edev) {
>> +	if (dwc->edev) {
>>  		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
>>  		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
>>  					       &dwc->edev_nb);
>> @@ -598,7 +593,14 @@ int dwc3_drd_init(struct dwc3 *dwc)
>>  		}
>>  
>>  		dwc3_drd_update(dwc);
>> -	} else {
>> +	}
>> +
>> +	if (ROLE_SWITCH &&
>> +	    device_property_read_bool(dwc->dev, "usb-role-switch")) {
>> +		ret = dwc3_setup_role_switch(dwc);
>> +		if (ret < 0)
>> +			return ret;
>> +	} else if (!dwc->edev) {
>>  		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
>>  
>>  		/* use OTG block to get ID event */
> 
> 
> Please check the patch by Andrey Smirnov and see if it works for you:
> https://lore.kernel.org/linux-usb/20220221192020.346622-1-andrew.smirnov@gmail.com/
> 

Thank you for pointing me this patch. I does solve my issue.


Regards,
Aswath

> Thanks,
> Thinh
>