linux-kernel - Re: [PATCH] usb: dwc2: Implement set

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Date:   Wed, 5 Feb 2020 12:05:37 +0000
From:   Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
To:     John Keeping <john@...anate.com>,
        Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
CC:     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>
Subject: Re: [PATCH] usb: dwc2: Implement set_selfpowered()

Hi,

On 2/5/2020 3:56 PM, John Keeping wrote:
> Hi Minas,
> 
> On Wed, 5 Feb 2020 07:59:48 +0000
> Minas Harutyunyan <Minas.Harutyunyan@...opsys.com> wrote:
> 
>> On 2/4/2020 7:29 PM, John Keeping wrote:
>>> dwc2 always reports as self-powered in response to a device status
>>> request.  Implement the set_selfpowered() operations so that the gadget
>>> can report as bus-powered when appropriate.
>>>
>>> This is modelled on the dwc3 implementation.
>>>
>>> Signed-off-by: John Keeping <john@...anate.com>
>>

Acked-by: Minas Harutyunyan <hminas@...opsys.com>

>> Good catch. Just one concern. Your patch partially fix my patch this is
>> why I think you need to add Fixes tag otherwise it can create merge
>> conflict if your patch will be merged to next earlier than my.
> 
> I don't think this is actually a fix for your patch, it's a separate fix
> which happens to touch the same code.
> 
> Since dwc2 has never supported the set_selfpowered() operation, I'm not
> really sure if this counts as a bugfix or a feature.
> 
> I'm happy to re-send with a fixes tag if you think it's necessary, but I
> don't think it's accurate in this case - your patch did not introduce a
> bug here :-)
> 
> 
> Regards,
> John
> 
>>> ---
>>>    drivers/usb/dwc2/gadget.c | 24 +++++++++++++++++++++++-
>>>    1 file changed, 23 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
>>> index 2717f4401b97..76c0a5242175 100644
>>> --- a/drivers/usb/dwc2/gadget.c
>>> +++ b/drivers/usb/dwc2/gadget.c
>>> @@ -1646,7 +1646,8 @@ static int dwc2_hsotg_process_req_status(struct dwc2_hsotg *hsotg,
>>>    
>>>    	switch (ctrl->bRequestType & USB_RECIP_MASK) {
>>>    	case USB_RECIP_DEVICE:
>>> -		status = 1 << USB_DEVICE_SELF_POWERED;
>>> +		status = hsotg->gadget.is_selfpowered <<
>>> +			 USB_DEVICE_SELF_POWERED;
>>>    		status |= hsotg->remote_wakeup_allowed <<
>>>    			  USB_DEVICE_REMOTE_WAKEUP;
>>>    		reply = cpu_to_le16(status);
>>> @@ -4530,6 +4531,26 @@ static int dwc2_hsotg_gadget_getframe(struct usb_gadget *gadget)
>>>    	return dwc2_hsotg_read_frameno(to_hsotg(gadget));
>>>    }
>>>    
>>> +/**
>>> + * dwc2_hsotg_set_selfpowered - set if device is self/bus powered
>>> + * @gadget: The usb gadget state
>>> + * @is_selfpowered: Whether the device is self-powered
>>> + *
>>> + * Set if the device is self or bus powered.
>>> + */
>>> +static int dwc2_hsotg_set_selfpowered(struct usb_gadget *gadget,
>>> +				      int is_selfpowered)
>>> +{
>>> +	struct dwc2_hsotg *hsotg = to_hsotg(gadget);
>>> +	unsigned long flags;
>>> +
>>> +	spin_lock_irqsave(&hsotg->lock, flags);
>>> +	gadget->is_selfpowered = !!is_selfpowered;
>>> +	spin_unlock_irqrestore(&hsotg->lock, flags);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>    /**
>>>     * dwc2_hsotg_pullup - connect/disconnect the USB PHY
>>>     * @gadget: The usb gadget state
>>> @@ -4621,6 +4642,7 @@ static int dwc2_hsotg_vbus_draw(struct usb_gadget *gadget, unsigned int mA)
>>>    
>>>    static const struct usb_gadget_ops dwc2_hsotg_gadget_ops = {
>>>    	.get_frame	= dwc2_hsotg_gadget_getframe,
>>> +	.set_selfpowered	= dwc2_hsotg_set_selfpowered,
>>>    	.udc_start		= dwc2_hsotg_udc_start,
>>>    	.udc_stop		= dwc2_hsotg_udc_stop,
>>>    	.pullup                 = dwc2_hsotg_pullup,
>>>    
>