linux-kernel - Re: [PATCH 6/6] media: uvcvideo: Handle IRQs from the privacy

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Date:   Wed, 4 Nov 2020 14:06:19 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Ricardo Ribalda <ribalda@...omium.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        tfiga@...omium.org
Subject: Re: [PATCH 6/6] media: uvcvideo: Handle IRQs from the privacy_pin

Hi Ricardo,

Thank you for the patch.

On Thu, Oct 22, 2020 at 03:37:53PM +0200, Ricardo Ribalda wrote:
> If the privacy pin produces an IRQ, read the gpio and notify userspace
> via an event.
> 
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> ---
>  drivers/media/usb/uvc/uvc_ctrl.c   |  3 +++
>  drivers/media/usb/uvc/uvc_driver.c | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 3a49a1326a90..00c41cba0f68 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1346,6 +1346,9 @@ static void uvc_ctrl_status_event_work(struct work_struct *work)
>  
>  	mutex_unlock(&chain->ctrl_mutex);
>  
> +	if (!w->urb)
> +		return;
> +
>  	/* Resubmit the URB. */
>  	w->urb->interval = dev->int_ep->desc.bInterval;
>  	ret = usb_submit_urb(w->urb, GFP_KERNEL);
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 180e503e900f..d1260d131bd8 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1460,6 +1460,25 @@ static int uvc_gpio_get_info(struct uvc_entity *entity, u8 cs, u8 *caps)
>  	return 0;
>  }
>  
> +static irqreturn_t uvc_privacy_gpio_irq(int irq, void *data)
> +{
> +	struct uvc_device *dev = data;
> +	struct uvc_video_chain *chain;
> +	struct uvc_entity *term;

The entity isn't a terminal, so I'd call the variable unit. I think
there was another occurrence of this issue in another patch in the
series.

> +	u8 value;
> +
> +	list_for_each_entry(chain, &dev->chains, list) {

This will effectively call uvc_ctrl_status_event() once per chain, is
that really what you were intending ?

> +		list_for_each_entry(term, &dev->entities, list) {
> +			if (UVC_ENTITY_TYPE(term) == UVC_GPIO_UNIT) {
> +				value = gpiod_get_value(term->gpio.gpio_privacy);
> +				uvc_ctrl_status_event(NULL, chain, term->controls, &value);

80 columns.

> +			}
> +		}
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static int uvc_parse_gpio(struct uvc_device *dev)
>  {
>  	struct uvc_entity *unit;
> @@ -1490,6 +1509,17 @@ static int uvc_parse_gpio(struct uvc_device *dev)
>  
>  	list_add_tail(&unit->list, &dev->entities);
>  
> +	irq = gpiod_to_irq(gpio_privacy);
> +

No need for a blank line.

And it looks like the local irq variable should be introduced in this
patch, not in the previous one. I think I'd squash this with 5/6.

> +	if (irq == -EPROBE_DEFER)
> +		return -EPROBE_DEFER;



> +
> +	if (irq < 0)
> +		return 0;
> +
> +	ret = devm_request_irq(&dev->udev->dev, irq, uvc_privacy_gpio_irq, IRQF_SHARED,

80 columns.

> +			       "uvc_privacy_gpio", dev);

Do we need to handle failures ?

> +
>  	return 0;
>  }
>  

-- 
Regards,

Laurent Pinchart