linux-kernel - Re: [PATCH v2 7/9] media: subdev: Support privacy led in v4l2_subdev_enable/disable

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Date: Wed, 10 Apr 2024 13:30:26 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
 Hans Verkuil <hverkuil@...all.nl>,
 Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Umang Jain <umang.jain@...asonboard.com>, linux-media@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 7/9] media: subdev: Support privacy led in
 v4l2_subdev_enable/disable_streams()

On 10/04/2024 13:11, Sakari Ailus wrote:
> Moi,
> 
> On Fri, Apr 05, 2024 at 12:14:25PM +0300, Tomi Valkeinen wrote:
>> We support camera privacy leds with the .s_stream, in call_s_stream, but
>> we don't have that support when the subdevice implements
>> .enable/disable_streams.
>>
>> Add the support by enabling the led when the first stream for a
>> subdevice is enabled, and disabling the led then the last stream is
>> disabled.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
>> ---
>>   drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index b4981447961a..015f2fb423c9 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -2149,6 +2149,7 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   {
>>   	struct device *dev = sd->entity.graph_obj.mdev->dev;
>>   	struct v4l2_subdev_state *state;
>> +	bool already_streaming;
>>   	u64 found_streams = 0;
>>   	unsigned int i;
>>   	int ret;
>> @@ -2197,6 +2198,11 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   
>>   	dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
>>   
>> +	already_streaming = v4l2_subdev_is_streaming(sd);
>> +
>> +	if (!already_streaming)
>> +		v4l2_subdev_enable_privacy_led(sd);
>> +
>>   	/* Call the .enable_streams() operation. */
>>   	ret = v4l2_subdev_call(sd, pad, enable_streams, state, pad,
>>   			       streams_mask);
>> @@ -2216,6 +2222,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   	}
>>   
>>   done:
>> +	if (ret && !already_streaming)
>> +		v4l2_subdev_disable_privacy_led(sd);
> 
> I think you could also lit the LED only if enabling streaming succeeds.

This matches the implementation in s_stream. I'll change it to match the 
new one being discussed.

  Tomi