linux-kernel - Re: [PATCH v11 2/7] cx25840: g_std operation really implements querystd operation

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Date:   Mon, 29 Apr 2019 10:05:04 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>,
        Michael Krufky <mkrufky@...uxtv.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Andy Walls <awalls@...metrocast.net>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v11 2/7] cx25840: g_std operation really implements
 querystd operation

On 4/27/19 4:50 PM, Maciej S. Szmigiero wrote:
> cx25840 driver g_std operation queries the currently detected video signal,
> however this is what querystd operation should do, so let's rename the
> handler.
> 
> None of the existing cx25840 driver users ever called the g_std operation,
> one of them calls querystd on each of its subdevs but then the result is
> only used to implement VIDIOC_QUERYSTD (as it should).
> 
> Signed-off-by: Maciej S. Szmigiero <mail@...iej.szmigiero.name>
> ---
>  drivers/media/i2c/cx25840/cx25840-core.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/cx25840/cx25840-core.c b/drivers/media/i2c/cx25840/cx25840-core.c
> index 0bf30222cf93..2bcaf239b0d2 100644
> --- a/drivers/media/i2c/cx25840/cx25840-core.c
> +++ b/drivers/media/i2c/cx25840/cx25840-core.c
> @@ -1772,7 +1772,7 @@ static int cx25840_s_stream(struct v4l2_subdev *sd, int enable)
>  }
>  
>  /* Query the current detected video format */
> -static int cx25840_g_std(struct v4l2_subdev *sd, v4l2_std_id *std)
> +static int cx25840_querystd(struct v4l2_subdev *sd, v4l2_std_id *std)
>  {
>  	struct i2c_client *client = v4l2_get_subdevdata(sd);
>  
> @@ -1800,8 +1800,9 @@ static int cx25840_g_std(struct v4l2_subdev *sd, v4l2_std_id *std)
>  	u32 fmt = (cx25840_read4(client, 0x40c) >> 8) & 0xf;
>  	*std = stds[ fmt ];
>  
> -	v4l_dbg(1, cx25840_debug, client, "g_std fmt = %x, v4l2_std_id = 0x%x\n",
> -		fmt, (unsigned int)stds[ fmt ]);
> +	v4l_dbg(1, cx25840_debug, client,
> +		"querystd fmt = %x, v4l2_std_id = 0x%x\n",
> +		fmt, (unsigned int)stds[fmt]);
>  
>  	return 0;
>  }
> @@ -5081,7 +5082,7 @@ static const struct v4l2_subdev_audio_ops cx25840_audio_ops = {
>  
>  static const struct v4l2_subdev_video_ops cx25840_video_ops = {
>  	.s_std = cx25840_s_std,
> -	.g_std = cx25840_g_std,
> +	.querystd = cx25840_querystd,
>  	.s_routing = cx25840_s_video_routing,
>  	.s_stream = cx25840_s_stream,
>  	.g_input_status = cx25840_g_input_status,
> 

Hmm, you are right, g_std really implements querystd. I wondered why this wasn't
noticed before, and it appears that no bridge driver ever calls the g_std op of the
cx25840 driver. It's all handled inside the bridge driver itself.

Can you add a new cx25840_g_std() op here that just returns state->std?

That would make much more sense.

You also need to use g_std in patch 6/7 (see my comments there)

Regards,

	Hans