Re: [PATCH] fixes! [max9286]: Validate link formats

[Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>]

Hi Jacopo,

On 19/05/2020 08:56, Jacopo Mondi wrote:
> Hi Kieran,
> 
> On Mon, May 18, 2020 at 05:11:59PM +0100, Kieran Bingham wrote:
>> Disallow setting a format on the source link, but enable link validation
>> by returning the format of the first bound source when getting the
>> format of the source pad.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>> ---
>>  drivers/media/i2c/max9286.c | 17 +++++++++++++----
>>  1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
>> index ef824d2b26b8..6c01595936d7 100644
>> --- a/drivers/media/i2c/max9286.c
>> +++ b/drivers/media/i2c/max9286.c
>> @@ -711,7 +711,10 @@ static int max9286_set_fmt(struct v4l2_subdev *sd,
>>  	struct max9286_priv *priv = sd_to_max9286(sd);
>>  	struct v4l2_mbus_framefmt *cfg_fmt;
>>
>> -	if (format->pad >= MAX9286_SRC_PAD)
>> +	/* \todo: Multiplexed streams support
> 
> I know where \todo comes from, but it's usually TODO.
> Also

to much time playing in doxygen ;-)

>         /*
>          * TODO:
> 
> if the comment is multiline
> 
>> +	 * Prevent setting the format on the shared multiplexed bus.
>> +	 */
>> +	if (format->pad == MAX9286_SRC_PAD)
>>  		return -EINVAL;
>>
>>  	/* Refuse non YUV422 formats as we hardcode DT to 8 bit YUV422 */
>> @@ -743,11 +746,17 @@ static int max9286_get_fmt(struct v4l2_subdev *sd,
>>  {
>>  	struct max9286_priv *priv = sd_to_max9286(sd);
>>  	struct v4l2_mbus_framefmt *cfg_fmt;
>> +	unsigned int pad = format->pad;
>>
>> -	if (format->pad >= MAX9286_SRC_PAD)
>> -		return -EINVAL;
>> +	/* \todo: Multiplexed Stream Support
>> +	 * Support link validation by returning the format of the first bound
>> +	 * link. All links must have the same format, as we do not support
>> +	 * mixing, and matching of cameras connected to the max9286.
>> +	 */
>> +	if (format->pad == MAX9286_SRC_PAD)
> 
> You can use pad

Sure ;-)
> 
>> +		pad = ffs(priv->bound_sources);
>>
>> -	cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
>> +	cfg_fmt = max9286_get_pad_format(priv, cfg, pad, format->which);
> 
> Or you could add one entry to struct max9286_priv.fmt for the source
> pad format, set the format there when is set on one sink, and just
> drop the check on the pad index in get_fmt. Up to you.
> 

I'd prefer to  reference the actual first source, rather than
duplicating as that's the link that we're validating against.

> Please squash in v10

Thanks, v10 soon!.

Just need to determine the best route for the remaining dt cleanups.

--
Kieran

> Thanks
>   j
> 
>>  	if (!cfg_fmt)
>>  		return -EINVAL;
>>
>> --
>> 2.25.1
>>