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

[Sakari Ailus <sakari.ailus@iki.fi>]

On Mon, May 18, 2020 at 07:44:41PM +0100, Kieran Bingham wrote:
> Hi Kieran
> 
> On 18/05/2020 17:11, 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
> > +	 * 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)
> > +		pad = ffs(priv->bound_sources);
> 
> of course this would have to be (ffs(priv->bound_sources) - 1) as the
> first pad index is 0 ;-)

You could be clever and use __ffs() instead. :-)

> 
> >  
> > -	cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
> > +	cfg_fmt = max9286_get_pad_format(priv, cfg, pad, format->which);
> >  	if (!cfg_fmt)
> >  		return -EINVAL;
> >  
> > 
> 

-- 
Sakari Ailus