Re: [PATCH] media: staging: max96712: Store format in subdev active state

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

Hello Laurent,

Thanks for your feedback.

On 2024-05-10 13:13:40 +0300, Laurent Pinchart wrote:
> Hi Niklas,
> 
> Thank you for the patch.
> 
> On Fri, May 10, 2024 at 12:03:47PM +0200, Niklas Söderlund wrote:
> > Create and store the subdevice format in the subdevices active state.
> > This change do not have a huge effect on the driver as it do not yet
> > support changing the format.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > ---
> > Hello,
> > 
> > This change is mostly to align all driver used in the R-Car VIN pipeline
> > to use the same set of API and to make it easier to extend them in
> > tandem going forward.
> > 
> > This should be seen as a compliment to Jacopo's larger work in "[PATCH
> > v3 00/11] media: renesas: rcar-csi2: Use the subdev active state" which
> > updates other drivers in the VIN pipeline to use the active state.
> > ---
> >  drivers/staging/media/max96712/max96712.c | 36 +++++++++++++++++------
> >  1 file changed, 27 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/staging/media/max96712/max96712.c b/drivers/staging/media/max96712/max96712.c
> > index c44145284aa1..2da65ccd2c57 100644
> > --- a/drivers/staging/media/max96712/max96712.c
> > +++ b/drivers/staging/media/max96712/max96712.c
> > @@ -242,21 +242,34 @@ static const struct v4l2_subdev_video_ops max96712_video_ops = {
> >  	.s_stream = max96712_s_stream,
> >  };
> >  
> > -static int max96712_get_pad_format(struct v4l2_subdev *sd,
> > -				   struct v4l2_subdev_state *sd_state,
> > -				   struct v4l2_subdev_format *format)
> > +static int max96712_init_state(struct v4l2_subdev *sd,
> > +			       struct v4l2_subdev_state *state)
> >  {
> > -	format->format.width = 1920;
> > -	format->format.height = 1080;
> > -	format->format.code = MEDIA_BUS_FMT_RGB888_1X24;
> > -	format->format.field = V4L2_FIELD_NONE;
> > +	static const struct v4l2_mbus_framefmt default_fmt = {
> > +		.width          = 1920,
> > +		.height         = 1080,
> > +		.code           = MEDIA_BUS_FMT_RGB888_1X24,
> > +		.colorspace     = V4L2_COLORSPACE_SRGB,
> > +		.field          = V4L2_FIELD_NONE,
> > +		.ycbcr_enc      = V4L2_YCBCR_ENC_DEFAULT,
> > +		.quantization   = V4L2_QUANTIZATION_DEFAULT,
> > +		.xfer_func      = V4L2_XFER_FUNC_DEFAULT,
> > +	};
> > +	struct v4l2_mbus_framefmt *fmt;
> > +
> > +	fmt = v4l2_subdev_state_get_format(state, 0);
> > +	*fmt = default_fmt;
> >  
> >  	return 0;
> >  }
> >  
> > +static const struct v4l2_subdev_internal_ops max96712_internal_ops = {
> > +	.init_state = max96712_init_state,
> > +};
> > +
> >  static const struct v4l2_subdev_pad_ops max96712_pad_ops = {
> > -	.get_fmt = max96712_get_pad_format,
> > -	.set_fmt = max96712_get_pad_format,
> > +	.get_fmt = v4l2_subdev_get_fmt,
> > +	.set_fmt = v4l2_subdev_get_fmt,
> >  };
> >  
> >  static const struct v4l2_subdev_ops max96712_subdev_ops = {
> > @@ -293,6 +306,7 @@ static int max96712_v4l2_register(struct max96712_priv *priv)
> >  	long pixel_rate;
> >  	int ret;
> >  
> > +	priv->sd.internal_ops = &max96712_internal_ops;
> >  	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max96712_subdev_ops);
> >  	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> >  	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> > @@ -324,6 +338,10 @@ static int max96712_v4l2_register(struct max96712_priv *priv)
> >  
> >  	v4l2_set_subdevdata(&priv->sd, priv);
> >  
> 
> I think it would be nice to already use the control handler lock as the
> active state lock. Apart from that, the patch looks good to me.

I also worked on this to learn a bit more about the active state API. I 
assume what you are asking for here is ?

    priv->sd.state_lock = priv->ctrl_handler.lock;

What is the rational for using the control handler lock over the default 
state lock? I checked Jacopo's series when working on this and there he 
uses no lock for the R-Car CSI-2 driver and a private driver global 
state lock for ADV748x.

> 
> > +	ret = v4l2_subdev_init_finalize(&priv->sd);
> > +	if (ret)
> > +		goto error;
> > +
> >  	ret = v4l2_async_register_subdev(&priv->sd);
> >  	if (ret < 0) {
> >  		dev_err(&priv->client->dev, "Unable to register subdevice\n");
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Kind Regards,
Niklas Söderlund