Re: [PATCH 2/3] rcar-vin: Add control for alpha component

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

Hi Laurent,

Thanks for your feedback.

On 2019-05-16 13:01:38 +0300, Laurent Pinchart wrote:
> Hi Niklas,
> 
> Thank you for the patch.
> 
> On Thu, May 16, 2019 at 02:47:45AM +0200, Niklas Söderlund wrote:
> > In preparation to adding support for RGB pixel formats with an alpha
> > component add a control to allow the user to control which alpha value
> > should be used.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > ---
> >  drivers/media/platform/rcar-vin/rcar-core.c | 53 ++++++++++++++++++++-
> >  drivers/media/platform/rcar-vin/rcar-dma.c  |  5 ++
> >  drivers/media/platform/rcar-vin/rcar-vin.h  |  5 ++
> >  3 files changed, 61 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
> > index 64f9cf790445d14e..ee6e6cb39c749675 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-core.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-core.c
> > @@ -389,6 +389,28 @@ static void rvin_group_put(struct rvin_dev *vin)
> >  	kref_put(&group->refcount, rvin_group_release);
> >  }
> >  
> > +/* -----------------------------------------------------------------------------
> > + * Controls
> > + */
> > +
> > +static int rvin_s_ctrl(struct v4l2_ctrl *ctrl)
> > +{
> > +	struct rvin_dev *vin =
> > +		container_of(ctrl->handler, struct rvin_dev, ctrl_handler);
> > +
> > +	switch (ctrl->id) {
> > +	case V4L2_CID_ALPHA_COMPONENT:
> > +		rvin_set_alpha(vin, ctrl->val);
> 
> You can set vin->alpha here directly, no need for a rvin_set_alpha()
> function.

I think you discovers the reason for this in 3/3. I could set vin->alpha 
directly here and introduce rvin_set_alpha() in 3/3. I opted for this 
approach as the reason form not margin 2/3 and 3/3 into a single patch 
is that I only want the register writes in 3/3.

> 
> > +		break;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct v4l2_ctrl_ops rvin_ctrl_ops = {
> > +	.s_ctrl = rvin_s_ctrl,
> > +};
> > +
> >  /* -----------------------------------------------------------------------------
> >   * Async notifier
> >   */
> > @@ -478,6 +500,15 @@ static int rvin_parallel_subdevice_attach(struct rvin_dev *vin,
> >  	if (ret < 0)
> >  		return ret;
> >  
> > +	v4l2_ctrl_new_std(&vin->ctrl_handler, &rvin_ctrl_ops,
> > +			  V4L2_CID_ALPHA_COMPONENT, 0, 255, 1, 255);
> > +
> > +	if (vin->ctrl_handler.error) {
> > +		ret = vin->ctrl_handler.error;
> > +		v4l2_ctrl_handler_free(&vin->ctrl_handler);
> > +		return ret;
> > +	}
> > +
> >  	ret = v4l2_ctrl_add_handler(&vin->ctrl_handler, subdev->ctrl_handler,
> >  				    NULL, true);
> >  	if (ret < 0) {
> > @@ -870,6 +901,21 @@ static int rvin_mc_init(struct rvin_dev *vin)
> >  	if (ret)
> >  		rvin_group_put(vin);
> >  
> > +	ret = v4l2_ctrl_handler_init(&vin->ctrl_handler, 1);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	v4l2_ctrl_new_std(&vin->ctrl_handler, &rvin_ctrl_ops,
> > +			  V4L2_CID_ALPHA_COMPONENT, 0, 255, 1, 255);
> > +
> > +	if (vin->ctrl_handler.error) {
> > +		ret = vin->ctrl_handler.error;
> > +		v4l2_ctrl_handler_free(&vin->ctrl_handler);
> > +		return ret;
> > +	}
> > +
> > +	vin->vdev.ctrl_handler = &vin->ctrl_handler;
> > +
> >  	return ret;
> >  }
> >  
> > @@ -1245,6 +1291,7 @@ static int rcar_vin_probe(struct platform_device *pdev)
> >  
> >  	vin->dev = &pdev->dev;
> >  	vin->info = of_device_get_match_data(&pdev->dev);
> > +	vin->alpha = 0xff;
> >  
> >  	/*
> >  	 * Special care is needed on r8a7795 ES1.x since it
> > @@ -1288,6 +1335,8 @@ static int rcar_vin_probe(struct platform_device *pdev)
> >  	return 0;
> >  
> >  error_group_unregister:
> > +	v4l2_ctrl_handler_free(&vin->ctrl_handler);
> > +
> >  	if (vin->info->use_mc) {
> >  		mutex_lock(&vin->group->lock);
> >  		if (&vin->v4l2_dev == vin->group->notifier.v4l2_dev) {
> > @@ -1323,10 +1372,10 @@ static int rcar_vin_remove(struct platform_device *pdev)
> >  		}
> >  		mutex_unlock(&vin->group->lock);
> >  		rvin_group_put(vin);
> > -	} else {
> > -		v4l2_ctrl_handler_free(&vin->ctrl_handler);
> >  	}
> >  
> > +	v4l2_ctrl_handler_free(&vin->ctrl_handler);
> > +
> >  	rvin_dma_unregister(vin);
> >  
> >  	return 0;
> > diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
> > index 2d146ecf93d66ad5..4e991cce5fb56a90 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-dma.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-dma.c
> > @@ -1343,3 +1343,8 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel)
> >  
> >  	return 0;
> >  }
> > +
> > +void rvin_set_alpha(struct rvin_dev *vin, unsigned int alpha)
> > +{
> > +	vin->alpha = alpha;
> > +}
> > diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
> > index 0b13b34d03e3dce4..365dfde06ec25add 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-vin.h
> > +++ b/drivers/media/platform/rcar-vin/rcar-vin.h
> > @@ -178,6 +178,8 @@ struct rvin_info {
> >   * @compose:		active composing
> >   * @source:		active size of the video source
> >   * @std:		active video standard of the video source
> > + *
> 
> Do you need a blank line here ?

I don't need it, but it make sens in my head on how I group variables in 
sturct rvin_info. There already exists blank lines in the structure for 
this grouping of variables thinking. If you are OK with it I would 
prefer to keep it, but I do not feel strongly about it.

> 
> Apart from that the patch looks good to me.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Thanks!

> 
> > + * @alpha:		Alpha component to fill in for supported pixel formats
> >   */
> >  struct rvin_dev {
> >  	struct device *dev;
> > @@ -215,6 +217,8 @@ struct rvin_dev {
> >  	struct v4l2_rect compose;
> >  	struct v4l2_rect source;
> >  	v4l2_std_id std;
> > +
> > +	unsigned int alpha;
> >  };
> >  
> >  #define vin_to_source(vin)		((vin)->parallel->subdev)
> > @@ -266,5 +270,6 @@ const struct rvin_video_format *rvin_format_from_pixel(u32 pixelformat);
> >  void rvin_crop_scale_comp(struct rvin_dev *vin);
> >  
> >  int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel);
> > +void rvin_set_alpha(struct rvin_dev *vin, unsigned int alpha);
> >  
> >  #endif
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Regards,
Niklas Söderlund