Re: [PATCH 08/20] media: soc_camera pad-aware driver initialisation

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

On Thursday 21 May 2015 07:55:10 Hans Verkuil wrote:
> On 05/20/2015 06:39 PM, William Towle wrote:
> > Add detection of source pad number for drivers aware of the media
> > controller API, so that soc_camera/rcar_vin can create device nodes
> > to support a driver such as adv7604.c (for HDMI on Lager) underneath.
> > 
> > Signed-off-by: William Towle <william.towle@codethink.co.uk>
> > Reviewed-by: Rob Taylor <rob.taylor@codethink.co.uk>
> > ---
> > 
> >  drivers/media/platform/soc_camera/rcar_vin.c   |    4 ++++
> >  drivers/media/platform/soc_camera/soc_camera.c |   27 ++++++++++++++++++-
> >  include/media/soc_camera.h                     |    1 +
> >  3 files changed, 31 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/platform/soc_camera/rcar_vin.c
> > b/drivers/media/platform/soc_camera/rcar_vin.c index 0f67646..b4e9b43
> > 100644
> > --- a/drivers/media/platform/soc_camera/rcar_vin.c
> > +++ b/drivers/media/platform/soc_camera/rcar_vin.c
> > @@ -1364,8 +1364,12 @@ static int rcar_vin_get_formats(struct
> > soc_camera_device *icd, unsigned int idx,
> >  		struct v4l2_mbus_framefmt *mf = &fmt.format;
> >  		struct v4l2_rect rect;
> >  		struct device *dev = icd->parent;
> > +		struct media_pad *remote_pad;
> >  		int shift;
> > 
> > +		remote_pad = media_entity_remote_pad(
> > +					&icd->vdev->entity.pads[0]);
> > +		fmt.pad = remote_pad->index;
> 
> This won't work if CONFIG_MEDIA_CONTROLLER isn't defined. All these media
> calls would all have to be under #ifdef CONFIG_MEDIA_CONTROLLER.
> 
> Unfortunately, if it is not defined, then you still have no way of finding
> the source pad.
> 
> Laurent, do you think if it would make sense to add a new subdev core op
> that will return the default source pad (I'm saying 'default' in case there
> are more) of a subdev? That way it can be used in non-MC drivers. We never
> needed the source pad before, but now we do, and this op only needs to be
> implemented if the default source pad != 0.

I'm not too fond of that. Is there something wrong with the method implemented 
in this patch ? Is the dependency on CONFIG_MEDIA_CONTROLLER an issue ?

> >  		ret = v4l2_subdev_call(sd, pad, get_fmt, NULL, &fmt);
> >  		if (ret < 0)
> >  			return ret;
> > diff --git a/drivers/media/platform/soc_camera/soc_camera.c
> > b/drivers/media/platform/soc_camera/soc_camera.c index d708df4..126d645
> > 100644
> > --- a/drivers/media/platform/soc_camera/soc_camera.c
> > +++ b/drivers/media/platform/soc_camera/soc_camera.c
> > @@ -1293,6 +1293,7 @@ static int soc_camera_probe_finish(struct
> > soc_camera_device *icd)
> >  		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> >  	};
> >  	struct v4l2_mbus_framefmt *mf = &fmt.format;
> > +	int src_pad_idx = -1;
> >  	int ret;
> >  	
> >  	sd->grp_id = soc_camera_grp_id(icd);
> > @@ -1311,7 +1312,25 @@ static int soc_camera_probe_finish(struct
> > soc_camera_device *icd)
> >  	}
> >  	
> >  	/* At this point client .probe() should have run already */
> > -	ret = soc_camera_init_user_formats(icd);
> > +	ret = media_entity_init(&icd->vdev->entity, 1, &icd->pad, 0);
> > +	if (!ret) {
> > +		for (src_pad_idx = 0; src_pad_idx < sd->entity.num_pads;
> > +				src_pad_idx++)
> > +			if (sd->entity.pads[src_pad_idx].flags
> > +						== MEDIA_PAD_FL_SOURCE)
> > +				break;
> > +
> > +		if (src_pad_idx < sd->entity.num_pads) {
> > +			if (!media_entity_create_link(
> > +				&icd->vdev->entity, 0,
> > +				&sd->entity, src_pad_idx,
> > +				MEDIA_LNK_FL_IMMUTABLE |
> > +				MEDIA_LNK_FL_ENABLED)) {
> > +				ret = soc_camera_init_user_formats(icd);
> > +			}
> > +		}
> > +	}
> > +
> >  	if (ret < 0)
> >  		goto eusrfmt;
> > 
> > @@ -1322,6 +1341,7 @@ static int soc_camera_probe_finish(struct
> > soc_camera_device *icd)
> >  		goto evidstart;
> >  	
> >  	/* Try to improve our guess of a reasonable window format */
> > +	fmt.pad = src_pad_idx;
> >  	if (!v4l2_subdev_call(sd, pad, get_fmt, NULL, &fmt)) {
> >  		icd->user_width		= mf->width;
> >  		icd->user_height	= mf->height;
> > @@ -1335,6 +1355,7 @@ static int soc_camera_probe_finish(struct
> > soc_camera_device *icd)
> >  evidstart:
> >  	soc_camera_free_user_formats(icd);
> >  
> >  eusrfmt:
> > +	media_entity_cleanup(&icd->vdev->entity);
> >  	soc_camera_remove_device(icd);
> >  	
> >  	return ret;
> > @@ -1856,6 +1877,10 @@ static int soc_camera_remove(struct
> > soc_camera_device *icd)> 
> >  	if (icd->num_user_formats)
> >  		soc_camera_free_user_formats(icd);
> > 
> > +	if (icd->vdev->entity.num_pads) {
> > +		media_entity_cleanup(&icd->vdev->entity);
> > +	}
> > +
> >  	if (icd->clk) {
> >  		/* For the synchronous case */
> >  		v4l2_clk_unregister(icd->clk);
> > diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
> > index 2f6261f..f0c5238 100644
> > --- a/include/media/soc_camera.h
> > +++ b/include/media/soc_camera.h
> > @@ -42,6 +42,7 @@ struct soc_camera_device {
> >  	unsigned char devnum;		/* Device number per host */
> >  	struct soc_camera_sense *sense;	/* See comment in struct definition
> >  	*/
> >  	struct video_device *vdev;
> > +	struct media_pad pad;
> >  	struct v4l2_ctrl_handler ctrl_handler;
> >  	const struct soc_camera_format_xlate *current_fmt;
> >  	struct soc_camera_format_xlate *user_formats;

-- 
Regards,

Laurent Pinchart