Re: [PATCH/RFC v2 2/4] Add media device related data structures and API.

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

Hi Sakari,

On Wednesday 22 October 2014 13:03:02 Sakari Ailus wrote:
> On Fri, Oct 17, 2014 at 04:54:40PM +0200, Jacek Anaszewski wrote:
> ...
> 
> > +/*
> > + * struct media_entity - media device entity data
> > + * @id:			media entity id within media controller
> > + * @name:		media entity name
> > + * @node_name:		media entity related device node name
> > + * @pads:		array of media_entity pads
> > + * @num_pads:		number of elements in the pads array
> > + * @links:		array of media_entity links
> > + * @num_links:		number of elements in the links array
> > + * @subdev_fmt:		related sub-device format
> > + * @fd:			related sub-device node file descriptor
> > + * @src_pad_id:		source pad id when entity is linked
> > + * @sink_pad_id:	sink pad id when entity is linked
> > + * @next:		pointer to the next data structure in the list
> > + */
> > +struct media_entity {
> > +	int id;
> > +	char name[32];
> > +	char node_name[32];
> > +	struct media_pad_desc *pads;
> > +	int num_pads;
> > +	struct media_link_desc *links;
> > +	int num_links;
> > +	struct v4l2_subdev_format subdev_fmt;
> > +	int fd;
> > +	int src_pad_id;
> > +	int sink_pad_id;
> > +	struct media_entity *next;
> > +};
> 
> Could you use libmediactl and libv4l2subdev instead here as well? They do
> actually implement much of what you do here. Feel free to comment on the
> API. The libraries have a little bit different background than this one.
> Obviously there's functionality in this library what's not in the two; some
> of this might belong to either of the two libraries.
> 
> I think we'll need V4L2 sub-device related information stored next to the
> media entities as well, so that's something to be added.

I generic mechanism to attach subsystem-specific data to entities sounds good 
to me. The fd field could then be moved out of struct media_entity.

-- 
Regards,

Laurent Pinchart