Well, I gave two alternatives :-)

Both are fine as far as I am concerned, but it would be nice to hear
what others think.

Regards,

	Hans

On 11/04/14 11:45, Boris Brezillon wrote:

Hi Hans,

On Tue, 04 Nov 2014 11:20:40 +0100
Hans Verkuil [off-list ref] wrote:

quoted

Hi Boris,

On 11/04/14 10:54, Boris Brezillon wrote:

quoted

Rename mediabus formats and move the enum into a separate header file so
that it can be used by DRM/KMS subsystem without any reference to the V4L2
subsystem.

Old V4L2_MBUS_FMT_ definitions are now referencing MEDIA_BUS_FMT_ value.

I missed earlier that v4l2-mediabus.h contained a struct as well, so it can't be
deprecated and neither can a #warning be added.

The best approach, I think, is to use a macro in media-bus-format.h
that will either define just the MEDIA_BUS value when compiled in the kernel, or
define both MEDIA_BUS and V4L2_MBUS values when compiled for userspace.

E.g. something like this:

#ifdef __KERNEL__
#define MEDIA_BUS_FMT_ENTRY(name, val) MEDIA_BUS_FMT_ # name = val
#else
/* Keep V4L2_MBUS_FMT for backwards compatibility */
#define MEDIA_BUS_FMT_ENTRY(name, val) \
	MEDIA_BUS_FMT_ # name = val, \
	V4L2_MBUS_FMT_ # name = val
#endif

Okay, but this means we keep adding V4L2_MBUS_FMT_ definitions even for
new formats (which definitely doesn't encourage people to move on).
Moreover, we add a V4L2 prefix in what was supposed to be a subsystem
neutral header.

Anyway, these are just nitpicks, and if you prefer this approach
I'll rework my series :-).

quoted

An alternative approach is to have v4l2-mediabus.h include media-bus-format.h,
put #ifndef __KERNEL__ around the enum v4l2_mbus_pixelcode and add a big comment
there that applications should use the defines from media-bus-format.h and that
this enum is frozen (i.e. new values are only added to media-bus-format.h).

But I think I like the macro idea best.

As you wish, my only intent is to use those bus format definitions in a
DRM driver :-).

Thanks,

Boris