Hi Hans, On Tue, 04 Nov 2014 11:20:40 +0100 Hans Verkuil <hansverk@xxxxxxxxx> wrote: > Hi Boris, > > On 11/04/14 10:54, Boris Brezillon wrote: > > 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 :-). > > 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 -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
