Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753271AbaKDLKU (ORCPT ); Tue, 4 Nov 2014 06:10:20 -0500 Received: from aer-iport-4.cisco.com ([173.38.203.54]:62549 "EHLO aer-iport-4.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750727AbaKDLKO (ORCPT ); Tue, 4 Nov 2014 06:10:14 -0500 X-IronPort-AV: E=Sophos;i="5.07,312,1413244800"; d="scan'208";a="230636637" Message-ID: <5458B407.6050701@cisco.com> Date: Tue, 04 Nov 2014 12:09:59 +0100 From: Hans Verkuil User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 To: Boris Brezillon CC: Mauro Carvalho Chehab , Hans Verkuil , Laurent Pinchart , linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Guennadi Liakhovetski Subject: Re: [PATCH 01/15] [media] Move mediabus format definition to a more standard place References: <1415094910-15899-1-git-send-email-boris.brezillon@free-electrons.com> <1415094910-15899-2-git-send-email-boris.brezillon@free-electrons.com> <5458A878.3010809@cisco.com> <20141104114503.309cb54f@bbrezillon> In-Reply-To: <20141104114503.309cb54f@bbrezillon> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Authenticated-User: hansverk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/