From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [Ksummit-2013-discuss] ARM topic: Is DT on ARM the solution, or is there something better? Date: Tue, 22 Oct 2013 22:12:29 +0200 Message-ID: <20131022201228.GB8037@mithrandir> References: <52644A9E.3060007@wwwdotorg.org> <20131020220839.GT2443@sirena.org.uk> <5264576F.6050307@wwwdotorg.org> <52658EBC.8020800@wwwdotorg.org> <20131022093923.GC15640@ulmo.nvidia.com> <20131022150426.GF29341@beef> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="rS8CxjVDS/+yyDmU" Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Nicolas Pitre Cc: Matt Porter , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ksummit-2013-discuss-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I@public.gmane.org" , Mark Brown , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Stephen Warren List-Id: devicetree@vger.kernel.org --rS8CxjVDS/+yyDmU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 22, 2013 at 01:42:48PM -0400, Nicolas Pitre wrote: > On Tue, 22 Oct 2013, Matt Porter wrote: >=20 > > DT has many benefits. It would be great to leverage them as long as it > > doesn't interfere with the rate of change and willingness to evolve code > > that's always been the strength of the kernel process. That strength is > > too valuable to trade away for the "DT as ABI" vision. >=20 > Amen. This is the best statement I've read about DT so far. >=20 > Having "stable" DT bindings is just a dream. Experience so far is=20 > showing that this is neither practical nor realistic. >=20 > The unstructured free-for-all approach isn't good either. Some=20 > compromise between the two extremes needs to be found. I agree. I think we need an easy way to mark bindings as unstable. One possible solution that I can think of would be to use some kind of special marker within the compatible value defined by a binding that would be used to qualify it as unstable. Perhaps something as simple as a preceding exclamation mark (!) would do. gpio { compatible =3D "!foo-gpio"; }; The DT core code could look for that when matching device nodes to the list of compatible values supported by a driver and output a big warning message to make users aware of the fact that the binding may change. The driver could use the same marker in the OF device ID table to make it clear that it implements an experimental binding. Whenever a binding is deemed stable we can simply remove the marker from both the driver and the binding, as well as DTS files. Thierry --rS8CxjVDS/+yyDmU Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJSZtwsAAoJEN0jrNd/PrOhXjwP/iB0Yg38wb/oQOHrDRK7XPXQ AJ+Y10R6d8F08HnIS78HsVYoC0I9pu56SGJg8keijoMMjKFbNcdJ+qC5ooqXRFa2 eOoBbXJvaXO0Xi3xqhyYYPVXRtZD10Weh3d56Xri3C5y3mLnWgeAyn2agqpIGpbF l5cL6rbQL4gHMYWJXGyNdny3srm1KubRk1OXdrW8xJZbNkUV838n8Ls2C/7LROzV rBAZ4bzDv1kCK84V2HfSxCwRs9uNlpjWlZ7MOpLggrr1rhdf6j12zGsl06HIqNZx XhF5Eru3dGjz4AnSxyEneTX0Fy8P0Yfk+RvsZsGXzpAekvv2GBfcqJoy3lvox3Rt s7Id14dZ0KlRAG+52QbVMq14DPukIZNs9wVmFUjkx2E9Jy1kqAFVWXZrzLQXuSrU HqC7Kxryy37AL42R9DjRCTpfjNI+S9ta/V5M9IkSv4Zyk0vSATMRJHwjeBuntbV0 v/asCWxWqkH6QfPzFlMhoHxUbwfWeFsEdNQjz3l3VQ9bWngA2QZ+2gB9ZAOf+NBo aYRAcMOOYgK+mK5xkFkEhO3BqrL8vHF4oRXWlm0fURlJoLRvWz/QshmFtDQFW0jC 2fAmyApeVJNxR9V3xij/TrqMJs5yVj7fb5BsVPhbv3k6XH9RjpG2VXjQB+5Phf4a h6hbFVLfDfPhKzQ3znBF =yU2E -----END PGP SIGNATURE----- --rS8CxjVDS/+yyDmU-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html