Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753842Ab3G1PuY (ORCPT ); Sun, 28 Jul 2013 11:50:24 -0400 Received: from mail-la0-f43.google.com ([209.85.215.43]:48791 "EHLO mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753670Ab3G1PuW (ORCPT ); Sun, 28 Jul 2013 11:50:22 -0400 MIME-Version: 1.0 In-Reply-To: <20130728153546.GB5224@netboy> References: <20130725175702.GC22291@e106331-lin.cambridge.arm.com> <1416484.XDfk5G56BI@flatron> <20130728131901.GA8864@netboy> <2529481.u8xHuXumcd@flatron> <20130728153546.GB5224@netboy> Date: Sun, 28 Jul 2013 11:50:19 -0400 Message-ID: Subject: Re: [Ksummit-2013-discuss] DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?] From: "jonsmirl@gmail.com" To: Richard Cochran Cc: Tomasz Figa , Arend van Spriel , Olof Johansson , Mark Brown , Mark Rutland , "devicetree@vger.kernel.org" , "ksummit-2013-discuss@lists.linuxfoundation.org" , Russell King - ARM Linux , Ian Campbell , Pawel Moll , Stephen Warren , Domenico Andreoli , "rob.herring@calxeda.com" , "linux-kernel@vger.kernel.org" , Jason Gunthorpe , Dave P Martin , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1582 Lines: 40 On Sun, Jul 28, 2013 at 11:35 AM, Richard Cochran wrote: > On Sun, Jul 28, 2013 at 10:09:57AM -0400, jonsmirl@gmail.com wrote: >> >> 3.z kernel is free to alter the schema. But it will have to supply the >> necessary quirks needed to keep those old dtb's functioning. > > The quirks idea sounds okay to me, if it can really provide forward > compatibility. In practice, I doubt anyone will really spend the > effort to make this work. I think it would be much easier to make sure > the bindings are "future proof" in the first place. "furture proof" is much easier to say that it is to do. We've been messing around with the audio bindings for three years and still don't have a really good scheme. It is pretty easy to come up with the first 90% of a device tree. It is really hard to work out that last 10%. You can easily get the chips into the tree. Doing that will load the correct device drivers. But now how are these chips wired together? Is the appropriate button, LED, etc attached to all the IO pins offered by the chip? Those answers vary by the PCB the chip was used in.. Trying to figure out a scheme for this has lead to some volatility in the device trees. The whole concept of pin mapping was missing from the early device trees. > > Thanks, > Richard -- Jon Smirl jonsmirl@gmail.com -- 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/