Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753752Ab2KGRZ3 (ORCPT ); Wed, 7 Nov 2012 12:25:29 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:49558 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748Ab2KGRZ1 (ORCPT ); Wed, 7 Nov 2012 12:25:27 -0500 Message-ID: <509A9984.3000709@wwwdotorg.org> Date: Wed, 07 Nov 2012 10:25:24 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Benoit Cousson CC: Pantelis Antoniou , Kevin Hilman , Matt Porter , Koen Kooi , linux-kernel , Felipe Balbi , Deepak Saxena , Scott Wood , Russ Dill , linux-omap@vger.kernel.org, devicetree-discuss@lists.ozlabs.org Subject: Re: [RFC] Device Tree Overlays Proposal (Was Re: capebus moving omap_devices to mach-omap2) References: <02FF5400-9F97-4B8A-AEF0-267B01C8099F@antoniou-consulting.com> <5ED17D42-07B8-4D4F-B54F-82B4CC60584C@antoniou-consulting.com> <509A3595.7050600@ti.com> In-Reply-To: <509A3595.7050600@ti.com> X-Enigmail-Version: 1.4.4 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3677 Lines: 99 On 11/07/2012 03:19 AM, Benoit Cousson wrote: > Hi Panto, > > On 11/07/2012 09:13 AM, Pantelis Antoniou wrote: >> Hi Grant >> >> On Nov 6, 2012, at 9:45 PM, Grant Likely wrote: >> >>> On Tue, Nov 6, 2012 at 7:34 PM, Pantelis Antoniou >>> wrote: >> >> [ snip ] >>> >>> g. >> >> Since we've started talking about longer term goals, and the versioning >> provision seems to stand, I hope we address how much the fragment versioning >> thing is similar to the way board revisions progress. >> >> If a versioning syntax is available then one could create a single DT >> file for a bunch of 'almost' similar board and board revisions. > > I even think that the version issue is probably much more important for the short term than the overlay aspect. Well at least as important. We start having as well a bunch a panda board version with different HW setup. > > Having a single board-XXX.dts that will support all these versions is probably the best approach to avoid choosing that from the bootloader. > > We need to figure out a format + mechanism compatible with the current non-versioned format to allow filtering the nodes at runtime to keep only the relevant one. > > Something that can find the driver that will provide the proper board version or subsystem version or whatever like that: > > compatible-version = "ti,panda-version", "panda"; > > Then at runtime we should create only the node with the correct match between the driver version and the string version. > > > /* regular panda audio routing */ > sound: sound { > compatible = "ti,abe-twl6040"; > ti,model = "PandaBoard"; > compatible-version = "ti,panda-version", "panda"; > > /* Audio routing */ > ti,audio-routing = > "Headset Stereophone", "HSOL", > "Headset Stereophone", "HSOR", > "Ext Spk", "HFL", > "Ext Spk", "HFR", > "Line Out", "AUXL", > "Line Out", "AUXR", > "HSMIC", "Headset Mic", > "Headset Mic", "Headset Mic Bias", > "AFML", "Line In", > "AFMR", "Line In"; > }; > > > /* Audio routing is different between PandaBoard4430 and PandaBoardES */ > &sound { > ti,model = "PandaBoardES"; > compatible-version = "ti,panda-version", "panda-es"; > > /* Audio routing */ > ti,audio-routing = > "Headset Stereophone", "HSOL", > "Headset Stereophone", "HSOR", > "Ext Spk", "HFL", > "Ext Spk", "HFR", > "Line Out", "AUXL", > "Line Out", "AUXR", > "AFML", "Line In", > "AFMR", "Line In"; > }; > > > Maybe some extra version match table can just be passed during the board machine_init > > of_platform_populate(NULL, omap_dt_match_table, NULL, NULL, panda_version_match_table); Is the only difference here the content of the ti,audio-routing property? If so, then I don't think there's any need for infra-structure for this; the driver code already reads that property and adjusts its behaviour based upon it. I do see that "Headset Mic" exists only in one of the tables above. Perhaps the driver could scan the routing table, and only create the ASoC object for the headset if it's mentioned in the routing table? If there are additional differences, then you can always use the .data field in of_device_id to automatically associate some configuration data with different compatible values. Even better might be to extend the binding so that all HW differences are represented explicitly as properties; that way you wouldn't even need different compatible values. -- 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/