Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031888AbbKFEp3 (ORCPT ); Thu, 5 Nov 2015 23:45:29 -0500 Received: from smtprelay.synopsys.com ([198.182.60.111]:38608 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030793AbbKFEp2 convert rfc822-to-8bit (ORCPT ); Thu, 5 Nov 2015 23:45:28 -0500 From: Vineet Gupta To: Alexey Brodkin CC: "linux-snps-arc@lists.infradead.org" , "jogo@openwrt.org" , lkml , Arnd Bergmann , Rob Herring Subject: Re: "compatible" and "model" properties in .dts for ARC boards Thread-Topic: "compatible" and "model" properties in .dts for ARC boards Thread-Index: AQHRF/rTP424hj5nWESg2aUBuB0FRQ== Date: Fri, 6 Nov 2015 04:45:24 +0000 Message-ID: References: <1446749422.3151.29.camel@synopsys.com> Accept-Language: en-US, en-IN Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.12.197.182] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2201 Lines: 55 +CC lkml,Arnd, Rob On Friday 06 November 2015 12:20 AM, Alexey Brodkin wrote: > Hi Vineet, > > During OpenWRT upsreaming process one interesting topic was raised. > See in the middle of https://lists.openwrt.org/pipermail/openwrt-devel/2015-November/036959.html > > In Device Tree descriptions for our boards we don't use "model" property > even though it is a required one as specified by ePAPR, see > http://free-electrons.com/~thomas/pub/Power_ePAPR_APPROVED_v1.0.pdf, > page 39 "Table 3-1 Root node properties". > > Instead we put 2 items in "compatible" property. > > For example: > ------------------->8---------------- > compatible = "snps,axs101", "snps,arc-sdp"; > ------------------->8---------------- > > And from ePAPR standpoint it makes sense to split contents of that "compatible" > property in 2: > ------------------->8---------------- > compatible = "snps,arc-sdp"; > model = "snps,axs101"; > ------------------->8---------------- It seems model is just a descriptive label and we can surely add them to existing DT. compatible on the other hand is more fundamental used for exact comparisons etc and follows the vendor,device convention. It is pretty common for compatible to have multiple strings for exactly the same reason as I have them here. Both axs101 and axs103 are based on sdp thus we want the ability to have both pieces of information and use as needed. While doing some other DT research recently, I found some of the best basic DT documentation is a somewhat misnamed in-kernel document Documentation/devicetree/booting-without-of.txt > But I do see problems with implementation of that thing. > Today we have a luxury of selection of AXS init functionality > based on that compatible value and if "snps,axs101" goes in > "model" then we'll need to add some more code in > arch/arc/plat-axs10x/axs10x.c that reads "model" value with > of_get_property() and then compare to "axs10{1|3}". > > Any thoughts? > > -Alexey -- 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/