From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0161AC4727F for ; Fri, 2 Oct 2020 08:41:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD6B420665 for ; Fri, 2 Oct 2020 08:41:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387740AbgJBIlX (ORCPT ); Fri, 2 Oct 2020 04:41:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbgJBIlW (ORCPT ); Fri, 2 Oct 2020 04:41:22 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44A0EC0613D0 for ; Fri, 2 Oct 2020 01:41:22 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kOGcx-0003Lp-Rq; Fri, 02 Oct 2020 10:41:19 +0200 Received: from mfe by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kOGcx-0004x9-21; Fri, 02 Oct 2020 10:41:19 +0200 Date: Fri, 2 Oct 2020 10:41:19 +0200 From: Marco Felsch To: Krzysztof Kozlowski Cc: Ahmad Fatoum , devicetree@vger.kernel.org, Robert Jones , Stefan Riedmueller , Anson Huang , Shawn Guo , Sascha Hauer , linux-kernel@vger.kernel.org, Li Yang , Rob Herring , NXP Linux Team , Pengutronix Kernel Team , Andreas Kemnade , Fabio Estevam , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 08/12] ARM: dts: imx6dl-pico: fix board compatibles Message-ID: <20201002084119.buc6z7hpesoahmg2@pengutronix.de> References: <20200930190143.27032-1-krzk@kernel.org> <20200930190143.27032-9-krzk@kernel.org> <0a0afea6-8cbb-3e89-5a4f-89660c942ca3@pengutronix.de> <20201001073208.GA5208@kozik-lap> <027fd826-6822-9e92-0c6c-2ebed63f4a07@pengutronix.de> <20201001103704.GA26287@kozik-lap> <7fcea21d-4651-9ba7-5331-86530296a847@pengutronix.de> <20201002082012.GA6605@pi3> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201002082012.GA6605@pi3> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:28:08 up 321 days, 23:46, 363 users, load average: 0.21, 0.18, 0.09 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, sorry for jumping in. On 20-10-02 10:20, Krzysztof Kozlowski wrote: > On Fri, Oct 02, 2020 at 09:41:28AM +0200, Ahmad Fatoum wrote: > > Hello, > > > > On 10/1/20 12:37 PM, Krzysztof Kozlowski wrote: > > >> The existing binding doesn't cover these boards then and needs to be > > >> extended, no? How about following patch? > > > > > > What do you mean it doesn't cover? It was added exactly to handle them: > > > + - technexion,imx6q-pico-dwarf # TechNexion i.MX6Q Pico-Dwarf > > > + - technexion,imx6q-pico-hobbit # TechNexion i.MX6Q Pico-Hobbit > > > + - technexion,imx6q-pico-nymph # TechNexion i.MX6Q Pico-Nymph > > > + - technexion,imx6q-pico-pi # TechNexion i.MX6Q Pico-Pi > > > > > > > Still they are unused. So I'd think these boards should be handled like boards > > that predated bindings: a binding is written that doesn't break existing users. > > OK, let's assume the binding is not correct and DTSes are good. > > > > > >> [I guess we need to keep the two-compatible list they were originally > > >> in for compatibility even if it's unused among upstream device trees?] > > > > > > You want to change both the binding (thus breaking the ABI) and update > > > the DTS to reflect new ABI. Then why having a binding at all? > > > > If we leave the old two-compatible enumeration intact, there is no ABI broken. > > Just to clarify, because I don't get here the "no ABI broken" part: > ABI is the binding, not the DTS. We can change intree DTS as we like, > replace compatibles, add nodes, remove nodes. There is no stability > requirement for DTS contents. > > If we leave two-compatible binding intact, it is a broken binding since > beginning. Removing non-working, fake ABI is not breaking it because it > could never work. The problem here is that it wasn't covered by the review and now we have the mess. I see the DTB and the Bootloader as Firmware. Now imagine if the bootloader for these boards had some dt-fixup logic which won't apply anymore or if the bootloader board init won't get called anymore since the bootloader folks used the compatible found in the DTS. This can cause a regression if the old Bootloader tries to boot the new Kernel+DTS. > > > I would assume that either binding is correct or DTS. You propose that > > > both are wrong and both need changes... in such case this is clearly > > > broken. > > > > IMO the DTS is the correct one. If you want to honor the author's intention > > that each base board has a different compatible, it should be an extra > > compatible and not replace the existing one that may be already in use. Question is what was the author's intention? @Fabio do you have any comments here? > OK, we can go with DTS approach. I fixed few of such cases as well, > assuming that DTS was intended and binding was incorrect. In such case > all boards will be documented under one compatible technexion,imx6q-pico > and DTS will not be changed. Or keep the exisiting bindings and adding the new one. Therefore the yaml needs to handle two cases for each imx6[qdl]: compatible = "technexion,imx6dl-pico-dwarf", "technexion,imx6dl-pico", "fsl,imx6dl"; and compatible = "technexion,imx6dl-pico", "fsl,imx6dl"; Regards, Marco