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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 EBC9FC4727F for ; Fri, 2 Oct 2020 08:34:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9F85206B8 for ; Fri, 2 Oct 2020 08:34:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387621AbgJBIef (ORCPT ); Fri, 2 Oct 2020 04:34:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbgJBIef (ORCPT ); Fri, 2 Oct 2020 04:34:35 -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 EB8CCC0613D0 for ; Fri, 2 Oct 2020 01:34:34 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[IPv6:::1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1kOGWN-0002M2-NK; Fri, 02 Oct 2020 10:34:31 +0200 Subject: Re: [PATCH v2 08/12] ARM: dts: imx6dl-pico: fix board compatibles To: Krzysztof Kozlowski Cc: Rob Herring , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Anson Huang , Andreas Kemnade , Stefan Riedmueller , Robert Jones , Li Yang , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org 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> From: Ahmad Fatoum Message-ID: <784e0528-f4c1-5c0f-44e8-b19afbffe3ba@pengutronix.de> Date: Fri, 2 Oct 2020 10:34:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201002082012.GA6605@pi3> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hello, On 10/2/20 10:20 AM, 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. Then I misunderstood you. I was thinking about possible out-of-tree users that have boards based on this and are adhering to the binding. Dropping the binding would break those (albeit it's a quite manageable form of brokenness here). >>> 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. > > 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. Sounds good. If further differentiation proves to be needed, it can be a new compatible added in a separate commit. Thanks Ahmad > > Best regards, > Krzysztof > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |