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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 0827AC433DB for ; Fri, 12 Mar 2021 17:40:47 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A6A4664EF4 for ; Fri, 12 Mar 2021 17:40:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A6A4664EF4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=dh-electronics.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References:Message-ID:Date: Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=j+DxJl46/UFE+oGwpEkimvN7zDfSAKvaAY6aNnnEfOU=; b=Tn2W32qcYqcRW3EuKetsCWOlh kwiVwtpNRQzMC6NpIFYUJgpoSApP+h5XKSZGvlFgwR4BGxONcZYmgpApuHO05DFZ5Bkm1GK829EM9 vheh8bTLVFDtyJ/SZsmEy7fvovbNI2hPfXF8TAdt5PwVWfsanzaewCV4dQqlCBZbN2hkZmsREqrLa MRBnQcQmnEodzHzYNA4g8Uk7E0NkQGL/ZAphfIThca/M/cW2VPdLoIUAMFAKVAHHkWlw1VnF+X3sk p9dG4836Z5yHYS9Y6tQ6v4eeubcXUt1P6ZkwSNbMN/x9/BCOPVm3IVEFXa5+e2mR8hsLojtuFp0aE X8Uhr36HQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKll1-00C6YF-H2; Fri, 12 Mar 2021 17:39:27 +0000 Received: from mx3.securetransport.de ([2a01:4f8:c0c:92be::1]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKlkx-00C6WB-8e for linux-arm-kernel@lists.infradead.org; Fri, 12 Mar 2021 17:39:25 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dh-electronics.com; s=dhelectronicscom; t=1615570747; bh=kwFSUiM0XW+i77YxiKzs8FGTe/uBYriKQRK5HQXP2ls=; h=From:To:CC:Subject:Date:References:In-Reply-To:From; b=SPWatne85RdrHSJhUbhtL3MwsALlUvG4P71gdXCeSsyyqwQbWerTvSRGEb62BPzId 1cb/Kd7wHjiB3QarbYyrL2Depvfc8tw/koFX8rZOTtGp+fh9jWn87Z3KwveP87OHfI rFDl307hbbtD0oJ3xHaxg1Y6Du4BOWKsmguBouxPnxHuV+8ufxOTD5DZKAdjmPk9/2 90cyOQQXG0d5+gGMT79r1tvjlb4UHII/5CtsDY6/IG0Ad9GQqbzCH/1qb7ENAwOxK/ WVg2O2CoSbmQ8T47i6uZaZe12uxOsNtou3H0qtPFJGrCiA2ideMN7WyyqLip4IuvhM WP1bzIwhr4ehg== X-secureTransport-forwarded: yes From: Christoph Niedermaier Complaints-To: abuse@cubewerk.de To: Marek Vasut , "linux-arm-kernel@lists.infradead.org" , "linus.walleij@linaro.org" CC: Alexandre Torgue , Patrice Chotard , Patrick Delaunay , "Maxime Coquelin" , "linux-stm32@st-md-mailman.stormreply.com" Subject: RE: [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96 Thread-Topic: [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96 Thread-Index: AQHWYaO6J/6XL1V4zEuDGmQGjfuCx6kpjSowgAEUzoCBVyUjUIAAGzqAgAAb63A= Date: Fri, 12 Mar 2021 17:38:59 +0000 Message-ID: <86beeb51e9594b14ac0f449495b46736@dh-electronics.com> References: <20200724101610.146403-1-marex@denx.de> <495b2f6b-04b7-c1eb-7aed-cd55636bef46@denx.de> <4530980295044f8ab9c1cfe14e02f90f@dh-electronics.com> <6616e8b0-2b7d-a157-c24f-0493ce03c45b@denx.de> In-Reply-To: <6616e8b0-2b7d-a157-c24f-0493ce03c45b@denx.de> Accept-Language: de-DE, en-US Content-Language: de-DE X-MS-Has-Attach: X-MS-TNEF-Correlator: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210312_173923_514802_1A6A4027 X-CRM114-Status: GOOD ( 27.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Marek Vasut [mailto:marex@denx.de] Sent: Friday, March 12, 2021 5:17 PM > To: Christoph Niedermaier ; linux-arm- > kernel@lists.infradead.org; linus.walleij@linaro.org > Cc: Alexandre Torgue ; Patrice Chotard > ; Patrick Delaunay ; > Maxime Coquelin ; linux-stm32@st-md- > mailman.stormreply.com > Subject: Re: [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96 > > ACHTUNG: Diese E-Mail kommt aus dem Internet und nicht aus unserem > Firmennetzwerk! > > > > On 3/12/21 4:17 PM, Christoph Niedermaier wrote: >> From: Marek Vasut [mailto:marex@denx.de] >> Sent: Thursday, August 6, 2020 9:30 AM >> >>> On 8/6/20 9:09 AM, Christoph Niedermaier wrote: >>>> From: Marek Vasut >>>> Sent: Friday, July 24, 2020 12:16 PM >>>>> >>>>> Fill in the custom GPIO line names used by DH. >>>>> >>>> [...] >>>>> +&gpioa { >>>>> + gpio-line-names = "", "", "", "", >>>>> + "", "", "", "", >>>>> + "", "", "", "DH-GPIO-K", >>>>> + "DH-GPIO-I", "", "DH-GPIO-A", ""; >>>>> +}; >>>>> + >>>> [...] >>>> >>>> We have been using the GPIO names at DH electronics for some time and also >>>> on other SOMs, but have not yet streamed them. We started with the naming >>>> only with a capital letter "A-W" since then without problems. To avoid a >>>> hard cut or patching for us and our customers it would be good if we could >>>> use the same naming in the mainline kernel as well. Marek, we would be >>>> happy if you would adopt our valued GPIO naming in your patch. >>> >>> My counter-argument to this is that the naming should be unique and >>> provide a hint where those GPIO lines come from, so maybe even DH-GPIO-n >>> should rather be DHCOM-n . I can't say I'm particularly fond of the >>> plain 'n' naming of GPIO lines, because then the GPIO label (and e.g. >>> listing in libgpiod tools) does not give any hint what the GPIO is or >>> where it comes from. Also, I worry a plain 'n' naming might clash with >>> other GPIO IPs easily, while a more unique name can not. >> >> Hello Marek, >> >> after an internal discussion, we decided the following: >> >> Could you update the patch for the Avenger96 to the GPIO naming "AV96-n". >> >> Moreover for the SOM layer (stm32mp15xx-dhcom-som.dtsi) we would prefer >> "DHCOM-n". It would be nice if you could create a patch for it. > > I don't think we should have any SoM-side gpio-line-names, because once > you plug the SoM into new carrier board, the gpio-lane-names will no > longer make sense. So, I think all the gpio-line-names should be > implemented in the carrier board DTS. The idea is to define the GPIO names on the SOM layer and then overwrite them on the carrier board DTS if needed. If there is no naming on the carrier board, at least you have access via the DHCOM GPIO names. The DHCOM GPIO names are standardized, so that you can be sure that the assignment to a pin always fits. > > As for the naming scheme, I was also hoping Linus might jump in and > provide some suggestion on best practice here. > > I think naming carrier board GPIOs "A", "B", "C",... is too opaque and > can easily collide e.g. with GPIO expanders which might be on I2C or so. > > A naming scheme which encodes the carrier board name is clearer and less > likely to cause collision, so "AV96-A", "AV96-B", etc. looks good to me. > It is obvious where the GPIO is located and unlikely to collide with any > other GPIO name. Regards, Christoph _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel