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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3033C433EF for ; Wed, 16 Feb 2022 10:14:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232706AbiBPKOn (ORCPT ); Wed, 16 Feb 2022 05:14:43 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:52544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232464AbiBPKOm (ORCPT ); Wed, 16 Feb 2022 05:14:42 -0500 X-Greylist: delayed 509 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 16 Feb 2022 02:14:30 PST Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [IPv6:2a01:37:1000::53df:5f64:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F5EB2ABD2C for ; Wed, 16 Feb 2022 02:14:30 -0800 (PST) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by bmailout1.hostsharing.net (Postfix) with ESMTPS id 48FF030001184; Wed, 16 Feb 2022 11:05:53 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 374FB2ECFF4; Wed, 16 Feb 2022 11:05:53 +0100 (CET) Date: Wed, 16 Feb 2022 11:05:53 +0100 From: Lukas Wunner To: Florian Fainelli Cc: Stefan Wahren , Linus Walleij , Nicolas Saenz Julienne , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com, linux-gpio@vger.kernel.org, Lino Sanfilippo , Philipp Rosenberger , linux-rpi-kernel@lists.infradead.org Subject: Re: [PATCH] pinctrl: bcm2835: Use bcm2835 gpio_chip label for bcm2711 Message-ID: <20220216100553.GA4315@wunner.de> References: <20220215144409.GA12830@wunner.de> <09a5a501-40d7-4dae-56c9-a3796fc95c4b@i2se.com> <2a5aad11-0ac6-943f-158a-585648b396be@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2a5aad11-0ac6-943f-158a-585648b396be@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Tue, Feb 15, 2022 at 09:17:49AM -0800, Florian Fainelli wrote: > >>> Am 15.02.22 um 06:52 schrieb Lukas Wunner: > >>>> Commit b1d84a3d0a26 ("pinctrl: bcm2835: Add support for all GPIOs on > >>>> BCM2711") used a different label for the bcm2711 gpio_chip vis-à-vis > >>>> the bcm2835. [...] > I agree with Stefan here, besides changing the driver name now would > mean potentially breaking user-space since the driver name is visible in > a variety of places. Seems to me like this is too late, we should have > caught this during the introduction of 2711. This isn't about the driver name but the gpio_chip label. The .name attribute of bcm2711_pinctrl_desc and bcm2711_pinctrl_gpio_range is only visible in debugfs, which doesn't count as user-space ABI. The .label attribute of bcm2711_gpio_chip is indeed visible in sysfs and could in theory be used by udev rules, though I doubt it. It definitely was a mistake not to use the same label as pinctrl-bcm2835. Using a different label hinges on the notion that it's a different chip, and while that may apply for the 4B+ and CM4, the assumption falls apart with the CM4S which seeks to be a drop-in replacement for CM1/CM3, but really is not because of mistakes like this one. We're likely not the only ones bitten by this, just the first to report. Thanks, Lukas