From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933337AbaJ1HKs (ORCPT ); Tue, 28 Oct 2014 03:10:48 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:58521 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932372AbaJ1HKr (ORCPT ); Tue, 28 Oct 2014 03:10:47 -0400 Message-ID: <544F4160.1000805@linux.com> Date: Tue, 28 Oct 2014 08:10:24 +0100 From: Matthias Klein User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Stephen Warren , linux-rpi-kernel@lists.infradead.org, linus.walleij@linaro.org CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] pinctrl: bcm2835: Start GPIO numeration at zero References: <1414447799-1284-1-git-send-email-matthias.klein@linux.com> <544ECAB2.3060706@wwwdotorg.org> <544ECFB4.7040704@linux.com> <544EDCB6.7090001@wwwdotorg.org> In-Reply-To: <544EDCB6.7090001@wwwdotorg.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 28.10.2014 um 01:00 schrieb Stephen Warren: > On 10/27/2014 05:05 PM, Matthias Klein wrote: > >> - To be in sync with the GPIO numbers in the datasheet / documentation > > I assume that's only relevant because of the second point; the GPIO > IDs in DT files already match the datasheet. > >> - For userland applications which rely on these GPIO numbers > > This isn't a scalable solution for that; this "fix" can only work for > a single GPIO controller in any one system. It'd be better for all > usage to search for the correct GPIO controller in sysfs, find the > base address of that, and then add on the controller-relative GPIO ID. > That way, the same approach is taken irrespective of which GPIO > controller is in use, and there are no special cases. > > Perhaps this could be simplified (removing the need to adding > base+offset to get the Linux ID) if the GPIO core exported a > per-controller directory in sysfs for GPIO manipulation (the files in > which used controller-relative numbering), rather than having a single > directory using Linux-internal global GPIO numbering; something like > /sys/class/gpio/gpio@7e200000/export which uses ID 0..N vs. > /sys/class/gpio/export which uses IDs X..X+N where X is arbitary. Would you accept a patch which implements the "gpio-base" property into the device tree for pinctrl-bcm2835?