From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755480AbeEaPKA (ORCPT ); Thu, 31 May 2018 11:10:00 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:56332 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755420AbeEaPJx (ORCPT ); Thu, 31 May 2018 11:09:53 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 7FBD560591 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=timur@codeaurora.org Subject: Re: [PATCH 4.16 269/272] pinctrl: msm: Use dynamic GPIO numbering To: Greg Kroah-Hartman Cc: Sebastian Gottschall , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Bjorn Andersson , Linus Walleij , Sasha Levin References: <20180528100240.256525891@linuxfoundation.org> <20180528100302.722883806@linuxfoundation.org> <7c34ccef-2fa8-8b53-2677-29f6fbe71a04@dd-wrt.com> <20180531114553.GB11598@kroah.com> <510e5f2c-718a-de42-8274-9345d13e7797@codeaurora.org> <20180531121251.GA13561@kroah.com> From: Timur Tabi Message-ID: <2898aafa-e185-8ad5-5f7f-9b81d4a36a8f@codeaurora.org> Date: Thu, 31 May 2018 10:09:50 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180531121251.GA13561@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/31/18 7:12 AM, Greg Kroah-Hartman wrote: > Why is it somehow ok for "future" kernels? You can't break the api in > the future for no reason. > > So this needs to be the same everywhere. If it is broken in 4.17-rc, it > needs to be reverted. This was discussed here: https://www.spinics.net/lists/linux-arm-msm/msg32572.html The code can't program the value to 0 *and* support multiple TLMM devices at the same time. Prior to 4.18, it is not possible to support multiple TLMMs anyway, so blindly setting the base to -1 in the 4.17 kernel just breaks existing user-space code that uses the legacy GPIO API. (This patch in 4.18 is what provides support for multiple TLMMs: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/pinctrl/qcom?id=f265e8b91bb50c7a732a171ddaeb0eef143bacd9) So you can see in the thread that I proposed a compromise: https://www.spinics.net/lists/linux-arm-msm/msg32596.html but that was rejected -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.