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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 C4C6BC43381 for ; Fri, 22 Mar 2019 18:36:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 993332175B for ; Fri, 22 Mar 2019 18:36:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728471AbfCVSgQ (ORCPT ); Fri, 22 Mar 2019 14:36:16 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:51399 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727395AbfCVSgQ (ORCPT ); Fri, 22 Mar 2019 14:36:16 -0400 Received: from [192.168.1.110] ([95.115.33.167]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.167]) with ESMTPSA (Nemesis) id 1N7zRz-1gufIp0V63-0152d9; Fri, 22 Mar 2019 19:35:44 +0100 Subject: Re: [PATCH] pinctrl: intel: Implements gpio free function To: Mika Westerberg , "zhuchangchun@cvte.com" Cc: "andriy.shevchenko" , "linus.walleij" , linux-gpio , linux-kernel , hendychu References: <1553135724-38331-1-git-send-email-zhuchangchun@cvte.com> <20190321084420.GG3622@lahna.fi.intel.com> <2019032119195575582546@cvte.com> <20190321120324.GI3622@lahna.fi.intel.com> <2019032120213955866649@cvte.com> <20190321123637.GJ3622@lahna.fi.intel.com> <2019032121342663125658@cvte.com> <20190321135642.GK3622@lahna.fi.intel.com> From: "Enrico Weigelt, metux IT consult" Organization: metux IT consult Message-ID: Date: Fri, 22 Mar 2019 19:35:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190321135642.GK3622@lahna.fi.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:fi2VMJExlxyfTU4iYoocUaUQO9ZpxA0WyS6iOcqeFDrUfgs8mYT +zcp6TFjnsRG9vGdXnGmAaPB0X5G8WlhwUBdj3/tiXFyFAiXEp/khyKos1uzxSMIiNy4FtH ppvgh+o9+wkj80zfI7cb2lhijfmRO70qdMrkWE6Wp6nXNUhu0ZG27fspz5jgaaNd1HTGtS5 c2E5rQit3xcZpImaWTiiw== X-UI-Out-Filterresults: notjunk:1;V03:K0:nx/XuRv/jpw=:5uZBS+Hl2f9QgqMhNsGnyE rG/La14NlTPlzJWYHY3nNs7RBH7dxavU0oxCrarDafQOQvWeVP0cgzaA3KQQ/1scuRpYevmrI 58yEvgkbBHw+9agyzvXVXE8avuxFRYTOjE2BNb674MwgptfZM2W+G9ZXiiglil/Y4NIJJhzce W1y/4tKoc7wCzsxsvrUXg1HwqdccBzU4MQJumtp573XF52W7VepqcibPy7jy2uUpyal4ndUkz uHEGh/iAhtMdpRl0Jar8H710ZyvDdxd3qwDlN+Ac73kSTnPcTySK0u1scbwZojmE4KzZnHbmw K70uYJsdisfeF38PfWsbf8PR8kkTNottRVvAFZS7hAx+rAfqTyEEj3GtFvkN7erbWqY0ew5l5 4zMJZNopCV1LFb9K+3OEIVqATynl8AIDODHJgZlkW+nzuY5pEJFwSna9f4g/DPgisLkhOchcT 22VG2L7aOArOHdBoxJDZToJQvKiMQoTiuhdy1YcPkCWieml2oygOQfWlV7UcV0sTCwrj4mnc2 yaU847A9mCArtdkrAiQZd6C8WW8JKjllF0TcBpNXpxJIwLVK1ClPIEqlzyq/fM0DkZfLENFx+ pQTtCJ1+4tyrbHxNCqFNqjo99aODGSkJHFlEy+nuGrsY4WlxDXj7oIUm5gPYVADB8l64vkYsQ LYlgWDk40OPIUYl6LWUiFnR5/0PSRDfmXoZ8EeHYnBZTK3vhI9oG7+vy/4d2Yek2atJ7C1v1a sImxiOFeJ382uS67QC9DOemV8M0MhNNMYRzyucoNnGR6Th9IZq1C+cZTQ6U= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21.03.19 14:56, Mika Westerberg wrote: > I checked it and you do this:> > + value |= PADCFG0_GPIORXDIS;> + value &= ~PADCFG0_GPIOTXDIS;> > which pretty much turns the pin GPIO output unconditionally. I don't> really think it is good idea. May work in your case but may cause> problems with others. Uh, please don't do this. In some cases it could be even dangerous. In general, I'd question whether such an gpio should be userland- controlled in the first place. Better write a driver for it, which also handles the reset properly. --mtx -- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@metux.net -- +49-151-27565287