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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 1D54AC33C9E for ; Tue, 7 Jan 2020 10:20:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7CF320678 for ; Tue, 7 Jan 2020 10:20:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="xCw2aOcD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727852AbgAGKUY (ORCPT ); Tue, 7 Jan 2020 05:20:24 -0500 Received: from mail-lf1-f68.google.com ([209.85.167.68]:44609 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727084AbgAGKUX (ORCPT ); Tue, 7 Jan 2020 05:20:23 -0500 Received: by mail-lf1-f68.google.com with SMTP id v201so38431926lfa.11 for ; Tue, 07 Jan 2020 02:20:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=eMXkNg8gjjjP4/UPSl/T3BVhY6m7trOu4dhjFlvWIdM=; b=xCw2aOcDbDhAosRUZpI6S8jMUrGPkDQqWqFwb5KY/DgItDqPB6ptgX5V8gs2yDC82+ TQSjZ5E2cLNKjaz6JtEmt4T7mFfIrrPYNyrT3jiAN6/2Iyc2srA526cttuVeaA9GgZy7 RsjrRB4c79+Wti1TvIpqtZa5J1rHZihfl2JV8GWrftEngwr59RFHWw/BAxyZc22OAW9/ mAqEQpKUAtdMyffk8S0eL1YYz/+fwuQPZL+9BCsW8/zdkEbMRl8S/rExnFRhho40HLDS VkvUCyyWA7t7vhznmbNtN4ENfD3DyIk0oCQtLNU+auQQZHfpdNT541zidQxXe0Qz4M0T FgfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=eMXkNg8gjjjP4/UPSl/T3BVhY6m7trOu4dhjFlvWIdM=; b=cQ1VJzkOfd/O9KARpgMgnOkkLekc+XixUPHMLdGOt3SqjleXuPog4ATStZW5j2bMVE wBtoJpLi5zznKsAS/ql33OvPX6MZt5IaNzNJGuFBzy6ZFtZSEcX9ohDD4bjsevUlwGJF rVx899TcZIqAh00H3nN0ABul7q+qEBVAcfgjc9CNRYsfMb/hjn6DLUPRrjmUgUOhNUQ/ HucCUEFsdW/y8KkdFgw5Mijf9HxuCACTlMbT7TxqgnyaC2gu17mmkL+G4Nu01l9INmuG BldTyJ4PHZzMudWeDcfUopR+Hr1dgbwqDeOOzk5eiDHkye/jz+6MBlYzLL8YBnzNsTWT 1NBg== X-Gm-Message-State: APjAAAVubEOG628oJjMrftvDLCkoHcbct26GRyLU0EqdE+x33sTAytbS OYasLwRsYNr3Mn9sbNVEzFluBeZxX50urhsopzY+8g== X-Google-Smtp-Source: APXvYqx+1HVleR9t6Yuyooq8t8xa7rjXdvZgR0S/2R2tmpjcPZ3EC1OYv8foVlifSxaWiiQHWGnQCar3duKMNpwhtnc= X-Received: by 2002:ac2:55a8:: with SMTP id y8mr58557682lfg.117.1578392421291; Tue, 07 Jan 2020 02:20:21 -0800 (PST) MIME-Version: 1.0 References: <1566206502-4347-1-git-send-email-mars.cheng@mediatek.com> <1566206502-4347-6-git-send-email-mars.cheng@mediatek.com> <1577022724.7468.20.camel@mtkswgap22> In-Reply-To: <1577022724.7468.20.camel@mtkswgap22> From: Linus Walleij Date: Tue, 7 Jan 2020 11:20:10 +0100 Message-ID: Subject: Re: [PATCH v2 05/11] pinctrl: mediatek: avoid virtual gpio trying to set reg To: Hanks Chen Cc: Mars Cheng , Matthias Brugger , Rob Herring , Marc Zyngier , Stephen Boyd , Sean Wang , CC Hwang , Loda Chou , "linux-kernel@vger.kernel.org" , "moderated list:ARM/Mediatek SoC support" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , wsd_upstream@mediatek.com, mtk01761 , linux-clk Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 23, 2019 at 4:11 AM Hanks Chen wrote: > On Fri, 2019-08-23 at 10:57 +0200, Linus Walleij wrote: > > On Mon, Aug 19, 2019 at 11:22 AM Mars Cheng wrote: > > This does not explain what a "virtual GPIO" is in this > > context, so please elaborate. What is this? Why does > > it exist? What is it used for? > > > > GPIO is "general purpose input/output" and it is a > > pretty rubbery category already as it is, so we need > > to define our terms pretty strictly. > > > Virtual GPIO only used inside SOC and not being exported to outside SOC > in MTK platform. Some modules use virtual GPIO as eint (e.g. pmic or > usb). I would call that internal GPIOs, those are very real rails inside the chip made with polysilicone so there is nothing "virtual" about them. If the documentation for the chip calls them virtual then explain in the driver that these are SoC-internal lines so that everyone will get it. Is the PMIC inside the SoC? I thought that was usually outside of it in its own chip. But I suppose there could be some interface to it in the SoC and then that interface has this EINT? > In MTK platform, external interrupt (EINT) and GPIO is 1-1 mapping and > we can set GPIO as eint. > But some modules use specific eint which doesn't have real GPIO pin. > So we use virtual GPIO to map it. OK I get it I think... just put these comments into the code as well so we understand when reading the code what is going on. > > > + if (mtk_is_virt_gpio(hw, gpio)) > > > + return 1; > > > > Why are "virtual GPIOs" always inputs? > > We set virtual GPIO as eint. > It mean virtual GPIO only used inside SOC and not being exported to > outside SOC. Are you saying that: - "Virtual" GPIOs are always and only used for interrupts - Since they are only used for interrupts, they are always inputs Then write that in a comment to the above change so we know this context. Yours, Linus Walleij