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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 D6250C4363A for ; Thu, 29 Oct 2020 17:33:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6226120796 for ; Thu, 29 Oct 2020 17:33:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Rbz+OdJu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726279AbgJ2Rc7 (ORCPT ); Thu, 29 Oct 2020 13:32:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726222AbgJ2Rc7 (ORCPT ); Thu, 29 Oct 2020 13:32:59 -0400 Received: from mail-oi1-x244.google.com (mail-oi1-x244.google.com [IPv6:2607:f8b0:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54AA3C0613D6 for ; Thu, 29 Oct 2020 10:32:59 -0700 (PDT) Received: by mail-oi1-x244.google.com with SMTP id u127so3824932oib.6 for ; Thu, 29 Oct 2020 10:32:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xpr5dmWGsbXVj8V8QwWAbYKKg0zqAXKIOGfjNJfVfCw=; b=Rbz+OdJuRecB1wYW89zpWZvTWYlAfvLlS1pLXAMuLvWvv8ZxozuT6yH0IvosHDnFfs 6bTQW5TJWr/7N4ZDkcgBDfUB0qq1TpgqgJbyHJO+Lsmw4nxYF4JMpFNeyV7or3UmIK1r VRd2S9xaMmgudyYpR1MmwJje5Fu3zJSZA8E8je5dYOiyoH/yOITvHRc9sRyyID3Aay/z kqu4gSRP7BZKZLAlti9Zw4CsgH2+W2SgoYBEIo/IIipwvSlD5VWFY23fFosj9+K8Tr02 uodBi5wpnUVye2zm0ACBETzTPbojBK+imDHNfPYG4naFslkmylDdMhL6VxvCXlCBtfJF 6htA== 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=xpr5dmWGsbXVj8V8QwWAbYKKg0zqAXKIOGfjNJfVfCw=; b=ejCUvEWOS9papqgErG+NzLPpU9qnsnS6lRGghUKfpntdU//Q/QXe7+ZoIsMkeic2GY ass7989sgE8ctV+mfq5Chf4vnjVZS0LbGrG5aAgPuWqyAGuzKFl0NL1ypRpf2dHhGadg H9Nf7wwgD0SbWaR5ih4FxtEyh/GbNBIcSXJY6g1pDRnmHVC+8tCTxC+tLh9t/t/7+VV4 Z6R484pFYH/Pk8TIVrHOTnfznXI+zhszr1bgrb9iikaOwKO3ToPl4SbDmCzZSAU68r+f 5njjhjRtw05jRwL+4opMr1kHJWmUWv9+lKqK9Ce6g6PlXI61LqosQsi7/W9nEHB3DgMu 9N8w== X-Gm-Message-State: AOAM530I1AATcmKvLhJ6L9bXWB/K1v1rDTIH+KYvvb/qOJPzjfB0z86G YBK4oM7FKMJ0IHOGkUOgEt6DHP4l87keanS+LqsIXw== X-Google-Smtp-Source: ABdhPJzS6eBqIeoZQgbrNPKsAwBuUlfoDEZ1zeFYCK+mIFTY99a/hMHi/w1Qyk1MwBfpBZsCiWyXpb2Va6xvZpmr4Es= X-Received: by 2002:a05:6808:602:: with SMTP id y2mr536585oih.11.1603992778474; Thu, 29 Oct 2020 10:32:58 -0700 (PDT) MIME-Version: 1.0 References: <20201028205101.47583-1-andriy.shevchenko@linux.intel.com> <20201028205101.47583-2-andriy.shevchenko@linux.intel.com> <20201029144656.GD4077@smile.fi.intel.com> In-Reply-To: From: Ricardo Ribalda Date: Thu, 29 Oct 2020 18:32:46 +0100 Message-ID: Subject: Re: [PATCH v1 2/3] Documentation: firmware-guide: gpio-properties: active_low only for GpioIo() To: Andy Shevchenko Cc: Andy Shevchenko , Mika Westerberg , ACPI Devel Maling List , "Rafael J. Wysocki" , "open list:GPIO SUBSYSTEM" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Andy On Thu, Oct 29, 2020 at 6:26 PM Andy Shevchenko wrote: > > On Thu, Oct 29, 2020 at 7:20 PM Andy Shevchenko > wrote: > > > > On Thu, Oct 29, 2020 at 7:17 PM Andy Shevchenko > > wrote: > > > On Thu, Oct 29, 2020 at 4:55 PM Ricardo Ribalda wrote: > > > > On Thu, Oct 29, 2020 at 3:45 PM Andy Shevchenko > > > > wrote: > > > > > On Wed, Oct 28, 2020 at 10:10:42PM +0100, Ricardo Ribalda wrote: > > > > > > ... > > > > > > > > ActiveLevel field is described in 19.6.55 GpioInt (GPIO Interrupt Connection > > > > > Resource Descriptor Macro). > > > > > > > > > > > Without using the active_low, how can we describe a pin that is > > > > > > active low and has to trigger an irq on both edges? > > > > > > > > > > This is nonsense. > > > > > What does it mean? > > > > > > > > Let me try to explain myself again: > > > > > > > > I have a gpio pin that produces IRQs on both edges. so ActiveLevel is Both > > > > > > > > The problem is that the value of that pin is inverted: Low means 1 and > > > > high means 0. > > > > > > > > How can I describe that the pin "is inverted" without using the _DSD field? > > > > > > "Both edges" and "inverted" or "polarity low" in one sentence make no sense. > > > > To be on the constructive side, I can *imagine* so badly designed > > hardware that uses level and edge at the same time, but before I go to > > conclusions, can you share relevant (pieces of) datasheet? > > The [1] is a real example of how GPIO is being used to detect changing > of current level of the signal. > Note, ACPI tables for that device have problems [2], but I guess you > may get the idea. This is exactly what I need to do. Get an IRQ whenever the value changes. But the pin is "inverted" This is the "schematic" : https://ibb.co/f8GMBbP . I want to pass to userspace a "1" when the switch is closed and "0" when it is open. > > > [1]: https://elixir.bootlin.com/linux/latest/source/drivers/extcon/extcon-intel-int3496.c#L138 > [2]: https://elixir.bootlin.com/linux/latest/source/drivers/extcon/extcon-intel-int3496.c#L45 > > -- > With Best Regards, > Andy Shevchenko -- Ricardo Ribalda