From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support Date: Wed, 24 Apr 2019 13:46:13 +0300 Message-ID: <20190424104613.GD2654@lahna.fi.intel.com> References: <20190424081802.GV2654@lahna.fi.intel.com> <5a28f22c-22f7-760a-d076-68ff19800d44@siemens.com> <20190424084259.GW2654@lahna.fi.intel.com> <7e328b7e-f4f0-851a-4152-a9ffd058201c@siemens.com> <20190424094506.GA2654@lahna.fi.intel.com> <292e6eff-82cc-6e4d-925b-77a60399e2e0@siemens.com> <20190424100130.GB2654@lahna.fi.intel.com> <1200464b-f969-ebc2-ae82-1f8ca98aaca1@siemens.com> <20190424103306.GC2654@lahna.fi.intel.com> <9377620b-d74a-04d9-a51e-8590400b1c0f@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <9377620b-d74a-04d9-a51e-8590400b1c0f@siemens.com> Sender: linux-kernel-owner@vger.kernel.org To: Jan Kiszka Cc: Andy Shevchenko , Linus Walleij , Bartosz Golaszewski , Linux Kernel Mailing List , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, "Rafael J. Wysocki" List-Id: linux-acpi@vger.kernel.org On Wed, Apr 24, 2019 at 12:39:35PM +0200, Jan Kiszka wrote: > On 24.04.19 12:33, Mika Westerberg wrote: > > On Wed, Apr 24, 2019 at 12:19:02PM +0200, Jan Kiszka wrote: > > > > I think what you want is "GPIO signaled ACPI event". It works so that > > > > you declare _AEI method below the GPIO controller listing the GPIOs you > > > > want to trigger events for and then either _Lxx, _Exx or _EVT method for > > > > each of them under the same controller. GPIO core then handles it > > > > automatically when you register the GPIO chip. See also > > > > acpi_gpiochip_request_interrupts(). > > > > > > Right, that is was I read as well. Let's assume I would be able to patch the > > > tables: Would I describe all the logic of this patch in ACPI terms? Where to > > > enable interrupts, how to dispatch the SCI event, how to acknowledge it > > > etc.? Will it also take care of locking? (BTW, my locking seems to have some > > > remaining inconsistency, on second look.) > > > > The GPIO core would then take care of it by requesting the GPIO in > > question and dispatching to the correct event handler. In this patch you > > just leave out the SCI part and only implement the irqchip like you did > > already. > > Could you point me to a gpio driver that works like that already? Would be > easier to learn that from an example. That infrastructure with all its > different modes is seriously complex and not very well documented. Pretty much all drivers under drivers/pinctrl/intel. > > > And even if that were possible, we would be back to the square of existing > > > devices without those definitions. If this were a recent chipset, I would > > > say, "go, fix future firmware versions". But this one is legacy. > > > > Is it fixing some real issue with these legacy platforms? I mean without > > the patch some GPE event is not handled properly? It was not clear to me > > from the commit message. > > > Without that patch, you are forced to poll for event changes in your > application, timer-driven. There are application that cannot process these > GPIOs because they lack such logic (mraa with node-red-node-intel-gpio is a > public example). But those are using the GPIOs via sysfs or the char device which should work without the SCI handling part of your patch, no? 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=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 B8AB9C10F11 for ; Wed, 24 Apr 2019 10:46:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91B0D21773 for ; Wed, 24 Apr 2019 10:46:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727007AbfDXKqn (ORCPT ); Wed, 24 Apr 2019 06:46:43 -0400 Received: from mga14.intel.com ([192.55.52.115]:55200 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726238AbfDXKqn (ORCPT ); Wed, 24 Apr 2019 06:46:43 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Apr 2019 03:46:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,389,1549958400"; d="scan'208";a="167454399" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by fmsmga001.fm.intel.com with SMTP; 24 Apr 2019 03:46:14 -0700 Received: by lahna (sSMTP sendmail emulation); Wed, 24 Apr 2019 13:46:14 +0300 Date: Wed, 24 Apr 2019 13:46:13 +0300 From: Mika Westerberg To: Jan Kiszka Cc: Andy Shevchenko , Linus Walleij , Bartosz Golaszewski , Linux Kernel Mailing List , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, "Rafael J. Wysocki" Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support Message-ID: <20190424104613.GD2654@lahna.fi.intel.com> References: <20190424081802.GV2654@lahna.fi.intel.com> <5a28f22c-22f7-760a-d076-68ff19800d44@siemens.com> <20190424084259.GW2654@lahna.fi.intel.com> <7e328b7e-f4f0-851a-4152-a9ffd058201c@siemens.com> <20190424094506.GA2654@lahna.fi.intel.com> <292e6eff-82cc-6e4d-925b-77a60399e2e0@siemens.com> <20190424100130.GB2654@lahna.fi.intel.com> <1200464b-f969-ebc2-ae82-1f8ca98aaca1@siemens.com> <20190424103306.GC2654@lahna.fi.intel.com> <9377620b-d74a-04d9-a51e-8590400b1c0f@siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <9377620b-d74a-04d9-a51e-8590400b1c0f@siemens.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Message-ID: <20190424104613.LbG9ztTgFrAimWYtxs11Dn0Je5HyKYr9rmGmXv9W_Wo@z> On Wed, Apr 24, 2019 at 12:39:35PM +0200, Jan Kiszka wrote: > On 24.04.19 12:33, Mika Westerberg wrote: > > On Wed, Apr 24, 2019 at 12:19:02PM +0200, Jan Kiszka wrote: > > > > I think what you want is "GPIO signaled ACPI event". It works so that > > > > you declare _AEI method below the GPIO controller listing the GPIOs you > > > > want to trigger events for and then either _Lxx, _Exx or _EVT method for > > > > each of them under the same controller. GPIO core then handles it > > > > automatically when you register the GPIO chip. See also > > > > acpi_gpiochip_request_interrupts(). > > > > > > Right, that is was I read as well. Let's assume I would be able to patch the > > > tables: Would I describe all the logic of this patch in ACPI terms? Where to > > > enable interrupts, how to dispatch the SCI event, how to acknowledge it > > > etc.? Will it also take care of locking? (BTW, my locking seems to have some > > > remaining inconsistency, on second look.) > > > > The GPIO core would then take care of it by requesting the GPIO in > > question and dispatching to the correct event handler. In this patch you > > just leave out the SCI part and only implement the irqchip like you did > > already. > > Could you point me to a gpio driver that works like that already? Would be > easier to learn that from an example. That infrastructure with all its > different modes is seriously complex and not very well documented. Pretty much all drivers under drivers/pinctrl/intel. > > > And even if that were possible, we would be back to the square of existing > > > devices without those definitions. If this were a recent chipset, I would > > > say, "go, fix future firmware versions". But this one is legacy. > > > > Is it fixing some real issue with these legacy platforms? I mean without > > the patch some GPE event is not handled properly? It was not clear to me > > from the commit message. > > > Without that patch, you are forced to poll for event changes in your > application, timer-driven. There are application that cannot process these > GPIOs because they lack such logic (mraa with node-red-node-intel-gpio is a > public example). But those are using the GPIOs via sysfs or the char device which should work without the SCI handling part of your patch, no?