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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS 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 32586C43218 for ; Fri, 26 Apr 2019 15:44:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A9B3208CA for ; Fri, 26 Apr 2019 15:44:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726428AbfDZPoY (ORCPT ); Fri, 26 Apr 2019 11:44:24 -0400 Received: from gecko.sbs.de ([194.138.37.40]:39988 "EHLO gecko.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726255AbfDZPoY (ORCPT ); Fri, 26 Apr 2019 11:44:24 -0400 Received: from mail1.sbs.de (mail1.sbs.de [192.129.41.35]) by gecko.sbs.de (8.15.2/8.15.2) with ESMTPS id x3QFiCJG019432 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 26 Apr 2019 17:44:12 +0200 Received: from [167.87.22.130] ([167.87.22.130]) by mail1.sbs.de (8.15.2/8.15.2) with ESMTP id x3QFiBTm030321; Fri, 26 Apr 2019 17:44:11 +0200 Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support To: Linus Walleij , Andy Shevchenko , Manivannan Sadhasivam Cc: Mika Westerberg , Bartosz Golaszewski , Linux Kernel Mailing List , "open list:GPIO SUBSYSTEM" , ACPI Devel Maling List , "Rafael J. Wysocki" 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> <20190426130615.GT9224@smile.fi.intel.com> From: Jan Kiszka Message-ID: <63b179c9-242d-ae90-9c33-49ed256bde28@siemens.com> Date: Fri, 26 Apr 2019 17:44:10 +0200 User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26.04.19 16:41, Linus Walleij wrote: > On Fri, Apr 26, 2019 at 3:06 PM Andy Shevchenko > wrote: >> 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: >> >>>>> 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). >> >> Just a side note: MRAA is a hack itself. It abuses almost all interfaces Linux >> kernel provides. > > I think it's pretty clean for GPIOs these days. My colleague Manivannan > was part of cleaning it up a while back and since then it is doing > what userspace should be doing if userspace absolutely cannot > abstain from using GPIOs directly (i.e. uses the character device). > https://github.com/intel-iot-devkit/mraa/blob/master/src/gpio/gpio_chardev.c > > I don't know about other resources than GPIOs though. That's valuable progress! OTOH, there still seem to be the broken pattern to address pins via hard-coded GPIO numbers. This broke our neck, e.g., when trying to replace the hacky BSP kernel with upstream. I started to create better infrastructure but never fished that. Thanks, Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux