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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 B6156C282C4 for ; Tue, 12 Feb 2019 11:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8AD26217FA for ; Tue, 12 Feb 2019 11:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728918AbfBLLFI (ORCPT ); Tue, 12 Feb 2019 06:05:08 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:35331 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727553AbfBLLFH (ORCPT ); Tue, 12 Feb 2019 06:05:07 -0500 Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gtVs7-0003oz-4f; Tue, 12 Feb 2019 12:05:03 +0100 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1gtVs6-0005IS-09; Tue, 12 Feb 2019 12:05:02 +0100 Date: Tue, 12 Feb 2019 12:05:01 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Marc Zyngier Cc: Bartosz Golaszewski , Bartosz Golaszewski , Linus Walleij , Thomas Gleixner , linux-gpio , LKML Subject: Re: [PATCH v2 3/9] irq/irq_sim: provide irq_sim_fire_type() Message-ID: <20190212110501.wd7ks7vms7pi63dk@pengutronix.de> References: <20190129084411.30495-1-brgl@bgdev.pl> <20190129084411.30495-4-brgl@bgdev.pl> <656763ec-41b9-cdee-22bd-1f32d74473a0@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 12, 2019 at 10:27:54AM +0000, Marc Zyngier wrote: > On 12/02/2019 09:19, Bartosz Golaszewski wrote: > > When userspace wants to monitor GPIO line interrupts, the GPIO > > framework requests a threaded interrupt with IRQF_TRIGGER_FALLING, > > IRQF_TRIGGER_RISING or both. The testing module tries to act like real > > hardware and so if we pass only one of the *_TRIGGER_* flags, we want > > the simulated interrupt of corresponding type to be fired. > > Well, that's not how HW works. I cannot follow. I agree with Bartosz here. If you configure your SoC's irq-controller to only fire on a raising edge, you don't get an event when the line falls. > > Another solution - if you don't like this one - would be to have more > > specialized functions: irq_sim_fire_rising() and > > irq_sim_fire_falling(). How about that? > > I think you're missing the point. So far, your API has been "an > interrupt has fired", no matter what the trigger is, and that's fine. > That's just modeling the output of an abstract interrupt controller into > whatever the irqsim is simulating. > > Now, what you're exposing is "this is how the line changed". Which is an > entirely different business, as you're now exposing the device output > line. Yes, you can model it with raising/falling, but you need at least > resampling for level interrupts, and actual edge detection (raising > followed by raising only generates a single interrupt, while > raising-falling-raising generates two). This matches my concern and that's why I suggested somewhere else in this thread to put the configuration of the sensitiveness and the actual tracking of the line in the same component (either irqsim or gpio-mockup). Given that there are only two irqsim users and the other one (something in iio) doesn't need that sensitiveness stuff (and I cannot imagine another user of irqsim with the sensitiveness support) I think it is best to move this to the mockup driver. That's how "normal" hardware drivers have to do it, too. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |