Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760043Ab3ICMn7 (ORCPT ); Tue, 3 Sep 2013 08:43:59 -0400 Received: from mail-ob0-f175.google.com ([209.85.214.175]:46296 "EHLO mail-ob0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760012Ab3ICMn5 (ORCPT ); Tue, 3 Sep 2013 08:43:57 -0400 MIME-Version: 1.0 In-Reply-To: <5220F8AE.2080300@wwwdotorg.org> References: <1377526030-32024-1-git-send-email-larsi@wh2.tu-dresden.de> <521D0964.2080209@wwwdotorg.org> <521FE637.3010805@collabora.co.uk> <5220F8AE.2080300@wwwdotorg.org> Date: Tue, 3 Sep 2013 14:43:57 +0200 Message-ID: Subject: Re: [PATCH v3] gpio: interrupt consistency check for OF GPIO IRQs From: Linus Walleij To: Stephen Warren , Alexandre Courbot Cc: Javier Martinez Canillas , Lars Poeschel , Lars Poeschel , Grant Likely , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , Mark Rutland , Ian Campbell , Kumar Gala , Pawel Moll , Tomasz Figa , Enric Balletbo i Serra , Jean-Christophe PLAGNIOL-VILLARD , Santosh Shilimkar , Kevin Hilman , Balaji T K , Tony Lindgren , Jon Hunter Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1917 Lines: 45 On Fri, Aug 30, 2013 at 9:55 PM, Stephen Warren wrote: > On 08/29/2013 06:24 PM, Javier Martinez Canillas wrote: > ... >> We have been trying to solve this issue for a few months by now and Linus' >> approach seems to be the most sensible solution to me. >> >> Drivers that request an IRQ and assume that platform code will request and setup >> the GPIO have been broken since the boards using these drivers were migrated to >> DT (e.g: smsc911x on OMAP2+ boards). > > That's only true if the driver for the GPIO controller is buggy. > Whatever request_irq() maps down to in the GPIO/IRQ controller driver > simply needs to set up the pin as an interrupt input, then it doesn't > matter which order the driver does things. As mentioned it can't do that, because doing that creates a restriction on which order the driver does things... But you mentioned that you wanted an API that would account for the case where the *same driver* requested the same resource (a GPIO line) to be used for both IRQ and GPIO, through two different calls. I would be happy to see how we could do that, preferably in a generic way. Since the gpio_request() does not contain the signature of the calling driver I don't see how we could do this without refactoring the whole world. In that case it would probably be easiest to *first* proceed to complete Alexandre's suggested refactorings for GPIO descriptors, which tie down GPIOs to be requested like clocks and regulators and thus tied to a device, so we can from there proceed to implement such a conditional request, as we will then have the required information in the GPIO subsystem. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/