From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 3/5] gpio/omap: Add DT support to GPIO driver Date: Wed, 27 Feb 2013 10:50:57 -0700 Message-ID: <512E4781.8050701@wwwdotorg.org> References: <1329321854-24490-1-git-send-email-b-cousson@ti.com> <1329321854-24490-4-git-send-email-b-cousson@ti.com> <4F44FA56.7020000@gmail.com> <4F44FC37.2000701@ti.com> <4F452484.5080503@gmail.com> <74CDBE0F657A3D45AFBB94109FB122FF17BD8BC6C1@HQMAIL01.nvidia.com> <4F47AD08.4030504@ti.com> <512D39DA.7020306@ti.com> <512D3AB1.1080202@wwwdotorg.org> <512D3EC2.6050408@ti.com> <512D3FE6.1010300@wwwdotorg.org> <512D490B.70900@ti.com> <512D4FC4.2060505@wwwdotorg.org> <512D5C58.4090500@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:48311 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760049Ab3B0RvB (ORCPT ); Wed, 27 Feb 2013 12:51:01 -0500 In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Javier Martinez Canillas Cc: Jon Hunter , Stephen Warren , Kevin Hilman , "devicetree-discuss@lists.ozlabs.org" , "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linus Walleij , Grant Likely On 02/26/2013 08:57 PM, Javier Martinez Canillas wrote: > On Wed, Feb 27, 2013 at 2:07 AM, Jon Hunter wrote: >> >> On 02/26/2013 06:13 PM, Stephen Warren wrote: >>> On 02/26/2013 04:45 PM, Jon Hunter wrote: ... >>>> One issue I see is that by not calling gpio_request, then potentially >>>> you could have someone request a gpio via gpio_request() and someone >>>> trying to use it as an interrupt source via request_irq(). Now obviously >>>> that represents a bug because there is only one physical gpio, but I >>>> gather it is something we need to protect against. >>> >>> I'm not sure it's really that much of an issue, but presumably the >>> solution is for a combined GPIO+IRQ driver to simply call gpio_request >>> internally from within some irq_chip function. It looks like struct >>> irq_chip doesn't have a request/free, but perhaps they could be added to >>> solve this? >> >> Yes I was wondering if we could do something like that. That would work, >> may be that's what we should propose. > > Something like that would definitely solve the GPIO request issue but > we still have the issue that the current OMAP GPIO controller binding > does not support #interrupt-cells = <2>. The binding documentation in Documentation/devicetree/bindings/gpio/gpio-omap.txt indicates that it does. If this doesn't work in practice, it's a driver bug that can presumably be easily fixed. And no need to change any ABI definitions:-) BTW, I notice in that binding document that the description of the two cells for #interrupt-cells is actually part of the description of the "interrupt-controller" property; it should be moved up one line really.