Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965545AbbEMPos (ORCPT ); Wed, 13 May 2015 11:44:48 -0400 Received: from exprod5og120.obsmtp.com ([64.18.0.137]:56356 "EHLO mail-ob0-f179.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965150AbbEMPoq (ORCPT ); Wed, 13 May 2015 11:44:46 -0400 MIME-Version: 1.0 In-Reply-To: References: <1426676484-21812-1-git-send-email-marc.zyngier@arm.com> <1426676484-21812-3-git-send-email-marc.zyngier@arm.com> Date: Wed, 13 May 2015 08:44:44 -0700 Message-ID: Subject: Re: [PATCH v4 2/3] irqchip: GIC: Add support for irq_{get,set}_irqchip_state From: Feng Kan To: Linus Walleij Cc: Marc Zyngier , Abhijeet Dharmapurikar , Stephen Boyd , Phong Vo , Tin Huynh , Y Vo , Thomas Gleixner , Toan Le , Bjorn Andersson , Jason Cooper , Arnd Bergmann , linux-arm-msm , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-gpio@vger.kernel.org" , Alexandre Courbot 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: 1690 Lines: 36 On Wed, May 13, 2015 at 4:58 AM, Linus Walleij wrote: > On Wed, May 13, 2015 at 4:25 AM, Feng Kan wrote: > >> Marc: >> >> Sorry for top posting. It seems with GIC-400, the get_irqstate is not a reliable >> way of accessing the GPIO status. In our case, the gpio interrupt status can >> only be read correctly with the SPISR register. So it seems we have to go >> back to the old way of mapping the SPISR portion of the GIC in our GPIO >> driver. We wanted to ask you if that is acceptable since SPISR in not >> standard in all GIC, perhaps we can treat it differently. > > As GPIO maintainer I am curious about what this is... > > Can you describe the scenario where your GPIO (!) driver needs > to be poking around in the GIC SPISR? We are using the gpio driver with gpio_key for power button. The gpio status can only be retrieved from the GIC register when the gpio is acting as a interrupt. Marc had provided a patch which allow the getting of the irq status using the PENDING_SET register, however it seems it is not reliable. Another register in the GIC call the SPISR always give the correct status but it is only available in the GIC-400 and hence not likely to be incorporated into the general GIC code. We would like to go back the version 1 of the patch and ioremap the region in the gpio driver and access the status that way. Please let us know what you think. > > 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/