From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH v2] gpio: Add Avionic Design N-bit GPIO expander support Date: Fri, 10 Aug 2012 10:15:55 +0100 Message-ID: <20120810091555.GX18957@n2100.arm.linux.org.uk> References: <1343044770-6591-1-git-send-email-thierry.reding@avionic-design.de> <20120809202054.GA24503@avionic-0098.mockup.avionic-design.de> <20120810083508.GA16251@avionic-0098.mockup.avionic-design.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Linus Walleij Cc: Thierry Reding , Grant Likely , Arnd Bergmann , linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, Linus Walleij , Rob Herring , Wolfram Sang List-Id: devicetree@vger.kernel.org On Fri, Aug 10, 2012 at 10:41:58AM +0200, Linus Walleij wrote: > On Fri, Aug 10, 2012 at 10:35 AM, Thierry Reding > wrote: > >> Consult the following article on LWN: > >> http://lwn.net/Articles/470820/ > >> > >> Then grep your gitlog and you'll see we got rid of it from ARM. > > > > Then why is there still the following in arch/arm/include/asm/irq.h? > > > > /* > > * Use this value to indicate lack of interrupt > > * capability > > */ > > #ifndef NO_IRQ > > #define NO_IRQ ((unsigned int)(-1)) > > #endif > > That's a question for Russell but I think it's basically there for > old platforms, on a "don't use it"-basis. (Maybe a comment could > be good.) Just don't use it. It's there for old stuff which still needs fixing. New code should not use it, and should test for one of: irq <= 0 irq == 0 And new code should set irq = 0 to indicate a lack of interrupt.