From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 0/4] gpio: introduce descriptor-based interface Date: Mon, 14 Jan 2013 10:46:12 +0000 Message-ID: <201301141046.12976.arnd@arndb.de> References: <1357629535-26033-1-git-send-email-acourbot@nvidia.com> <201301101008.45091.arnd@arndb.de> <50F3DC2B.6000603@nvidia.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50F3DC2B.6000603@nvidia.com> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Alex Courbot Cc: Mike Frysinger , Geert Uytterhoeven , Grant Likely , Linus Walleij , Guenter Roeck , Linux Kernel Mailing List , linux-arch , "linux-arm-kernel@lists.infradead.org" , "devicetree-discuss@lists.ozlabs.org" , gnurou@gmail.com, linux-m68k@lists.linux-m68k.org, uclinux-dist-devel@blackfin.uclinux.org On Monday 14 January 2013, Alex Courbot wrote: > On 01/10/2013 07:08 PM, Arnd Bergmann wrote: > > I found two that provide the generic gpio interfaces when gpiolib > > is disabled, but use gpiolib otherwise for the same hardware, > > arch/m68k/include/asm/mcfgpio.h and arch/blackfin/include/asm/gpio.h. > > I would assume that we can simply remove the non-gpiolib shortcut > > here at cost of a small overhead. > > I performed a search on my side too (checking configurations options > which select GENERIC_GPIO but not ARCH_REQUIRE_GPIOLIB) and found the > same list. This takes some time btw - many platforms use this combo to > make GPIO support optional. Can I ask how you figured out these two archs? I basically grepped for GENERIC_GPIO and looked at the individual implementations. > > Then there are a bunch that use gpiolib but have a nontrivial > > implementation of gpio_get_value and other functions. I'm not sure > > if these are a problematic with your code. > > AFAICT these all implement an inline path that bypasses GPIOlib when the > GPIO number is known at compile time, for faster bitbanging I presume. > It should be totally harmless to keep them. Unfortunately, I don't think > it would be possible to have a similar trick using handlers. Right, makes sense. Arnd