From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven King Subject: Re: [PATCH 0/4] gpio: introduce descriptor-based interface Date: Thu, 17 Jan 2013 08:50:43 -0800 Message-ID: <201301170850.43655.sfking@fdwdc.com> References: <1357629535-26033-1-git-send-email-acourbot@nvidia.com> <50F7E83E.8000105@uclinux.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50F7E83E.8000105@uclinux.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Greg Ungerer Cc: linux-arch , Arnd Bergmann , Linus Walleij , Linux Kernel Mailing List , Grant Likely , Alex Courbot , "linux-arm-kernel@lists.infradead.org" , Geert Uytterhoeven , "devicetree-discuss@lists.ozlabs.org" , Guenter Roeck List-Id: linux-arch.vger.kernel.org On Thursday 17 January 2013 4:02:06 am Greg Ungerer wrote: > Hi Linus, > > (My gerg@snapgear.com email no longer gets to me, gerg@uclinux.org is > the best direct email for me now). > > On 01/17/2013 09:15 PM, Linus Walleij wrote: > > On Thu, Jan 10, 2013 at 11:08 AM, Arnd Bergmann wrote: > >> I've tried to find platforms that don't yet use GPIOLIB and fortunately > >> there are very few left: > >> > >> 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. > > > > Geert/Greg: interested in looking into this issue? > > > > The GPIO maintainers want to get rid of non-gpiolib platforms. > > Steven King did most of the ColdFire GPIO work (CC'ed on this). > Steven: are you happy to drop the non-gpiolib support? > > Regards > Greg Well, my concern is the small, single chip platforms with limited ram and speeds measured in MHz. My goal was that these platforms that had very basic gpio needs, no offboard gpio, just toggling a few pins for spi or whatever, could do that without pulling in a bunch of code they dont need. I realize that for x86 or arm people with their giga Hz cpus with gigabytes of ram, its no big deal, but my little 60 MHz coldfire v2s with only 16 megs of ram (and even more constraining, 2 megs of flash) need all the help they can get. I haven't been keeping up with the kernel list of late, can someone point me to what''s being discussed so I can see what were talking about here? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nm3.access.bullet.mail.mud.yahoo.com ([66.94.237.204]:24374 "EHLO nm3.access.bullet.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753635Ab3AQQ4b (ORCPT ); Thu, 17 Jan 2013 11:56:31 -0500 From: Steven King Subject: Re: [PATCH 0/4] gpio: introduce descriptor-based interface Date: Thu, 17 Jan 2013 08:50:43 -0800 References: <1357629535-26033-1-git-send-email-acourbot@nvidia.com> <50F7E83E.8000105@uclinux.org> In-Reply-To: <50F7E83E.8000105@uclinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-ID: <201301170850.43655.sfking@fdwdc.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Greg Ungerer Cc: Linus Walleij , Arnd Bergmann , Geert Uytterhoeven , Alex Courbot , Grant Likely , Guenter Roeck , Linux Kernel Mailing List , linux-arch , "linux-arm-kernel@lists.infradead.org" , "devicetree-discuss@lists.ozlabs.org" Message-ID: <20130117165043.MPMXp1Lc76dap_55sA862NhjjqI5Rz-01sEOnoh68oM@z> On Thursday 17 January 2013 4:02:06 am Greg Ungerer wrote: > Hi Linus, > > (My gerg@snapgear.com email no longer gets to me, gerg@uclinux.org is > the best direct email for me now). > > On 01/17/2013 09:15 PM, Linus Walleij wrote: > > On Thu, Jan 10, 2013 at 11:08 AM, Arnd Bergmann wrote: > >> I've tried to find platforms that don't yet use GPIOLIB and fortunately > >> there are very few left: > >> > >> 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. > > > > Geert/Greg: interested in looking into this issue? > > > > The GPIO maintainers want to get rid of non-gpiolib platforms. > > Steven King did most of the ColdFire GPIO work (CC'ed on this). > Steven: are you happy to drop the non-gpiolib support? > > Regards > Greg Well, my concern is the small, single chip platforms with limited ram and speeds measured in MHz. My goal was that these platforms that had very basic gpio needs, no offboard gpio, just toggling a few pins for spi or whatever, could do that without pulling in a bunch of code they dont need. I realize that for x86 or arm people with their giga Hz cpus with gigabytes of ram, its no big deal, but my little 60 MHz coldfire v2s with only 16 megs of ram (and even more constraining, 2 megs of flash) need all the help they can get. I haven't been keeping up with the kernel list of late, can someone point me to what''s being discussed so I can see what were talking about here? From mboxrd@z Thu Jan 1 00:00:00 1970 From: sfking@fdwdc.com (Steven King) Date: Thu, 17 Jan 2013 08:50:43 -0800 Subject: [PATCH 0/4] gpio: introduce descriptor-based interface In-Reply-To: <50F7E83E.8000105@uclinux.org> References: <1357629535-26033-1-git-send-email-acourbot@nvidia.com> <50F7E83E.8000105@uclinux.org> Message-ID: <201301170850.43655.sfking@fdwdc.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday 17 January 2013 4:02:06 am Greg Ungerer wrote: > Hi Linus, > > (My gerg at snapgear.com email no longer gets to me, gerg at uclinux.org is > the best direct email for me now). > > On 01/17/2013 09:15 PM, Linus Walleij wrote: > > On Thu, Jan 10, 2013 at 11:08 AM, Arnd Bergmann wrote: > >> I've tried to find platforms that don't yet use GPIOLIB and fortunately > >> there are very few left: > >> > >> 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. > > > > Geert/Greg: interested in looking into this issue? > > > > The GPIO maintainers want to get rid of non-gpiolib platforms. > > Steven King did most of the ColdFire GPIO work (CC'ed on this). > Steven: are you happy to drop the non-gpiolib support? > > Regards > Greg Well, my concern is the small, single chip platforms with limited ram and speeds measured in MHz. My goal was that these platforms that had very basic gpio needs, no offboard gpio, just toggling a few pins for spi or whatever, could do that without pulling in a bunch of code they dont need. I realize that for x86 or arm people with their giga Hz cpus with gigabytes of ram, its no big deal, but my little 60 MHz coldfire v2s with only 16 megs of ram (and even more constraining, 2 megs of flash) need all the help they can get. I haven't been keeping up with the kernel list of late, can someone point me to what''s being discussed so I can see what were talking about here?