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From: Steven King <sfking@fdwdc.com>
To: Greg Ungerer <gerg@uclinux.org>
Cc: linux-arch <linux-arch@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Grant Likely <grant.likely@secretlab.ca>,
	Alex Courbot <acourbot@nvidia.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"devicetree-discuss@lists.ozlabs.org"
	<devicetree-discuss@lists.ozlabs.org>,
	Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH 0/4] gpio: introduce descriptor-based interface
Date: Thu, 17 Jan 2013 08:50:43 -0800	[thread overview]
Message-ID: <201301170850.43655.sfking@fdwdc.com> (raw)
In-Reply-To: <50F7E83E.8000105@uclinux.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 <arnd@arndb.de> 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?

WARNING: multiple messages have this Message-ID (diff)
From: Steven King <sfking@fdwdc.com>
To: Greg Ungerer <gerg@uclinux.org>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Alex Courbot <acourbot@nvidia.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Guenter Roeck <linux@roeck-us.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"devicetree-discuss@lists.ozlabs.org"
	<devicetree-discuss@lists.ozlabs.org>
Subject: Re: [PATCH 0/4] gpio: introduce descriptor-based interface
Date: Thu, 17 Jan 2013 08:50:43 -0800	[thread overview]
Message-ID: <201301170850.43655.sfking@fdwdc.com> (raw)
Message-ID: <20130117165043.MPMXp1Lc76dap_55sA862NhjjqI5Rz-01sEOnoh68oM@z> (raw)
In-Reply-To: <50F7E83E.8000105@uclinux.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 <arnd@arndb.de> 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?

WARNING: multiple messages have this Message-ID (diff)
From: sfking@fdwdc.com (Steven King)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 0/4] gpio: introduce descriptor-based interface
Date: Thu, 17 Jan 2013 08:50:43 -0800	[thread overview]
Message-ID: <201301170850.43655.sfking@fdwdc.com> (raw)
In-Reply-To: <50F7E83E.8000105@uclinux.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 <arnd@arndb.de> 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?

  reply	other threads:[~2013-01-17 16:50 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-08  7:18 [PATCH 0/4] gpio: introduce descriptor-based interface Alexandre Courbot
2013-01-08  7:18 ` Alexandre Courbot
2013-01-08  7:18 ` Alexandre Courbot
2013-01-08  7:18 ` [PATCH 1/4] gpiolib: introduce descriptor-based GPIO interface Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08 12:59   ` Arnd Bergmann
2013-01-08 12:59     ` Arnd Bergmann
2013-01-09  1:06     ` Alexandre Courbot
2013-01-09  1:06       ` Alexandre Courbot
2013-01-09 10:25       ` Russell King - ARM Linux
2013-01-09 10:25         ` Russell King - ARM Linux
2013-01-09 10:35       ` Arnd Bergmann
2013-01-09 10:35         ` Arnd Bergmann
2013-01-09 10:44         ` Russell King - ARM Linux
2013-01-09 10:44           ` Russell King - ARM Linux
2013-01-09 11:10           ` Russell King - ARM Linux
2013-01-09 11:10             ` Russell King - ARM Linux
     [not found]             ` <20130109111055.GG3931-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2013-01-09 11:52               ` Arnd Bergmann
2013-01-09 11:52                 ` Arnd Bergmann
2013-01-09 11:52                 ` Arnd Bergmann
2013-01-09 14:44             ` Nicolas Pitre
2013-01-09 14:44               ` Nicolas Pitre
2013-01-09 15:04               ` [PATCH] Proposed removal of IS_ERR_OR_NULL() (was: Re: [PATCH 1/4] gpiolib: introduce descriptor-based GPIO interface) Russell King - ARM Linux
2013-01-09 15:04                 ` Russell King - ARM Linux
     [not found]                 ` <20130109150427.GL3931-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2013-01-09 15:21                   ` Grant Likely
2013-01-09 15:21                     ` Grant Likely
2013-01-09 15:21                     ` Grant Likely
2013-01-09 15:26                     ` Arnd Bergmann
2013-01-09 15:26                       ` Arnd Bergmann
2013-01-09 15:27                 ` Nicolas Pitre
2013-01-09 15:27                   ` Nicolas Pitre
2013-01-09 15:51                   ` Russell King - ARM Linux
2013-01-09 15:51                     ` Russell King - ARM Linux
2013-01-09 16:09                     ` Nicolas Pitre
2013-01-09 16:09                       ` Nicolas Pitre
2013-01-09 16:21                       ` Russell King - ARM Linux
2013-01-09 16:21                         ` Russell King - ARM Linux
2013-01-09 17:12                         ` Russell King - ARM Linux
2013-01-09 17:12                           ` Russell King - ARM Linux
2013-01-09 17:52                           ` Tony Lindgren
2013-01-09 17:52                             ` Tony Lindgren
2013-01-17 10:28                 ` Linus Walleij
2013-01-17 10:28                   ` Linus Walleij
2013-01-10  8:36             ` [PATCH 1/4] gpiolib: introduce descriptor-based GPIO interface Thierry Reding
2013-01-10  8:36               ` Thierry Reding
2013-01-08  7:18 ` [PATCH 2/4] gpiolib: add gpiod_get and gpiod_put functions Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08 13:07   ` Arnd Bergmann
2013-01-08 13:07     ` Arnd Bergmann
2013-01-09  1:49     ` Alexandre Courbot
2013-01-09  1:49       ` Alexandre Courbot
2013-01-08  7:18 ` [PATCH 3/4] gpiolib: of: convert OF helpers to descriptor API Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08  7:18 ` [PATCH 4/4] gpiolib: add documentation for new gpiod_ API Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08  7:18   ` Alexandre Courbot
2013-01-08 13:06 ` [PATCH 0/4] gpio: introduce descriptor-based interface Arnd Bergmann
2013-01-08 13:06   ` Arnd Bergmann
2013-01-09  1:48   ` Alexandre Courbot
2013-01-09  1:48     ` Alexandre Courbot
2013-01-09 10:46     ` Arnd Bergmann
2013-01-09 10:46       ` Arnd Bergmann
2013-01-10  4:07       ` Alex Courbot
2013-01-10  4:07         ` Alex Courbot
2013-01-10 10:08         ` Arnd Bergmann
2013-01-10 10:08           ` Arnd Bergmann
2013-01-14 10:21           ` Alex Courbot
2013-01-14 10:21           ` Alex Courbot
2013-01-14 10:21             ` Alex Courbot
2013-01-14 10:21             ` Alex Courbot
2013-01-14 10:46             ` Arnd Bergmann
2013-01-14 10:46               ` Arnd Bergmann
2013-01-14 10:46               ` Arnd Bergmann
2013-01-17 11:15           ` Linus Walleij
2013-01-17 11:15             ` Linus Walleij
2013-01-17 12:02             ` Greg Ungerer
2013-01-17 12:02               ` Greg Ungerer
2013-01-17 16:50               ` Steven King [this message]
2013-01-17 16:50                 ` Steven King
2013-01-17 16:50                 ` Steven King
2013-01-17 19:22                 ` Arnd Bergmann
2013-01-17 19:22                   ` Arnd Bergmann
2013-01-20  6:07                 ` Alex Courbot
2013-01-20  6:07                   ` Alex Courbot
2013-01-20  6:07                   ` Alex Courbot
2013-01-22  8:55                   ` Linus Walleij
2013-01-22  8:55                     ` Linus Walleij
2013-01-17 11:25           ` Linus Walleij
2013-01-17 11:25             ` Linus Walleij

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