From: florian.vaussard@epfl.ch (Florian Vaussard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] gpiolib: add gpio_export_with_name
Date: Thu, 30 May 2013 11:19:33 +0200 [thread overview]
Message-ID: <51A719A5.50906@epfl.ch> (raw)
In-Reply-To: <20121126135911.2F1D33E187C@localhost>
Hello Grant,
On 11/26/2012 02:59 PM, Grant Likely wrote:
> On Wed, 21 Nov 2012 11:14:08 +0100, Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> wrote:
>> allow to specify a name to an exported gpio
>>
>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
>
> The gpio sysfs ABI is already horrible, racy, and unsafe. Really, we
> need a proper chrdev interface for controlling gpios. Sysfs is fine for
> poking around and experimenting, but we cannot provide any fine grained
> access control, locking or faster IO with the one-file-per-gpio sysfs
> model. So, no, I don't think this is a good idea to extend gpiolib in
> this way.
>
Would it make sense to provide only the DT binding to export a GPIO,
without changing the sysfs ABI? Even if work is progressing towards
having gpio-controlled reset pins [1], some boards still need GPIOs to
be exported to userspace for other functionalities.
Regards,
Florian
[1] http://article.gmane.org/gmane.linux.power-management.general/31364
WARNING: multiple messages have this Message-ID (diff)
From: Florian Vaussard <florian.vaussard-p8DiymsW2f8@public.gmane.org>
To: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 1/2] gpiolib: add gpio_export_with_name
Date: Thu, 30 May 2013 11:19:33 +0200 [thread overview]
Message-ID: <51A719A5.50906@epfl.ch> (raw)
In-Reply-To: <20121126135911.2F1D33E187C@localhost>
Hello Grant,
On 11/26/2012 02:59 PM, Grant Likely wrote:
> On Wed, 21 Nov 2012 11:14:08 +0100, Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org> wrote:
>> allow to specify a name to an exported gpio
>>
>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
>
> The gpio sysfs ABI is already horrible, racy, and unsafe. Really, we
> need a proper chrdev interface for controlling gpios. Sysfs is fine for
> poking around and experimenting, but we cannot provide any fine grained
> access control, locking or faster IO with the one-file-per-gpio sysfs
> model. So, no, I don't think this is a good idea to extend gpiolib in
> this way.
>
Would it make sense to provide only the DT binding to export a GPIO,
without changing the sysfs ABI? Even if work is progressing towards
having gpio-controlled reset pins [1], some boards still need GPIOs to
be exported to userspace for other functionalities.
Regards,
Florian
[1] http://article.gmane.org/gmane.linux.power-management.general/31364
next prev parent reply other threads:[~2013-05-30 9:19 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-21 10:12 [PATCH 0/2] gpio: dt: add gpio-export support Jean-Christophe PLAGNIOL-VILLARD
2012-11-21 10:12 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-21 10:14 ` [PATCH 1/2] gpiolib: add gpio_export_with_name Jean-Christophe PLAGNIOL-VILLARD
2012-11-21 10:14 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-21 10:14 ` [PATCH 2/2] gpiolib-of: ad gpio-export support Jean-Christophe PLAGNIOL-VILLARD
2012-11-21 10:14 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-26 13:59 ` [PATCH 1/2] gpiolib: add gpio_export_with_name Grant Likely
2012-11-26 13:59 ` Grant Likely
2012-11-28 20:19 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-28 20:19 ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-18 6:04 ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-18 6:04 ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-19 13:11 ` Grant Likely
2012-12-19 13:11 ` Grant Likely
2013-05-30 9:19 ` Florian Vaussard [this message]
2013-05-30 9:19 ` Florian Vaussard
2013-05-30 20:03 ` Linus Walleij
2013-05-30 20:03 ` Linus Walleij
2013-05-30 20:38 ` Florian Vaussard
2013-05-30 20:38 ` Florian Vaussard
2013-05-30 21:11 ` Linus Walleij
2013-05-30 21:11 ` Linus Walleij
2013-05-31 8:17 ` Florian Vaussard
2013-05-31 8:17 ` Florian Vaussard
2012-11-21 14:43 ` [PATCH 0/2] gpio: dt: add gpio-export support Linus Walleij
2012-11-21 14:43 ` Linus Walleij
2012-11-24 18:48 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-24 18:48 ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-01 16:56 ` Linus Walleij
2012-12-01 16:56 ` Linus Walleij
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