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From: Alexandre Courbot <gnurou@gmail.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
	Alexandre Courbot <acourbot@nvidia.com>,
	Enric Balletbo i Serra <eballetbo@gmail.com>,
	Grant Likely <grant.likely@linaro.org>,
	Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>,
	Santosh Shilimkar <santosh.shilimkar@ti.com>,
	Stephen Warren <swarren@wwwdotorg.org>
Subject: Re: [PATCH 1/2] gpio: add API to be strict about GPIO IRQ usage
Date: Fri, 11 Oct 2013 09:57:07 -0700	[thread overview]
Message-ID: <CAAVeFuLqWTciAkEq+D_8c3e3_UH91djQPVO9CnEMwWogkgxEwA@mail.gmail.com> (raw)
In-Reply-To: <1381483935-12165-1-git-send-email-linus.walleij@linaro.org>

On Fri, Oct 11, 2013 at 2:32 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> It is currently often possible in many GPIO drivers to request
> a GPIO line to be used as IRQ after calling gpio_to_irq() and,
> as the gpiolib is not aware of this, set the same line to
> output and start driving it, with undesired side effects.
>
> As it is a bogus usage scenario to request a line flagged as
> output to used as IRQ, we introduce APIs to let gpiolib track
> the use of a line as IRQ, and also set this flag from the
> userspace ABI.
>
> The API is symmetric so that lines can also be flagged from
> .irq_enable() and unflagged from IRQ by .irq_disable().
> The debugfs file is altered so that we see if a line is
> reserved for IRQ.

A much-welcome safety measure.

Acked-by: Alexandre Courbot <acourbot@nvidia.com>

  reply	other threads:[~2013-10-11 16:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-11  9:32 [PATCH 1/2] gpio: add API to be strict about GPIO IRQ usage Linus Walleij
2013-10-11 16:57 ` Alexandre Courbot [this message]
2013-10-11 19:16 ` Stephen Warren

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