Date: Mon, 14 Feb 2011 17:08:12 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Peter Tyser <ptyser@xes-inc.com>
Cc: linux-kernel@vger.kernel.org, Alek Du <alek.du@intel.com>,
        Samuel Ortiz <sameo@linux.intel.com>,
        David Brownell <dbrownell@users.sourceforge.net>,
        Eric Miao <eric.y.miao@gmail.com>,
        Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>,
        Mark Brown <broonie@opensource.wolfsonmicro.com>,
        Joe Perches <joe@perches.com>,
        "grant.likely" <grant.likely@secretlab.ca>
Subject: Re: [PATCH 1/3] gpiolib: Add ability to get GPIO pin direction
Message-ID: <20110214170812.6f54a4bb@lxorguk.ukuu.org.uk>
In-Reply-To: <1297698493.965.5475.camel@petert>
References: <1294343654-20354-1-git-send-email-ptyser@xes-inc.com>
	<1297698493.965.5475.camel@petert>
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> > If a GPIO driver implements get_direction(), it is called in
> > gpio_request() to set the initial direction of the pin accurately.
> 
> I see Grant was just added as a GPIO maintainer, so added him on CC.
> 
> Anything gating getting these 3 patches being picked up?

We need four states for a gpio pin direction though. A pin can be

- input
- output
- unknown (hardware lacks get functionality and it has not been set by
  software yet)
- alt_func (pin is in use for some other purpose)

(and being able to set them alt_func was proposed a while ago and I think
wants revisiting judging by the number of platforms which use gpio, and
in their own arch code are privately handling alt_func stuff)

Alan
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