Date: Fri, 18 Feb 2011 09:51:23 +0100
From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= 
	<u.kleine-koenig@pengutronix.de>
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>,
        Mark Brown <broonie@opensource.wolfsonmicro.com>,
        Joe Perches <joe@perches.com>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
        Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH v3 1/4] gpiolib: Add "unknown" direction support
Message-ID: <20110218085123.GW22310@pengutronix.de>
References: <1297983799-4747-1-git-send-email-ptyser@xes-inc.com>
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Hello,

On Thu, Feb 17, 2011 at 05:03:16PM -0600, Peter Tyser wrote:
> Previously, gpiolib would unconditionally flag all GPIO pins as inputs,
> regardless of their true state.  This resulted in all GPIO output pins
> initially being incorrectly identified as "input" in the GPIO sysfs.
> 
> Since the direction of GPIOs is not known prior to having their
> direction set, instead set the default direction to "unknown" to prevent
> user confusion.  A pin with an "unknown" direction can not be written or
> read via sysfs; it must first be configured as an input or output before
> it can be used.
> 
> While we're playing with the direction flag in/out defines, rename them to
> a more descriptive FLAG_DIR_* format.
Would it make sense to reset the state to unknown on gpio_free?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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