gpio: <linux/gpio.h> and "no GPIO support here" stubs

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Add a <linux/gpio.h> defining fail/warn stubs for GPIO calls on platforms that
don't support the GPIO programming interface.  That includes the arch-specific
implementation glue otherwise.

This facilitates a new model for GPIO usage: drivers that can use GPIOs if
they're available, but don't require them.  One example of such a driver is
NAND driver for various FreeScale chips.  On platforms update with GPIO
support, they can be used instead of a worst-case delay to verify that the
BUSY signal is off.

(Also includes a couple minor unrelated doc updates.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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David Brownell 2008-03-04 14:28:27 -08:00 • committed by Linus Torvalds

parent 83c7c693ed

commit 7560fa60fc

2 changed files with 107 additions and 4 deletions

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95

include/linux/gpio.h

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