tree 2089d826b0b9230752f318b20884dca20b3847d5
parent 83c7c693ed3e61535ad6a097ad991a88aafc54b8
author David Brownell <david-b@pacbell.net> 1204669707 -0800
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1204677310 -0800

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

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>