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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
2 files changed
