diff options
author | David Brownell <david-b@pacbell.net> | 2008-03-05 01:28:27 +0300 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-03-05 03:35:10 +0300 |
commit | 7560fa60fcdcdb0da662f6a9fad9064b554ef46c (patch) | |
tree | 2089d826b0b9230752f318b20884dca20b3847d5 /include/linux | |
parent | 83c7c693ed3e61535ad6a097ad991a88aafc54b8 (diff) | |
download | linux-7560fa60fcdcdb0da662f6a9fad9064b554ef46c.tar.xz |
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>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/gpio.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/include/linux/gpio.h b/include/linux/gpio.h new file mode 100644 index 000000000000..4987a84078ef --- /dev/null +++ b/include/linux/gpio.h @@ -0,0 +1,95 @@ +#ifndef __LINUX_GPIO_H +#define __LINUX_GPIO_H + +/* see Documentation/gpio.txt */ + +#ifdef CONFIG_GENERIC_GPIO +#include <asm/gpio.h> + +#else + +/* + * Some platforms don't support the GPIO programming interface. + * + * In case some driver uses it anyway (it should normally have + * depended on GENERIC_GPIO), these routines help the compiler + * optimize out much GPIO-related code ... or trigger a runtime + * warning when something is wrongly called. + */ + +static inline int gpio_is_valid(int number) +{ + return 0; +} + +static inline int gpio_request(unsigned gpio, const char *label) +{ + return -ENOSYS; +} + +static inline void gpio_free(unsigned gpio) +{ + /* GPIO can never have been requested */ + WARN_ON(1); +} + +static inline int gpio_direction_input(unsigned gpio) +{ + return -ENOSYS; +} + +static inline int gpio_direction_output(unsigned gpio, int value) +{ + return -ENOSYS; +} + +static inline int gpio_get_value(unsigned gpio) +{ + /* GPIO can never have been requested or set as {in,out}put */ + WARN_ON(1); + return 0; +} + +static inline void gpio_set_value(unsigned gpio, int value) +{ + /* GPIO can never have been requested or set as output */ + WARN_ON(1); +} + +static inline int gpio_cansleep(unsigned gpio) +{ + /* GPIO can never have been requested or set as {in,out}put */ + WARN_ON(1); + return 0; +} + +static inline int gpio_get_value_cansleep(unsigned gpio) +{ + /* GPIO can never have been requested or set as {in,out}put */ + WARN_ON(1); + return 0; +} + +static inline void gpio_set_value_cansleep(unsigned gpio, int value) +{ + /* GPIO can never have been requested or set as output */ + WARN_ON(1); +} + +static inline int gpio_to_irq(unsigned gpio) +{ + /* GPIO can never have been requested or set as input */ + WARN_ON(1); + return -EINVAL; +} + +static inline int irq_to_gpio(unsigned irq) +{ + /* irq can never have been returned from gpio_to_irq() */ + WARN_ON(1); + return -EINVAL; +} + +#endif + +#endif /* __LINUX_GPIO_H */ |