From 7560fa60fcdcdb0da662f6a9fad9064b554ef46c Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 4 Mar 2008 14:28:27 -0800 Subject: gpio: and "no GPIO support here" stubs Add a 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gpio.h | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 include/linux/gpio.h (limited to 'include') diff --git a/include/linux/gpio.h b/include/linux/gpio.h new file mode 100644 index 00000000000..4987a84078e --- /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 + +#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 */ -- cgit v1.2.3