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gpiolib: annotate gpio-intialization with __must_check 

Because GPIOs can have crucial functions especially in embedded systems,
we are better safe than sorry regarding their configuration.  For
gpio_request, the documentation is simply enforced: <quote>"The return
value of gpio_request() must be checked."</quote> For gpio_direction_* and
gpio_request_*, we now act accordingly.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Wolfram Sang 2011-01-12 17:00:23 -08:00 committed by Linus Torvalds
parent 49a367937f
commit 0fdae42d36
3 changed files with 9 additions and 9 deletions
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2
Documentation/gpio.txt
View File

@ -135,7 +135,7 @@ setting up a platform_device using the GPIO, is mark its direction:
int gpio_direction_input(unsigned gpio); int gpio_direction_input(unsigned gpio);
int gpio_direction_output(unsigned gpio, int value); int gpio_direction_output(unsigned gpio, int value);
The return value is zero for success, else a negative errno. It should The return value is zero for success, else a negative errno. It must
be checked, since the get/set calls don't have error returns and since be checked, since the get/set calls don't have error returns and since
misconfiguration is possible. You should normally issue these calls from misconfiguration is possible. You should normally issue these calls from
a task context. However, for spinlock-safe GPIOs it's OK to use them a task context. However, for spinlock-safe GPIOs it's OK to use them

10
include/asm-generic/gpio.h
View File

@ -147,11 +147,11 @@ extern struct gpio_chip *gpiochip_find(void *data,
/* Always use the library code for GPIO management calls, /* Always use the library code for GPIO management calls,
* or when sleeping may be involved. * or when sleeping may be involved.
*/ */
extern int gpio_request(unsigned gpio, const char *label); extern int __must_check gpio_request(unsigned gpio, const char *label);
extern void gpio_free(unsigned gpio); extern void gpio_free(unsigned gpio);
extern int gpio_direction_input(unsigned gpio); extern int __must_check gpio_direction_input(unsigned gpio);
extern int gpio_direction_output(unsigned gpio, int value); extern int __must_check gpio_direction_output(unsigned gpio, int value);
extern int gpio_set_debounce(unsigned gpio, unsigned debounce); extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
@ -192,8 +192,8 @@ struct gpio {
const char *label; const char *label;
}; };
extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); extern int __must_check gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
extern int gpio_request_array(struct gpio *array, size_t num); extern int __must_check gpio_request_array(struct gpio *array, size_t num);
extern void gpio_free_array(struct gpio *array, size_t num); extern void gpio_free_array(struct gpio *array, size_t num);
#ifdef CONFIG_GPIO_SYSFS #ifdef CONFIG_GPIO_SYSFS

6
include/linux/gpio.h
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@ -29,7 +29,7 @@ static inline int gpio_is_valid(int number)
return 0; return 0;
} }
static inline int gpio_request(unsigned gpio, const char *label) static inline int __must_check gpio_request(unsigned gpio, const char *label)
{ {
return -ENOSYS; return -ENOSYS;
} }
@ -42,12 +42,12 @@ static inline void gpio_free(unsigned gpio)
WARN_ON(1); WARN_ON(1);
} }
static inline int gpio_direction_input(unsigned gpio) static inline int __must_check gpio_direction_input(unsigned gpio)
{ {
return -ENOSYS; return -ENOSYS;
} }
static inline int gpio_direction_output(unsigned gpio, int value) static inline int __must_check gpio_direction_output(unsigned gpio, int value)
{ {
return -ENOSYS; return -ENOSYS;
} }