Commit 0fdae42d authored by Wolfram Sang's avatar Wolfram Sang Committed by Linus Torvalds
Browse files

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: default avatarWolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 49a36793

Documentation/gpio.txt

+1 −1
Original line number Diff line number Diff line
@@ -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_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

misconfiguration is possible.  You should normally issue these calls from

a task context.  However, for spinlock-safe GPIOs it's OK to use them

include/asm-generic/gpio.h

+5 −5
Original line number Diff line number Diff line
@@ -147,11 +147,11 @@ extern struct gpio_chip *gpiochip_find(void *data, 
/* Always use the library code for GPIO management calls,

 * 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 int gpio_direction_input(unsigned gpio);

extern int gpio_direction_output(unsigned gpio, int value);

extern int __must_check gpio_direction_input(unsigned gpio);

extern int __must_check gpio_direction_output(unsigned gpio, int value);



extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
@@ -192,8 +192,8 @@ struct gpio { 
	const char	*label;

};



extern int 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_one(unsigned gpio, unsigned long flags, const char *label);

extern int __must_check gpio_request_array(struct gpio *array, size_t num);

extern void gpio_free_array(struct gpio *array, size_t num);



#ifdef CONFIG_GPIO_SYSFS

include/linux/gpio.h

+3 −3
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ static inline int gpio_is_valid(int number) 
	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;

}
@@ -42,12 +42,12 @@ static inline void gpio_free(unsigned gpio) 
	WARN_ON(1);

}



static inline int gpio_direction_input(unsigned gpio)

static inline int __must_check gpio_direction_input(unsigned gpio)

{

	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;

}

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