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of/gpio: Implement of_gpio_count() 

This function is used to count how many GPIOs are specified for
a device node.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Anton Vorontsov 2008-12-05 08:15:54 +00:00 committed by Paul Mackerras
parent 7736a3db98
commit 749820928a
2 changed files with 40 additions and 0 deletions
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34
drivers/of/gpio.c
View File

@ -79,6 +79,40 @@ err0:
}
EXPORT_SYMBOL(of_get_gpio_flags);
/**
* of_gpio_count - Count GPIOs for a device
* @np: device node to count GPIOs for
*
* The function returns the count of GPIOs specified for a node.
*
* Note that the empty GPIO specifiers counts too. For example,
*
* gpios = <0
* &pio1 1 2
* 0
* &pio2 3 4>;
*
* defines four GPIOs (so this function will return 4), two of which
* are not specified.
*/
unsigned int of_gpio_count(struct device_node *np)
{
unsigned int cnt = 0;
do {
int ret;
ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
cnt, NULL, NULL);
/* A hole in the gpios = <> counts anyway. */
if (ret < 0 && ret != -EEXIST)
break;
} while (++cnt);
return cnt;
}
EXPORT_SYMBOL(of_gpio_count);
/**
* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
* @of_gc: pointer to the of_gpio_chip structure

6
include/linux/of_gpio.h
View File

@ -65,6 +65,7 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
extern int of_get_gpio_flags(struct device_node *np, int index,
enum of_gpio_flags *flags);
extern unsigned int of_gpio_count(struct device_node *np);
extern int of_mm_gpiochip_add(struct device_node *np,
struct of_mm_gpio_chip *mm_gc);
@ -81,6 +82,11 @@ static inline int of_get_gpio_flags(struct device_node *np, int index,
return -ENOSYS;
}
static inline unsigned int of_gpio_count(struct device_node *np)
{
return 0;
}
#endif /* CONFIG_OF_GPIO */
/**