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dm: gpio: Add a function to read an ID from a list of GPIOs 

For board IDs a common approach is to set aside several GPIOs for use in
determining the board ID. This can provide information about board features
and the revision.

Add a function that turns a list of GPIOs into an integer by assigning
each GPIO to a single bit.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2014-11-10 18:00:21 -07:00
parent 469a579df2
commit e5901c94e3
2 changed files with 29 additions and 1 deletions
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19
drivers/gpio/gpio-uclass.c
View File

@ -390,6 +390,25 @@ int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize)
return 0;
}
/*
* get a number comprised of multiple GPIO values. gpio_num_array points to
* the array of gpio pin numbers to scan, terminated by -1.
*/
unsigned gpio_get_values_as_int(const int *gpio_num_array)
{
int gpio;
unsigned bitmask = 1;
unsigned vector = 0;
while (bitmask &&
((gpio = *gpio_num_array++) != -1)) {
if (gpio_get_value(gpio))
vector |= bitmask;
bitmask <<= 1;
}
return vector;
}
/* We need to renumber the GPIOs when any driver is probed/removed */
static int gpio_renumber(struct udevice *removed_dev)
{

11
include/asm-generic/gpio.h
View File

@ -257,6 +257,15 @@ const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
int gpio_lookup_name(const char *name, struct udevice **devp,
unsigned int *offsetp, unsigned int *gpiop);
int name_to_gpio(const char *name);
/**
* get_gpios() - Turn the values of a list of GPIOs into an integer
*
* This puts the value of the first GPIO into bit 0, the second into bit 1,
* etc. then returns the resulting integer.
*
* @gpio_list: List of GPIOs to collect
* @return resulting integer value
*/
unsigned gpio_get_values_as_int(const int *gpio_list);
#endif /* _ASM_GENERIC_GPIO_H_ */