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

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)
{