gpio: add a function to read GPIO array as base-2 value

This adds gpio_base2_value() which reads an array of 2-state
GPIOs and returns a base-2 value, where gpio[0] represents the
least significant bit.

BUG=none
BRANCH=none
TEST=tested with follow-up patches for pinky

Change-Id: I0d6bfac369da0d68079a38de0988c7b59d269a97
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 27873b7a9ea237d13f0cbafd10033a8d0f821cbe
Original-Change-Id: Ia7ffc16eb60e93413c0812573b9cf0999b92828e
Original-Signed-off-by: David Hendricks <dhendrix@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/228323
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/9412
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
This commit is contained in:
David Hendricks 2014-11-06 15:05:35 -08:00 committed by Patrick Georgi
parent 3fc6368e1c
commit 21db62eb0e
2 changed files with 21 additions and 0 deletions

View File

@ -34,6 +34,15 @@ void gpio_input_pullup(gpio_t gpio);
void gpio_input(gpio_t gpio);
void gpio_output(gpio_t gpio, int value);
/*
* Read the value presented by the set of GPIOs, when each pin is interpreted
* as a base-2 digit (LOW = 0, HIGH = 1).
*
* gpio[]: pin positions to read. gpio[0] is less significant than gpio[1].
* num_gpio: number of pins to read.
*/
int gpio_base2_value(gpio_t gpio[], int num_gpio);
/*
* Read the value presented by the set of GPIOs, when each pin is interpreted
* as a base-3 digit (LOW = 0, HIGH = 1, Z/floating = 2).

View File

@ -22,6 +22,18 @@
#include <delay.h>
#include <gpio.h>
int gpio_base2_value(gpio_t gpio[], int num_gpio)
{
int i, result = 0;
for (i = 0; i < num_gpio; i++) {
gpio_input(gpio[i]);
result |= gpio_get(gpio[i]) << i;
}
return result;
}
int gpio_base3_value(gpio_t gpio[], int num_gpio)
{
/*