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>
2 files changed