The current gpio_get_level() is pretty slow because it looks things up each
time. Add a new function to find out the register address and mask to use
to check the value for a particular GPIO.
Time-critical code can then use this to check a GPIO.
BUG=chrome-os-partner:10146
TEST=manual:
build and boot on snow;
Power on the board, hold power button for 10s and see that it powers off
Power control still works, thus GPIOs are functional
Change-Id: Ifc6c56f5cb811e0243e7712725a51948eabd42ab
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/26175
aa64550a3f