gpio: Add function to clear pending interrupt

Currently if an interrupt is pending before it is enabled the interrupt
will fire immediately.  In most cases this is fine, but if we want to
use the interrupt to trigger something like waking the AP it should be
sure that it won't immediately fire once enabled.

For example: on the Eve board we have the trackpad interrupt run to the
AP and the EC in order to support wake from Deep S3 (magic AP state that
only the EC can wake it from).  This interrupt is used in S0 by the AP
while ignored by the EC, and then enabled on the transition to S3 in
order to be able to wake.  Since it has been active the interrupt may
be pending in the EC (depending on the chip), which can result in the
interrupt firing immediately and waking the AP.

BUG=chrome-os-partner:62224
BRANCH=none
TEST=This has been functionally tested on npcx only as that is what I
have a use case and system for, the others compile and look right but
have not been directly tested.

Change-Id: I9e0877d99e7f09f4c30bf9861fbad81c12c059ad
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://chromium-review.googlesource.com/446962
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/chip/it83xx/intc.h b/chip/it83xx/intc.h
index 642571bb26..8c6d35aa02 100644
--- a/chip/it83xx/intc.h
+++ b/chip/it83xx/intc.h
@@ -20,7 +20,6 @@ void lpcrst_interrupt(enum gpio_signal signal);
 void peci_interrupt(void);
 void adc_interrupt(void);
 void i2c_interrupt(int port);
-int gpio_clear_pending_interrupt(enum gpio_signal signal);
 void clock_sleep_mode_wakeup_isr(void);
 int clock_ec_wake_from_sleep(void);
 void __enter_hibernate(uint32_t seconds, uint32_t microseconds);