diff options
| author | Craig Hesling <hesling@chromium.org> | 2019-11-04 17:09:25 -0800 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2019-11-08 22:58:55 +0000 |
| commit | 4c349a1eafa02a1f520d7603464cdda1e0c62a7f (patch) | |
| tree | 867b77469aefefb254ec842bae1645e55444e3d6 | |
| parent | fe21ab18622825f2a402b970cfec50e429cc14f5 (diff) | |
| download | chrome-ec-4c349a1eafa02a1f520d7603464cdda1e0c62a7f.tar.gz | |
stm32f4: Implement UNUSED pins
This CL adds support for UNUSED pins to the STM32F4 family
of chips. This places the unused/unconnected pins in the lowest
power state.
In this case, ST recommends that you configure the pin as analog-in to
disable the schmitt trigger logic.
This codified the work done in crrev.com/c/1883127 .
The CL should have no functional change for boards that have not
specified UNUSED pins in their gpio.inc.
BRANCH=nocturne,hatch
BUG=b:130561737
TEST=make buildall -j
Change-Id: I444b868b277b016a896e410dccae84429b68839e
Signed-off-by: Craig Hesling <hesling@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1894242
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
| -rw-r--r-- | chip/stm32/gpio.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/chip/stm32/gpio.c b/chip/stm32/gpio.c index fe79ca5aad..bb45f0e388 100644 --- a/chip/stm32/gpio.c +++ b/chip/stm32/gpio.c @@ -23,6 +23,7 @@ static uint8_t exti_events[16]; void gpio_pre_init(void) { const struct gpio_info *g = gpio_list; + const struct unused_pin_info *u = unused_pin_list; int is_warm = system_is_reboot_warm(); int i; @@ -59,6 +60,19 @@ void gpio_pre_init(void) /* Set up GPIO based on flags */ gpio_set_flags_by_mask(g->port, g->mask, flags); } + + /* Configure optional unused pins for low power optimization. */ + for (i = 0; i < unused_pin_count; i++, u++) { + /* + * Configure unused pins as ANALOG INPUT to save power. + * For more info, please see + * "USING STM32F4 MCU POWER MODES WITH BEST DYNAMIC EFFICIENCY" + * ("AN4365") section 1.2.6 and section 7.3.12 of the STM32F412 + * reference manual. + */ + if (IS_ENABLED(CHIP_FAMILY_STM32F4)) + gpio_set_flags_by_mask(u->port, u->mask, GPIO_ANALOG); + } } test_mockable int gpio_get_level(enum gpio_signal signal) |