diff options
| author | Patrick Delaunay <patrick.delaunay@foss.st.com> | 2021-07-09 09:53:37 +0200 |
|---|---|---|
| committer | Patrick Delaunay <patrick.delaunay@foss.st.com> | 2021-07-27 09:47:40 +0200 |
| commit | 2a7034c77d628627c9462e27865e2d9258aeadd0 (patch) | |
| tree | bd25a731bce90adcc5a204213616cdc67202255b /board/st | |
| parent | 8b71b20e0e5431f0243a5a8078ac62be0af2189e (diff) | |
| download | u-boot-2a7034c77d628627c9462e27865e2d9258aeadd0.tar.gz | |
stm32mp1: add pull-up for gpio button PA13 and PA14
When a push-button is released and PA13/PA14 are defined as input (high-Z)
the LED should not be active as the circuit is open but a small current
leak through PCB or push-button close the circuit and allows a small LED
bias giving erroneous level voltage.
So it is recommended to activate an internal pull-up in order to clearly
fix the voltage at PA13/PA14 when button is released and to wait
a short delay before to read the GPIO value only when the pull-up is
correctly configured.
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Diffstat (limited to 'board/st')
| -rw-r--r-- | board/st/stm32mp1/stm32mp1.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c index 2faf5c81b4..59fb6e548c 100644 --- a/board/st/stm32mp1/stm32mp1.c +++ b/board/st/stm32mp1/stm32mp1.c @@ -155,6 +155,7 @@ static void board_key_check(void) &gpio, GPIOD_IS_IN)) { log_debug("could not find a /config/st,fastboot-gpios\n"); } else { + udelay(20); if (dm_gpio_get_value(&gpio)) { log_notice("Fastboot key pressed, "); boot_mode = BOOT_FASTBOOT; @@ -168,6 +169,7 @@ static void board_key_check(void) &gpio, GPIOD_IS_IN)) { log_debug("could not find a /config/st,stm32prog-gpios\n"); } else { + udelay(20); if (dm_gpio_get_value(&gpio)) { log_notice("STM32Programmer key pressed, "); boot_mode = BOOT_STM32PROG; |