Hi Patrick
On 7/9/21 9:53 AM, Patrick Delaunay wrote:
> 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.delau...@foss.st.com>
> ---
>
> arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi | 4 ++--
> arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi | 4 ++--
> board/st/stm32mp1/stm32mp1.c | 2 ++
> 3 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
> b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
> index 6787619290..d44da7566f 100644
> --- a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
> +++ b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
> @@ -18,8 +18,8 @@
> u-boot,error-led = "error";
> u-boot,mmc-env-partition = "ssbl";
> st,adc_usb_pd = <&adc1 18>, <&adc1 19>;
> - st,fastboot-gpios = <&gpioa 13 GPIO_ACTIVE_LOW>;
> - st,stm32prog-gpios = <&gpioa 14 GPIO_ACTIVE_LOW>;
> + st,fastboot-gpios = <&gpioa 13 (GPIO_ACTIVE_LOW |
> GPIO_PULL_UP)>;
> + st,stm32prog-gpios = <&gpioa 14 (GPIO_ACTIVE_LOW |
> GPIO_PULL_UP)>;
> };
>
> firmware {
> diff --git a/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
> b/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
> index f3002e995b..3b94218b2f 100644
> --- a/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
> +++ b/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
> @@ -18,8 +18,8 @@
> u-boot,boot-led = "heartbeat";
> u-boot,error-led = "error";
> u-boot,mmc-env-partition = "ssbl";
> - st,fastboot-gpios = <&gpioa 13 GPIO_ACTIVE_LOW>;
> - st,stm32prog-gpios = <&gpioa 14 GPIO_ACTIVE_LOW>;
> + st,fastboot-gpios = <&gpioa 13 (GPIO_ACTIVE_LOW |
> GPIO_PULL_UP)>;
> + st,stm32prog-gpios = <&gpioa 14 (GPIO_ACTIVE_LOW |
> GPIO_PULL_UP)>;
> };
>
> firmware {
> diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
> index 18b8870269..e1796e7e31 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;
>
Reviewed-by: Patrice Chotard <patrice.chot...@foss.st.com>
Thanks
Patrice
