From 2a7034c77d628627c9462e27865e2d9258aeadd0 Mon Sep 17 00:00:00 2001 From: Patrick Delaunay Date: Fri, 9 Jul 2021 09:53:37 +0200 Subject: 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 Reviewed-by: Patrice Chotard --- arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi | 4 ++-- arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi index 7dcc96c19c..4b37797f21 100644 --- a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi +++ b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi @@ -17,8 +17,8 @@ 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 46a43371bd..fc6066aab2 100644 --- a/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi +++ b/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi @@ -16,8 +16,8 @@ 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 { -- cgit v1.2.3