GPIO Interrupt on Linx Userspace Application

I don't know about STM32MP1 specific information, but once I did some tutorials for another board: https://github.com/FrankBau/raspi-repo-manifest/wiki/Kernel-Module-1---Hello-World. Hope they are still useful.

KnarfB

Hi @JS.2chneider​ 

We are providing one exemple of GPIO management from user space base on gpiolib under

/usr/local/Linux-A7-examples/GPIO/buttons/

unfortunately I just discovered it's somewhat buggy.

Please use this version instead (diff in bold) :

#!/bin/sh

val=1

while true; do

    pid=$$

    gpiomon --num-events=1 --silent --rising-edge gpiochip0 13

    trap 'kill -9 $pid' 2

    if [ $val -eq 1 ]; then

        val=0

    else

        val=1

    fi

    gpioset gpiochip0 14=$val

done

Green LED5 on PA14 will toggle on each action on USER2 button (PA13)

This is working on all GPIO not already configured/assigned in Device Tree.

Else, you can also assign gpio and set related interruption inside a DT node.

Refer to https://wiki.st.com/stm32mpu/wiki/Interrupt_overview and related binding documentation.

For example you can refer to what is done in stm32mp157c-ev1-a7-examples.dts ( you need to install kernel source code cf https://wiki.st.com/stm32mpu/wiki/STM32MP1_Developer_Package_-_Linux_kernel) :

button@1 {

label = "PA13";

linux,code = <BTN_1>;

interrupts-extended = <&gpioa 13 IRQ_TYPE_EDGE_FALLING>;

status = "okay";

wakeup-source;

};

Hope it help,

Olivier