How can I control GPIO's in Linux user-space?
To see the current status of GPIO's in Linux user-space:
cat /sys/kernel/debug/gpio
Choose the GPIO you would like to control, export it to become a sysfs node, in this example GPIO 23
echo 23 > /sys/class/gpio/export
Set it as "i an input or output by echoing "in" or "out":
echo out > /sys/class/gpio/gpio23/direction
Now set it high "1", or low "0":
echo 1 > /sys/class/gpio/gpio23/value
You can check your work by performing the cat command again.