Shell scripts used to test GPIO LEDs and buttons, fork and improve based on http://wiki.openwrt.org/doc/devel/add.new.device

gpio_button_test.example

Single GPIO test
root@OpenWrt:/# gpio_button_test.sh 1 1
[GPIO1] value 0
root@OpenWrt:/#

GPIO range test
root@OpenWrt:/# gpio_button_test.sh 0 2
[GPIO0] value 0
[GPIO1] value 0
[GPIO2] value 0
root@OpenWrt:/#

All GPIOs test
root@OpenWrt:~# gpio_button_test.sh 
[GPIO0] value 0
[GPIO1] value 0
[GPIO2] value 0
[GPIO3] value 0
[GPIO4] value 1
[GPIO5] value 1
[GPIO6] value 1
[GPIO7] value 1
[GPIO8] value 0
[GPIO9] value
...

gpio_button_test.sh

#!/bin/sh
GPIOCHIP=0
BASE=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/base)
NGPIO=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/ngpio)
max=${2:-$(($BASE+$NGPIO-1))}
gpio=${1:-$BASE}
while [ $gpio -le $max ] ; do
  echo $gpio > /sys/class/gpio/export
  [ -d /sys/class/gpio/gpio${gpio} ] || echo "Failed to export [GPIO$gpio]"
  [ -d /sys/class/gpio/gpio${gpio} ] && {
    echo in > /sys/class/gpio/gpio${gpio}/direction
    echo "[GPIO${gpio}] value $(cat /sys/class/gpio/gpio${gpio}/value)"
    echo ${gpio} > /sys/class/gpio/unexport
  }
  gpio=$((gpio+1))
done

gpio_led_test.example

Single GPIO test
root@OpenWrt:~# gpio_led_test.sh 18 18
Testing [GPIO18]...
[GPIO18] Trying value 0
[GPIO18] Trying value 1
root@OpenWrt:~#

GPIO range test
root@OpenWrt:~# gpio_led_test.sh 0 2
Testing [GPIO0]...
[GPIO0] Trying value 0
[GPIO0] Trying value 1
Testing [GPIO1]...
[GPIO1] Trying value 0
[GPIO1] Trying value 1
Testing [GPIO2]...
[GPIO2] Trying value 0
[GPIO2] Trying value 1
root@OpenWrt:~#

Test all GPIOs
root@OpenWrt:~# gpio_led_test.sh
Testing [GPIO0]...
[GPIO0] Trying value 0
[GPIO0] Trying value 1
Testing [GPIO1]...
[GPIO1] Trying value 0
[GPIO1] Trying value 1
Testing [GPIO2]...
[GPIO2] Trying value 0
[GPIO2] Trying value 1
Testing [GPIO3]...
[GPIO3] Trying value 0
[GPIO3] Trying value 1
Testing [GPIO4]...
[GPIO4] Trying value 0
[GPIO4] Trying value 1
Testing [GPIO5]...
[GPIO5] Trying value 0
[GPIO5] Trying value 1
Testing [GPIO6]...
[GPIO6] Trying value 0
[GPIO6] Trying value 1
Testing [GPIO7]...
[GPIO7] Trying value 0
[GPIO7] Trying value 1
Testing [GPIO8]...
[GPIO8] Trying value 0
[GPIO8] Trying value 1
Testing [GPIO9]...
[GPIO9] Trying value 0
^@[GPIO9] Trying value 1
Testing [GPIO10]...
[GPIO10] Trying value 0
[GPIO10] Trying value 1
Testing [GPIO11]...
sh: write error: Device or resource busy
Failed to export [GPIO11]
Testing [GPIO12]...
sh: write error: Device or resource busy
Failed to export [GPIO12]
Testing [GPIO13]...
sh: write error: Device or resource busy
Failed to export [GPIO13]
Testing [GPIO14]...
sh: write error: Device or resource busy
Failed to export [GPIO14]
Testing [GPIO15]...
sh: write error: Device or resource busy
Failed to export [GPIO15]
Testing [GPIO16]...
sh: write error: Device or resource busy
Failed to export [GPIO16]
Testing [GPIO17]...
[GPIO17] Trying value 0
[GPIO17] Trying value 1
Testing [GPIO18]...
[GPIO18] Trying value 0
[GPIO18] Trying value 1
Testing [GPIO19]...
[GPIO19] Trying value 0
[GPIO19] Trying value 1
Testing [GPIO20]...
[GPIO20] Trying value 0
[GPIO20] Trying value 1
Testing [GPIO21]...
[GPIO21] Trying value 0
[GPIO21] Trying value 1
Testing [GPIO22]...
[GPIO22] Trying value 0
[GPIO22] Trying value 1
root@OpenWrt:~#

gpio_led_test.sh

#!/bin/sh
GPIOCHIP=0
BASE=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/base)
NGPIO=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/ngpio)
max=${2:-$(($BASE+$NGPIO-1))}
gpio=${1:-$BASE}
while [ $gpio -le $max ] ; do
  echo "Testing [GPIO$gpio]..."
  echo $gpio > /sys/class/gpio/export
  [ -d /sys/class/gpio/gpio${gpio} ] || echo "Failed to export [GPIO$gpio]"
  [ -d /sys/class/gpio/gpio${gpio} ] && {
    echo out > /sys/class/gpio/gpio$gpio/direction

    echo "[GPIO$gpio] Trying value 0"
    echo 0 > /sys/class/gpio/gpio$gpio/value
    sleep 3s

    echo "[GPIO$gpio] Trying value 1"
    echo 1 > /sys/class/gpio/gpio$gpio/value
    sleep 3s

    echo $gpio > /sys/class/gpio/unexport
  }
  gpio=$((gpio+1))
done