Copy test porgram from \Examples\ key_led to development board and run it, Press the K3 and K4, See changes in the LED.
# ./key_led /dev/input/event0 type:1, code:1, value:1 type:1, code:1, value:0 # ./key_led /dev/input/event0 type:1, code:102, value:1 type:1, code:102, value:0