1. 输入命令evtest 查看系统下所有按键、输入设备：

  root@rk3568:~# evtest
  No device specified, trying to scan all of /dev/input/event*
  Available devices:
  /dev/input/event0:      rk805 pwrkey
  /dev/input/event1:      Lenovo Precision USB Mouse
  /dev/input/event2:      HID 04f3:0103
  /dev/input/event3:      HID 04f3:0103 Consumer Control
  /dev/input/event4:      HID 04f3:0103 System Control
  /dev/input/event5:      adc-keys
  /dev/input/event6:      rk-headset
  Select the device event number [0-6]: 

2. 按照上面提示选择测试按键，如RK3568 boot按键为 /dev/input/event5:      adc-keys

 则event number 为 5：按下按键会打印value 1,松开按键则会打印value 0,如下图：
  
{{arm:rk3568:linuxkey.jpg?600|key}}
 
3. 自定义按键功能，配置文件为：

  /etc/triggerhappy/triggers.d/example.conf
如下,定义按键为reboot功能，也是系统默认配置，用户可以根据需要自定义

  KEY_VOLUMEUP    1   reboot