使用红外接收头在树莓派上遥控libreELEC
1.修改config.txt文件：
默认只读模式，重新挂载为读写模式
文档地址：https://wiki.libreelec.tv/config.txt
mount -o remount,rw /flash
nano /flash/config.txt
mount -o remount,ro /flash
2.添加gpio-ir
Add the following line to /flash/config.txt (read Raspberry Pi Config.txt for detailed instructions):
dtoverlay=gpio-ir
Add the gpio_pin parameter if you used a custom GPIO (default is 18). eg:
dtoverlay=gpio-ir,gpio_pin=5
3.测试按键输出代码，建立keymaps
ir-keytable -t
Testing events. Please, press CTRL-C to abort.
293.356686: lirc protocol(nec): scancode = 0x46
293.406665: lirc protocol(nec): scancode = 0x46 repeat
293.636664: lirc protocol(nec): scancode = 0x46
293.690013: lirc protocol(nec): scancode = 0x46 repeat
294.560006: lirc protocol(nec): scancode = 0x15
294.613348: lirc protocol(nec): scancode = 0x15 repeat
294.879998: lirc protocol(nec): scancode = 0x15
295.180040: lirc protocol(nec): scancode = 0x15
295.436699: lirc protocol(nec): scancode = 0x15
295.786679: lirc protocol(nec): scancode = 0x15
295.836676: lirc protocol(nec): scancode = 0x15 repeat
296.059997: lirc protocol(nec): scancode = 0x15
296.556677: lirc protocol(nec): scancode = 0x44
297.140018: lirc protocol(nec): scancode = 0x44
根据编码在/storage/.config/rc_keymaps/下创建my_custom_remote
我的定义：注意nec是上面的协议，可再用ir-keytable -t -p nec进行测试
# table my_custom_remote, type: nec
0x46 KEY_UP
0x15 KEY_DOWN
0x44 KEY_LEFT
0x43 KEY_RIGHT
0x40 KEY_OK
0x7 KEY_BACK
0x9 KEY_MENU
4.停止服务：
systemctl stop kodi
systemctl stop eventlircd
5.载入新的keymaps：
ir-keytable -c -w /storage/.config/rc_keymaps/my_custom_remote
再进行测试
ir-keytable -t
如果能看到上面的按键显示输出，表明测试成功
6. 开启服务，进行测试
systemctl start kodi
systemctl start eventlircd
7.添加：/storage/.config/rc_maps.cfg文件
文档说明：When you’re finished with all buttons, save the keytable, stop ir-keytable -t with CTRL+C and then test if it works. If testing succeeds, make it permanent via a /storage/.config/rc_maps.cfg file like this:
* * my_custom_remote
总结：在4.19内核版本和前面4.14内核版本中lirc配置有所不同。
本文主要参考官方文档：
文档地址：Infrared Remotes