求助在rk3399上怎么安装ch340串口驱动呢

我是ubuntu 16.04
firefly@firefly:~/123$ uname -ar
Linux firefly 4.4.77 #1 SMP Thu Feb 1 17:02:29 CST 2018 aarch64 aarch64 aarch64 GNU/Linux
firefly@firefly:~/123$ lsusb
Bus 001 Device 009: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter
但是firefly@firefly:/dev$ ll ttyU*
ls: cannot access 'ttyU*': No such file or directory
那位帮我一下，我不知道怎么安装ch340串口驱动