OpenWrt Chaos Calmer 15.05.1。USB 加密狗中兴 MF190。我执行了本教程中的一些安装命令。现在dmesg | grep usb向我展示以下内容：
[ 4.150000] usbcore: registered new interface driver usbfs
[ 4.160000] usbcore: registered new interface driver hub
[ 4.160000] usbcore: registered new device driver usb
[ 4.560000] usb 1-1: new high-speed USB device number 2 using ehci-platform
[ 12.520000] usbcore: registered new interface driver usbserial
[ 12.530000] usbcore: registered new interface driver usbserial_generic
[ 12.530000] usbserial: USB Serial support registered for generic
[ 12.800000] usbcore: registered new interface driver option
[ 12.800000] usbserial: USB Serial support registered for GSM modem (1-port)
据我了解，操作系统检测到调制解调器并加载了相应的内核模块。但！没有“/dev/ttyUSBX”设备。如何获取设备文件？