When I connect the USB interface from my arduino nano to my openwrt router then the command lsusb shows:
Bus 001 Device 003: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter
But I do not get a new serial device in /dev/tty*
I have kmod-usb-serial installed.
Posting this in case it is useful to others. The answer turns out to be that I needed the kmod-usb-serial-ch341 kernel package:
opkg install kmod-usb-serial-ch341
The HL-340 is a CH 340 compatible device.
Once the ch341 driver is installed the nano appears as /dev/ttyUSB0 and defaults to 115200 baud. From dmesg
[ 20.000000] usbcore: registered new interface driver ch341
[ 20.000000] usbserial: USB Serial support registered for ch341-uart
[ 20.010000] ch341 1-1.2:1.0: ch341-uart converter detected
[ 20.040000] usb 1-1.2: ch341-uart converter now attached to ttyUSB0
