root@OpenWrt:~# cat /proc/devices 
Character devices:
  1 mem
  2 pty
  3 ttyp
  4 ttyS
  5 /dev/tty
  5 /dev/console
  5 /dev/ptmx
 10 misc
 89 i2c
 90 mtd
108 ppp
128 ptm
136 pts
166 ttyACM
180 usb
188 ttyUSB
189 usb_device
254 rtc

Block devices:
259 blkext
 31 mtdblock