So now that you have Comedi talking to the hardware, try to talk to Comedi. Call the command comedi_board_info, which provides information about each subdevice on the board. Here's part of the output for the USB-DUX sigma board (which is on /dev/comedi0), as a result of the command comedi_board_info -v.

overall info:
  version code: 0x00074c
  driver name: usbduxsigma
  board name: usbduxsigma
  number of subdevices: 4
subdevice 0:
  type: 1 (analog input)
  flags: 0x10119000
          SDF_CMD_READ:can do asynchronous input commands
          SDF_READABLE:subdevice can be read
          SDF_GROUND:can do aref=ground
          SDF_LSAMPL:subdevice uses 32-bit samples for commands
  number of channels: 16
  max data value: 16777215
  ranges:
    all chans: [-1.325 V,1.325 V]
  command:
    start: now|int
    scan_begin: timer
    convert: now
    scan_end: count
    stop: none|count
  command structure filled with probe_cmd_generic_timed for 16 channels:
    start: now 0
    scan_begin: timer 1000000
      scan_begin_src = TRIG_TIMER:
      The sampling rate is defined per scan
      meaning all channels are sampled at
      the same time. The maximum sampling rate is f=1000 Hz
    convert: now 0
    scan_end: count 16
    stop: count 2
subdevice 1:
  type: 2 (analog output)
  flags: 0x00125000
          SDF_CMD_WRITE:can do asynchronous output commands
          SDF_WRITABLE:subdevice can be written
          SDF_GROUND:can do aref=ground
  number of channels: 4
  max data value: 255
  ranges:
    all chans: [0 V,2.5 V]
  command:
    start: now|int
    scan_begin: timer
    convert: now
    scan_end: count
    stop: none|count
  command structure filled with probe_cmd_generic_timed for 4 channels:
    start: now 0
    scan_begin: timer 1000000
      scan_begin_src = TRIG_TIMER:
      The sampling rate is defined per scan
      meaning all channels are sampled at
      the same time. The maximum sampling rate is f=1000 Hz
    convert: now 0
    scan_end: count 4
    stop: count 2
subdevice 2:
  type: 5 (digital I/O)
  flags: 0x00030000
          SDF_READABLE:subdevice can be read
          SDF_WRITABLE:subdevice can be written
  number of channels: 24
  max data value: 1
  ranges:
    all chans: [0 V,5 V]
  command:
    not supported
subdevice 3:
  type: 12 (pwm)
  flags: 0x00020100
          SDF_MODE1:can do mode 1
          SDF_WRITABLE:subdevice can be written
  number of channels: 8
  max data value: 512
  ranges:
    all chans: [0,1]
  command:
    not supported

This board has four subdevices. Devices are separated into subdevices that each have a distinct purpose; e.g., analog input, analog output, digital input/output.

Here's the information from Comedi's /proc/comedi file, which indicates what drivers are loaded and which boards are configured:

cat /proc/comedi

comedi version 0.7.76
format string: "%2d: %-20s %-20s %4d",i,driver_name,board_name,n_subdevices
 0: usbduxsigma          usbduxsigma             4
usbduxfast:
 usbduxfast
usbduxsigma:
 usbduxsigma

This documentation feature currently returns the driver name, the device name, and the number of subdevices. Following those lines are a list of the Comedi kernel driver modules currently loaded, each followed by a list of the board names it recognizes (names that can be used with comedi_config).