I've run a "arecord" on hw:1,0 (via pulseaudio, oh my....) to show that one of the devices (pcm0c) is currently capturing audio. Below is the "hardware status" as reported by alsa. On the pavucontrol UI application (again pulseaudio) the recording application is also shown.

     ➜  ~  find /proc/asound/card* -name status | xargs grep ""
     /proc/asound/card0/pcm0c/sub0/status:closed
     /proc/asound/card0/pcm0p/sub0/status:closed
     /proc/asound/card0/pcm2c/sub0/status:closed
     /proc/asound/card0/pcm3p/sub0/status:closed
     /proc/asound/card0/pcm7p/sub0/status:closed
     /proc/asound/card0/pcm8p/sub0/status:closed
     #### ---v--- this one records
     /proc/asound/card1/pcm0c/sub0/status:state: RUNNING
     /proc/asound/card1/pcm0c/sub0/status:owner_pid   : 1260
     /proc/asound/card1/pcm0c/sub0/status:trigger_time: 108525.846389845
     /proc/asound/card1/pcm0c/sub0/status:tstamp      : 108558.575144693
     /proc/asound/card1/pcm0c/sub0/status:delay       : 96
     /proc/asound/card1/pcm0c/sub0/status:avail       : 96
     /proc/asound/card1/pcm0c/sub0/status:avail_max   : 96
     /proc/asound/card1/pcm0c/sub0/status:-----
     /proc/asound/card1/pcm0c/sub0/status:hw_ptr      : 1570901
     /proc/asound/card1/pcm0c/sub0/status:appl_ptr    : 1570805
     #### ---^---
     /proc/asound/card1/pcm0p/sub0/status:closed

The nomenclature here is hw:N,M corresponds to cardN/pcmMc (c: capture, p: playback).