Nexus 7 2012 cards and pcm

shell@grouper:/ $ cat /proc/asound/cards
cat /proc/asound/cards
 0 [Tegra          ]: HDA-Intel - HDA NVIDIA Tegra
                      HDA NVIDIA Tegra at 0x70038000 irq 113
 1 [tegrart5640    ]: tegra-rt5640 - tegra-rt5640
                      tegra-rt5640
shell@grouper:/ $ cat /proc/asound/pcm
cat /proc/asound/pcm
00-03: HDMI 0 : HDMI 0 : playback 1
01-00: RT5640 PCM rt5640-aif1-0 :  : playback 1 : capture 1
01-01: SPDIF PCM dit-hifi-1 :  : playback 1 : capture 1
01-02: BT SCO PCM dit-hifi-2 :  : playback 1 : capture 1