Alsa tool to capture raw PDM data from input mic over SAI interface

Usage: mxc_pdm_test.out <options>
<options>   -device     the pdm audio device like hw:4:0
            -log        log debug info into output file
            -help       print help options menu
            -output     output file name
            -rate       sample rate
            -seconds    number of seconds to capture
            -channels   number of channels
            -block      output samples per run per channel
            -gain       output multiplier scale factor
            -type       5 order cic decoder type
                        [12, 16, 32, 48]

For example:

- Built-in decimation algorithm:

Capture raw pdm data and convert to raw wav file:
mxc_pdm_test.out -device hw:4,0 -output test-16k.raw -rate 16000 -seconds 60

Capture raw pdm data and write debug info data in output file
mxc_pdm_test.out -device hw:4,0 -output test-16k.raw -rate 16000 -seconds 60 -log

Playback converted pdm to pcm raw audio file:
aplay -t raw -c 1 -f S24_LE -r 16000 test-16k.raw

- imx-sw-pdm libimxspdm simd library:

Capture raw pdm data and convert to raw wav file:
mxc_pdm_test.out -device hw:1,0 -output test-4ch-16k.raw -rate 16000 -seconds 60 \
-channels 4 -type 32 -block 40

Playback converted pdm to pcm raw audio file:
aplay -t raw -c 4 -f S24_LE -r 16000 test-4ch-16k.raw
