PDM Converter Plugin
====================================================

The plugin in swpdm subdirectory is an external PDM converter using
the NXP swpdm converter library. You can use this PDM converter
plugin by defining a pcm device such as:

	pcm.cic {
		type cicFilter
		slave "hw:imxswpdmaudio,0"
		delay 100000 #time in us. Recommended value Optional value.
		gain 0       #Gain facotr. Optional Value.
		OSR 48   #Decimation. Optional value.
	}

Write the above in your ~/.asoundrc or /etc/asound.conf.

Restrictions:

This plugin depends on the imxswpdmaudio sound card.
please use correct dts with kernel:
i.MX8MM: imx8mm-evk-8mic-swpdm.dts
i.MX8MP: imx8mp-evk-8mic-swpdm.dts

The output channel is fixed to 4
The output format is fixed to S32_LE

The supported rate and OSR are showed in below table:
rate\osr
	48	64	96	128	192
8000	Support	Support	Support	Support	Support
11025	N/A	Support	N/A	Support	N/A
12000	N/A	N/A	N/A	N/A	N/A
16000	Support	Support	Support	Support	Support
22050	N/A	Support	N/A	Support	N/A
24000	N/A	Support	N/A	Support	N/A
32000	Support	Support	Support	N/A	N/A
44100	N/A	Support	N/A	N/A	N/A
48000	N/A	Support	N/A	N/A	N/A
64000	Support	N/A	N/A	N/A	N/A
88200	N/A	N/A	N/A	N/A	N/A
96000	N/A	N/A	N/A	N/A	N/A
