General I2S slave I/O device tree overlay for Raspberry pi.
Tested with Raspberry pi Compute Module 3+ and Asahi Kasei AK4556.

• I2S slave: Raspberry pi
• I2S master: Audio codec(ex. AK4556)

I2S Master version

Compile on Raspberry Pi

dtc -@ -H epapr -O dtb -o genericstereoaudiocodec.dtbo -Wno-unit_address_vs_reg genericstereoaudiocodec.dts

Copy i2smaster.dtbo to /boot/overlays

sudo cp genericstereoaudiocodec.dtbo /boot/overlays

Edit /boot/config.txt
Enable I2S and add i2smaster device tree overlay

#dtparam=i2c_arm=on
dtparam=i2s=on
#dtparam=spi=on
dtoverlay=genericstereoaudiocodec

If you don't need HDMI audio output and Raspberry Pi's headphone output, comment out "dtparam=audio=on" by hash.
like this.

#dtparam=audio=on