Hello!
The first thing that you need to check is that the pinmux for the I2S pins are configured correctly. Are you using the Jetson Xavier NX devkit or the Jetson Xavier NX module with another board?
You can check the pinmux by executing the following …
$ sudo grep dap3 /sys/kernel/debug/tegra_pinctrl_reg
Bank: 0 Reg: 0x02431048 Val: 0x00000440 -> dap3_fs_pt4
Bank: 0 Reg: 0x02431050 Val: 0x00000450 -> dap3_din_pt3
Bank: 0 Reg: 0x02431058 Val: 0x00000400 -> dap3_dout_pt2
Bank: 0 Reg: 0x02431060 Val: 0x00000440 -> dap3_sclk_pt1
You should see the above.
If that looks good then please refer to this thread.
Regards,
Jon