How to load and install module automatically at kernel bootup in standalone build?

[RVT]

Hello, NXP experts:

By using demo files (LF_v6.1.1_1.0.0_images_IMX8MPEVK or LF_v5.15.71-2.2.0_images_IMX8MPEVK) from "https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...", all peripherals can be found and loaded properly on i.MX 8M Plus EVK.

For example, WM8960 can be found with demo files.

But there is no peripherals found by using the standalone built image with "https://github.com/nxp-imx/linux-imx". The default "imx_v8_defconfig" and "imx8mp-evk.dts" are applied in the build.

For example, no soundcard can be found with standalone built kernel image.

How can I build the same kernel image as the demo files?

Thanks.

[Dhruvit]

Hi @RVT,

I hope you are doing well.

One needs to enable menuconfig options in the kernel to load specific modules.

Please refer to 7.1.4.6 Menu Configuration Options in i.MX Linux Reference Manual to enable SoC Audio supports for WM8958, WM8960, and WM8962 CODEC.

One can add module names in /etc/modules-load.d/<module_list>.conf to automatically load kernel modules.

Thanks & Regards,
Dhruvit Vasavada

[RVT]

Hi Dhruvit,

Attached please find the .config & imx_v8_defconfig files at iMX Linux kernel at https://github.com/nxp-imx/linux-imx.

There is no option for wm8960 as shown in 7.1.4.6.

I intend to port another codec to EVK platform by following the baseline EVK kernel code. Therefore, I would like to know all know-how in order to let a new codec to work with iMX8MP SAI and audio framework. Firstly, I have to build the same as the demo files. 

Also, can NXP provide something like audio subsystem linux porting guide - user manual?

Thanks.

[Dhruvit · Accepted solution]

Hi @RVT,

I hope you are doing well.

Please make sure that snd-soc-fsl-asoc-card.ko module is loaded correctly.

One can try building a linux image using yocto.

Please refer to i.MX Yocto Project User's Guide

One can refer to the below-mentioned documents related to Audio Codec porting.

1. Chapter 7 Audio - i.MX Linux Reference Manual

2. Chapter - 16 Porting Audio Codecs in i.MX Porting Guide

3 . Audio Codec WM8960 Porting Notes

4. WM8960 audio codec

5. Porting custom audio codec in Linux BSP

Thanks & Regards,
Dhruvit Vasavada