cannot create directory 'device-tree': Operation not permitted

I am on linux operating system. I am Trying to Load device tree Overlays via Configfs.

I tried below steps:

$ sudo su
# mount -t configfs none /sys/kernel/config

The mount was successful. however when I try to create a directory, I get error:

mkdir -p /sys/kernel/config/device-tree/overlays/

mkdir: cannot create directory 'device-tree': Operation not permitted

I am having trouble creating a device-tree folder in config.

I used Kernel Version: 4.19.73 I have CONFIG_OF_CONFIGFS=y in kernel.

Best Regards Sami