If you are on a relatively recent kernel, the kernel probably already has support, but the default DTB has it disabled.
This is from a bookworm nightly build for a radxa zero 3
~$ grep rknpu /usr/lib/modules/6.1.115-vendor-rk35xx/modules.builtin
kernel/drivers/rknpu/rknpu.ko
However, it's disabled in the DTB by default
$ cat /sys/firmware/devicetree/base/npu@fde40000/status
disabled
For the board that I am using, the vendor publises a DTO source that enables it at https://github.com/radxa-pkg/radxa-overlays/blob/main/arch/arm64/boot/dts/rockchip/overlays/rk3568-npu-enable.dts
Which works well with armbian-add-overlay.
Though you may need to make a similar overlay for your DTB if it is different enough.
Note that the NPU in the 3566 and 3568 are interoperable.
