Once we know how to compile the module externally, we are ready to prepare a Linux kernel module Yocto recipe for it:

1. We place the module source file and Makefile in recipes-kernel/hello-world/files/ inside our meta-bsp-custom layer.
2. We then create a recipes-kernel/hello-world/hello-world.bb file with the following content:

# Copyright (C) 2017 Packt Publishing. SUMMARY = "Simplest hello world kernel module." LICENSE = "GPLv2" LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/GPL-2.0;md5=801f80980d171dd6425610833a22dbe6" inherit module SRC_URI = " \ file://hello_world.c \ file://Makefile \ " S = "${WORKDIR}" COMPATIBLE_MACHINE = "(wandboard)" 

The recipe defines the source directory and the two module files after inheriting ...