Prototype Kernel
The prototype-kernel project is meant for compiling kernel modules outside the normal kernel git tree, but still using the kernels make system.
Note
It is a pre-requisite that you have a developement kernel tree available for compiling against (or install your distributions kernel-devel package).
The purpose is getting a separate git development tree for developing and refining your kernel module over time, before pushing it upstream for the Linux Kernel.
See the build process document.