Yocto - Adding drivers to kernel source without patching

I know about the traditional way of making changes to the kernel source by editing the kernel repository and creating patches with git, I did read about devtool as well. Both solutions create patches in the end.

Is there a different way of achieving the same effect? Perhaps by adding *.c and *.h files and telling Yocto to build them, similarly to how Device Tree blobs are added to the image? It seems obvious to me that getting rid of the patching step make's the development process easier.

If i am correct you try to append files in your kernel sources or modify it without applying patches for a time being. If so, I suggest you to clone your repository somewhere in your workspace.

cd ~ && mkdir  workspace && cd workspace
git clone https://github.com/mykernelsource.git

Then setup you kernel recipe to build from this local git source. To achieve this you can comment the actual SRC_URI
Afterwards, add yours as follow:

SRC_URI = "git:///home/user/workspace/mykernelsource/;protocol=file"

Do not forget to append three / after git
Bitbake support different protocol of file fetcher which is really well documented here

Note that you should take care of SRCREV variable.
If SRCREV = "${AUTOREV}" then you have to commit each time before building. You can also provide your own source revision to this variable. Just type git log to find yours.