On Tue, May 02, 2017 at 09:05:18AM +1000, Dushara Jayasinghe wrote:

Hi all,

Not sure if this has been covered elsewhere. I'm working on a sama5d2 
based device where the kernel supported by the hardware vendor is 4.4. 
Any drivers we develop and test are based on this version of the kernel. 
Do the kernel maintainers accept drivers for older (but maintained) 
versions of the kernel?

Nope, for the simple reason that we can't go back in time and add them
to old releases :)

Is there some general policy regarding this or is it a question that I
need to ask the maintainer of the subsystem that the driver belongs
to?

Have you read the stable_kernel_rules.txt file in the Documentation
directory for what type of patch is allowed in the stable kernel
releases?  It should answer this question. Also look at the
development_process/ "book" in the tree, that should help out.

In short, you always have to add new features to the latest development
verison of the kernel.

hope this helps,

greg k-h