Kernel version for new drivers

[Greg KH]

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