Hello Andy, first thanks for your review.
And why it's under arch/x86? Is it uncore part? I suppose it should go under drivers/platform/x86.
I am using a "PC Engines" alix6 board. This is the precursor of the new APU boards for "PC Engines". The button device declaration for the alix borads is under "arch/platform/x86/geode/alix.c".
So I thought the new one should go there as well. But I will change this. Thanks for the hint.