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While there's one file there with briefily describes the uAPI,
the documentation was written just like most subsystems: focused
on kernel developers. So, add it together with driver-api books.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Signed-off-by: Jonathan Corbet <corbet@lwn.net>