buffer.h supplies everything needed for devices using buffers.
buffer_impl.h supplies access to the internals as needed to write
a buffer implementation.

This was really motivated by the mess that turned up in the
kernel-doc documentation pulled in by the new sphinx docs.
It made it clear that our logical separations in headers were
generally terrible.  The buffer case was easy to sort out without
greatly effecting drivers so here it is.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

These were only getting access to the internals of struct iio_dev via
the include of iio.h within buffer.h.  This should always have been
explicitly included by the buffer implementations themselves.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

As a precursor to splitting buffer.h, lets make sure all drivers
include the relevant headers rather than relying on picking them
up from kfifo_buf.h.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

For generic IIO trigger implementations we already have a sub-directory,
but the generic buffer implementations currently reside in the IIO
top-level directory. The main reason is that things have historically grown
into this form.

With more generic buffer implementations on its way now is the perfect time
to clean this up and introduce a sub-directory for generic buffer
implementations to avoid too much clutter in the top-level directory.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>