This patch adds new interface to existing driver. New code is not used yet,
it will be enabled later.
Changes are prepared in small steps to keep patches readable.
Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Piotr Bugalski <bugalski.piotr@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>