ACE is a submodule of IVSC which controls camera sensor's
ownership, belonging to host or IVSC. When IVSC owns camera
sensor, it is for algorithm computing. When host wants to
control camera sensor, ACE module needs to be informed of
ownership with defined interface.

The interface is via MEI. There is a separate MEI UUID, which
this driver uses to enumerate.

To switch ownership of camera sensor between IVSC and host,
the caller specifies the defined ownership information which
will be sent to firmware by sending MEI command.

Device link(device_link_add) is used to set the right camera
sensor ownership before accessing the sensor via I2C. With
DL_FLAG_PM_RUNTIME and DL_FLAG_RPM_ACTIVE, the supplier device
will be PM runtime resumed before the consumer(camera sensor).
So use runtime PM callbacks to transfer the ownership between
host and IVSC.
Signed-off-by: Wentong Wu <wentong.wu@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>