media: subdev: pass also the active state to subdevs from ioctls

media: subdev: pass also the active state to subdevs from ioctls

At the moment when a subdev op is called, the TRY subdev state
(subdev_fh->state) is passed as a parameter even for the ACTIVE case, or
alternatively a NULL can be passed for ACTIVE case. This used to make
sense, as the ACTIVE state was handled internally by the subdev drivers.

We now have a state for the ACTIVE case in a standard place, and can
pass that also to the drivers. This patch changes the subdev ioctls to
either pass the TRY or ACTIVE state to the subdev.

Unfortunately many drivers call ops from other subdevs, and implicitly
pass NULL as the state, so this is just a partial solution. A coccinelle
spatch could perhaps be created which fixes the drivers' subdev calls.

For all current upstream drivers this doesn't matter, as they do not
expect to get a valid state for ACTIVE case. But future drivers which
support multiplexed streaming and routing will depend on getting a state
for both active and try cases.

For new drivers we can mandate that the pipelines where the drivers are
used need to pass the state properly, or preferably, not call such
subdev ops at all.

However, if an existing subdev driver is changed to support multiplexed
streams, the driver has to consider cases where its ops will be called
with NULL state. The problem can easily be solved by using the
v4l2_subdev_lock_and_get_active_state() helper, introduced in a follow
up patch.

Another follow up patch adds wrappers for pad ops dealing with subdev
state, which automate the use of
v4l2_subdev_lock_and_get_active_state() for cases where the state is
NULL.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>