media: camss: csid: Add support for events triggered by user controls

Changing a user control value can trigger an event to other
users. Add support for that.
Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/qcom/camss/camss-csid.c

@@ -17,6 +17,7 @@
 #include <linux/regulator/consumer.h>
 #include <media/media-entity.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-event.h>
 #include <media/v4l2-subdev.h>
 
 #include "camss-csid.h"
@@ -1273,6 +1274,8 @@ static int csid_link_setup(struct media_entity *entity,
 
 static const struct v4l2_subdev_core_ops csid_core_ops = {
 	.s_power = csid_set_power,
+	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
+	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
 };
 
 static const struct v4l2_subdev_video_ops csid_video_ops = {
@@ -1318,7 +1321,8 @@ int msm_csid_register_entity(struct csid_device *csid,
 
 	v4l2_subdev_init(sd, &csid_v4l2_ops);
 	sd->internal_ops = &csid_v4l2_internal_ops;
-	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
+		     V4L2_SUBDEV_FL_HAS_EVENTS;
 	snprintf(sd->name, ARRAY_SIZE(sd->name), "%s%d",
 		 MSM_CSID_NAME, csid->id);
 	v4l2_set_subdevdata(sd, csid);