[PATCH 4/4] media: i2c: ov9734: Support control events

[Afonso Figuinha <afonso.figuinha@gmail.com>]

The driver exposes V4L2 controls on its subdev node but does not
implement event subscription, so v4l2-compliance reports a failure for
VIDIOC_SUBSCRIBE_EVENT.

Set V4L2_SUBDEV_FL_HAS_EVENTS and use the control event helpers for
subscribe_event and unsubscribe_event.

The change and this description were drafted with an AI coding
assistant (Claude Code, model Claude Opus 5.5). The author reviewed
them and tested them on a Microsoft Surface Laptop 1.

Signed-off-by: Afonso Figuinha <afonso.figuinha@gmail.com>
---
 drivers/media/i2c/ov9734.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/ov9734.c b/drivers/media/i2c/ov9734.c
index bf19ea56f..095dae964 100644
--- a/drivers/media/i2c/ov9734.c
+++ b/drivers/media/i2c/ov9734.c
@@ -13,6 +13,7 @@
 
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-event.h>
 #include <media/v4l2-fwnode.h>
 
 #define OV9734_LINK_FREQ_180MHZ		180000000ULL
@@ -803,7 +804,13 @@ static const struct v4l2_subdev_pad_ops ov9734_pad_ops = {
 	.enum_frame_size = ov9734_enum_frame_size,
 };
 
+static const struct v4l2_subdev_core_ops ov9734_core_ops = {
+	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
+	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
+};
+
 static const struct v4l2_subdev_ops ov9734_subdev_ops = {
+	.core = &ov9734_core_ops,
 	.video = &ov9734_video_ops,
 	.pad = &ov9734_pad_ops,
 };
@@ -1013,7 +1020,8 @@ static int ov9734_probe(struct i2c_client *client)
 	}
 
 	ov9734->sd.internal_ops = &ov9734_internal_ops;
-	ov9734->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ov9734->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
+			     V4L2_SUBDEV_FL_HAS_EVENTS;
 	ov9734->sd.entity.ops = &ov9734_subdev_entity_ops;
 	ov9734->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
 	ov9734->pad.flags = MEDIA_PAD_FL_SOURCE;
-- 
2.53.0