[media] v4l2: make vidioc_(un)subscribe_event const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_(un)subscribe_event.
Adding const for write-only ioctls was decided during the 2012 Media Workshop.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/pci/ivtv/ivtv-ioctl.c

@@ -1460,7 +1460,7 @@ static int ivtv_overlay(struct file *file, void *fh, unsigned int on)
 	return 0;
 }
 
-static int ivtv_subscribe_event(struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
+static int ivtv_subscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub)
 {
 	switch (sub->type) {
 	case V4L2_EVENT_VSYNC:

drivers/media/platform/omap3isp/ispccdc.c

@@ -1706,7 +1706,7 @@ static long ccdc_ioctl(struct v4l2_subdev *sd, unsigned int cmd, void *arg)
 }
 
 static int ccdc_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
-				struct v4l2_event_subscription *sub)
+				const struct v4l2_event_subscription *sub)
 {
 	if (sub->type != V4L2_EVENT_FRAME_SYNC)
 		return -EINVAL;
@@ -1719,7 +1719,7 @@ static int ccdc_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
 }
 
 static int ccdc_unsubscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
-				  struct v4l2_event_subscription *sub)
+				  const struct v4l2_event_subscription *sub)
 {
 	return v4l2_event_unsubscribe(fh, sub);
 }

drivers/media/platform/omap3isp/ispstat.c

@@ -1025,7 +1025,7 @@ void omap3isp_stat_dma_isr(struct ispstat *stat)
 
 int omap3isp_stat_subscribe_event(struct v4l2_subdev *subdev,
 				  struct v4l2_fh *fh,
-				  struct v4l2_event_subscription *sub)
+				  const struct v4l2_event_subscription *sub)
 {
 	struct ispstat *stat = v4l2_get_subdevdata(subdev);
 
@@ -1037,7 +1037,7 @@ int omap3isp_stat_subscribe_event(struct v4l2_subdev *subdev,
 
 int omap3isp_stat_unsubscribe_event(struct v4l2_subdev *subdev,
 				    struct v4l2_fh *fh,
-				    struct v4l2_event_subscription *sub)
+				    const struct v4l2_event_subscription *sub)
 {
 	return v4l2_event_unsubscribe(fh, sub);
 }

drivers/media/platform/omap3isp/ispstat.h

@@ -147,10 +147,10 @@ int omap3isp_stat_init(struct ispstat *stat, const char *name,
 void omap3isp_stat_cleanup(struct ispstat *stat);
 int omap3isp_stat_subscribe_event(struct v4l2_subdev *subdev,
 				  struct v4l2_fh *fh,
-				  struct v4l2_event_subscription *sub);
+				  const struct v4l2_event_subscription *sub);
 int omap3isp_stat_unsubscribe_event(struct v4l2_subdev *subdev,
 				    struct v4l2_fh *fh,
-				    struct v4l2_event_subscription *sub);
+				    const struct v4l2_event_subscription *sub);
 int omap3isp_stat_s_stream(struct v4l2_subdev *subdev, int enable);
 
 int omap3isp_stat_busy(struct ispstat *stat);

drivers/media/v4l2-core/v4l2-ctrls.c

@@ -2699,7 +2699,7 @@ int v4l2_ctrl_log_status(struct file *file, void *fh)
 EXPORT_SYMBOL(v4l2_ctrl_log_status);
 
 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
-				struct v4l2_event_subscription *sub)
+				const struct v4l2_event_subscription *sub)
 {
 	if (sub->type == V4L2_EVENT_CTRL)
 		return v4l2_event_subscribe(fh, sub, 0, &v4l2_ctrl_sub_ev_ops);

drivers/media/v4l2-core/v4l2-event.c

@@ -203,7 +203,7 @@ int v4l2_event_pending(struct v4l2_fh *fh)
 EXPORT_SYMBOL_GPL(v4l2_event_pending);
 
 int v4l2_event_subscribe(struct v4l2_fh *fh,
-			 struct v4l2_event_subscription *sub, unsigned elems,
+			 const struct v4l2_event_subscription *sub, unsigned elems,
 			 const struct v4l2_subscribed_event_ops *ops)
 {
 	struct v4l2_subscribed_event *sev, *found_ev;
@@ -278,7 +278,7 @@ void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
 
 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
-			   struct v4l2_event_subscription *sub)
+			   const struct v4l2_event_subscription *sub)
 {
 	struct v4l2_subscribed_event *sev;
 	unsigned long flags;

include/media/v4l2-ctrls.h

@@ -546,7 +546,7 @@ int v4l2_ctrl_log_status(struct file *file, void *fh);
 /* Can be used as a vidioc_subscribe_event function that just subscribes
    control events. */
 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
-				struct v4l2_event_subscription *sub);
+				const struct v4l2_event_subscription *sub);
 
 /* Can be used as a poll function that just polls for control events. */
 unsigned int v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);

include/media/v4l2-event.h

@@ -124,10 +124,10 @@ void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev);
 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev);
 int v4l2_event_pending(struct v4l2_fh *fh);
 int v4l2_event_subscribe(struct v4l2_fh *fh,
-			 struct v4l2_event_subscription *sub, unsigned elems,
+			 const struct v4l2_event_subscription *sub, unsigned elems,
 			 const struct v4l2_subscribed_event_ops *ops);
 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
-			   struct v4l2_event_subscription *sub);
+			   const struct v4l2_event_subscription *sub);
 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh);
 
 #endif /* V4L2_EVENT_H */

include/media/v4l2-ioctl.h

@@ -273,9 +273,9 @@ struct v4l2_ioctl_ops {
 				    struct v4l2_dv_timings_cap *cap);
 
 	int (*vidioc_subscribe_event)  (struct v4l2_fh *fh,
-					struct v4l2_event_subscription *sub);
+					const struct v4l2_event_subscription *sub);
 	int (*vidioc_unsubscribe_event)(struct v4l2_fh *fh,
-					struct v4l2_event_subscription *sub);
+					const struct v4l2_event_subscription *sub);
 
 	/* For other private ioctls */
 	long (*vidioc_default)	       (struct file *file, void *fh,