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authorHans Verkuil <hans.verkuil@cisco.com>2011-06-10 05:56:39 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-07-27 17:53:20 -0300
commitce7275747bd548e0da7425ba0b7edb6f2c7657a2 (patch)
tree5e230670266e64ed7f4317df5f39700bb92d5825 /include/media/v4l2-ctrls.h
parent6e239399e5807132f86f64af6c659411c6a3d1a5 (diff)
[media] v4l2-ctrls: simplify event subscription
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'include/media/v4l2-ctrls.h')
-rw-r--r--include/media/v4l2-ctrls.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index c45bf40e080d..de68a59c7d84 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -169,6 +169,7 @@ struct v4l2_ctrl_ref {
* control is needed multiple times, so this is a simple
* optimization.
* @buckets: Buckets for the hashing. Allows for quick control lookup.
+ * @nr_of_refs: Total number of control references in the list.
* @nr_of_buckets: Total number of buckets in the array.
* @error: The error code of the first failed control addition.
*/
@@ -178,6 +179,7 @@ struct v4l2_ctrl_handler {
struct list_head ctrl_refs;
struct v4l2_ctrl_ref *cached;
struct v4l2_ctrl_ref **buckets;
+ u16 nr_of_refs;
u16 nr_of_buckets;
int error;
};
@@ -494,11 +496,29 @@ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
*/
int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
+/* Internal helper functions that deal with control events. */
void v4l2_ctrl_add_fh(struct v4l2_ctrl_handler *hdl,
struct v4l2_ctrl_fh *ctrl_fh,
struct v4l2_event_subscription *sub);
void v4l2_ctrl_del_fh(struct v4l2_ctrl *ctrl, struct v4l2_fh *fh);
+/** v4l2_ctrl_subscribe_fh() - Helper function that subscribes a control event.
+ * @fh: The file handler that subscribed the control event.
+ * @sub: The event to subscribe (type must be V4L2_EVENT_CTRL).
+ * @n: How many events should be allocated? (Passed to v4l2_event_alloc).
+ * Recommended to set to twice the number of controls plus whatever
+ * is needed for other events. This function will set n to
+ * max(n, 2 * fh->ctrl_handler->nr_of_refs).
+ *
+ * A helper function that initializes the fh for events, allocates the
+ * list of events and subscribes the control event.
+ *
+ * Typically called in the handler of VIDIOC_SUBSCRIBE_EVENT in the
+ * V4L2_EVENT_CTRL case.
+ */
+int v4l2_ctrl_subscribe_fh(struct v4l2_fh *fh,
+ struct v4l2_event_subscription *sub, unsigned n);
+
/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);

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