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[media] v4l2-ctrls: simplify event subscription 

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2011-06-10 05:56:39 -03:00 committed by Mauro Carvalho Chehab
parent 6e239399e5
commit ce7275747b
2 changed files with 40 additions and 0 deletions
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20
drivers/media/video/v4l2-ctrls.c
View File

@ -1013,6 +1013,7 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
insertion is an O(1) operation. */
if (list_empty(&hdl->ctrl_refs) || id > node2id(hdl->ctrl_refs.prev)) {
list_add_tail(&new_ref->node, &hdl->ctrl_refs);
hdl->nr_of_refs++;
goto insert_in_hash;
}
@ -2061,3 +2062,22 @@ void v4l2_ctrl_del_fh(struct v4l2_ctrl *ctrl, struct v4l2_fh *fh)
v4l2_ctrl_unlock(ctrl);
}
EXPORT_SYMBOL(v4l2_ctrl_del_fh);
int v4l2_ctrl_subscribe_fh(struct v4l2_fh *fh,
struct v4l2_event_subscription *sub, unsigned n)
{
struct v4l2_ctrl_handler *hdl = fh->ctrl_handler;
int ret = 0;
if (!fh->events)
ret = v4l2_event_init(fh);
if (!ret) {
if (hdl->nr_of_refs * 2 > n)
n = hdl->nr_of_refs * 2;
ret = v4l2_event_alloc(fh, n);
}
if (!ret)
ret = v4l2_event_subscribe(fh, sub);
return ret;
}
EXPORT_SYMBOL(v4l2_ctrl_subscribe_fh);

20
include/media/v4l2-ctrls.h
View File

@ -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);