[media] v4l2-events/fh: merge v4l2_events into v4l2_fh
[pandora-kernel.git] / drivers / media / video / v4l2-fh.c
1 /*
2  * v4l2-fh.c
3  *
4  * V4L2 file handles.
5  *
6  * Copyright (C) 2009--2010 Nokia Corporation.
7  *
8  * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License
12  * version 2 as published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22  * 02110-1301 USA
23  */
24
25 #include <linux/bitops.h>
26 #include <linux/slab.h>
27 #include <media/v4l2-dev.h>
28 #include <media/v4l2-fh.h>
29 #include <media/v4l2-event.h>
30 #include <media/v4l2-ioctl.h>
31
32 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
33 {
34         fh->vdev = vdev;
35         /* Inherit from video_device. May be overridden by the driver. */
36         fh->ctrl_handler = vdev->ctrl_handler;
37         INIT_LIST_HEAD(&fh->list);
38         set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
39         fh->prio = V4L2_PRIORITY_UNSET;
40
41         init_waitqueue_head(&fh->wait);
42         INIT_LIST_HEAD(&fh->free);
43         INIT_LIST_HEAD(&fh->available);
44         INIT_LIST_HEAD(&fh->subscribed);
45         fh->sequence = -1;
46 }
47 EXPORT_SYMBOL_GPL(v4l2_fh_init);
48
49 void v4l2_fh_add(struct v4l2_fh *fh)
50 {
51         unsigned long flags;
52
53         if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
54                 v4l2_prio_open(fh->vdev->prio, &fh->prio);
55         spin_lock_irqsave(&fh->vdev->fh_lock, flags);
56         list_add(&fh->list, &fh->vdev->fh_list);
57         spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
58 }
59 EXPORT_SYMBOL_GPL(v4l2_fh_add);
60
61 int v4l2_fh_open(struct file *filp)
62 {
63         struct video_device *vdev = video_devdata(filp);
64         struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
65
66         filp->private_data = fh;
67         if (fh == NULL)
68                 return -ENOMEM;
69         v4l2_fh_init(fh, vdev);
70         v4l2_fh_add(fh);
71         return 0;
72 }
73 EXPORT_SYMBOL_GPL(v4l2_fh_open);
74
75 void v4l2_fh_del(struct v4l2_fh *fh)
76 {
77         unsigned long flags;
78
79         spin_lock_irqsave(&fh->vdev->fh_lock, flags);
80         list_del_init(&fh->list);
81         spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
82         if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
83                 v4l2_prio_close(fh->vdev->prio, fh->prio);
84 }
85 EXPORT_SYMBOL_GPL(v4l2_fh_del);
86
87 void v4l2_fh_exit(struct v4l2_fh *fh)
88 {
89         if (fh->vdev == NULL)
90                 return;
91         v4l2_event_free(fh);
92         fh->vdev = NULL;
93 }
94 EXPORT_SYMBOL_GPL(v4l2_fh_exit);
95
96 int v4l2_fh_release(struct file *filp)
97 {
98         struct v4l2_fh *fh = filp->private_data;
99
100         if (fh) {
101                 v4l2_fh_del(fh);
102                 v4l2_fh_exit(fh);
103                 kfree(fh);
104         }
105         return 0;
106 }
107 EXPORT_SYMBOL_GPL(v4l2_fh_release);
108
109 int v4l2_fh_is_singular(struct v4l2_fh *fh)
110 {
111         unsigned long flags;
112         int is_singular;
113
114         if (fh == NULL || fh->vdev == NULL)
115                 return 0;
116         spin_lock_irqsave(&fh->vdev->fh_lock, flags);
117         is_singular = list_is_singular(&fh->list);
118         spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
119         return is_singular;
120 }
121 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);