Merge branch 'topic/hda-cache' into topic/hda
[linux-2.6] / drivers / media / video / v4l2-device.c
1 /*
2     V4L2 device support.
3
4     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>
5
6     This program is free software; you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation; either version 2 of the License, or
9     (at your option) any later version.
10
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15
16     You should have received a copy of the GNU General Public License
17     along with this program; if not, write to the Free Software
18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20
21 #include <linux/types.h>
22 #include <linux/ioctl.h>
23 #include <linux/i2c.h>
24 #include <linux/videodev2.h>
25 #include <media/v4l2-device.h>
26
27 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
28 {
29         if (v4l2_dev == NULL)
30                 return -EINVAL;
31
32         INIT_LIST_HEAD(&v4l2_dev->subdevs);
33         spin_lock_init(&v4l2_dev->lock);
34         v4l2_dev->dev = dev;
35         if (dev == NULL) {
36                 /* If dev == NULL, then name must be filled in by the caller */
37                 WARN_ON(!v4l2_dev->name[0]);
38                 return 0;
39         }
40
41         /* Set name to driver name + device name if it is empty. */
42         if (!v4l2_dev->name[0])
43                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
44                         dev->driver->name, dev_name(dev));
45         if (dev_get_drvdata(dev))
46                 v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");
47         dev_set_drvdata(dev, v4l2_dev);
48         return 0;
49 }
50 EXPORT_SYMBOL_GPL(v4l2_device_register);
51
52 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
53 {
54         if (v4l2_dev->dev) {
55                 dev_set_drvdata(v4l2_dev->dev, NULL);
56                 v4l2_dev->dev = NULL;
57         }
58 }
59 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
60
61 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
62 {
63         struct v4l2_subdev *sd, *next;
64
65         if (v4l2_dev == NULL)
66                 return;
67         v4l2_device_disconnect(v4l2_dev);
68
69         /* Unregister subdevs */
70         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
71                 v4l2_device_unregister_subdev(sd);
72 }
73 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
74
75 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
76                                                 struct v4l2_subdev *sd)
77 {
78         /* Check for valid input */
79         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
80                 return -EINVAL;
81         /* Warn if we apparently re-register a subdev */
82         WARN_ON(sd->v4l2_dev != NULL);
83         if (!try_module_get(sd->owner))
84                 return -ENODEV;
85         sd->v4l2_dev = v4l2_dev;
86         spin_lock(&v4l2_dev->lock);
87         list_add_tail(&sd->list, &v4l2_dev->subdevs);
88         spin_unlock(&v4l2_dev->lock);
89         return 0;
90 }
91 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
92
93 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
94 {
95         /* return if it isn't registered */
96         if (sd == NULL || sd->v4l2_dev == NULL)
97                 return;
98         spin_lock(&sd->v4l2_dev->lock);
99         list_del(&sd->list);
100         spin_unlock(&sd->v4l2_dev->lock);
101         sd->v4l2_dev = NULL;
102         module_put(sd->owner);
103 }
104 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);