V4L/DVB (11396): cx88: avoid reprogramming every audio register on A2 stereo/mono...
[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 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
53                                                 atomic_t *instance)
54 {
55         int num = atomic_inc_return(instance) - 1;
56         int len = strlen(basename);
57
58         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
59                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
60                                 "%s-%d", basename, num);
61         else
62                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
63                                 "%s%d", basename, num);
64         return num;
65 }
66 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
67
68 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
69 {
70         if (v4l2_dev->dev) {
71                 dev_set_drvdata(v4l2_dev->dev, NULL);
72                 v4l2_dev->dev = NULL;
73         }
74 }
75 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
76
77 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
78 {
79         struct v4l2_subdev *sd, *next;
80
81         if (v4l2_dev == NULL)
82                 return;
83         v4l2_device_disconnect(v4l2_dev);
84
85         /* Unregister subdevs */
86         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
87                 v4l2_device_unregister_subdev(sd);
88 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
89                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
90                         struct i2c_client *client = v4l2_get_subdevdata(sd);
91
92                         /* We need to unregister the i2c client explicitly.
93                            We cannot rely on i2c_del_adapter to always
94                            unregister clients for us, since if the i2c bus
95                            is a platform bus, then it is never deleted. */
96                         if (client)
97                                 i2c_unregister_device(client);
98                 }
99 #endif
100         }
101 }
102 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
103
104 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
105                                                 struct v4l2_subdev *sd)
106 {
107         /* Check for valid input */
108         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
109                 return -EINVAL;
110         /* Warn if we apparently re-register a subdev */
111         WARN_ON(sd->v4l2_dev != NULL);
112         if (!try_module_get(sd->owner))
113                 return -ENODEV;
114         sd->v4l2_dev = v4l2_dev;
115         spin_lock(&v4l2_dev->lock);
116         list_add_tail(&sd->list, &v4l2_dev->subdevs);
117         spin_unlock(&v4l2_dev->lock);
118         return 0;
119 }
120 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
121
122 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
123 {
124         /* return if it isn't registered */
125         if (sd == NULL || sd->v4l2_dev == NULL)
126                 return;
127         spin_lock(&sd->v4l2_dev->lock);
128         list_del(&sd->list);
129         spin_unlock(&sd->v4l2_dev->lock);
130         sd->v4l2_dev = NULL;
131         module_put(sd->owner);
132 }
133 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);