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);