LXR linux/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
  27int 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}
  50EXPORT_SYMBOL_GPL(v4l2_device_register);
  51
  52int 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}
  66EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  67
  68void 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}
  75EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
  76
  77void 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}
 102EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 103
 104int 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}
 120EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 121
 122void 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}
 133EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
 134