linux/drivers/media/video/v4l2-device.c
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   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#if defined(CONFIG_SPI)
  25#include <linux/spi/spi.h>
  26#endif
  27#include <linux/videodev2.h>
  28#include <media/v4l2-device.h>
  29
  30int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
  31{
  32        if (v4l2_dev == NULL)
  33                return -EINVAL;
  34
  35        INIT_LIST_HEAD(&v4l2_dev->subdevs);
  36        spin_lock_init(&v4l2_dev->lock);
  37        v4l2_dev->dev = dev;
  38        if (dev == NULL) {
  39                /* If dev == NULL, then name must be filled in by the caller */
  40                WARN_ON(!v4l2_dev->name[0]);
  41                return 0;
  42        }
  43
  44        /* Set name to driver name + device name if it is empty. */
  45        if (!v4l2_dev->name[0])
  46                snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  47                        dev->driver->name, dev_name(dev));
  48        if (dev_get_drvdata(dev))
  49                v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");
  50        dev_set_drvdata(dev, v4l2_dev);
  51        return 0;
  52}
  53EXPORT_SYMBOL_GPL(v4l2_device_register);
  54
  55int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  56                                                atomic_t *instance)
  57{
  58        int num = atomic_inc_return(instance) - 1;
  59        int len = strlen(basename);
  60
  61        if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  62                snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  63                                "%s-%d", basename, num);
  64        else
  65                snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  66                                "%s%d", basename, num);
  67        return num;
  68}
  69EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  70
  71void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  72{
  73        if (v4l2_dev->dev) {
  74                dev_set_drvdata(v4l2_dev->dev, NULL);
  75                v4l2_dev->dev = NULL;
  76        }
  77}
  78EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
  79
  80void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
  81{
  82        struct v4l2_subdev *sd, *next;
  83
  84        if (v4l2_dev == NULL)
  85                return;
  86        v4l2_device_disconnect(v4l2_dev);
  87
  88        /* Unregister subdevs */
  89        list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
  90                v4l2_device_unregister_subdev(sd);
  91#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
  92                if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
  93                        struct i2c_client *client = v4l2_get_subdevdata(sd);
  94
  95                        /* We need to unregister the i2c client explicitly.
  96                           We cannot rely on i2c_del_adapter to always
  97                           unregister clients for us, since if the i2c bus
  98                           is a platform bus, then it is never deleted. */
  99                        if (client)
 100                                i2c_unregister_device(client);
 101                }
 102#endif
 103#if defined(CONFIG_SPI)
 104                if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 105                        struct spi_device *spi = v4l2_get_subdevdata(sd);
 106
 107                        if (spi)
 108                                spi_unregister_device(spi);
 109                }
 110#endif
 111        }
 112}
 113EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 114
 115int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 116                                                struct v4l2_subdev *sd)
 117{
 118        /* Check for valid input */
 119        if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 120                return -EINVAL;
 121        /* Warn if we apparently re-register a subdev */
 122        WARN_ON(sd->v4l2_dev != NULL);
 123        if (!try_module_get(sd->owner))
 124                return -ENODEV;
 125        sd->v4l2_dev = v4l2_dev;
 126        spin_lock(&v4l2_dev->lock);
 127        list_add_tail(&sd->list, &v4l2_dev->subdevs);
 128        spin_unlock(&v4l2_dev->lock);
 129        return 0;
 130}
 131EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 132
 133void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 134{
 135        /* return if it isn't registered */
 136        if (sd == NULL || sd->v4l2_dev == NULL)
 137                return;
 138        spin_lock(&sd->v4l2_dev->lock);
 139        list_del(&sd->list);
 140        spin_unlock(&sd->v4l2_dev->lock);
 141        sd->v4l2_dev = NULL;
 142        module_put(sd->owner);
 143}
 144EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
 145