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 #if defined(CONFIG_SPI)
  25 #include <linux/spi/spi.h>
  26 #endif
  27 #include <linux/videodev2.h>
  28 #include <media/v4l2-device.h>
  29 #include <media/v4l2-ctrls.h>
  30
  31 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
  32 {
  33         if (v4l2_dev == NULL)
  34                 return -EINVAL;
  35
  36         INIT_LIST_HEAD(&v4l2_dev->subdevs);
  37         spin_lock_init(&v4l2_dev->lock);
  38         mutex_init(&v4l2_dev->ioctl_lock);
  39         v4l2_dev->dev = dev;
  40         if (dev == NULL) {
  41                 /* If dev == NULL, then name must be filled in by the caller */
  42                 WARN_ON(!v4l2_dev->name[0]);
  43                 return 0;
  44         }
  45
  46         /* Set name to driver name + device name if it is empty. */
  47         if (!v4l2_dev->name[0])
  48                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  49                         dev->driver->name, dev_name(dev));
  50         if (!dev_get_drvdata(dev))
  51                 dev_set_drvdata(dev, v4l2_dev);
  52         return 0;
  53 }
  54 EXPORT_SYMBOL_GPL(v4l2_device_register);
  55
  56 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  57                                                 atomic_t *instance)
  58 {
  59         int num = atomic_inc_return(instance) - 1;
  60         int len = strlen(basename);
  61
  62         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  63                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  64                                 "%s-%d", basename, num);
  65         else
  66                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  67                                 "%s%d", basename, num);
  68         return num;
  69 }
  70 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  71
  72 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  73 {
  74         if (v4l2_dev->dev == NULL)
  75                 return;
  76
  77         if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
  78                 dev_set_drvdata(v4l2_dev->dev, NULL);
  79         v4l2_dev->dev = NULL;
  80 }
  81 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
  82
  83 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
  84 {
  85         struct v4l2_subdev *sd, *next;
  86
  87         if (v4l2_dev == NULL)
  88                 return;
  89         v4l2_device_disconnect(v4l2_dev);
  90
  91         /* Unregister subdevs */
  92         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
  93                 v4l2_device_unregister_subdev(sd);
  94 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
  95                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
  96                         struct i2c_client *client = v4l2_get_subdevdata(sd);
  97
  98                         /* We need to unregister the i2c client explicitly.
  99                            We cannot rely on i2c_del_adapter to always
 100                            unregister clients for us, since if the i2c bus
 101                            is a platform bus, then it is never deleted. */
 102                         if (client)
 103                                 i2c_unregister_device(client);
 104                         continue;
 105                 }
 106 #endif
 107 #if defined(CONFIG_SPI)
 108                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 109                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 110
 111                         if (spi)
 112                                 spi_unregister_device(spi);
 113                         continue;
 114                 }
 115 #endif
 116         }
 117 }
 118 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 119
 120 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 121                                                 struct v4l2_subdev *sd)
 122 {
 123         int err;
 124
 125         /* Check for valid input */
 126         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 127                 return -EINVAL;
 128
 129         /* Warn if we apparently re-register a subdev */
 130         WARN_ON(sd->v4l2_dev != NULL);
 131
 132         if (!try_module_get(sd->owner))
 133                 return -ENODEV;
 134
 135         sd->v4l2_dev = v4l2_dev;
 136         if (sd->internal_ops && sd->internal_ops->registered) {
 137                 err = sd->internal_ops->registered(sd);
 138                 if (err)
 139                         return err;
 140         }
 141
 142         /* This just returns 0 if either of the two args is NULL */
 143         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
 144         if (err) {
 145                 if (sd->internal_ops && sd->internal_ops->unregistered)
 146                         sd->internal_ops->unregistered(sd);
 147                 return err;
 148         }
 149
 150         spin_lock(&v4l2_dev->lock);
 151         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 152         spin_unlock(&v4l2_dev->lock);
 153
 154         return 0;
 155 }
 156 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 157
 158 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 159 {
 160         struct video_device *vdev;
 161         struct v4l2_subdev *sd;
 162         int err;
 163
 164         /* Register a device node for every subdev marked with the
 165          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 166          */
 167         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 168                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 169                         continue;
 170
 171                 vdev = &sd->devnode;
 172                 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 173                 vdev->v4l2_dev = v4l2_dev;
 174                 vdev->fops = &v4l2_subdev_fops;
 175                 vdev->release = video_device_release_empty;
 176                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 177                                               sd->owner);
 178                 if (err < 0)
 179                         return err;
 180         }
 181
 182         return 0;
 183 }
 184 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 185
 186 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 187 {
 188         /* return if it isn't registered */
 189         if (sd == NULL || sd->v4l2_dev == NULL)
 190                 return;
 191
 192         spin_lock(&sd->v4l2_dev->lock);
 193         list_del(&sd->list);
 194         spin_unlock(&sd->v4l2_dev->lock);
 195         if (sd->internal_ops && sd->internal_ops->unregistered)
 196                 sd->internal_ops->unregistered(sd);
 197         sd->v4l2_dev = NULL;
 198
 199         video_unregister_device(&sd->devnode);
 200         module_put(sd->owner);
 201 }
 202 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);