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/module.h>
  24 #include <linux/i2c.h>
  25 #include <linux/slab.h>
  26 #if defined(CONFIG_SPI)
  27 #include <linux/spi/spi.h>
  28 #endif
  29 #include <linux/videodev2.h>
  30 #include <media/v4l2-device.h>
  31 #include <media/v4l2-ctrls.h>
  32
  33 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
  34 {
  35         if (v4l2_dev == NULL)
  36                 return -EINVAL;
  37
  38         INIT_LIST_HEAD(&v4l2_dev->subdevs);
  39         spin_lock_init(&v4l2_dev->lock);
  40         mutex_init(&v4l2_dev->ioctl_lock);
  41         v4l2_prio_init(&v4l2_dev->prio);
  42         kref_init(&v4l2_dev->ref);
  43         get_device(dev);
  44         v4l2_dev->dev = dev;
  45         if (dev == NULL) {
  46                 /* If dev == NULL, then name must be filled in by the caller */
  47                 WARN_ON(!v4l2_dev->name[0]);
  48                 return 0;
  49         }
  50
  51         /* Set name to driver name + device name if it is empty. */
  52         if (!v4l2_dev->name[0])
  53                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  54                         dev->driver->name, dev_name(dev));
  55         if (!dev_get_drvdata(dev))
  56                 dev_set_drvdata(dev, v4l2_dev);
  57         return 0;
  58 }
  59 EXPORT_SYMBOL_GPL(v4l2_device_register);
  60
  61 static void v4l2_device_release(struct kref *ref)
  62 {
  63         struct v4l2_device *v4l2_dev =
  64                 container_of(ref, struct v4l2_device, ref);
  65
  66         if (v4l2_dev->release)
  67                 v4l2_dev->release(v4l2_dev);
  68 }
  69
  70 int v4l2_device_put(struct v4l2_device *v4l2_dev)
  71 {
  72         return kref_put(&v4l2_dev->ref, v4l2_device_release);
  73 }
  74 EXPORT_SYMBOL_GPL(v4l2_device_put);
  75
  76 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  77                                                 atomic_t *instance)
  78 {
  79         int num = atomic_inc_return(instance) - 1;
  80         int len = strlen(basename);
  81
  82         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  83                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  84                                 "%s-%d", basename, num);
  85         else
  86                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  87                                 "%s%d", basename, num);
  88         return num;
  89 }
  90 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  91
  92 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  93 {
  94         if (v4l2_dev->dev == NULL)
  95                 return;
  96
  97         if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
  98                 dev_set_drvdata(v4l2_dev->dev, NULL);
  99         put_device(v4l2_dev->dev);
 100         v4l2_dev->dev = NULL;
 101 }
 102 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
 103
 104 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 105 {
 106         struct v4l2_subdev *sd, *next;
 107
 108         if (v4l2_dev == NULL)
 109                 return;
 110         v4l2_device_disconnect(v4l2_dev);
 111
 112         /* Unregister subdevs */
 113         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 114                 v4l2_device_unregister_subdev(sd);
 115 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
 116                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 117                         struct i2c_client *client = v4l2_get_subdevdata(sd);
 118
 119                         /* We need to unregister the i2c client explicitly.
 120                            We cannot rely on i2c_del_adapter to always
 121                            unregister clients for us, since if the i2c bus
 122                            is a platform bus, then it is never deleted. */
 123                         if (client)
 124                                 i2c_unregister_device(client);
 125                         continue;
 126                 }
 127 #endif
 128 #if defined(CONFIG_SPI)
 129                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 130                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 131
 132                         if (spi)
 133                                 spi_unregister_device(spi);
 134                         continue;
 135                 }
 136 #endif
 137         }
 138 }
 139 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 140
 141 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 142                                 struct v4l2_subdev *sd)
 143 {
 144 #if defined(CONFIG_MEDIA_CONTROLLER)
 145         struct media_entity *entity = &sd->entity;
 146 #endif
 147         int err;
 148
 149         /* Check for valid input */
 150         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 151                 return -EINVAL;
 152
 153         /* Warn if we apparently re-register a subdev */
 154         WARN_ON(sd->v4l2_dev != NULL);
 155
 156         if (!try_module_get(sd->owner))
 157                 return -ENODEV;
 158
 159         sd->v4l2_dev = v4l2_dev;
 160         if (sd->internal_ops && sd->internal_ops->registered) {
 161                 err = sd->internal_ops->registered(sd);
 162                 if (err) {
 163                         module_put(sd->owner);
 164                         return err;
 165                 }
 166         }
 167
 168         /* This just returns 0 if either of the two args is NULL */
 169         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
 170         if (err) {
 171                 if (sd->internal_ops && sd->internal_ops->unregistered)
 172                         sd->internal_ops->unregistered(sd);
 173                 module_put(sd->owner);
 174                 return err;
 175         }
 176
 177 #if defined(CONFIG_MEDIA_CONTROLLER)
 178         /* Register the entity. */
 179         if (v4l2_dev->mdev) {
 180                 err = media_device_register_entity(v4l2_dev->mdev, entity);
 181                 if (err < 0) {
 182                         if (sd->internal_ops && sd->internal_ops->unregistered)
 183                                 sd->internal_ops->unregistered(sd);
 184                         module_put(sd->owner);
 185                         return err;
 186                 }
 187         }
 188 #endif
 189
 190         spin_lock(&v4l2_dev->lock);
 191         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 192         spin_unlock(&v4l2_dev->lock);
 193
 194         return 0;
 195 }
 196 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 197
 198 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 199 {
 200         struct v4l2_subdev *sd = video_get_drvdata(vdev);
 201         sd->devnode = NULL;
 202         kfree(vdev);
 203 }
 204
 205 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 206 {
 207         struct video_device *vdev;
 208         struct v4l2_subdev *sd;
 209         int err;
 210
 211         /* Register a device node for every subdev marked with the
 212          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 213          */
 214         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 215                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 216                         continue;
 217
 218                 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 219                 if (!vdev) {
 220                         err = -ENOMEM;
 221                         goto clean_up;
 222                 }
 223
 224                 video_set_drvdata(vdev, sd);
 225                 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 226                 vdev->v4l2_dev = v4l2_dev;
 227                 vdev->fops = &v4l2_subdev_fops;
 228                 vdev->release = v4l2_device_release_subdev_node;
 229                 vdev->ctrl_handler = sd->ctrl_handler;
 230                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 231                                               sd->owner);
 232                 if (err < 0) {
 233                         kfree(vdev);
 234                         goto clean_up;
 235                 }
 236 #if defined(CONFIG_MEDIA_CONTROLLER)
 237                 sd->entity.v4l.major = VIDEO_MAJOR;
 238                 sd->entity.v4l.minor = vdev->minor;
 239 #endif
 240                 sd->devnode = vdev;
 241         }
 242         return 0;
 243
 244 clean_up:
 245         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 246                 if (!sd->devnode)
 247                         break;
 248                 video_unregister_device(sd->devnode);
 249         }
 250
 251         return err;
 252 }
 253 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 254
 255 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 256 {
 257         struct v4l2_device *v4l2_dev;
 258
 259         /* return if it isn't registered */
 260         if (sd == NULL || sd->v4l2_dev == NULL)
 261                 return;
 262
 263         v4l2_dev = sd->v4l2_dev;
 264
 265         spin_lock(&v4l2_dev->lock);
 266         list_del(&sd->list);
 267         spin_unlock(&v4l2_dev->lock);
 268
 269         if (sd->internal_ops && sd->internal_ops->unregistered)
 270                 sd->internal_ops->unregistered(sd);
 271         sd->v4l2_dev = NULL;
 272
 273 #if defined(CONFIG_MEDIA_CONTROLLER)
 274         if (v4l2_dev->mdev)
 275                 media_device_unregister_entity(&sd->entity);
 276 #endif
 277         video_unregister_device(sd->devnode);
 278         module_put(sd->owner);
 279 }
 280 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);