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