drivers/media/v4l2-core/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                 if (WARN_ON(!v4l2_dev->name[0]))
  48                         return -EINVAL;
  49                 return 0;
  50         }
  51
  52         /* Set name to driver name + device name if it is empty. */
  53         if (!v4l2_dev->name[0])
  54                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  55                         dev->driver->name, dev_name(dev));
  56         if (!dev_get_drvdata(dev))
  57                 dev_set_drvdata(dev, v4l2_dev);
  58         return 0;
  59 }
  60 EXPORT_SYMBOL_GPL(v4l2_device_register);
  61
  62 static void v4l2_device_release(struct kref *ref)
  63 {
  64         struct v4l2_device *v4l2_dev =
  65                 container_of(ref, struct v4l2_device, ref);
  66
  67         if (v4l2_dev->release)
  68                 v4l2_dev->release(v4l2_dev);
  69 }
  70
  71 int v4l2_device_put(struct v4l2_device *v4l2_dev)
  72 {
  73         return kref_put(&v4l2_dev->ref, v4l2_device_release);
  74 }
  75 EXPORT_SYMBOL_GPL(v4l2_device_put);
  76
  77 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  78                                                 atomic_t *instance)
  79 {
  80         int num = atomic_inc_return(instance) - 1;
  81         int len = strlen(basename);
  82
  83         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  84                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  85                                 "%s-%d", basename, num);
  86         else
  87                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  88                                 "%s%d", basename, num);
  89         return num;
  90 }
  91 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  92
  93 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  94 {
  95         if (v4l2_dev->dev == NULL)
  96                 return;
  97
  98         if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
  99                 dev_set_drvdata(v4l2_dev->dev, NULL);
 100         put_device(v4l2_dev->dev);
 101         v4l2_dev->dev = NULL;
 102 }
 103 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
 104
 105 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 106 {
 107         struct v4l2_subdev *sd, *next;
 108
 109         /* Just return if v4l2_dev is NULL or if it was already
 110          * unregistered before. */
 111         if (v4l2_dev == NULL || !v4l2_dev->name[0])
 112                 return;
 113         v4l2_device_disconnect(v4l2_dev);
 114
 115         /* Unregister subdevs */
 116         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 117                 v4l2_device_unregister_subdev(sd);
 118 #if IS_ENABLED(CONFIG_I2C)
 119                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 120                         struct i2c_client *client = v4l2_get_subdevdata(sd);
 121
 122                         /* We need to unregister the i2c client explicitly.
 123                            We cannot rely on i2c_del_adapter to always
 124                            unregister clients for us, since if the i2c bus
 125                            is a platform bus, then it is never deleted. */
 126                         if (client)
 127                                 i2c_unregister_device(client);
 128                         continue;
 129                 }
 130 #endif
 131 #if defined(CONFIG_SPI)
 132                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 133                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 134
 135                         if (spi)
 136                                 spi_unregister_device(spi);
 137                         continue;
 138                 }
 139 #endif
 140         }
 141         /* Mark as unregistered, thus preventing duplicate unregistrations */
 142         v4l2_dev->name[0] = '\0';
 143 }
 144 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 145
 146 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 147                                 struct v4l2_subdev *sd)
 148 {
 149 #if defined(CONFIG_MEDIA_CONTROLLER)
 150         struct media_entity *entity = &sd->entity;
 151 #endif
 152         int err;
 153
 154         /* Check for valid input */
 155         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 156                 return -EINVAL;
 157
 158         /* Warn if we apparently re-register a subdev */
 159         WARN_ON(sd->v4l2_dev != NULL);
 160
 161         /*
 162          * The reason to acquire the module here is to avoid unloading
 163          * a module of sub-device which is registered to a media
 164          * device. To make it possible to unload modules for media
 165          * devices that also register sub-devices, do not
 166          * try_module_get() such sub-device owners.
 167          */
 168         sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
 169                 sd->owner == v4l2_dev->dev->driver->owner;
 170
 171         if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
 172                 return -ENODEV;
 173
 174         sd->v4l2_dev = v4l2_dev;
 175         if (sd->internal_ops && sd->internal_ops->registered) {
 176                 err = sd->internal_ops->registered(sd);
 177                 if (err)
 178                         goto error_module;
 179         }
 180
 181         /* This just returns 0 if either of the two args is NULL */
 182         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
 183         if (err)
 184                 goto error_unregister;
 185
 186 #if defined(CONFIG_MEDIA_CONTROLLER)
 187         /* Register the entity. */
 188         if (v4l2_dev->mdev) {
 189                 err = media_device_register_entity(v4l2_dev->mdev, entity);
 190                 if (err < 0)
 191                         goto error_unregister;
 192         }
 193 #endif
 194
 195         spin_lock(&v4l2_dev->lock);
 196         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 197         spin_unlock(&v4l2_dev->lock);
 198
 199         return 0;
 200
 201 error_unregister:
 202         if (sd->internal_ops && sd->internal_ops->unregistered)
 203                 sd->internal_ops->unregistered(sd);
 204 error_module:
 205         if (!sd->owner_v4l2_dev)
 206                 module_put(sd->owner);
 207         sd->v4l2_dev = NULL;
 208         return err;
 209 }
 210 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 211
 212 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 213 {
 214         struct v4l2_subdev *sd = video_get_drvdata(vdev);
 215         sd->devnode = NULL;
 216         kfree(vdev);
 217 }
 218
 219 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 220 {
 221         struct video_device *vdev;
 222         struct v4l2_subdev *sd;
 223         int err;
 224
 225         /* Register a device node for every subdev marked with the
 226          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 227          */
 228         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 229                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 230                         continue;
 231
 232                 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 233                 if (!vdev) {
 234                         err = -ENOMEM;
 235                         goto clean_up;
 236                 }
 237
 238                 video_set_drvdata(vdev, sd);
 239                 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 240                 vdev->v4l2_dev = v4l2_dev;
 241                 vdev->fops = &v4l2_subdev_fops;
 242                 vdev->release = v4l2_device_release_subdev_node;
 243                 vdev->ctrl_handler = sd->ctrl_handler;
 244                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 245                                               sd->owner);
 246                 if (err < 0) {
 247                         kfree(vdev);
 248                         goto clean_up;
 249                 }
 250 #if defined(CONFIG_MEDIA_CONTROLLER)
 251                 sd->entity.info.v4l.major = VIDEO_MAJOR;
 252                 sd->entity.info.v4l.minor = vdev->minor;
 253 #endif
 254                 sd->devnode = vdev;
 255         }
 256         return 0;
 257
 258 clean_up:
 259         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 260                 if (!sd->devnode)
 261                         break;
 262                 video_unregister_device(sd->devnode);
 263         }
 264
 265         return err;
 266 }
 267 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 268
 269 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 270 {
 271         struct v4l2_device *v4l2_dev;
 272
 273         /* return if it isn't registered */
 274         if (sd == NULL || sd->v4l2_dev == NULL)
 275                 return;
 276
 277         v4l2_dev = sd->v4l2_dev;
 278
 279         spin_lock(&v4l2_dev->lock);
 280         list_del(&sd->list);
 281         spin_unlock(&v4l2_dev->lock);
 282
 283         if (sd->internal_ops && sd->internal_ops->unregistered)
 284                 sd->internal_ops->unregistered(sd);
 285         sd->v4l2_dev = NULL;
 286
 287 #if defined(CONFIG_MEDIA_CONTROLLER)
 288         if (v4l2_dev->mdev) {
 289                 media_entity_remove_links(&sd->entity);
 290                 media_device_unregister_entity(&sd->entity);
 291         }
 292 #endif
 293         video_unregister_device(sd->devnode);
 294         if (!sd->owner_v4l2_dev)
 295                 module_put(sd->owner);
 296 }
 297 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);