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         v4l2_prio_init(&v4l2_dev->prio);
  41         kref_init(&v4l2_dev->ref);
  42         get_device(dev);
  43         v4l2_dev->dev = dev;
  44         if (dev == NULL) {
  45                 /* If dev == NULL, then name must be filled in by the caller */
  46                 if (WARN_ON(!v4l2_dev->name[0]))
  47                         return -EINVAL;
  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         /* Just return if v4l2_dev is NULL or if it was already
 109          * unregistered before. */
 110         if (v4l2_dev == NULL || !v4l2_dev->name[0])
 111                 return;
 112         v4l2_device_disconnect(v4l2_dev);
 113
 114         /* Unregister subdevs */
 115         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 116                 v4l2_device_unregister_subdev(sd);
 117 #if IS_ENABLED(CONFIG_I2C)
 118                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 119                         struct i2c_client *client = v4l2_get_subdevdata(sd);
 120
 121                         /*
 122                          * We need to unregister the i2c client
 123                          * explicitly. We cannot rely on
 124                          * i2c_del_adapter to always unregister
 125                          * clients for us, since if the i2c bus is a
 126                          * platform bus, then it is never deleted.
 127                          *
 128                          * Device tree or ACPI based devices must not
 129                          * be unregistered as they have not been
 130                          * registered by us, and would not be
 131                          * re-created by just probing the V4L2 driver.
 132                          */
 133                         if (client &&
 134                             !client->dev.of_node && !client->dev.fwnode)
 135                                 i2c_unregister_device(client);
 136                         continue;
 137                 }
 138 #endif
 139 #if defined(CONFIG_SPI)
 140                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 141                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 142
 143                         if (spi && !spi->dev.of_node && !spi->dev.fwnode)
 144                                 spi_unregister_device(spi);
 145                         continue;
 146                 }
 147 #endif
 148         }
 149         /* Mark as unregistered, thus preventing duplicate unregistrations */
 150         v4l2_dev->name[0] = '\0';
 151 }
 152 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 153
 154 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 155                                 struct v4l2_subdev *sd)
 156 {
 157 #if defined(CONFIG_MEDIA_CONTROLLER)
 158         struct media_entity *entity = &sd->entity;
 159 #endif
 160         int err;
 161
 162         /* Check for valid input */
 163         if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
 164                 return -EINVAL;
 165
 166         /*
 167          * The reason to acquire the module here is to avoid unloading
 168          * a module of sub-device which is registered to a media
 169          * device. To make it possible to unload modules for media
 170          * devices that also register sub-devices, do not
 171          * try_module_get() such sub-device owners.
 172          */
 173         sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
 174                 sd->owner == v4l2_dev->dev->driver->owner;
 175
 176         if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
 177                 return -ENODEV;
 178
 179         sd->v4l2_dev = v4l2_dev;
 180         /* This just returns 0 if either of the two args is NULL */
 181         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
 182                                     NULL, true);
 183         if (err)
 184                 goto error_module;
 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_module;
 192         }
 193 #endif
 194
 195         if (sd->internal_ops && sd->internal_ops->registered) {
 196                 err = sd->internal_ops->registered(sd);
 197                 if (err)
 198                         goto error_unregister;
 199         }
 200
 201         spin_lock(&v4l2_dev->lock);
 202         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 203         spin_unlock(&v4l2_dev->lock);
 204
 205         return 0;
 206
 207 error_unregister:
 208 #if defined(CONFIG_MEDIA_CONTROLLER)
 209         media_device_unregister_entity(entity);
 210 #endif
 211 error_module:
 212         if (!sd->owner_v4l2_dev)
 213                 module_put(sd->owner);
 214         sd->v4l2_dev = NULL;
 215         return err;
 216 }
 217 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 218
 219 static void v4l2_subdev_release(struct v4l2_subdev *sd)
 220 {
 221         struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
 222
 223         if (sd->internal_ops && sd->internal_ops->release)
 224                 sd->internal_ops->release(sd);
 225         module_put(owner);
 226 }
 227
 228 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 229 {
 230         v4l2_subdev_release(video_get_drvdata(vdev));
 231         kfree(vdev);
 232 }
 233
 234 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 235 {
 236         struct video_device *vdev;
 237         struct v4l2_subdev *sd;
 238         int err;
 239
 240         /* Register a device node for every subdev marked with the
 241          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 242          */
 243         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 244                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 245                         continue;
 246
 247                 if (sd->devnode)
 248                         continue;
 249
 250                 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 251                 if (!vdev) {
 252                         err = -ENOMEM;
 253                         goto clean_up;
 254                 }
 255
 256                 video_set_drvdata(vdev, sd);
 257                 strscpy(vdev->name, sd->name, sizeof(vdev->name));
 258                 vdev->dev_parent = sd->dev;
 259                 vdev->v4l2_dev = v4l2_dev;
 260                 vdev->fops = &v4l2_subdev_fops;
 261                 vdev->release = v4l2_device_release_subdev_node;
 262                 vdev->ctrl_handler = sd->ctrl_handler;
 263                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 264                                               sd->owner);
 265                 if (err < 0) {
 266                         kfree(vdev);
 267                         goto clean_up;
 268                 }
 269                 sd->devnode = vdev;
 270 #if defined(CONFIG_MEDIA_CONTROLLER)
 271                 sd->entity.info.dev.major = VIDEO_MAJOR;
 272                 sd->entity.info.dev.minor = vdev->minor;
 273
 274                 /* Interface is created by __video_register_device() */
 275                 if (vdev->v4l2_dev->mdev) {
 276                         struct media_link *link;
 277
 278                         link = media_create_intf_link(&sd->entity,
 279                                                       &vdev->intf_devnode->intf,
 280                                                       MEDIA_LNK_FL_ENABLED |
 281                                                       MEDIA_LNK_FL_IMMUTABLE);
 282                         if (!link) {
 283                                 err = -ENOMEM;
 284                                 goto clean_up;
 285                         }
 286                 }
 287 #endif
 288         }
 289         return 0;
 290
 291 clean_up:
 292         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 293                 if (!sd->devnode)
 294                         break;
 295                 video_unregister_device(sd->devnode);
 296         }
 297
 298         return err;
 299 }
 300 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 301
 302 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 303 {
 304         struct v4l2_device *v4l2_dev;
 305
 306         /* return if it isn't registered */
 307         if (sd == NULL || sd->v4l2_dev == NULL)
 308                 return;
 309
 310         v4l2_dev = sd->v4l2_dev;
 311
 312         spin_lock(&v4l2_dev->lock);
 313         list_del(&sd->list);
 314         spin_unlock(&v4l2_dev->lock);
 315
 316         if (sd->internal_ops && sd->internal_ops->unregistered)
 317                 sd->internal_ops->unregistered(sd);
 318         sd->v4l2_dev = NULL;
 319
 320 #if defined(CONFIG_MEDIA_CONTROLLER)
 321         if (v4l2_dev->mdev) {
 322                 /*
 323                  * No need to explicitly remove links, as both pads and
 324                  * links are removed by the function below, in the right order
 325                  */
 326                 media_device_unregister_entity(&sd->entity);
 327         }
 328 #endif
 329         if (sd->devnode)
 330                 video_unregister_device(sd->devnode);
 331         else
 332                 v4l2_subdev_release(sd);
 333 }
 334 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);