kernel/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                         /* We need to unregister the i2c client explicitly.
 122                            We cannot rely on i2c_del_adapter to always
 123                            unregister clients for us, since if the i2c bus
 124                            is a platform bus, then it is never deleted. */
 125                         if (client)
 126                                 i2c_unregister_device(client);
 127                         continue;
 128                 }
 129 #endif
 130 #if defined(CONFIG_SPI)
 131                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 132                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 133
 134                         if (spi)
 135                                 spi_unregister_device(spi);
 136                         continue;
 137                 }
 138 #endif
 139         }
 140         /* Mark as unregistered, thus preventing duplicate unregistrations */
 141         v4l2_dev->name[0] = '\0';
 142 }
 143 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 144
 145 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 146                                 struct v4l2_subdev *sd)
 147 {
 148 #if defined(CONFIG_MEDIA_CONTROLLER)
 149         struct media_entity *entity = &sd->entity;
 150 #endif
 151         int err;
 152
 153         /* Check for valid input */
 154         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 155                 return -EINVAL;
 156
 157         /* Warn if we apparently re-register a subdev */
 158         WARN_ON(sd->v4l2_dev != NULL);
 159
 160         /*
 161          * The reason to acquire the module here is to avoid unloading
 162          * a module of sub-device which is registered to a media
 163          * device. To make it possible to unload modules for media
 164          * devices that also register sub-devices, do not
 165          * try_module_get() such sub-device owners.
 166          */
 167         sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
 168                 sd->owner == v4l2_dev->dev->driver->owner;
 169
 170         if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
 171                 return -ENODEV;
 172
 173         sd->v4l2_dev = v4l2_dev;
 174         if (sd->internal_ops && sd->internal_ops->registered) {
 175                 err = sd->internal_ops->registered(sd);
 176                 if (err)
 177                         goto error_module;
 178         }
 179
 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, NULL);
 182         if (err)
 183                 goto error_unregister;
 184
 185 #if defined(CONFIG_MEDIA_CONTROLLER)
 186         /* Register the entity. */
 187         if (v4l2_dev->mdev) {
 188                 err = media_device_register_entity(v4l2_dev->mdev, entity);
 189                 if (err < 0)
 190                         goto error_unregister;
 191         }
 192 #endif
 193
 194         spin_lock(&v4l2_dev->lock);
 195         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 196         spin_unlock(&v4l2_dev->lock);
 197
 198         return 0;
 199
 200 error_unregister:
 201         if (sd->internal_ops && sd->internal_ops->unregistered)
 202                 sd->internal_ops->unregistered(sd);
 203 error_module:
 204         if (!sd->owner_v4l2_dev)
 205                 module_put(sd->owner);
 206         sd->v4l2_dev = NULL;
 207         return err;
 208 }
 209 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 210
 211 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 212 {
 213         struct v4l2_subdev *sd = video_get_drvdata(vdev);
 214         sd->devnode = NULL;
 215         kfree(vdev);
 216 }
 217
 218 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 219 {
 220         struct video_device *vdev;
 221         struct v4l2_subdev *sd;
 222         int err;
 223
 224         /* Register a device node for every subdev marked with the
 225          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 226          */
 227         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 228                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 229                         continue;
 230
 231                 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 232                 if (!vdev) {
 233                         err = -ENOMEM;
 234                         goto clean_up;
 235                 }
 236
 237                 video_set_drvdata(vdev, sd);
 238                 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 239                 vdev->v4l2_dev = v4l2_dev;
 240                 vdev->fops = &v4l2_subdev_fops;
 241                 vdev->release = v4l2_device_release_subdev_node;
 242                 vdev->ctrl_handler = sd->ctrl_handler;
 243                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 244                                               sd->owner);
 245                 if (err < 0) {
 246                         kfree(vdev);
 247                         goto clean_up;
 248                 }
 249 #if defined(CONFIG_MEDIA_CONTROLLER)
 250                 sd->entity.info.dev.major = VIDEO_MAJOR;
 251                 sd->entity.info.dev.minor = vdev->minor;
 252 #endif
 253                 sd->devnode = vdev;
 254         }
 255         return 0;
 256
 257 clean_up:
 258         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 259                 if (!sd->devnode)
 260                         break;
 261                 video_unregister_device(sd->devnode);
 262         }
 263
 264         return err;
 265 }
 266 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 267
 268 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 269 {
 270         struct v4l2_device *v4l2_dev;
 271
 272         /* return if it isn't registered */
 273         if (sd == NULL || sd->v4l2_dev == NULL)
 274                 return;
 275
 276         v4l2_dev = sd->v4l2_dev;
 277
 278         spin_lock(&v4l2_dev->lock);
 279         list_del(&sd->list);
 280         spin_unlock(&v4l2_dev->lock);
 281
 282         if (sd->internal_ops && sd->internal_ops->unregistered)
 283                 sd->internal_ops->unregistered(sd);
 284         sd->v4l2_dev = NULL;
 285
 286 #if defined(CONFIG_MEDIA_CONTROLLER)
 287         if (v4l2_dev->mdev) {
 288                 media_entity_remove_links(&sd->entity);
 289                 media_device_unregister_entity(&sd->entity);
 290         }
 291 #endif
 292         video_unregister_device(sd->devnode);
 293         if (!sd->owner_v4l2_dev)
 294                 module_put(sd->owner);
 295 }
 296 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);