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