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