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 #if defined(CONFIG_SPI)
  25 #include <linux/spi/spi.h>
  26 #endif
  27 #include <linux/videodev2.h>
  28 #include <media/v4l2-device.h>
  29 #include <media/v4l2-ctrls.h>
  30
  31 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
  32 {
  33         if (v4l2_dev == NULL)
  34                 return -EINVAL;
  35
  36         INIT_LIST_HEAD(&v4l2_dev->subdevs);
  37         spin_lock_init(&v4l2_dev->lock);
  38         mutex_init(&v4l2_dev->ioctl_lock);
  39         v4l2_prio_init(&v4l2_dev->prio);
  40         kref_init(&v4l2_dev->ref);
  41         get_device(dev);
  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         put_device(v4l2_dev->dev);
  98         v4l2_dev->dev = NULL;
  99 }
 100 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
 101
 102 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 103 {
 104         struct v4l2_subdev *sd, *next;
 105
 106         if (v4l2_dev == NULL)
 107                 return;
 108         v4l2_device_disconnect(v4l2_dev);
 109
 110         /* Unregister subdevs */
 111         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 112                 v4l2_device_unregister_subdev(sd);
 113 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
 114                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 115                         struct i2c_client *client = v4l2_get_subdevdata(sd);
 116
 117                         /* We need to unregister the i2c client explicitly.
 118                            We cannot rely on i2c_del_adapter to always
 119                            unregister clients for us, since if the i2c bus
 120                            is a platform bus, then it is never deleted. */
 121                         if (client)
 122                                 i2c_unregister_device(client);
 123                         continue;
 124                 }
 125 #endif
 126 #if defined(CONFIG_SPI)
 127                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 128                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 129
 130                         if (spi)
 131                                 spi_unregister_device(spi);
 132                         continue;
 133                 }
 134 #endif
 135         }
 136 }
 137 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 138
 139 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 140                                 struct v4l2_subdev *sd)
 141 {
 142 #if defined(CONFIG_MEDIA_CONTROLLER)
 143         struct media_entity *entity = &sd->entity;
 144 #endif
 145         int err;
 146
 147         /* Check for valid input */
 148         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 149                 return -EINVAL;
 150
 151         /* Warn if we apparently re-register a subdev */
 152         WARN_ON(sd->v4l2_dev != NULL);
 153
 154         if (!try_module_get(sd->owner))
 155                 return -ENODEV;
 156
 157         sd->v4l2_dev = v4l2_dev;
 158         if (sd->internal_ops && sd->internal_ops->registered) {
 159                 err = sd->internal_ops->registered(sd);
 160                 if (err) {
 161                         module_put(sd->owner);
 162                         return err;
 163                 }
 164         }
 165
 166         /* This just returns 0 if either of the two args is NULL */
 167         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
 168         if (err) {
 169                 if (sd->internal_ops && sd->internal_ops->unregistered)
 170                         sd->internal_ops->unregistered(sd);
 171                 module_put(sd->owner);
 172                 return err;
 173         }
 174
 175 #if defined(CONFIG_MEDIA_CONTROLLER)
 176         /* Register the entity. */
 177         if (v4l2_dev->mdev) {
 178                 err = media_device_register_entity(v4l2_dev->mdev, entity);
 179                 if (err < 0) {
 180                         if (sd->internal_ops && sd->internal_ops->unregistered)
 181                                 sd->internal_ops->unregistered(sd);
 182                         module_put(sd->owner);
 183                         return err;
 184                 }
 185         }
 186 #endif
 187
 188         spin_lock(&v4l2_dev->lock);
 189         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 190         spin_unlock(&v4l2_dev->lock);
 191
 192         return 0;
 193 }
 194 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 195
 196 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 197 {
 198         struct video_device *vdev;
 199         struct v4l2_subdev *sd;
 200         int err;
 201
 202         /* Register a device node for every subdev marked with the
 203          * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 204          */
 205         list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 206                 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 207                         continue;
 208
 209                 vdev = &sd->devnode;
 210                 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 211                 vdev->v4l2_dev = v4l2_dev;
 212                 vdev->fops = &v4l2_subdev_fops;
 213                 vdev->release = video_device_release_empty;
 214                 vdev->ctrl_handler = sd->ctrl_handler;
 215                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 216                                               sd->owner);
 217                 if (err < 0)
 218                         return err;
 219 #if defined(CONFIG_MEDIA_CONTROLLER)
 220                 sd->entity.v4l.major = VIDEO_MAJOR;
 221                 sd->entity.v4l.minor = vdev->minor;
 222 #endif
 223         }
 224         return 0;
 225 }
 226 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 227
 228 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 229 {
 230         struct v4l2_device *v4l2_dev;
 231
 232         /* return if it isn't registered */
 233         if (sd == NULL || sd->v4l2_dev == NULL)
 234                 return;
 235
 236         v4l2_dev = sd->v4l2_dev;
 237
 238         spin_lock(&v4l2_dev->lock);
 239         list_del(&sd->list);
 240         spin_unlock(&v4l2_dev->lock);
 241
 242         if (sd->internal_ops && sd->internal_ops->unregistered)
 243                 sd->internal_ops->unregistered(sd);
 244         sd->v4l2_dev = NULL;
 245
 246 #if defined(CONFIG_MEDIA_CONTROLLER)
 247         if (v4l2_dev->mdev)
 248                 media_device_unregister_entity(&sd->entity);
 249 #endif
 250         video_unregister_device(&sd->devnode);
 251         module_put(sd->owner);
 252 }
 253 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);