linux/drivers/media/v4l2-core/v4l2-device.c
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   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
  33int 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}
  59EXPORT_SYMBOL_GPL(v4l2_device_register);
  60
  61static 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
  70int v4l2_device_put(struct v4l2_device *v4l2_dev)
  71{
  72        return kref_put(&v4l2_dev->ref, v4l2_device_release);
  73}
  74EXPORT_SYMBOL_GPL(v4l2_device_put);
  75
  76int 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}
  90EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  91
  92void 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}
 102EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
 103
 104void 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}
 152EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 153
 154int 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, NULL);
 182        if (err)
 183                goto error_module;
 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_module;
 191        }
 192#endif
 193
 194        if (sd->internal_ops && sd->internal_ops->registered) {
 195                err = sd->internal_ops->registered(sd);
 196                if (err)
 197                        goto error_unregister;
 198        }
 199
 200        spin_lock(&v4l2_dev->lock);
 201        list_add_tail(&sd->list, &v4l2_dev->subdevs);
 202        spin_unlock(&v4l2_dev->lock);
 203
 204        return 0;
 205
 206error_unregister:
 207#if defined(CONFIG_MEDIA_CONTROLLER)
 208        media_device_unregister_entity(entity);
 209#endif
 210error_module:
 211        if (!sd->owner_v4l2_dev)
 212                module_put(sd->owner);
 213        sd->v4l2_dev = NULL;
 214        return err;
 215}
 216EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 217
 218static void v4l2_device_release_subdev_node(struct video_device *vdev)
 219{
 220        struct v4l2_subdev *sd = video_get_drvdata(vdev);
 221        sd->devnode = NULL;
 222        kfree(vdev);
 223}
 224
 225int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 226{
 227        struct video_device *vdev;
 228        struct v4l2_subdev *sd;
 229        int err;
 230
 231        /* Register a device node for every subdev marked with the
 232         * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 233         */
 234        list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 235                if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 236                        continue;
 237
 238                if (sd->devnode)
 239                        continue;
 240
 241                vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 242                if (!vdev) {
 243                        err = -ENOMEM;
 244                        goto clean_up;
 245                }
 246
 247                video_set_drvdata(vdev, sd);
 248                strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 249                vdev->v4l2_dev = v4l2_dev;
 250                vdev->fops = &v4l2_subdev_fops;
 251                vdev->release = v4l2_device_release_subdev_node;
 252                vdev->ctrl_handler = sd->ctrl_handler;
 253                err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 254                                              sd->owner);
 255                if (err < 0) {
 256                        kfree(vdev);
 257                        goto clean_up;
 258                }
 259                sd->devnode = vdev;
 260#if defined(CONFIG_MEDIA_CONTROLLER)
 261                sd->entity.info.dev.major = VIDEO_MAJOR;
 262                sd->entity.info.dev.minor = vdev->minor;
 263
 264                /* Interface is created by __video_register_device() */
 265                if (vdev->v4l2_dev->mdev) {
 266                        struct media_link *link;
 267
 268                        link = media_create_intf_link(&sd->entity,
 269                                                      &vdev->intf_devnode->intf,
 270                                                      MEDIA_LNK_FL_ENABLED);
 271                        if (!link) {
 272                                err = -ENOMEM;
 273                                goto clean_up;
 274                        }
 275                }
 276#endif
 277        }
 278        return 0;
 279
 280clean_up:
 281        list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 282                if (!sd->devnode)
 283                        break;
 284                video_unregister_device(sd->devnode);
 285        }
 286
 287        return err;
 288}
 289EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
 290
 291void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 292{
 293        struct v4l2_device *v4l2_dev;
 294
 295        /* return if it isn't registered */
 296        if (sd == NULL || sd->v4l2_dev == NULL)
 297                return;
 298
 299        v4l2_dev = sd->v4l2_dev;
 300
 301        spin_lock(&v4l2_dev->lock);
 302        list_del(&sd->list);
 303        spin_unlock(&v4l2_dev->lock);
 304
 305        if (sd->internal_ops && sd->internal_ops->unregistered)
 306                sd->internal_ops->unregistered(sd);
 307        sd->v4l2_dev = NULL;
 308
 309#if defined(CONFIG_MEDIA_CONTROLLER)
 310        if (v4l2_dev->mdev) {
 311                /*
 312                 * No need to explicitly remove links, as both pads and
 313                 * links are removed by the function below, in the right order
 314                 */
 315                media_device_unregister_entity(&sd->entity);
 316        }
 317#endif
 318        video_unregister_device(sd->devnode);
 319        if (!sd->owner_v4l2_dev)
 320                module_put(sd->owner);
 321}
 322EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
 323