drivers/media/media-device.c

   1 /*
   2  * Media device
   3  *
   4  * Copyright (C) 2010 Nokia Corporation
   5  *
   6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   7  *           Sakari Ailus <sakari.ailus@iki.fi>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/types.h>
  24 #include <linux/ioctl.h>
  25 #include <linux/media.h>
  26
  27 #include <media/media-device.h>
  28 #include <media/media-devnode.h>
  29 #include <media/media-entity.h>
  30
  31 /* -----------------------------------------------------------------------------
  32  * Userspace API
  33  */
  34
  35 static int media_device_open(struct file *filp)
  36 {
  37         return 0;
  38 }
  39
  40 static int media_device_close(struct file *filp)
  41 {
  42         return 0;
  43 }
  44
  45 static int media_device_get_info(struct media_device *dev,
  46                                  struct media_device_info __user *__info)
  47 {
  48         struct media_device_info info;
  49
  50         memset(&info, 0, sizeof(info));
  51
  52         strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
  53         strlcpy(info.model, dev->model, sizeof(info.model));
  54         strlcpy(info.serial, dev->serial, sizeof(info.serial));
  55         strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));
  56
  57         info.media_version = MEDIA_API_VERSION;
  58         info.hw_revision = dev->hw_revision;
  59         info.driver_version = dev->driver_version;
  60
  61         return copy_to_user(__info, &info, sizeof(*__info));
  62 }
  63
  64 static long media_device_ioctl(struct file *filp, unsigned int cmd,
  65                                unsigned long arg)
  66 {
  67         struct media_devnode *devnode = media_devnode_data(filp);
  68         struct media_device *dev = to_media_device(devnode);
  69         long ret;
  70
  71         switch (cmd) {
  72         case MEDIA_IOC_DEVICE_INFO:
  73                 ret = media_device_get_info(dev,
  74                                 (struct media_device_info __user *)arg);
  75                 break;
  76
  77         default:
  78                 ret = -ENOIOCTLCMD;
  79         }
  80
  81         return ret;
  82 }
  83
  84 static const struct media_file_operations media_device_fops = {
  85         .owner = THIS_MODULE,
  86         .open = media_device_open,
  87         .ioctl = media_device_ioctl,
  88         .release = media_device_close,
  89 };
  90
  91 /* -----------------------------------------------------------------------------
  92  * sysfs
  93  */
  94
  95 static ssize_t show_model(struct device *cd,
  96                           struct device_attribute *attr, char *buf)
  97 {
  98         struct media_device *mdev = to_media_device(to_media_devnode(cd));
  99
 100         return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
 101 }
 102
 103 static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
 104
 105 /* -----------------------------------------------------------------------------
 106  * Registration/unregistration
 107  */
 108
 109 static void media_device_release(struct media_devnode *mdev)
 110 {
 111 }
 112
 113 /**
 114  * media_device_register - register a media device
 115  * @mdev:       The media device
 116  *
 117  * The caller is responsible for initializing the media device before
 118  * registration. The following fields must be set:
 119  *
 120  * - dev must point to the parent device
 121  * - model must be filled with the device model name
 122  */
 123 int __must_check media_device_register(struct media_device *mdev)
 124 {
 125         int ret;
 126
 127         if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
 128                 return -EINVAL;
 129
 130         mdev->entity_id = 1;
 131         INIT_LIST_HEAD(&mdev->entities);
 132         spin_lock_init(&mdev->lock);
 133         mutex_init(&mdev->graph_mutex);
 134
 135         /* Register the device node. */
 136         mdev->devnode.fops = &media_device_fops;
 137         mdev->devnode.parent = mdev->dev;
 138         mdev->devnode.release = media_device_release;
 139         ret = media_devnode_register(&mdev->devnode);
 140         if (ret < 0)
 141                 return ret;
 142
 143         ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
 144         if (ret < 0) {
 145                 media_devnode_unregister(&mdev->devnode);
 146                 return ret;
 147         }
 148
 149         return 0;
 150 }
 151 EXPORT_SYMBOL_GPL(media_device_register);
 152
 153 /**
 154  * media_device_unregister - unregister a media device
 155  * @mdev:       The media device
 156  *
 157  */
 158 void media_device_unregister(struct media_device *mdev)
 159 {
 160         struct media_entity *entity;
 161         struct media_entity *next;
 162
 163         list_for_each_entry_safe(entity, next, &mdev->entities, list)
 164                 media_device_unregister_entity(entity);
 165
 166         device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 167         media_devnode_unregister(&mdev->devnode);
 168 }
 169 EXPORT_SYMBOL_GPL(media_device_unregister);
 170
 171 /**
 172  * media_device_register_entity - Register an entity with a media device
 173  * @mdev:       The media device
 174  * @entity:     The entity
 175  */
 176 int __must_check media_device_register_entity(struct media_device *mdev,
 177                                               struct media_entity *entity)
 178 {
 179         /* Warn if we apparently re-register an entity */
 180         WARN_ON(entity->parent != NULL);
 181         entity->parent = mdev;
 182
 183         spin_lock(&mdev->lock);
 184         if (entity->id == 0)
 185                 entity->id = mdev->entity_id++;
 186         else
 187                 mdev->entity_id = max(entity->id + 1, mdev->entity_id);
 188         list_add_tail(&entity->list, &mdev->entities);
 189         spin_unlock(&mdev->lock);
 190
 191         return 0;
 192 }
 193 EXPORT_SYMBOL_GPL(media_device_register_entity);
 194
 195 /**
 196  * media_device_unregister_entity - Unregister an entity
 197  * @entity:     The entity
 198  *
 199  * If the entity has never been registered this function will return
 200  * immediately.
 201  */
 202 void media_device_unregister_entity(struct media_entity *entity)
 203 {
 204         struct media_device *mdev = entity->parent;
 205
 206         if (mdev == NULL)
 207                 return;
 208
 209         spin_lock(&mdev->lock);
 210         list_del(&entity->list);
 211         spin_unlock(&mdev->lock);
 212         entity->parent = NULL;
 213 }
 214 EXPORT_SYMBOL_GPL(media_device_unregister_entity);