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_dev->dev = dev;
  40         if (dev == NULL) {
  41                 /* If dev == NULL, then name must be filled in by the caller */
  42                 WARN_ON(!v4l2_dev->name[0]);
  43                 return 0;
  44         }
  45
  46         /* Set name to driver name + device name if it is empty. */
  47         if (!v4l2_dev->name[0])
  48                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  49                         dev->driver->name, dev_name(dev));
  50         if (dev_get_drvdata(dev))
  51                 v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");
  52         dev_set_drvdata(dev, v4l2_dev);
  53         return 0;
  54 }
  55 EXPORT_SYMBOL_GPL(v4l2_device_register);
  56
  57 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  58                                                 atomic_t *instance)
  59 {
  60         int num = atomic_inc_return(instance) - 1;
  61         int len = strlen(basename);
  62
  63         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  64                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  65                                 "%s-%d", basename, num);
  66         else
  67                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  68                                 "%s%d", basename, num);
  69         return num;
  70 }
  71 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  72
  73 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  74 {
  75         if (v4l2_dev->dev) {
  76                 dev_set_drvdata(v4l2_dev->dev, NULL);
  77                 v4l2_dev->dev = NULL;
  78         }
  79 }
  80 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
  81
  82 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
  83 {
  84         struct v4l2_subdev *sd, *next;
  85
  86         if (v4l2_dev == NULL)
  87                 return;
  88         v4l2_device_disconnect(v4l2_dev);
  89
  90         /* Unregister subdevs */
  91         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
  92                 v4l2_device_unregister_subdev(sd);
  93 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
  94                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
  95                         struct i2c_client *client = v4l2_get_subdevdata(sd);
  96
  97                         /* We need to unregister the i2c client explicitly.
  98                            We cannot rely on i2c_del_adapter to always
  99                            unregister clients for us, since if the i2c bus
 100                            is a platform bus, then it is never deleted. */
 101                         if (client)
 102                                 i2c_unregister_device(client);
 103                         continue;
 104                 }
 105 #endif
 106 #if defined(CONFIG_SPI)
 107                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 108                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 109
 110                         if (spi)
 111                                 spi_unregister_device(spi);
 112                         continue;
 113                 }
 114 #endif
 115         }
 116 }
 117 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 118
 119 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 120                                                 struct v4l2_subdev *sd)
 121 {
 122         int err;
 123
 124         /* Check for valid input */
 125         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 126                 return -EINVAL;
 127         /* Warn if we apparently re-register a subdev */
 128         WARN_ON(sd->v4l2_dev != NULL);
 129         if (!try_module_get(sd->owner))
 130                 return -ENODEV;
 131         sd->v4l2_dev = v4l2_dev;
 132         if (sd->internal_ops && sd->internal_ops->registered) {
 133                 err = sd->internal_ops->registered(sd);
 134                 if (err)
 135                         return err;
 136         }
 137         /* This just returns 0 if either of the two args is NULL */
 138         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
 139         if (err) {
 140                 if (sd->internal_ops && sd->internal_ops->unregistered)
 141                         sd->internal_ops->unregistered(sd);
 142                 return err;
 143         }
 144         spin_lock(&v4l2_dev->lock);
 145         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 146         spin_unlock(&v4l2_dev->lock);
 147         return 0;
 148 }
 149 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 150
 151 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 152 {
 153         /* return if it isn't registered */
 154         if (sd == NULL || sd->v4l2_dev == NULL)
 155                 return;
 156         spin_lock(&sd->v4l2_dev->lock);
 157         list_del(&sd->list);
 158         spin_unlock(&sd->v4l2_dev->lock);
 159         if (sd->internal_ops && sd->internal_ops->unregistered)
 160                 sd->internal_ops->unregistered(sd);
 161         sd->v4l2_dev = NULL;
 162         module_put(sd->owner);
 163 }
 164 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);