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
  30 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
  31 {
  32         if (v4l2_dev == NULL)
  33                 return -EINVAL;
  34
  35         INIT_LIST_HEAD(&v4l2_dev->subdevs);
  36         spin_lock_init(&v4l2_dev->lock);
  37         v4l2_dev->dev = dev;
  38         if (dev == NULL) {
  39                 /* If dev == NULL, then name must be filled in by the caller */
  40                 WARN_ON(!v4l2_dev->name[0]);
  41                 return 0;
  42         }
  43
  44         /* Set name to driver name + device name if it is empty. */
  45         if (!v4l2_dev->name[0])
  46                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
  47                         dev->driver->name, dev_name(dev));
  48         if (dev_get_drvdata(dev))
  49                 v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");
  50         dev_set_drvdata(dev, v4l2_dev);
  51         return 0;
  52 }
  53 EXPORT_SYMBOL_GPL(v4l2_device_register);
  54
  55 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  56                                                 atomic_t *instance)
  57 {
  58         int num = atomic_inc_return(instance) - 1;
  59         int len = strlen(basename);
  60
  61         if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
  62                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  63                                 "%s-%d", basename, num);
  64         else
  65                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
  66                                 "%s%d", basename, num);
  67         return num;
  68 }
  69 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
  70
  71 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
  72 {
  73         if (v4l2_dev->dev) {
  74                 dev_set_drvdata(v4l2_dev->dev, NULL);
  75                 v4l2_dev->dev = NULL;
  76         }
  77 }
  78 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
  79
  80 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
  81 {
  82         struct v4l2_subdev *sd, *next;
  83
  84         if (v4l2_dev == NULL)
  85                 return;
  86         v4l2_device_disconnect(v4l2_dev);
  87
  88         /* Unregister subdevs */
  89         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
  90                 v4l2_device_unregister_subdev(sd);
  91 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
  92                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
  93                         struct i2c_client *client = v4l2_get_subdevdata(sd);
  94
  95                         /* We need to unregister the i2c client explicitly.
  96                            We cannot rely on i2c_del_adapter to always
  97                            unregister clients for us, since if the i2c bus
  98                            is a platform bus, then it is never deleted. */
  99                         if (client)
 100                                 i2c_unregister_device(client);
 101                 }
 102 #endif
 103 #if defined(CONFIG_SPI)
 104                 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 105                         struct spi_device *spi = v4l2_get_subdevdata(sd);
 106
 107                         if (spi)
 108                                 spi_unregister_device(spi);
 109                 }
 110 #endif
 111         }
 112 }
 113 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 114
 115 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 116                                                 struct v4l2_subdev *sd)
 117 {
 118         /* Check for valid input */
 119         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 120                 return -EINVAL;
 121         /* Warn if we apparently re-register a subdev */
 122         WARN_ON(sd->v4l2_dev != NULL);
 123         if (!try_module_get(sd->owner))
 124                 return -ENODEV;
 125         sd->v4l2_dev = v4l2_dev;
 126         spin_lock(&v4l2_dev->lock);
 127         list_add_tail(&sd->list, &v4l2_dev->subdevs);
 128         spin_unlock(&v4l2_dev->lock);
 129         return 0;
 130 }
 131 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 132
 133 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 134 {
 135         /* return if it isn't registered */
 136         if (sd == NULL || sd->v4l2_dev == NULL)
 137                 return;
 138         spin_lock(&sd->v4l2_dev->lock);
 139         list_del(&sd->list);
 140         spin_unlock(&sd->v4l2_dev->lock);
 141         sd->v4l2_dev = NULL;
 142         module_put(sd->owner);
 143 }
 144 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);