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