include/media/v4l2-device.h

   1 /*
   2     V4L2 device support header.
   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 #ifndef _V4L2_DEVICE_H
  22 #define _V4L2_DEVICE_H
  23
  24 #include <media/v4l2-subdev.h>
  25
  26 /* Each instance of a V4L2 device should create the v4l2_device struct,
  27    either stand-alone or embedded in a larger struct.
  28
  29    It allows easy access to sub-devices (see v4l2-subdev.h) and provides
  30    basic V4L2 device-level support.
  31  */
  32
  33 #define V4L2_DEVICE_NAME_SIZE (BUS_ID_SIZE + 16)
  34
  35 struct v4l2_device {
  36         /* dev->driver_data points to this struct */
  37         struct device *dev;
  38         /* used to keep track of the registered subdevs */
  39         struct list_head subdevs;
  40         /* lock this struct; can be used by the driver as well if this
  41            struct is embedded into a larger struct. */
  42         spinlock_t lock;
  43         /* unique device name, by default the driver name + bus ID */
  44         char name[V4L2_DEVICE_NAME_SIZE];
  45 };
  46
  47 /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev */
  48 int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
  49 /* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */
  50 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
  51
  52 /* Register a subdev with a v4l2 device. While registered the subdev module
  53    is marked as in-use. An error is returned if the module is no longer
  54    loaded when you attempt to register it. */
  55 int __must_check v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd);
  56 /* Unregister a subdev with a v4l2 device. Can also be called if the subdev
  57    wasn't registered. In that case it will do nothing. */
  58 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
  59
  60 /* Iterate over all subdevs. */
  61 #define v4l2_device_for_each_subdev(sd, dev)                            \
  62         list_for_each_entry(sd, &(dev)->subdevs, list)
  63
  64 /* Call the specified callback for all subdevs matching the condition.
  65    Ignore any errors. Note that you cannot add or delete a subdev
  66    while walking the subdevs list. */
  67 #define __v4l2_device_call_subdevs(dev, cond, o, f, args...)            \
  68         do {                                                            \
  69                 struct v4l2_subdev *sd;                                 \
  70                                                                         \
  71                 list_for_each_entry(sd, &(dev)->subdevs, list)          \
  72                         if ((cond) && sd->ops->o && sd->ops->o->f)      \
  73                                 sd->ops->o->f(sd , ##args);             \
  74         } while (0)
  75
  76 /* Call the specified callback for all subdevs matching the condition.
  77    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
  78    return with that error code. Note that you cannot add or delete a
  79    subdev while walking the subdevs list. */
  80 #define __v4l2_device_call_subdevs_until_err(dev, cond, o, f, args...)  \
  81 ({                                                                      \
  82         struct v4l2_subdev *sd;                                         \
  83         long err = 0;                                                   \
  84                                                                         \
  85         list_for_each_entry(sd, &(dev)->subdevs, list) {                \
  86                 if ((cond) && sd->ops->o && sd->ops->o->f)              \
  87                         err = sd->ops->o->f(sd , ##args);               \
  88                 if (err && err != -ENOIOCTLCMD)                         \
  89                         break;                                          \
  90         }                                                               \
  91         (err == -ENOIOCTLCMD) ? 0 : err;                                \
  92 })
  93
  94 /* Call the specified callback for all subdevs matching grp_id (if 0, then
  95    match them all). Ignore any errors. Note that you cannot add or delete
  96    a subdev while walking the subdevs list. */
  97 #define v4l2_device_call_all(dev, grpid, o, f, args...)                 \
  98         __v4l2_device_call_subdevs(dev,                                 \
  99                         !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 100
 101 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 102    match them all). If the callback returns an error other than 0 or
 103    -ENOIOCTLCMD, then return with that error code. Note that you cannot
 104    add or delete a subdev while walking the subdevs list. */
 105 #define v4l2_device_call_until_err(dev, grpid, o, f, args...)           \
 106         __v4l2_device_call_subdevs_until_err(dev,                       \
 107                        !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 108
 109 #endif