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 (20 + 16)
  34
  35 struct v4l2_device {
  36         /* dev->driver_data points to this struct.
  37            Note: dev might be NULL if there is no parent device
  38            as is the case with e.g. ISA devices. */
  39         struct device *dev;
  40         /* used to keep track of the registered subdevs */
  41         struct list_head subdevs;
  42         /* lock this struct; can be used by the driver as well if this
  43            struct is embedded into a larger struct. */
  44         spinlock_t lock;
  45         /* unique device name, by default the driver name + bus ID */
  46         char name[V4L2_DEVICE_NAME_SIZE];
  47         /* notify callback called by some sub-devices. */
  48         void (*notify)(struct v4l2_subdev *sd,
  49                         unsigned int notification, void *arg);
  50 };
  51
  52 /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
  53    dev may be NULL in rare cases (ISA devices). In that case you
  54    must fill in the v4l2_dev->name field before calling this function. */
  55 int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
  56
  57 /* Optional function to initialize the name field of struct v4l2_device using
  58    the driver name and a driver-global atomic_t instance.
  59    This function will increment the instance counter and returns the instance
  60    value used in the name.
  61
  62    Example:
  63
  64    static atomic_t drv_instance = ATOMIC_INIT(0);
  65
  66    ...
  67
  68    instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
  69
  70    The first time this is called the name field will be set to foo0 and
  71    this function returns 0. If the name ends with a digit (e.g. cx18),
  72    then the name will be set to cx18-0 since cx180 looks really odd. */
  73 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  74                                                 atomic_t *instance);
  75
  76 /* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
  77    Since the parent disappears this ensures that v4l2_dev doesn't have an
  78    invalid parent pointer. */
  79 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
  80
  81 /* Unregister all sub-devices and any other resources related to v4l2_dev. */
  82 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
  83
  84 /* Register a subdev with a v4l2 device. While registered the subdev module
  85    is marked as in-use. An error is returned if the module is no longer
  86    loaded when you attempt to register it. */
  87 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
  88                                                 struct v4l2_subdev *sd);
  89 /* Unregister a subdev with a v4l2 device. Can also be called if the subdev
  90    wasn't registered. In that case it will do nothing. */
  91 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
  92
  93 /* Iterate over all subdevs. */
  94 #define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
  95         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
  96
  97 /* Call the specified callback for all subdevs matching the condition.
  98    Ignore any errors. Note that you cannot add or delete a subdev
  99    while walking the subdevs list. */
 100 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)       \
 101         do {                                                            \
 102                 struct v4l2_subdev *sd;                                 \
 103                                                                         \
 104                 list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)     \
 105                         if ((cond) && sd->ops->o && sd->ops->o->f)      \
 106                                 sd->ops->o->f(sd , ##args);             \
 107         } while (0)
 108
 109 /* Call the specified callback for all subdevs matching the condition.
 110    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
 111    return with that error code. Note that you cannot add or delete a
 112    subdev while walking the subdevs list. */
 113 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
 114 ({                                                                      \
 115         struct v4l2_subdev *sd;                                         \
 116         long err = 0;                                                   \
 117                                                                         \
 118         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) {           \
 119                 if ((cond) && sd->ops->o && sd->ops->o->f)              \
 120                         err = sd->ops->o->f(sd , ##args);               \
 121                 if (err && err != -ENOIOCTLCMD)                         \
 122                         break;                                          \
 123         }                                                               \
 124         (err == -ENOIOCTLCMD) ? 0 : err;                                \
 125 })
 126
 127 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 128    match them all). Ignore any errors. Note that you cannot add or delete
 129    a subdev while walking the subdevs list. */
 130 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)            \
 131         __v4l2_device_call_subdevs(v4l2_dev,                            \
 132                         !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 133
 134 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 135    match them all). If the callback returns an error other than 0 or
 136    -ENOIOCTLCMD, then return with that error code. Note that you cannot
 137    add or delete a subdev while walking the subdevs list. */
 138 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)      \
 139         __v4l2_device_call_subdevs_until_err(v4l2_dev,                  \
 140                        !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 141
 142 #endif