linux/include/media/v4l2-device.h
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   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/media-device.h>
  25#include <media/v4l2-subdev.h>
  26#include <media/v4l2-dev.h>
  27
  28/* Each instance of a V4L2 device should create the v4l2_device struct,
  29   either stand-alone or embedded in a larger struct.
  30
  31   It allows easy access to sub-devices (see v4l2-subdev.h) and provides
  32   basic V4L2 device-level support.
  33 */
  34
  35#define V4L2_DEVICE_NAME_SIZE (20 + 16)
  36
  37struct v4l2_ctrl_handler;
  38
  39struct v4l2_device {
  40        /* dev->driver_data points to this struct.
  41           Note: dev might be NULL if there is no parent device
  42           as is the case with e.g. ISA devices. */
  43        struct device *dev;
  44#if defined(CONFIG_MEDIA_CONTROLLER)
  45        struct media_device *mdev;
  46#endif
  47        /* used to keep track of the registered subdevs */
  48        struct list_head subdevs;
  49        /* lock this struct; can be used by the driver as well if this
  50           struct is embedded into a larger struct. */
  51        spinlock_t lock;
  52        /* unique device name, by default the driver name + bus ID */
  53        char name[V4L2_DEVICE_NAME_SIZE];
  54        /* notify callback called by some sub-devices. */
  55        void (*notify)(struct v4l2_subdev *sd,
  56                        unsigned int notification, void *arg);
  57        /* The control handler. May be NULL. */
  58        struct v4l2_ctrl_handler *ctrl_handler;
  59        /* Device's priority state */
  60        struct v4l2_prio_state prio;
  61        /* BKL replacement mutex. Temporary solution only. */
  62        struct mutex ioctl_lock;
  63        /* Keep track of the references to this struct. */
  64        struct kref ref;
  65        /* Release function that is called when the ref count goes to 0. */
  66        void (*release)(struct v4l2_device *v4l2_dev);
  67};
  68
  69static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
  70{
  71        kref_get(&v4l2_dev->ref);
  72}
  73
  74int v4l2_device_put(struct v4l2_device *v4l2_dev);
  75
  76/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
  77   dev may be NULL in rare cases (ISA devices). In that case you
  78   must fill in the v4l2_dev->name field before calling this function. */
  79int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
  80
  81/* Optional function to initialize the name field of struct v4l2_device using
  82   the driver name and a driver-global atomic_t instance.
  83   This function will increment the instance counter and returns the instance
  84   value used in the name.
  85
  86   Example:
  87
  88   static atomic_t drv_instance = ATOMIC_INIT(0);
  89
  90   ...
  91
  92   instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
  93
  94   The first time this is called the name field will be set to foo0 and
  95   this function returns 0. If the name ends with a digit (e.g. cx18),
  96   then the name will be set to cx18-0 since cx180 looks really odd. */
  97int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  98                                                atomic_t *instance);
  99
 100/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
 101   Since the parent disappears this ensures that v4l2_dev doesn't have an
 102   invalid parent pointer. */
 103void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
 104
 105/* Unregister all sub-devices and any other resources related to v4l2_dev. */
 106void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
 107
 108/* Register a subdev with a v4l2 device. While registered the subdev module
 109   is marked as in-use. An error is returned if the module is no longer
 110   loaded when you attempt to register it. */
 111int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 112                                                struct v4l2_subdev *sd);
 113/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
 114   wasn't registered. In that case it will do nothing. */
 115void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
 116
 117/* Register device nodes for all subdev of the v4l2 device that are marked with
 118 * the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 119 */
 120int __must_check
 121v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
 122
 123/* Iterate over all subdevs. */
 124#define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
 125        list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
 126
 127/* Call the specified callback for all subdevs matching the condition.
 128   Ignore any errors. Note that you cannot add or delete a subdev
 129   while walking the subdevs list. */
 130#define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...) \
 131        do {                                                            \
 132                list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)   \
 133                        if ((cond) && (sd)->ops->o && (sd)->ops->o->f)  \
 134                                (sd)->ops->o->f((sd) , ##args);         \
 135        } while (0)
 136
 137#define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)       \
 138        do {                                                            \
 139                struct v4l2_subdev *__sd;                               \
 140                                                                        \
 141                __v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,   \
 142                                                f , ##args);            \
 143        } while (0)
 144
 145/* Call the specified callback for all subdevs matching the condition.
 146   If the callback returns an error other than 0 or -ENOIOCTLCMD, then
 147   return with that error code. Note that you cannot add or delete a
 148   subdev while walking the subdevs list. */
 149#define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
 150({                                                                      \
 151        long __err = 0;                                                 \
 152                                                                        \
 153        list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {         \
 154                if ((cond) && (sd)->ops->o && (sd)->ops->o->f)          \
 155                        __err = (sd)->ops->o->f((sd) , ##args);         \
 156                if (__err && __err != -ENOIOCTLCMD)                     \
 157                        break;                                          \
 158        }                                                               \
 159        (__err == -ENOIOCTLCMD) ? 0 : __err;                            \
 160})
 161
 162#define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
 163({                                                                      \
 164        struct v4l2_subdev *__sd;                                       \
 165        __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o, \
 166                                                f , ##args);            \
 167})
 168
 169/* Call the specified callback for all subdevs matching grp_id (if 0, then
 170   match them all). Ignore any errors. Note that you cannot add or delete
 171   a subdev while walking the subdevs list. */
 172#define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)            \
 173        do {                                                            \
 174                struct v4l2_subdev *__sd;                               \
 175                                                                        \
 176                __v4l2_device_call_subdevs_p(v4l2_dev, __sd,            \
 177                        !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 178                        ##args);                                        \
 179        } while (0)
 180
 181/* Call the specified callback for all subdevs matching grp_id (if 0, then
 182   match them all). If the callback returns an error other than 0 or
 183   -ENOIOCTLCMD, then return with that error code. Note that you cannot
 184   add or delete a subdev while walking the subdevs list. */
 185#define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)      \
 186({                                                                      \
 187        struct v4l2_subdev *__sd;                                       \
 188        __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,          \
 189                        !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 190                        ##args);                                        \
 191})
 192
 193#endif
 194
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