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/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
  37 struct v4l2_ctrl_handler;
  38
  39 struct 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
  69 static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
  70 {
  71         kref_get(&v4l2_dev->ref);
  72 }
  73
  74 int 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. */
  79 int __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. */
  97 int 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. */
 103 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
 104
 105 /* Unregister all sub-devices and any other resources related to v4l2_dev. */
 106 void 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. */
 111 int __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. */
 115 void 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  */
 120 int __must_check
 121 v4l2_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