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         /* Keep track of the references to this struct. */
  62         struct kref ref;
  63         /* Release function that is called when the ref count goes to 0. */
  64         void (*release)(struct v4l2_device *v4l2_dev);
  65 };
  66
  67 static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
  68 {
  69         kref_get(&v4l2_dev->ref);
  70 }
  71
  72 int v4l2_device_put(struct v4l2_device *v4l2_dev);
  73
  74 /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
  75    dev may be NULL in rare cases (ISA devices). In that case you
  76    must fill in the v4l2_dev->name field before calling this function. */
  77 int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
  78
  79 /* Optional function to initialize the name field of struct v4l2_device using
  80    the driver name and a driver-global atomic_t instance.
  81    This function will increment the instance counter and returns the instance
  82    value used in the name.
  83
  84    Example:
  85
  86    static atomic_t drv_instance = ATOMIC_INIT(0);
  87
  88    ...
  89
  90    instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
  91
  92    The first time this is called the name field will be set to foo0 and
  93    this function returns 0. If the name ends with a digit (e.g. cx18),
  94    then the name will be set to cx18-0 since cx180 looks really odd. */
  95 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  96                                                 atomic_t *instance);
  97
  98 /* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
  99    Since the parent disappears this ensures that v4l2_dev doesn't have an
 100    invalid parent pointer. */
 101 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
 102
 103 /* Unregister all sub-devices and any other resources related to v4l2_dev. */
 104 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
 105
 106 /* Register a subdev with a v4l2 device. While registered the subdev module
 107    is marked as in-use. An error is returned if the module is no longer
 108    loaded when you attempt to register it. */
 109 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 110                                                 struct v4l2_subdev *sd);
 111 /* Unregister a subdev with a v4l2 device. Can also be called if the subdev
 112    wasn't registered. In that case it will do nothing. */
 113 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
 114
 115 /* Register device nodes for all subdev of the v4l2 device that are marked with
 116  * the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 117  */
 118 int __must_check
 119 v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
 120
 121 /* Send a notification to v4l2_device. */
 122 static inline void v4l2_subdev_notify(struct v4l2_subdev *sd,
 123                                       unsigned int notification, void *arg)
 124 {
 125         if (sd && sd->v4l2_dev && sd->v4l2_dev->notify)
 126                 sd->v4l2_dev->notify(sd, notification, arg);
 127 }
 128
 129 /* Iterate over all subdevs. */
 130 #define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
 131         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
 132
 133 /* Call the specified callback for all subdevs matching the condition.
 134    Ignore any errors. Note that you cannot add or delete a subdev
 135    while walking the subdevs list. */
 136 #define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...) \
 137         do {                                                            \
 138                 list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)   \
 139                         if ((cond) && (sd)->ops->o && (sd)->ops->o->f)  \
 140                                 (sd)->ops->o->f((sd) , ##args);         \
 141         } while (0)
 142
 143 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)       \
 144         do {                                                            \
 145                 struct v4l2_subdev *__sd;                               \
 146                                                                         \
 147                 __v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,   \
 148                                                 f , ##args);            \
 149         } while (0)
 150
 151 /* Call the specified callback for all subdevs matching the condition.
 152    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
 153    return with that error code. Note that you cannot add or delete a
 154    subdev while walking the subdevs list. */
 155 #define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
 156 ({                                                                      \
 157         long __err = 0;                                                 \
 158                                                                         \
 159         list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {         \
 160                 if ((cond) && (sd)->ops->o && (sd)->ops->o->f)          \
 161                         __err = (sd)->ops->o->f((sd) , ##args);         \
 162                 if (__err && __err != -ENOIOCTLCMD)                     \
 163                         break;                                          \
 164         }                                                               \
 165         (__err == -ENOIOCTLCMD) ? 0 : __err;                            \
 166 })
 167
 168 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
 169 ({                                                                      \
 170         struct v4l2_subdev *__sd;                                       \
 171         __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o, \
 172                                                 f , ##args);            \
 173 })
 174
 175 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 176    match them all). Ignore any errors. Note that you cannot add or delete
 177    a subdev while walking the subdevs list. */
 178 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)            \
 179         do {                                                            \
 180                 struct v4l2_subdev *__sd;                               \
 181                                                                         \
 182                 __v4l2_device_call_subdevs_p(v4l2_dev, __sd,            \
 183                         !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 184                         ##args);                                        \
 185         } while (0)
 186
 187 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 188    match them all). If the callback returns an error other than 0 or
 189    -ENOIOCTLCMD, then return with that error code. Note that you cannot
 190    add or delete a subdev while walking the subdevs list. */
 191 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)      \
 192 ({                                                                      \
 193         struct v4l2_subdev *__sd;                                       \
 194         __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,          \
 195                         !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 196                         ##args);                                        \
 197 })
 198
 199 #define v4l2_device_has_op(v4l2_dev, o, f)                              \
 200 ({                                                                      \
 201         struct v4l2_subdev *__sd;                                       \
 202         bool __result = false;                                          \
 203         list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {         \
 204                 if (v4l2_subdev_has_op(__sd, o, f)) {                   \
 205                         __result = true;                                \
 206                         break;                                          \
 207                 }                                                       \
 208         }                                                               \
 209         __result;                                                       \
 210 })
 211
 212 #endif