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 #define V4L2_DEVICE_NAME_SIZE (20 + 16)
  29
  30 struct v4l2_ctrl_handler;
  31
  32 /**
  33  * struct v4l2_device - main struct to for V4L2 device drivers
  34  *
  35  * @dev: pointer to struct device.
  36  * @mdev: pointer to struct media_device
  37  * @subdevs: used to keep track of the registered subdevs
  38  * @lock: lock this struct; can be used by the driver as well
  39  *      if this struct is embedded into a larger struct.
  40  * @name: unique device name, by default the driver name + bus ID
  41  * @notify: notify callback called by some sub-devices.
  42  * @ctrl_handler: The control handler. May be NULL.
  43  * @prio: Device's priority state
  44  * @ref: Keep track of the references to this struct.
  45  * @release: Release function that is called when the ref count
  46  *      goes to 0.
  47  *
  48  * Each instance of a V4L2 device should create the v4l2_device struct,
  49  * either stand-alone or embedded in a larger struct.
  50  *
  51  * It allows easy access to sub-devices (see v4l2-subdev.h) and provides
  52  * basic V4L2 device-level support.
  53  *
  54  * .. note::
  55  *
  56  *    #) dev->driver_data points to this struct.
  57  *    #) dev might be NULL if there is no parent device
  58  */
  59
  60 struct v4l2_device {
  61         struct device *dev;
  62 #if defined(CONFIG_MEDIA_CONTROLLER)
  63         struct media_device *mdev;
  64 #endif
  65         struct list_head subdevs;
  66         spinlock_t lock;
  67         char name[V4L2_DEVICE_NAME_SIZE];
  68         void (*notify)(struct v4l2_subdev *sd,
  69                         unsigned int notification, void *arg);
  70         struct v4l2_ctrl_handler *ctrl_handler;
  71         struct v4l2_prio_state prio;
  72         struct kref ref;
  73         void (*release)(struct v4l2_device *v4l2_dev);
  74 };
  75
  76 /**
  77  * v4l2_device_get - gets a V4L2 device reference
  78  *
  79  * @v4l2_dev: pointer to struct v4l2_device
  80  *
  81  * This is an ancillary routine meant to increment the usage for the
  82  * struct v4l2_device pointed by @v4l2_dev.
  83  */
  84 static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
  85 {
  86         kref_get(&v4l2_dev->ref);
  87 }
  88
  89 /**
  90  * v4l2_device_put - putss a V4L2 device reference
  91  *
  92  * @v4l2_dev: pointer to struct v4l2_device
  93  *
  94  * This is an ancillary routine meant to decrement the usage for the
  95  * struct v4l2_device pointed by @v4l2_dev.
  96  */
  97 int v4l2_device_put(struct v4l2_device *v4l2_dev);
  98
  99 /**
 100  * v4l2_device_register -Initialize v4l2_dev and make dev->driver_data
 101  *      point to v4l2_dev.
 102  *
 103  * @dev: pointer to struct device
 104  * @v4l2_dev: pointer to struct v4l2_device
 105  *
 106  * .. note::
 107  *      dev may be NULL in rare cases (ISA devices).
 108  *      In such case the caller must fill in the v4l2_dev->name field
 109  *      before calling this function.
 110  */
 111 int __must_check v4l2_device_register(struct device *dev,
 112                                       struct v4l2_device *v4l2_dev);
 113
 114 /**
 115  * v4l2_device_set_name - Optional function to initialize the
 116  *      name field of struct v4l2_device
 117  *
 118  * @v4l2_dev: pointer to struct v4l2_device
 119  * @basename: base name for the device name
 120  * @instance: pointer to a static atomic_t var with the instance usage for
 121  *      the device driver.
 122  *
 123  * v4l2_device_set_name() initializes the name field of struct v4l2_device
 124  * using the driver name and a driver-global atomic_t instance.
 125  *
 126  * This function will increment the instance counter and returns the
 127  * instance value used in the name.
 128  *
 129  * Example:
 130  *
 131  *   static atomic_t drv_instance = ATOMIC_INIT(0);
 132  *
 133  *   ...
 134  *
 135  *   instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
 136  *
 137  * The first time this is called the name field will be set to foo0 and
 138  * this function returns 0. If the name ends with a digit (e.g. cx18),
 139  * then the name will be set to cx18-0 since cx180 would look really odd.
 140  */
 141 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
 142                          atomic_t *instance);
 143
 144 /**
 145  * v4l2_device_disconnect - Change V4L2 device state to disconnected.
 146  *
 147  * @v4l2_dev: pointer to struct v4l2_device
 148  *
 149  * Should be called when the USB parent disconnects.
 150  * Since the parent disappears, this ensures that v4l2_dev doesn't have
 151  * an invalid parent pointer.
 152  *
 153  * .. note:: This function sets v4l2_dev->dev to NULL.
 154  */
 155 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
 156
 157 /**
 158  *  v4l2_device_unregister - Unregister all sub-devices and any other
 159  *       resources related to v4l2_dev.
 160  *
 161  * @v4l2_dev: pointer to struct v4l2_device
 162  */
 163 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
 164
 165 /**
 166  * v4l2_device_register_subdev - Registers a subdev with a v4l2 device.
 167  *
 168  * @v4l2_dev: pointer to struct v4l2_device
 169  * @sd: pointer to struct v4l2_subdev
 170  *
 171  * While registered, the subdev module is marked as in-use.
 172  *
 173  * An error is returned if the module is no longer loaded on any attempts
 174  * to register it.
 175  */
 176 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 177                                              struct v4l2_subdev *sd);
 178
 179 /**
 180  * v4l2_device_unregister_subdev - Unregisters a subdev with a v4l2 device.
 181  *
 182  * @sd: pointer to struct v4l2_subdev
 183  *
 184  * .. note ::
 185  *
 186  *      Can also be called if the subdev wasn't registered. In such
 187  *      case, it will do nothing.
 188  */
 189 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
 190
 191 /**
 192  * v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs
 193  *      of the v4l2 device that are marked with
 194  *      the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 195  *
 196  * @v4l2_dev: pointer to struct v4l2_device
 197  */
 198 int __must_check
 199 v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
 200
 201 /**
 202  * v4l2_subdev_notify - Sends a notification to v4l2_device.
 203  *
 204  * @sd: pointer to struct v4l2_subdev
 205  * @notification: type of notification. Please notice that the notification
 206  *      type is driver-specific.
 207  * @arg: arguments for the notification. Those are specific to each
 208  *      notification type.
 209  */
 210 static inline void v4l2_subdev_notify(struct v4l2_subdev *sd,
 211                                       unsigned int notification, void *arg)
 212 {
 213         if (sd && sd->v4l2_dev && sd->v4l2_dev->notify)
 214                 sd->v4l2_dev->notify(sd, notification, arg);
 215 }
 216
 217 /* Iterate over all subdevs. */
 218 #define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
 219         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
 220
 221 /* Call the specified callback for all subdevs matching the condition.
 222    Ignore any errors. Note that you cannot add or delete a subdev
 223    while walking the subdevs list. */
 224 #define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...) \
 225         do {                                                            \
 226                 list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)   \
 227                         if ((cond) && (sd)->ops->o && (sd)->ops->o->f)  \
 228                                 (sd)->ops->o->f((sd) , ##args);         \
 229         } while (0)
 230
 231 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)       \
 232         do {                                                            \
 233                 struct v4l2_subdev *__sd;                               \
 234                                                                         \
 235                 __v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,   \
 236                                                 f , ##args);            \
 237         } while (0)
 238
 239 /* Call the specified callback for all subdevs matching the condition.
 240    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
 241    return with that error code. Note that you cannot add or delete a
 242    subdev while walking the subdevs list. */
 243 #define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
 244 ({                                                                      \
 245         long __err = 0;                                                 \
 246                                                                         \
 247         list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {         \
 248                 if ((cond) && (sd)->ops->o && (sd)->ops->o->f)          \
 249                         __err = (sd)->ops->o->f((sd) , ##args);         \
 250                 if (__err && __err != -ENOIOCTLCMD)                     \
 251                         break;                                          \
 252         }                                                               \
 253         (__err == -ENOIOCTLCMD) ? 0 : __err;                            \
 254 })
 255
 256 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
 257 ({                                                                      \
 258         struct v4l2_subdev *__sd;                                       \
 259         __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o, \
 260                                                 f , ##args);            \
 261 })
 262
 263 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 264    match them all). Ignore any errors. Note that you cannot add or delete
 265    a subdev while walking the subdevs list. */
 266 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)            \
 267         do {                                                            \
 268                 struct v4l2_subdev *__sd;                               \
 269                                                                         \
 270                 __v4l2_device_call_subdevs_p(v4l2_dev, __sd,            \
 271                         !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 272                         ##args);                                        \
 273         } while (0)
 274
 275 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 276    match them all). If the callback returns an error other than 0 or
 277    -ENOIOCTLCMD, then return with that error code. Note that you cannot
 278    add or delete a subdev while walking the subdevs list. */
 279 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)      \
 280 ({                                                                      \
 281         struct v4l2_subdev *__sd;                                       \
 282         __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,          \
 283                         !(grpid) || __sd->grp_id == (grpid), o, f ,     \
 284                         ##args);                                        \
 285 })
 286
 287 /*
 288  * Call the specified callback for all subdevs where grp_id & grpmsk != 0
 289  * (if grpmsk == `0, then match them all). Ignore any errors. Note that you
 290  * cannot add or delete a subdev while walking the subdevs list.
 291  */
 292 #define v4l2_device_mask_call_all(v4l2_dev, grpmsk, o, f, args...)      \
 293         do {                                                            \
 294                 struct v4l2_subdev *__sd;                               \
 295                                                                         \
 296                 __v4l2_device_call_subdevs_p(v4l2_dev, __sd,            \
 297                         !(grpmsk) || (__sd->grp_id & (grpmsk)), o, f ,  \
 298                         ##args);                                        \
 299         } while (0)
 300
 301 /*
 302  * Call the specified callback for all subdevs where grp_id & grpmsk != 0
 303  * (if grpmsk == `0, then match them all). If the callback returns an error
 304  * other than 0 or -ENOIOCTLCMD, then return with that error code. Note that
 305  * you cannot add or delete a subdev while walking the subdevs list.
 306  */
 307 #define v4l2_device_mask_call_until_err(v4l2_dev, grpmsk, o, f, args...) \
 308 ({                                                                      \
 309         struct v4l2_subdev *__sd;                                       \
 310         __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,          \
 311                         !(grpmsk) || (__sd->grp_id & (grpmsk)), o, f ,  \
 312                         ##args);                                        \
 313 })
 314
 315 /*
 316  * Does any subdev with matching grpid (or all if grpid == 0) has the given
 317  * op?
 318  */
 319 #define v4l2_device_has_op(v4l2_dev, grpid, o, f)                       \
 320 ({                                                                      \
 321         struct v4l2_subdev *__sd;                                       \
 322         bool __result = false;                                          \
 323         list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {         \
 324                 if ((grpid) && __sd->grp_id != (grpid))                 \
 325                         continue;                                       \
 326                 if (v4l2_subdev_has_op(__sd, o, f)) {                   \
 327                         __result = true;                                \
 328                         break;                                          \
 329                 }                                                       \
 330         }                                                               \
 331         __result;                                                       \
 332 })
 333
 334 /*
 335  * Does any subdev with matching grpmsk (or all if grpmsk == 0) has the given
 336  * op?
 337  */
 338 #define v4l2_device_mask_has_op(v4l2_dev, grpmsk, o, f)                 \
 339 ({                                                                      \
 340         struct v4l2_subdev *__sd;                                       \
 341         bool __result = false;                                          \
 342         list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {         \
 343                 if ((grpmsk) && !(__sd->grp_id & (grpmsk)))             \
 344                         continue;                                       \
 345                 if (v4l2_subdev_has_op(__sd, o, f)) {                   \
 346                         __result = true;                                \
 347                         break;                                          \
 348                 }                                                       \
 349         }                                                               \
 350         __result;                                                       \
 351 })
 352
 353 #endif