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