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 };
  55
  56 /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
  57    dev may be NULL in rare cases (ISA devices). In that case you
  58    must fill in the v4l2_dev->name field before calling this function. */
  59 int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
  60
  61 /* Optional function to initialize the name field of struct v4l2_device using
  62    the driver name and a driver-global atomic_t instance.
  63    This function will increment the instance counter and returns the instance
  64    value used in the name.
  65
  66    Example:
  67
  68    static atomic_t drv_instance = ATOMIC_INIT(0);
  69
  70    ...
  71
  72    instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
  73
  74    The first time this is called the name field will be set to foo0 and
  75    this function returns 0. If the name ends with a digit (e.g. cx18),
  76    then the name will be set to cx18-0 since cx180 looks really odd. */
  77 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
  78                                                 atomic_t *instance);
  79
  80 /* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
  81    Since the parent disappears this ensures that v4l2_dev doesn't have an
  82    invalid parent pointer. */
  83 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
  84
  85 /* Unregister all sub-devices and any other resources related to v4l2_dev. */
  86 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
  87
  88 /* Register a subdev with a v4l2 device. While registered the subdev module
  89    is marked as in-use. An error is returned if the module is no longer
  90    loaded when you attempt to register it. */
  91 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
  92                                                 struct v4l2_subdev *sd);
  93 /* Unregister a subdev with a v4l2 device. Can also be called if the subdev
  94    wasn't registered. In that case it will do nothing. */
  95 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
  96
  97 /* Iterate over all subdevs. */
  98 #define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
  99         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
 100
 101 /* Call the specified callback for all subdevs matching the condition.
 102    Ignore any errors. Note that you cannot add or delete a subdev
 103    while walking the subdevs list. */
 104 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)       \
 105         do {                                                            \
 106                 struct v4l2_subdev *sd;                                 \
 107                                                                         \
 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 /* Call the specified callback for all subdevs matching the condition.
 114    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
 115    return with that error code. Note that you cannot add or delete a
 116    subdev while walking the subdevs list. */
 117 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
 118 ({                                                                      \
 119         struct v4l2_subdev *sd;                                         \
 120         long err = 0;                                                   \
 121                                                                         \
 122         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) {           \
 123                 if ((cond) && sd->ops->o && sd->ops->o->f)              \
 124                         err = sd->ops->o->f(sd , ##args);               \
 125                 if (err && err != -ENOIOCTLCMD)                         \
 126                         break;                                          \
 127         }                                                               \
 128         (err == -ENOIOCTLCMD) ? 0 : err;                                \
 129 })
 130
 131 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 132    match them all). Ignore any errors. Note that you cannot add or delete
 133    a subdev while walking the subdevs list. */
 134 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)            \
 135         __v4l2_device_call_subdevs(v4l2_dev,                            \
 136                         !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 137
 138 /* Call the specified callback for all subdevs matching grp_id (if 0, then
 139    match them all). If the callback returns an error other than 0 or
 140    -ENOIOCTLCMD, then return with that error code. Note that you cannot
 141    add or delete a subdev while walking the subdevs list. */
 142 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)      \
 143         __v4l2_device_call_subdevs_until_err(v4l2_dev,                  \
 144                        !(grpid) || sd->grp_id == (grpid), o, f , ##args)
 145
 146 #endif