include/media/v4l2-async.h

   1 /*
   2  * V4L2 asynchronous subdevice registration API
   3  *
   4  * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   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 version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #ifndef V4L2_ASYNC_H
  12 #define V4L2_ASYNC_H
  13
  14 #include <linux/list.h>
  15 #include <linux/mutex.h>
  16
  17 struct device;
  18 struct device_node;
  19 struct v4l2_device;
  20 struct v4l2_subdev;
  21 struct v4l2_async_notifier;
  22
  23 /* A random max subdevice number, used to allocate an array on stack */
  24 #define V4L2_MAX_SUBDEVS 128U
  25
  26 /**
  27  * enum v4l2_async_match_type - type of asynchronous subdevice logic to be used
  28  *      in order to identify a match
  29  *
  30  * @V4L2_ASYNC_MATCH_CUSTOM: Match will use the logic provided by &struct
  31  *      v4l2_async_subdev.match ops
  32  * @V4L2_ASYNC_MATCH_DEVNAME: Match will use the device name
  33  * @V4L2_ASYNC_MATCH_I2C: Match will check for I2C adapter ID and address
  34  * @V4L2_ASYNC_MATCH_OF: Match will use OF node
  35  *
  36  * This enum is used by the asyncrhronous sub-device logic to define the
  37  * algorithm that will be used to match an asynchronous device.
  38  */
  39 enum v4l2_async_match_type {
  40         V4L2_ASYNC_MATCH_CUSTOM,
  41         V4L2_ASYNC_MATCH_DEVNAME,
  42         V4L2_ASYNC_MATCH_I2C,
  43         V4L2_ASYNC_MATCH_OF,
  44 };
  45
  46 /**
  47  * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge
  48  *
  49  * @match_type: type of match that will be used
  50  * @match:      union of per-bus type matching data sets
  51  * @list:       used to link struct v4l2_async_subdev objects, waiting to be
  52  *              probed, to a notifier->waiting list
  53  */
  54 struct v4l2_async_subdev {
  55         enum v4l2_async_match_type match_type;
  56         union {
  57                 struct {
  58                         const struct device_node *node;
  59                 } of;
  60                 struct {
  61                         const char *name;
  62                 } device_name;
  63                 struct {
  64                         int adapter_id;
  65                         unsigned short address;
  66                 } i2c;
  67                 struct {
  68                         bool (*match)(struct device *,
  69                                       struct v4l2_async_subdev *);
  70                         void *priv;
  71                 } custom;
  72         } match;
  73
  74         /* v4l2-async core private: not to be used by drivers */
  75         struct list_head list;
  76 };
  77
  78 /**
  79  * struct v4l2_async_notifier - v4l2_device notifier data
  80  *
  81  * @num_subdevs: number of subdevices
  82  * @subdevs:    array of pointers to subdevice descriptors
  83  * @v4l2_dev:   pointer to struct v4l2_device
  84  * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
  85  * @done:       list of struct v4l2_subdev, already probed
  86  * @list:       member in a global list of notifiers
  87  * @bound:      a subdevice driver has successfully probed one of subdevices
  88  * @complete:   all subdevices have been probed successfully
  89  * @unbind:     a subdevice is leaving
  90  */
  91 struct v4l2_async_notifier {
  92         unsigned int num_subdevs;
  93         struct v4l2_async_subdev **subdevs;
  94         struct v4l2_device *v4l2_dev;
  95         struct list_head waiting;
  96         struct list_head done;
  97         struct list_head list;
  98         int (*bound)(struct v4l2_async_notifier *notifier,
  99                      struct v4l2_subdev *subdev,
 100                      struct v4l2_async_subdev *asd);
 101         int (*complete)(struct v4l2_async_notifier *notifier);
 102         void (*unbind)(struct v4l2_async_notifier *notifier,
 103                        struct v4l2_subdev *subdev,
 104                        struct v4l2_async_subdev *asd);
 105 };
 106
 107 /**
 108  * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
 109  *
 110  * @v4l2_dev: pointer to &struct v4l2_device
 111  * @notifier: pointer to &struct v4l2_async_notifier
 112  */
 113 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 114                                  struct v4l2_async_notifier *notifier);
 115
 116 /**
 117  * v4l2_async_notifier_unregister - unregisters a subdevice asynchronous notifier
 118  *
 119  * @notifier: pointer to &struct v4l2_async_notifier
 120  */
 121 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 122
 123 /**
 124  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
 125  *      subdevice framework
 126  *
 127  * @sd: pointer to &struct v4l2_subdev
 128  */
 129 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
 130
 131 /**
 132  * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
 133  *      subdevice framework
 134  *
 135  * @sd: pointer to &struct v4l2_subdev
 136  */
 137 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
 138 #endif