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_FWNODE: Match will use firmware 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_FWNODE,
  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  * When this struct is used as a member in a driver specific struct,
  55  * the driver specific struct shall contain the &struct
  56  * v4l2_async_subdev as its first member.
  57  */
  58 struct v4l2_async_subdev {
  59         enum v4l2_async_match_type match_type;
  60         union {
  61                 struct {
  62                         struct fwnode_handle *fwnode;
  63                 } fwnode;
  64                 struct {
  65                         const char *name;
  66                 } device_name;
  67                 struct {
  68                         int adapter_id;
  69                         unsigned short address;
  70                 } i2c;
  71                 struct {
  72                         bool (*match)(struct device *,
  73                                       struct v4l2_async_subdev *);
  74                         void *priv;
  75                 } custom;
  76         } match;
  77
  78         /* v4l2-async core private: not to be used by drivers */
  79         struct list_head list;
  80 };
  81
  82 /**
  83  * struct v4l2_async_notifier_operations - Asynchronous V4L2 notifier operations
  84  * @bound:      a subdevice driver has successfully probed one of the subdevices
  85  * @complete:   All subdevices have been probed successfully. The complete
  86  *              callback is only executed for the root notifier.
  87  * @unbind:     a subdevice is leaving
  88  */
  89 struct v4l2_async_notifier_operations {
  90         int (*bound)(struct v4l2_async_notifier *notifier,
  91                      struct v4l2_subdev *subdev,
  92                      struct v4l2_async_subdev *asd);
  93         int (*complete)(struct v4l2_async_notifier *notifier);
  94         void (*unbind)(struct v4l2_async_notifier *notifier,
  95                        struct v4l2_subdev *subdev,
  96                        struct v4l2_async_subdev *asd);
  97 };
  98
  99 /**
 100  * struct v4l2_async_notifier - v4l2_device notifier data
 101  *
 102  * @ops:        notifier operations
 103  * @num_subdevs: number of subdevices used in the subdevs array
 104  * @max_subdevs: number of subdevices allocated in the subdevs array
 105  * @subdevs:    array of pointers to subdevice descriptors
 106  * @v4l2_dev:   v4l2_device of the root notifier, NULL otherwise
 107  * @sd:         sub-device that registered the notifier, NULL otherwise
 108  * @parent:     parent notifier
 109  * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
 110  * @done:       list of struct v4l2_subdev, already probed
 111  * @list:       member in a global list of notifiers
 112  */
 113 struct v4l2_async_notifier {
 114         const struct v4l2_async_notifier_operations *ops;
 115         unsigned int num_subdevs;
 116         unsigned int max_subdevs;
 117         struct v4l2_async_subdev **subdevs;
 118         struct v4l2_device *v4l2_dev;
 119         struct v4l2_subdev *sd;
 120         struct v4l2_async_notifier *parent;
 121         struct list_head waiting;
 122         struct list_head done;
 123         struct list_head list;
 124 };
 125
 126 /**
 127  * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
 128  *
 129  * @v4l2_dev: pointer to &struct v4l2_device
 130  * @notifier: pointer to &struct v4l2_async_notifier
 131  */
 132 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 133                                  struct v4l2_async_notifier *notifier);
 134
 135 /**
 136  * v4l2_async_subdev_notifier_register - registers a subdevice asynchronous
 137  *                                       notifier for a sub-device
 138  *
 139  * @sd: pointer to &struct v4l2_subdev
 140  * @notifier: pointer to &struct v4l2_async_notifier
 141  */
 142 int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
 143                                         struct v4l2_async_notifier *notifier);
 144
 145 /**
 146  * v4l2_async_notifier_unregister - unregisters a subdevice asynchronous notifier
 147  *
 148  * @notifier: pointer to &struct v4l2_async_notifier
 149  */
 150 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 151
 152 /**
 153  * v4l2_async_notifier_cleanup - clean up notifier resources
 154  * @notifier: the notifier the resources of which are to be cleaned up
 155  *
 156  * Release memory resources related to a notifier, including the async
 157  * sub-devices allocated for the purposes of the notifier but not the notifier
 158  * itself. The user is responsible for calling this function to clean up the
 159  * notifier after calling @v4l2_async_notifier_parse_fwnode_endpoints or
 160  * @v4l2_fwnode_reference_parse_sensor_common.
 161  *
 162  * There is no harm from calling v4l2_async_notifier_cleanup in other
 163  * cases as long as its memory has been zeroed after it has been
 164  * allocated.
 165  */
 166 void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier);
 167
 168 /**
 169  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
 170  *      subdevice framework
 171  *
 172  * @sd: pointer to &struct v4l2_subdev
 173  */
 174 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
 175
 176 /**
 177  * v4l2_async_register_subdev_sensor_common - registers a sensor sub-device to
 178  *                                            the asynchronous sub-device
 179  *                                            framework and parse set up common
 180  *                                            sensor related devices
 181  *
 182  * @sd: pointer to struct &v4l2_subdev
 183  *
 184  * This function is just like v4l2_async_register_subdev() with the exception
 185  * that calling it will also parse firmware interfaces for remote references
 186  * using v4l2_async_notifier_parse_fwnode_sensor_common() and registers the
 187  * async sub-devices. The sub-device is similarly unregistered by calling
 188  * v4l2_async_unregister_subdev().
 189  *
 190  * While registered, the subdev module is marked as in-use.
 191  *
 192  * An error is returned if the module is no longer loaded on any attempts
 193  * to register it.
 194  */
 195 int __must_check v4l2_async_register_subdev_sensor_common(
 196         struct v4l2_subdev *sd);
 197
 198 /**
 199  * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
 200  *      subdevice framework
 201  *
 202  * @sd: pointer to &struct v4l2_subdev
 203  */
 204 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
 205 #endif