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  * @match.fwnode:
  52  *              pointer to &struct fwnode_handle to be matched.
  53  *              Used if @match_type is %V4L2_ASYNC_MATCH_FWNODE.
  54  * @match.device_name:
  55  *              string containing the device name to be matched.
  56  *              Used if @match_type is %V4L2_ASYNC_MATCH_DEVNAME.
  57  * @match.i2c:  embedded struct with I2C parameters to be matched.
  58  *              Both @match.i2c.adapter_id and @match.i2c.address
  59  *              should be matched.
  60  *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
  61  * @match.i2c.adapter_id:
  62  *              I2C adapter ID to be matched.
  63  *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
  64  * @match.i2c.address:
  65  *              I2C address to be matched.
  66  *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
  67  * @match.custom:
  68  *              Driver-specific match criteria.
  69  *              Used if @match_type is %V4L2_ASYNC_MATCH_CUSTOM.
  70  * @match.custom.match:
  71  *              Driver-specific match function to be used if
  72  *              %V4L2_ASYNC_MATCH_CUSTOM.
  73  * @match.custom.priv:
  74  *              Driver-specific private struct with match parameters
  75  *              to be used if %V4L2_ASYNC_MATCH_CUSTOM.
  76  * @list:       used to link struct v4l2_async_subdev objects, waiting to be
  77  *              probed, to a notifier->waiting list
  78  *
  79  * When this struct is used as a member in a driver specific struct,
  80  * the driver specific struct shall contain the &struct
  81  * v4l2_async_subdev as its first member.
  82  */
  83 struct v4l2_async_subdev {
  84         enum v4l2_async_match_type match_type;
  85         union {
  86                 struct fwnode_handle *fwnode;
  87                 const char *device_name;
  88                 struct {
  89                         int adapter_id;
  90                         unsigned short address;
  91                 } i2c;
  92                 struct {
  93                         bool (*match)(struct device *,
  94                                       struct v4l2_async_subdev *);
  95                         void *priv;
  96                 } custom;
  97         } match;
  98
  99         /* v4l2-async core private: not to be used by drivers */
 100         struct list_head list;
 101 };
 102
 103 /**
 104  * struct v4l2_async_notifier_operations - Asynchronous V4L2 notifier operations
 105  * @bound:      a subdevice driver has successfully probed one of the subdevices
 106  * @complete:   All subdevices have been probed successfully. The complete
 107  *              callback is only executed for the root notifier.
 108  * @unbind:     a subdevice is leaving
 109  */
 110 struct v4l2_async_notifier_operations {
 111         int (*bound)(struct v4l2_async_notifier *notifier,
 112                      struct v4l2_subdev *subdev,
 113                      struct v4l2_async_subdev *asd);
 114         int (*complete)(struct v4l2_async_notifier *notifier);
 115         void (*unbind)(struct v4l2_async_notifier *notifier,
 116                        struct v4l2_subdev *subdev,
 117                        struct v4l2_async_subdev *asd);
 118 };
 119
 120 /**
 121  * struct v4l2_async_notifier - v4l2_device notifier data
 122  *
 123  * @ops:        notifier operations
 124  * @num_subdevs: number of subdevices used in the subdevs array
 125  * @max_subdevs: number of subdevices allocated in the subdevs array
 126  * @subdevs:    array of pointers to subdevice descriptors
 127  * @v4l2_dev:   v4l2_device of the root notifier, NULL otherwise
 128  * @sd:         sub-device that registered the notifier, NULL otherwise
 129  * @parent:     parent notifier
 130  * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
 131  * @done:       list of struct v4l2_subdev, already probed
 132  * @list:       member in a global list of notifiers
 133  */
 134 struct v4l2_async_notifier {
 135         const struct v4l2_async_notifier_operations *ops;
 136         unsigned int num_subdevs;
 137         unsigned int max_subdevs;
 138         struct v4l2_async_subdev **subdevs;
 139         struct v4l2_device *v4l2_dev;
 140         struct v4l2_subdev *sd;
 141         struct v4l2_async_notifier *parent;
 142         struct list_head waiting;
 143         struct list_head done;
 144         struct list_head list;
 145 };
 146
 147 /**
 148  * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
 149  *
 150  * @v4l2_dev: pointer to &struct v4l2_device
 151  * @notifier: pointer to &struct v4l2_async_notifier
 152  */
 153 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 154                                  struct v4l2_async_notifier *notifier);
 155
 156 /**
 157  * v4l2_async_subdev_notifier_register - registers a subdevice asynchronous
 158  *                                       notifier for a sub-device
 159  *
 160  * @sd: pointer to &struct v4l2_subdev
 161  * @notifier: pointer to &struct v4l2_async_notifier
 162  */
 163 int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
 164                                         struct v4l2_async_notifier *notifier);
 165
 166 /**
 167  * v4l2_async_notifier_unregister - unregisters a subdevice asynchronous notifier
 168  *
 169  * @notifier: pointer to &struct v4l2_async_notifier
 170  */
 171 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 172
 173 /**
 174  * v4l2_async_notifier_cleanup - clean up notifier resources
 175  * @notifier: the notifier the resources of which are to be cleaned up
 176  *
 177  * Release memory resources related to a notifier, including the async
 178  * sub-devices allocated for the purposes of the notifier but not the notifier
 179  * itself. The user is responsible for calling this function to clean up the
 180  * notifier after calling @v4l2_async_notifier_parse_fwnode_endpoints or
 181  * @v4l2_fwnode_reference_parse_sensor_common.
 182  *
 183  * There is no harm from calling v4l2_async_notifier_cleanup in other
 184  * cases as long as its memory has been zeroed after it has been
 185  * allocated.
 186  */
 187 void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier);
 188
 189 /**
 190  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
 191  *      subdevice framework
 192  *
 193  * @sd: pointer to &struct v4l2_subdev
 194  */
 195 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
 196
 197 /**
 198  * v4l2_async_register_subdev_sensor_common - registers a sensor sub-device to
 199  *                                            the asynchronous sub-device
 200  *                                            framework and parse set up common
 201  *                                            sensor related devices
 202  *
 203  * @sd: pointer to struct &v4l2_subdev
 204  *
 205  * This function is just like v4l2_async_register_subdev() with the exception
 206  * that calling it will also parse firmware interfaces for remote references
 207  * using v4l2_async_notifier_parse_fwnode_sensor_common() and registers the
 208  * async sub-devices. The sub-device is similarly unregistered by calling
 209  * v4l2_async_unregister_subdev().
 210  *
 211  * While registered, the subdev module is marked as in-use.
 212  *
 213  * An error is returned if the module is no longer loaded on any attempts
 214  * to register it.
 215  */
 216 int __must_check v4l2_async_register_subdev_sensor_common(
 217         struct v4l2_subdev *sd);
 218
 219 /**
 220  * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
 221  *      subdevice framework
 222  *
 223  * @sd: pointer to &struct v4l2_subdev
 224  */
 225 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
 226 #endif