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  * @asd_list:   used to add struct v4l2_async_subdev objects to the
  77  *              master notifier @asd_list
  78  * @list:       used to link struct v4l2_async_subdev objects, waiting to be
  79  *              probed, to a notifier->waiting list
  80  *
  81  * When this struct is used as a member in a driver specific struct,
  82  * the driver specific struct shall contain the &struct
  83  * v4l2_async_subdev as its first member.
  84  */
  85 struct v4l2_async_subdev {
  86         enum v4l2_async_match_type match_type;
  87         union {
  88                 struct fwnode_handle *fwnode;
  89                 const char *device_name;
  90                 struct {
  91                         int adapter_id;
  92                         unsigned short address;
  93                 } i2c;
  94                 struct {
  95                         bool (*match)(struct device *,
  96                                       struct v4l2_async_subdev *);
  97                         void *priv;
  98                 } custom;
  99         } match;
 100
 101         /* v4l2-async core private: not to be used by drivers */
 102         struct list_head list;
 103         struct list_head asd_list;
 104 };
 105
 106 /**
 107  * struct v4l2_async_notifier_operations - Asynchronous V4L2 notifier operations
 108  * @bound:      a subdevice driver has successfully probed one of the subdevices
 109  * @complete:   All subdevices have been probed successfully. The complete
 110  *              callback is only executed for the root notifier.
 111  * @unbind:     a subdevice is leaving
 112  */
 113 struct v4l2_async_notifier_operations {
 114         int (*bound)(struct v4l2_async_notifier *notifier,
 115                      struct v4l2_subdev *subdev,
 116                      struct v4l2_async_subdev *asd);
 117         int (*complete)(struct v4l2_async_notifier *notifier);
 118         void (*unbind)(struct v4l2_async_notifier *notifier,
 119                        struct v4l2_subdev *subdev,
 120                        struct v4l2_async_subdev *asd);
 121 };
 122
 123 /**
 124  * struct v4l2_async_notifier - v4l2_device notifier data
 125  *
 126  * @ops:        notifier operations
 127  * @num_subdevs: number of subdevices used in the subdevs array
 128  * @max_subdevs: number of subdevices allocated in the subdevs array
 129  * @subdevs:    array of pointers to subdevice descriptors
 130  * @v4l2_dev:   v4l2_device of the root notifier, NULL otherwise
 131  * @sd:         sub-device that registered the notifier, NULL otherwise
 132  * @parent:     parent notifier
 133  * @asd_list:   master list of struct v4l2_async_subdev, replaces @subdevs
 134  * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
 135  * @done:       list of struct v4l2_subdev, already probed
 136  * @list:       member in a global list of notifiers
 137  */
 138 struct v4l2_async_notifier {
 139         const struct v4l2_async_notifier_operations *ops;
 140         unsigned int num_subdevs;
 141         unsigned int max_subdevs;
 142         struct v4l2_async_subdev **subdevs;
 143         struct v4l2_device *v4l2_dev;
 144         struct v4l2_subdev *sd;
 145         struct v4l2_async_notifier *parent;
 146         struct list_head asd_list;
 147         struct list_head waiting;
 148         struct list_head done;
 149         struct list_head list;
 150 };
 151
 152 /**
 153  * v4l2_async_notifier_init - Initialize a notifier.
 154  *
 155  * @notifier: pointer to &struct v4l2_async_notifier
 156  *
 157  * This function initializes the notifier @asd_list. It must be called
 158  * before the first call to @v4l2_async_notifier_add_subdev.
 159  */
 160 void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier);
 161
 162 /**
 163  * v4l2_async_notifier_add_subdev - Add an async subdev to the
 164  *                              notifier's master asd list.
 165  *
 166  * @notifier: pointer to &struct v4l2_async_notifier
 167  * @asd: pointer to &struct v4l2_async_subdev
 168  *
 169  * This can be used before registering a notifier to add an
 170  * asd to the notifiers @asd_list. If the caller uses this
 171  * method to compose an asd list, it must never allocate
 172  * or place asd's in the @subdevs array.
 173  */
 174 int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
 175                                    struct v4l2_async_subdev *asd);
 176
 177 /**
 178  * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
 179  *
 180  * @v4l2_dev: pointer to &struct v4l2_device
 181  * @notifier: pointer to &struct v4l2_async_notifier
 182  */
 183 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 184                                  struct v4l2_async_notifier *notifier);
 185
 186 /**
 187  * v4l2_async_subdev_notifier_register - registers a subdevice asynchronous
 188  *                                       notifier for a sub-device
 189  *
 190  * @sd: pointer to &struct v4l2_subdev
 191  * @notifier: pointer to &struct v4l2_async_notifier
 192  */
 193 int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
 194                                         struct v4l2_async_notifier *notifier);
 195
 196 /**
 197  * v4l2_async_notifier_unregister - unregisters a subdevice asynchronous notifier
 198  *
 199  * @notifier: pointer to &struct v4l2_async_notifier
 200  */
 201 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 202
 203 /**
 204  * v4l2_async_notifier_cleanup - clean up notifier resources
 205  * @notifier: the notifier the resources of which are to be cleaned up
 206  *
 207  * Release memory resources related to a notifier, including the async
 208  * sub-devices allocated for the purposes of the notifier but not the notifier
 209  * itself. The user is responsible for calling this function to clean up the
 210  * notifier after calling
 211  * @v4l2_async_notifier_add_subdev,
 212  * @v4l2_async_notifier_parse_fwnode_endpoints or
 213  * @v4l2_fwnode_reference_parse_sensor_common.
 214  *
 215  * There is no harm from calling v4l2_async_notifier_cleanup in other
 216  * cases as long as its memory has been zeroed after it has been
 217  * allocated.
 218  */
 219 void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier);
 220
 221 /**
 222  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
 223  *      subdevice framework
 224  *
 225  * @sd: pointer to &struct v4l2_subdev
 226  */
 227 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
 228
 229 /**
 230  * v4l2_async_register_subdev_sensor_common - registers a sensor sub-device to
 231  *                                            the asynchronous sub-device
 232  *                                            framework and parse set up common
 233  *                                            sensor related devices
 234  *
 235  * @sd: pointer to struct &v4l2_subdev
 236  *
 237  * This function is just like v4l2_async_register_subdev() with the exception
 238  * that calling it will also parse firmware interfaces for remote references
 239  * using v4l2_async_notifier_parse_fwnode_sensor_common() and registers the
 240  * async sub-devices. The sub-device is similarly unregistered by calling
 241  * v4l2_async_unregister_subdev().
 242  *
 243  * While registered, the subdev module is marked as in-use.
 244  *
 245  * An error is returned if the module is no longer loaded on any attempts
 246  * to register it.
 247  */
 248 int __must_check v4l2_async_register_subdev_sensor_common(
 249         struct v4l2_subdev *sd);
 250
 251 /**
 252  * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
 253  *      subdevice framework
 254  *
 255  * @sd: pointer to &struct v4l2_subdev
 256  */
 257 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
 258 #endif