drivers/staging/iio/chrdev.h

   1 /* The industrial I/O core - character device related
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  */
   9
  10 #ifndef _IIO_CHRDEV_H_
  11 #define _IIO_CHRDEV_H_
  12 struct iio_dev;
  13
  14 /**
  15  * struct iio_handler - Structure used to specify file operations
  16  *                      for a particular chrdev
  17  * @chrdev:     character device structure
  18  * @id:         the location in the handler table - used for deallocation.
  19  * @flags:      file operations related flags including busy flag.
  20  * @private:    handler specific data used by the fileops registered with
  21  *              the chrdev.
  22  */
  23 struct iio_handler {
  24         struct cdev     chrdev;
  25         int             id;
  26         unsigned long   flags;
  27         void            *private;
  28 };
  29
  30 #define iio_cdev_to_handler(cd)                         \
  31         container_of(cd, struct iio_handler, chrdev)
  32
  33 /**
  34  * struct iio_event_data - The actual event being pushed to userspace
  35  * @id:         event identifier
  36  * @timestamp:  best estimate of time of event occurrence (often from
  37  *              the interrupt handler)
  38  */
  39 struct iio_event_data {
  40         int     id;
  41         s64     timestamp;
  42 };
  43
  44 /**
  45  * struct iio_detected_event_list - list element for events that have occurred
  46  * @list:               linked list header
  47  * @ev:                 the event itself
  48  */
  49 struct iio_detected_event_list {
  50         struct list_head                list;
  51         struct iio_event_data           ev;
  52 };
  53
  54 /**
  55  * struct iio_event_interface - chrdev interface for an event line
  56  * @dev:                device assocated with event interface
  57  * @handler:            fileoperations and related control for the chrdev
  58  * @wait:               wait queue to allow blocking reads of events
  59  * @event_list_lock:    mutex to protect the list of detected events
  60  * @det_events:         list of detected events
  61  * @max_events:         maximum number of events before new ones are dropped
  62  * @current_events:     number of events in detected list
  63  */
  64 struct iio_event_interface {
  65         struct device                           dev;
  66         struct iio_handler                      handler;
  67         wait_queue_head_t                       wait;
  68         struct mutex                            event_list_lock;
  69         struct list_head                        det_events;
  70         int                                     max_events;
  71         int                                     current_events;
  72         struct list_head dev_attr_list;
  73 };
  74
  75 #endif