drivers/staging/iio/trigger.h

   1 /* The industrial I/O core, trigger handling functions
   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 #ifndef _IIO_TRIGGER_H_
  10 #define _IIO_TRIGGER_H_
  11
  12 /**
  13  * struct iio_trigger - industrial I/O trigger device
  14  *
  15  * @id:                 [INTERN] unique id number
  16  * @name:               [DRIVER] unique name
  17  * @dev:                [DRIVER] associated device (if relevant)
  18  * @private_data:       [DRIVER] device specific data
  19  * @list:               [INTERN] used in maintenance of global trigger list
  20  * @alloc_list:         [DRIVER] used for driver specific trigger list
  21  * @pollfunc_list_lock: [INTERN] protection of the polling function list
  22  * @pollfunc_list:      [INTERN] list of functions to run on trigger.
  23  * @control_attrs:      [DRIVER] sysfs attributes relevant to trigger type
  24  * @timestamp:          [INTERN] timestamp usesd by some trigs (e.g. datardy)
  25  * @owner:              [DRIVER] used to monitor usage count of the trigger.
  26  * @use_count:          use count for the trigger
  27  * @set_trigger_state:  [DRIVER] switch on/off the trigger on demand
  28  * @try_reenable:       function to reenable the trigger when the
  29  *                      use count is zero (may be NULL)
  30  **/
  31 struct iio_trigger {
  32         int                             id;
  33         const char                      *name;
  34         struct device                   dev;
  35
  36         void                            *private_data;
  37         struct list_head                list;
  38         struct list_head                alloc_list;
  39         spinlock_t                      pollfunc_list_lock;
  40         struct list_head                pollfunc_list;
  41         const struct attribute_group    *control_attrs;
  42         s64                             timestamp;
  43         struct module                   *owner;
  44         int use_count;
  45
  46         int (*set_trigger_state)(struct iio_trigger *trig, bool state);
  47         int (*try_reenable)(struct iio_trigger *trig);
  48 };
  49
  50 static inline struct iio_trigger *to_iio_trigger(struct device *d)
  51 {
  52         return container_of(d, struct iio_trigger, dev);
  53 };
  54
  55 static inline void iio_put_trigger(struct iio_trigger *trig)
  56 {
  57         put_device(&trig->dev);
  58         module_put(trig->owner);
  59 };
  60
  61 static inline void iio_get_trigger(struct iio_trigger *trig)
  62 {
  63         __module_get(trig->owner);
  64         get_device(&trig->dev);
  65 };
  66
  67 /**
  68  * iio_trigger_read_name() - sysfs access function to get the trigger name
  69  * @dev: the system device
  70  * @attr: device attributes for the device
  71  * @buf: output buffer to store the trigger name
  72  **/
  73 ssize_t iio_trigger_read_name(struct device *dev,
  74                               struct device_attribute *attr,
  75                               char *buf);
  76
  77 #define IIO_TRIGGER_NAME_ATTR DEVICE_ATTR(name, S_IRUGO,                \
  78                                           iio_trigger_read_name,        \
  79                                           NULL);
  80
  81 /**
  82  * iio_trigger_find_by_name() - search global trigger list
  83  * @name: trigger name to search for
  84  * @len: trigger name string length to compare
  85  **/
  86 struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len);
  87
  88 /**
  89  * iio_trigger_register() - register a trigger with the IIO core
  90  * @trig_info:  trigger to be registered
  91  **/
  92 int iio_trigger_register(struct iio_trigger *trig_info);
  93
  94 /**
  95  * iio_trigger_unregister() - unregister a trigger from the core
  96  * @trig_info:  trigger to be unregistered
  97  **/
  98 void iio_trigger_unregister(struct iio_trigger *trig_info);
  99
 100 /**
 101  * iio_trigger_attach_poll_func() - add a function pair to be run on trigger
 102  * @trig:       trigger to which the function pair are being added
 103  * @pf:         poll function pair
 104  **/
 105 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 106                                  struct iio_poll_func *pf);
 107
 108 /**
 109  * iio_trigger_dettach_poll_func() -    remove function pair from those to be
 110  *                                      run on trigger
 111  * @trig:       trigger from which the function is being removed
 112  * @pf:         poll function pair
 113  **/
 114 int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 115                                   struct iio_poll_func *pf);
 116
 117 /**
 118  * iio_trigger_poll() - called on a trigger occurring
 119  * @trig: trigger which occurred
 120  *
 121  * Typically called in relevant hardware interrupt handler.
 122  **/
 123 void iio_trigger_poll(struct iio_trigger *trig);
 124 void iio_trigger_notify_done(struct iio_trigger *trig);
 125
 126 /**
 127  * struct iio_poll_func - poll function pair
 128  *
 129  * @list:                       associate this with a triggers pollfunc_list
 130  * @private_data:               data specific to device (passed into poll func)
 131  * @poll_func_immediate:        function in here is run first. They should be
 132  *                              extremely lightweight.  Typically used for latch
 133  *                              control on sensor supporting it.
 134  * @poll_func_main:             function in here is run after all immediates.
 135  *                              Reading from sensor etc typically involves
 136  *                              scheduling from here.
 137  *
 138  * The two stage approach used here is only important when multiple sensors are
 139  * being triggered by a single trigger. This really comes into its own with
 140  * simultaneous sampling devices where a simple latch command can be used to
 141  * make the device store the values on all inputs.
 142  **/
 143 struct iio_poll_func {
 144         struct                          list_head list;
 145         void                            *private_data;
 146         void (*poll_func_immediate)(struct iio_dev *indio_dev);
 147         void (*poll_func_main)(struct iio_dev  *private_data);
 148
 149 };
 150
 151 struct iio_trigger *iio_allocate_trigger(void);
 152
 153 void iio_free_trigger(struct iio_trigger *trig);
 154
 155
 156 #endif /* _IIO_TRIGGER_H_ */