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  * @owner:              [DRIVER] used to monitor usage count of the trigger.
  25  * @use_count:          use count for the trigger
  26  * @set_trigger_state:  [DRIVER] switch on/off the trigger on demand
  27  * @try_reenable:       function to reenable the trigger when the
  28  *                      use count is zero (may be NULL)
  29  **/
  30 struct iio_trigger {
  31         int                             id;
  32         const char                      *name;
  33         struct device                   dev;
  34
  35         void                            *private_data;
  36         struct list_head                list;
  37         struct list_head                alloc_list;
  38         spinlock_t                      pollfunc_list_lock;
  39         struct list_head                pollfunc_list;
  40         const struct attribute_group    *control_attrs;
  41         struct module                   *owner;
  42         int use_count;
  43
  44         int (*set_trigger_state)(struct iio_trigger *trig, bool state);
  45         int (*try_reenable)(struct iio_trigger *trig);
  46 };
  47
  48 static inline struct iio_trigger *to_iio_trigger(struct device *d)
  49 {
  50         return container_of(d, struct iio_trigger, dev);
  51 };
  52
  53 static inline void iio_put_trigger(struct iio_trigger *trig)
  54 {
  55         put_device(&trig->dev);
  56         module_put(trig->owner);
  57 };
  58
  59 static inline void iio_get_trigger(struct iio_trigger *trig)
  60 {
  61         __module_get(trig->owner);
  62         get_device(&trig->dev);
  63 };
  64
  65 /**
  66  * iio_trigger_read_name() - sysfs access function to get the trigger name
  67  * @dev: the system device
  68  * @attr: device attributes for the device
  69  * @buf: output buffer to store the trigger name
  70  **/
  71 ssize_t iio_trigger_read_name(struct device *dev,
  72                               struct device_attribute *attr,
  73                               char *buf);
  74
  75 #define IIO_TRIGGER_NAME_ATTR DEVICE_ATTR(name, S_IRUGO,                \
  76                                           iio_trigger_read_name,        \
  77                                           NULL);
  78
  79 /**
  80  * iio_trigger_find_by_name() - search global trigger list
  81  * @name: trigger name to search for
  82  * @len: trigger name string length to compare
  83  **/
  84 struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len);
  85
  86 /**
  87  * iio_trigger_register() - register a trigger with the IIO core
  88  * @trig_info:  trigger to be registered
  89  **/
  90 int iio_trigger_register(struct iio_trigger *trig_info);
  91
  92 /**
  93  * iio_trigger_unregister() - unregister a trigger from the core
  94  * @trig_info:  trigger to be unregistered
  95  **/
  96 void iio_trigger_unregister(struct iio_trigger *trig_info);
  97
  98 /**
  99  * iio_trigger_attach_poll_func() - add a function pair to be run on trigger
 100  * @trig:       trigger to which the function pair are being added
 101  * @pf:         poll function pair
 102  **/
 103 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 104                                  struct iio_poll_func *pf);
 105
 106 /**
 107  * iio_trigger_dettach_poll_func() -    remove function pair from those to be
 108  *                                      run on trigger
 109  * @trig:       trigger from which the function is being removed
 110  * @pf:         poll function pair
 111  **/
 112 int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 113                                   struct iio_poll_func *pf);
 114
 115 /**
 116  * iio_trigger_poll() - called on a trigger occurring
 117  * @trig: trigger which occurred
 118  *
 119  * Typically called in relevant hardware interrupt handler.
 120  **/
 121 void iio_trigger_poll(struct iio_trigger *trig, s64 time);
 122 void iio_trigger_notify_done(struct iio_trigger *trig);
 123
 124 /**
 125  * struct iio_poll_func - poll function pair
 126  *
 127  * @list:                       associate this with a triggers pollfunc_list
 128  * @private_data:               data specific to device (passed into poll func)
 129  * @poll_func_immediate:        function in here is run first. They should be
 130  *                              extremely lightweight.  Typically used for latch
 131  *                              control on sensor supporting it.
 132  * @poll_func_main:             function in here is run after all immediates.
 133  *                              Reading from sensor etc typically involves
 134  *                              scheduling from here.
 135  *
 136  * The two stage approach used here is only important when multiple sensors are
 137  * being triggered by a single trigger. This really comes into its own with
 138  * simultaneous sampling devices where a simple latch command can be used to
 139  * make the device store the values on all inputs.
 140  **/
 141 struct iio_poll_func {
 142         struct                          list_head list;
 143         void                            *private_data;
 144         void (*poll_func_immediate)(struct iio_dev *indio_dev);
 145         void (*poll_func_main)(struct iio_dev *private_data, s64 time);
 146
 147 };
 148
 149 int iio_alloc_pollfunc(struct iio_dev *indio_dev,
 150                        void (*immediate)(struct iio_dev *indio_dev),
 151                        void (*main)(struct iio_dev *private_data, s64 time));
 152
 153 /*
 154  * Two functions for common case where all that happens is a pollfunc
 155  * is attached and detached from a trigger
 156  */
 157 int iio_triggered_ring_postenable(struct iio_dev *indio_dev);
 158 int iio_triggered_ring_predisable(struct iio_dev *indio_dev);
 159
 160 struct iio_trigger *iio_allocate_trigger(void);
 161
 162 void iio_free_trigger(struct iio_trigger *trig);
 163
 164 #endif /* _IIO_TRIGGER_H_ */