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 #define IIO_TRIGGER_NAME_LENGTH 20
  12 #define IIO_TRIGGER_ID_PREFIX "iio:trigger"
  13 #define IIO_TRIGGER_ID_FORMAT IIO_TRIGGER_ID_PREFIX "%d"
  14
  15
  16 /**
  17  * struct iio_trigger - industrial I/O trigger device
  18  *
  19  * @id:                 [INTERN] unique id number
  20  * @name:               [DRIVER] unique name
  21  * @dev:                [DRIVER] associated device (if relevant)
  22  * @private_data:       [DRIVER] device specific data
  23  * @list:               [INTERN] used in maintenance of global trigger list
  24  * @alloc_list:         [DRIVER] used for driver specific trigger list
  25  * @pollfunc_list_lock: [INTERN] protection of the polling function list
  26  * @pollfunc_list:      [INTERN] list of functions to run on trigger.
  27  * @control_attrs:      [DRIVER] sysfs attributes relevant to trigger type
  28  * @timestamp:          [INTERN] timestamp usesd by some trigs (e.g. datardy)
  29  * @owner:              [DRIVER] used to monitor usage count of the trigger.
  30  * @use_count:          use count for the trigger
  31  * @set_trigger_state:  [DRIVER] switch on/off the trigger on demand
  32  * @try_reenable:       function to reenable the trigger when the
  33  *                      use count is zero (may be NULL)
  34  **/
  35 struct iio_trigger {
  36         int                             id;
  37         const char                      *name;
  38         struct device                   dev;
  39
  40         void                            *private_data;
  41         struct list_head                list;
  42         struct list_head                alloc_list;
  43         spinlock_t                      pollfunc_list_lock;
  44         struct list_head                pollfunc_list;
  45         const struct attribute_group    *control_attrs;
  46         s64                             timestamp;
  47         struct module                   *owner;
  48         int use_count;
  49
  50         int (*set_trigger_state)(struct iio_trigger *trig, bool state);
  51         int (*try_reenable)(struct iio_trigger *trig);
  52 };
  53
  54 static inline struct iio_trigger *to_iio_trigger(struct device *d)
  55 {
  56         return container_of(d, struct iio_trigger, dev);
  57 };
  58
  59 static inline void iio_put_trigger(struct iio_trigger *trig)
  60 {
  61         put_device(&trig->dev);
  62         module_put(trig->owner);
  63 };
  64
  65 static inline void iio_get_trigger(struct iio_trigger *trig)
  66 {
  67         __module_get(trig->owner);
  68         get_device(&trig->dev);
  69 };
  70
  71 /**
  72  * iio_trigger_read_name() - sysfs access function to get the trigger name
  73  * @dev: the system device
  74  * @attr: device attributes for the device
  75  * @buf: output buffer to store the trigger name
  76  **/
  77 ssize_t iio_trigger_read_name(struct device *dev,
  78                               struct device_attribute *attr,
  79                               char *buf);
  80
  81 #define IIO_TRIGGER_NAME_ATTR DEVICE_ATTR(name, S_IRUGO,                \
  82                                           iio_trigger_read_name,        \
  83                                           NULL);
  84
  85 /**
  86  * iio_trigger_find_by_name() - search global trigger list
  87  * @name: trigger name to search for
  88  * @len: trigger name string length to compare
  89  **/
  90 struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len);
  91
  92 /**
  93  * iio_trigger_register() - register a trigger with the IIO core
  94  * @trig_info:  trigger to be registered
  95  **/
  96 int iio_trigger_register(struct iio_trigger *trig_info);
  97
  98 /**
  99  * iio_trigger_unregister() - unregister a trigger from the core
 100  * @trig_info:  trigger to be unregistered
 101  **/
 102 void iio_trigger_unregister(struct iio_trigger *trig_info);
 103
 104 /**
 105  * iio_trigger_attach_poll_func() - add a function pair to be run on trigger
 106  * @trig:       trigger to which the function pair are being added
 107  * @pf:         poll function pair
 108  **/
 109 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 110                                  struct iio_poll_func *pf);
 111
 112 /**
 113  * iio_trigger_dettach_poll_func() -    remove function pair from those to be
 114  *                                      run on trigger
 115  * @trig:       trigger from which the function is being removed
 116  * @pf:         poll function pair
 117  **/
 118 int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 119                                   struct iio_poll_func *pf);
 120
 121 /**
 122  * iio_trigger_poll() - called on a trigger occurring
 123  * @trig: trigger which occurred
 124  *
 125  * Typically called in relevant hardware interrupt handler.
 126  **/
 127 void iio_trigger_poll(struct iio_trigger *trig);
 128 void iio_trigger_notify_done(struct iio_trigger *trig);
 129
 130 /**
 131  * struct iio_poll_func - poll function pair
 132  *
 133  * @list:                       associate this with a triggers pollfunc_list
 134  * @private_data:               data specific to device (passed into poll func)
 135  * @poll_func_immediate:        function in here is run first. They should be
 136  *                              extremely lightweight.  Typically used for latch
 137  *                              control on sensor supporting it.
 138  * @poll_func_main:             function in here is run after all immediates.
 139  *                              Reading from sensor etc typically involves
 140  *                              scheduling from here.
 141  *
 142  * The two stage approach used here is only important when multiple sensors are
 143  * being triggered by a single trigger. This really comes into its own with
 144  * simultaneous sampling devices where a simple latch command can be used to
 145  * make the device store the values on all inputs.
 146  **/
 147 struct iio_poll_func {
 148         struct                          list_head list;
 149         void                            *private_data;
 150         void (*poll_func_immediate)(struct iio_dev *indio_dev);
 151         void (*poll_func_main)(struct iio_dev  *private_data);
 152
 153 };
 154
 155 struct iio_trigger *iio_allocate_trigger(void);
 156
 157 void iio_free_trigger(struct iio_trigger *trig);
 158
 159
 160 #endif /* _IIO_TRIGGER_H_ */