trigger.h revision 15744090c5ad3ed404a541bdec6f4f9ae1996fc9 
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 **/
31struct 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
50static inline struct iio_trigger *to_iio_trigger(struct device *d)
51{
52	return container_of(d, struct iio_trigger, dev);
53};
54
55static inline void iio_put_trigger(struct iio_trigger *trig)
56{
57	put_device(&trig->dev);
58	module_put(trig->owner);
59};
60
61static 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 **/
73ssize_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 **/
86struct 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 **/
92int 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 **/
98void 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 **/
105int 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 **/
114int 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 **/
123void iio_trigger_poll(struct iio_trigger *trig);
124void 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 **/
143struct 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
151int iio_alloc_pollfunc(struct iio_dev *indio_dev,
152		       void (*immediate)(struct iio_dev *indio_dev),
153		       void (*main)(struct iio_dev  *private_data));
154
155struct iio_trigger *iio_allocate_trigger(void);
156
157void iio_free_trigger(struct iio_trigger *trig);
158
159#endif /* _IIO_TRIGGER_H_ */
160