trigger.h revision 299475e0d961c3dcf2f0b1a8a2ec6d61846aa52b 
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 **/
30struct 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
48static inline struct iio_trigger *to_iio_trigger(struct device *d)
49{
50	return container_of(d, struct iio_trigger, dev);
51};
52
53static inline void iio_put_trigger(struct iio_trigger *trig)
54{
55	put_device(&trig->dev);
56	module_put(trig->owner);
57};
58
59static 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 **/
71ssize_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 **/
84struct 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 **/
90int 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 **/
96void 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 **/
103int 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 **/
112int 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 **/
121void iio_trigger_poll(struct iio_trigger *trig, s64 time);
122void 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 **/
141struct 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
149int 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 form a trigger
156 */
157int iio_triggered_ring_postenable(struct iio_dev *indio_dev);
158int iio_triggered_ring_predisable(struct iio_dev *indio_dev);
159
160struct iio_trigger *iio_allocate_trigger(void);
161
162void iio_free_trigger(struct iio_trigger *trig);
163
164#endif /* _IIO_TRIGGER_H_ */
165