1 ========
2 Triggers
3 ========
4
5 * struct iio_trigger — industrial I/O trigge
6 * :c:func:`devm_iio_trigger_alloc` — Resourc
7 * :c:func:`devm_iio_trigger_register` — Reso
8 iio_trigger_unregister
9 * :c:func:`iio_trigger_validate_own_device` â€
10 device belong to the same device
11
12 In many situations it is useful for a driver t
13 on some external event (trigger) as opposed to
14 An IIO trigger can be provided by a device dri
15 based on hardware generated events (e.g. data
16 provided by a separate driver from an independ
17 line connected to some external system, timer
18 a specific file in sysfs). A trigger may initi
19 sensors and also it may be completely unrelate
20
21 IIO trigger sysfs interface
22 ===========================
23
24 There are two locations in sysfs related to tr
25
26 * :file:`/sys/bus/iio/devices/trigger{Y}/*`, t
27 IIO trigger is registered with the IIO core
28 with index Y.
29 Because triggers can be very different depen
30 standard attributes that we can describe her
31
32 * :file:`name`, trigger name that can be lat
33 device.
34 * :file:`sampling_frequency`, some timer bas
35 specify the frequency for trigger calls.
36
37 * :file:`/sys/bus/iio/devices/iio:device{X}/tr
38 created once the device supports a triggered
39 trigger with our device by writing the trigg
40 :file:`current_trigger` file.
41
42 IIO trigger setup
43 =================
44
45 Let's see a simple example of how to setup a t
46
47 struct iio_trigger_ops trigger_ops = {
48 .set_trigger_state = sample_trigger_
49 .validate_device = sample_validate_d
50 }
51
52 struct iio_trigger *trig;
53
54 /* first, allocate memory for our trigge
55 trig = iio_trigger_alloc(dev, "trig-%s-%
56
57 /* setup trigger operations field */
58 trig->ops = &trigger_ops;
59
60 /* now register the trigger with the IIO
61 iio_trigger_register(trig);
62
63 IIO trigger ops
64 ===============
65
66 * struct iio_trigger_ops — operations struct
67
68 Notice that a trigger has a set of operations
69
70 * :file:`set_trigger_state`, switch the trigge
71 * :file:`validate_device`, function to validat
72 trigger gets changed.
73
74 More details
75 ============
76 .. kernel-doc:: include/linux/iio/trigger.h
77 .. kernel-doc:: drivers/iio/industrialio-trigg
78 :export:
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