1 ================= 1 =================
2 Triggered Buffers 2 Triggered Buffers
3 ================= 3 =================
4 4
5 Now that we know what buffers and triggers are 5 Now that we know what buffers and triggers are let's see how they work together.
6 6
7 IIO triggered buffer setup 7 IIO triggered buffer setup
8 ========================== 8 ==========================
9 9
10 * :c:func:`iio_triggered_buffer_setup` — Set 10 * :c:func:`iio_triggered_buffer_setup` — Setup triggered buffer and pollfunc
11 * :c:func:`iio_triggered_buffer_cleanup` — F 11 * :c:func:`iio_triggered_buffer_cleanup` — Free resources allocated by
12 :c:func:`iio_triggered_buffer_setup` 12 :c:func:`iio_triggered_buffer_setup`
13 * struct iio_buffer_setup_ops — buffer setup 13 * struct iio_buffer_setup_ops — buffer setup related callbacks
14 14
15 A typical triggered buffer setup looks like th 15 A typical triggered buffer setup looks like this::
16 16
17 const struct iio_buffer_setup_ops sensor_b 17 const struct iio_buffer_setup_ops sensor_buffer_setup_ops = {
18 .preenable = sensor_buffer_preenable, 18 .preenable = sensor_buffer_preenable,
19 .postenable = sensor_buffer_postenable 19 .postenable = sensor_buffer_postenable,
20 .postdisable = sensor_buffer_postdisabl 20 .postdisable = sensor_buffer_postdisable,
21 .predisable = sensor_buffer_predisable 21 .predisable = sensor_buffer_predisable,
22 }; 22 };
23 23
24 irqreturn_t sensor_iio_pollfunc(int irq, v 24 irqreturn_t sensor_iio_pollfunc(int irq, void *p)
25 { 25 {
26 pf->timestamp = iio_get_time_ns((struc 26 pf->timestamp = iio_get_time_ns((struct indio_dev *)p);
27 return IRQ_WAKE_THREAD; 27 return IRQ_WAKE_THREAD;
28 } 28 }
29 29
30 irqreturn_t sensor_trigger_handler(int irq 30 irqreturn_t sensor_trigger_handler(int irq, void *p)
31 { 31 {
32 u16 buf[8]; 32 u16 buf[8];
33 int i = 0; 33 int i = 0;
34 34
35 /* read data for each active channel * 35 /* read data for each active channel */
36 for_each_set_bit(bit, active_scan_mask 36 for_each_set_bit(bit, active_scan_mask, masklength)
37 buf[i++] = sensor_get_data(bit) 37 buf[i++] = sensor_get_data(bit)
38 38
39 iio_push_to_buffers_with_timestamp(ind 39 iio_push_to_buffers_with_timestamp(indio_dev, buf, timestamp);
40 40
41 iio_trigger_notify_done(trigger); 41 iio_trigger_notify_done(trigger);
42 return IRQ_HANDLED; 42 return IRQ_HANDLED;
43 } 43 }
44 44
45 /* setup triggered buffer, usually in prob 45 /* setup triggered buffer, usually in probe function */
46 iio_triggered_buffer_setup(indio_dev, sens 46 iio_triggered_buffer_setup(indio_dev, sensor_iio_polfunc,
47 sensor_trigger_ 47 sensor_trigger_handler,
48 sensor_buffer_s 48 sensor_buffer_setup_ops);
49 49
50 The important things to notice here are: 50 The important things to notice here are:
51 51
52 * :c:type:`iio_buffer_setup_ops`, the buffer s 52 * :c:type:`iio_buffer_setup_ops`, the buffer setup functions to be called at
53 predefined points in the buffer configuratio 53 predefined points in the buffer configuration sequence (e.g. before enable,
54 after disable). If not specified, the IIO co 54 after disable). If not specified, the IIO core uses the default
55 iio_triggered_buffer_setup_ops. 55 iio_triggered_buffer_setup_ops.
56 * **sensor_iio_pollfunc**, the function that w 56 * **sensor_iio_pollfunc**, the function that will be used as top half of poll
57 function. It should do as little processing 57 function. It should do as little processing as possible, because it runs in
58 interrupt context. The most common operation 58 interrupt context. The most common operation is recording of the current
59 timestamp and for this reason one can use th 59 timestamp and for this reason one can use the IIO core defined
60 :c:func:`iio_pollfunc_store_time` function. 60 :c:func:`iio_pollfunc_store_time` function.
61 * **sensor_trigger_handler**, the function tha 61 * **sensor_trigger_handler**, the function that will be used as bottom half of
62 the poll function. This runs in the context 62 the poll function. This runs in the context of a kernel thread and all the
63 processing takes place here. It usually read 63 processing takes place here. It usually reads data from the device and
64 stores it in the internal buffer together wi 64 stores it in the internal buffer together with the timestamp recorded in the
65 top half. 65 top half.
66 66
67 More details 67 More details
68 ============ 68 ============
69 .. kernel-doc:: drivers/iio/buffer/industriali 69 .. kernel-doc:: drivers/iio/buffer/industrialio-triggered-buffer.c
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