1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (c) 2011 Jonathan Cameron |
4 | * |
5 | * Buffer handling elements of industrial I/O reference driver. |
6 | * Uses the kfifo buffer. |
7 | * |
8 | * To test without hardware use the sysfs trigger. |
9 | */ |
10 | |
11 | #include <linux/kernel.h> |
12 | #include <linux/export.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/interrupt.h> |
15 | #include <linux/irq.h> |
16 | #include <linux/bitmap.h> |
17 | |
18 | #include <linux/iio/iio.h> |
19 | #include <linux/iio/buffer.h> |
20 | #include <linux/iio/trigger_consumer.h> |
21 | #include <linux/iio/triggered_buffer.h> |
22 | |
23 | #include "iio_simple_dummy.h" |
24 | |
25 | /* Some fake data */ |
26 | |
27 | static const s16 fakedata[] = { |
28 | [DUMMY_INDEX_VOLTAGE_0] = 7, |
29 | [DUMMY_INDEX_DIFFVOLTAGE_1M2] = -33, |
30 | [DUMMY_INDEX_DIFFVOLTAGE_3M4] = -2, |
31 | [DUMMY_INDEX_ACCELX] = 344, |
32 | }; |
33 | |
34 | /** |
35 | * iio_simple_dummy_trigger_h() - the trigger handler function |
36 | * @irq: the interrupt number |
37 | * @p: private data - always a pointer to the poll func. |
38 | * |
39 | * This is the guts of buffered capture. On a trigger event occurring, |
40 | * if the pollfunc is attached then this handler is called as a threaded |
41 | * interrupt (and hence may sleep). It is responsible for grabbing data |
42 | * from the device and pushing it into the associated buffer. |
43 | */ |
44 | static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p) |
45 | { |
46 | struct iio_poll_func *pf = p; |
47 | struct iio_dev *indio_dev = pf->indio_dev; |
48 | int i = 0, j; |
49 | u16 *data; |
50 | |
51 | data = kmalloc(size: indio_dev->scan_bytes, GFP_KERNEL); |
52 | if (!data) |
53 | goto done; |
54 | |
55 | /* |
56 | * Three common options here: |
57 | * hardware scans: |
58 | * certain combinations of channels make up a fast read. The capture |
59 | * will consist of all of them. Hence we just call the grab data |
60 | * function and fill the buffer without processing. |
61 | * software scans: |
62 | * can be considered to be random access so efficient reading is just |
63 | * a case of minimal bus transactions. |
64 | * software culled hardware scans: |
65 | * occasionally a driver may process the nearest hardware scan to avoid |
66 | * storing elements that are not desired. This is the fiddliest option |
67 | * by far. |
68 | * Here let's pretend we have random access. And the values are in the |
69 | * constant table fakedata. |
70 | */ |
71 | for_each_set_bit(j, indio_dev->active_scan_mask, indio_dev->masklength) |
72 | data[i++] = fakedata[j]; |
73 | |
74 | iio_push_to_buffers_with_timestamp(indio_dev, data, |
75 | timestamp: iio_get_time_ns(indio_dev)); |
76 | |
77 | kfree(objp: data); |
78 | |
79 | done: |
80 | /* |
81 | * Tell the core we are done with this trigger and ready for the |
82 | * next one. |
83 | */ |
84 | iio_trigger_notify_done(trig: indio_dev->trig); |
85 | |
86 | return IRQ_HANDLED; |
87 | } |
88 | |
89 | static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = { |
90 | }; |
91 | |
92 | int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev) |
93 | { |
94 | return iio_triggered_buffer_setup(indio_dev, NULL, |
95 | iio_simple_dummy_trigger_h, |
96 | &iio_simple_dummy_buffer_setup_ops); |
97 | } |
98 | |
99 | /** |
100 | * iio_simple_dummy_unconfigure_buffer() - release buffer resources |
101 | * @indio_dev: device instance state |
102 | */ |
103 | void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev) |
104 | { |
105 | iio_triggered_buffer_cleanup(indio_dev); |
106 | } |
107 | |