Linux kernel mirror (for testing)
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linux
1/*
2 * Industrial I/O in kernel consumer interface
3 *
4 * Copyright (c) 2011 Jonathan Cameron
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10#ifndef _IIO_INKERN_CONSUMER_H_
11#define _IIO_INKERN_CONSUMER_H_
12#include <linux/iio/types.h>
13
14struct iio_dev;
15struct iio_chan_spec;
16
17/**
18 * struct iio_channel - everything needed for a consumer to use a channel
19 * @indio_dev: Device on which the channel exists.
20 * @channel: Full description of the channel.
21 */
22struct iio_channel {
23 struct iio_dev *indio_dev;
24 const struct iio_chan_spec *channel;
25};
26
27/**
28 * iio_channel_get() - get description of all that is needed to access channel.
29 * @name: Unique name of the device as provided in the iio_map
30 * with which the desired provider to consumer mapping
31 * was registered.
32 * @consumer_channel: Unique name to identify the channel on the consumer
33 * side. This typically describes the channels use within
34 * the consumer. E.g. 'battery_voltage'
35 */
36struct iio_channel *iio_channel_get(const char *name,
37 const char *consumer_channel);
38
39/**
40 * iio_channel_release() - release channels obtained via iio_channel_get
41 * @chan: The channel to be released.
42 */
43void iio_channel_release(struct iio_channel *chan);
44
45/**
46 * iio_channel_get_all() - get all channels associated with a client
47 * @name: name of consumer device.
48 *
49 * Returns an array of iio_channel structures terminated with one with
50 * null iio_dev pointer.
51 * This function is used by fairly generic consumers to get all the
52 * channels registered as having this consumer.
53 */
54struct iio_channel *iio_channel_get_all(const char *name);
55
56/**
57 * iio_channel_release_all() - reverse iio_channel_get_all
58 * @chan: Array of channels to be released.
59 */
60void iio_channel_release_all(struct iio_channel *chan);
61
62/**
63 * iio_read_channel_raw() - read from a given channel
64 * @chan: The channel being queried.
65 * @val: Value read back.
66 *
67 * Note raw reads from iio channels are in adc counts and hence
68 * scale will need to be applied if standard units required.
69 */
70int iio_read_channel_raw(struct iio_channel *chan,
71 int *val);
72
73/**
74 * iio_read_channel_processed() - read processed value from a given channel
75 * @chan: The channel being queried.
76 * @val: Value read back.
77 *
78 * Returns an error code or 0.
79 *
80 * This function will read a processed value from a channel. A processed value
81 * means that this value will have the correct unit and not some device internal
82 * representation. If the device does not support reporting a processed value
83 * the function will query the raw value and the channels scale and offset and
84 * do the appropriate transformation.
85 */
86int iio_read_channel_processed(struct iio_channel *chan, int *val);
87
88/**
89 * iio_get_channel_type() - get the type of a channel
90 * @channel: The channel being queried.
91 * @type: The type of the channel.
92 *
93 * returns the enum iio_chan_type of the channel
94 */
95int iio_get_channel_type(struct iio_channel *channel,
96 enum iio_chan_type *type);
97
98/**
99 * iio_read_channel_scale() - read the scale value for a channel
100 * @chan: The channel being queried.
101 * @val: First part of value read back.
102 * @val2: Second part of value read back.
103 *
104 * Note returns a description of what is in val and val2, such
105 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
106 * + val2/1e6
107 */
108int iio_read_channel_scale(struct iio_channel *chan, int *val,
109 int *val2);
110
111/**
112 * iio_convert_raw_to_processed() - Converts a raw value to a processed value
113 * @chan: The channel being queried
114 * @raw: The raw IIO to convert
115 * @processed: The result of the conversion
116 * @scale: Scale factor to apply during the conversion
117 *
118 * Returns an error code or 0.
119 *
120 * This function converts a raw value to processed value for a specific channel.
121 * A raw value is the device internal representation of a sample and the value
122 * returned by iio_read_channel_raw, so the unit of that value is device
123 * depended. A processed value on the other hand is value has a normed unit
124 * according with the IIO specification.
125 *
126 * The scale factor allows to increase the precession of the returned value. For
127 * a scale factor of 1 the function will return the result in the normal IIO
128 * unit for the channel type. E.g. millivolt for voltage channels, if you want
129 * nanovolts instead pass 1000 as the scale factor.
130 */
131int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
132 int *processed, unsigned int scale);
133
134#endif