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
13#include <linux/types.h>
14#include <linux/iio/types.h>
15
16struct iio_dev;
17struct iio_chan_spec;
18struct device;
19
20/**
21 * struct iio_channel - everything needed for a consumer to use a channel
22 * @indio_dev:		Device on which the channel exists.
23 * @channel:		Full description of the channel.
24 * @data:		Data about the channel used by consumer.
25 */
26struct iio_channel {
27	struct iio_dev *indio_dev;
28	const struct iio_chan_spec *channel;
29	void *data;
30};
31
32/**
33 * iio_channel_get() - get description of all that is needed to access channel.
34 * @dev:		Pointer to consumer device. Device name must match
35 *			the name of the device as provided in the iio_map
36 *			with which the desired provider to consumer mapping
37 *			was registered.
38 * @consumer_channel:	Unique name to identify the channel on the consumer
39 *			side. This typically describes the channels use within
40 *			the consumer. E.g. 'battery_voltage'
41 */
42struct iio_channel *iio_channel_get(struct device *dev,
43				    const char *consumer_channel);
44
45/**
46 * iio_channel_release() - release channels obtained via iio_channel_get
47 * @chan:		The channel to be released.
48 */
49void iio_channel_release(struct iio_channel *chan);
50
51/**
52 * iio_channel_get_all() - get all channels associated with a client
53 * @dev:		Pointer to consumer device.
54 *
55 * Returns an array of iio_channel structures terminated with one with
56 * null iio_dev pointer.
57 * This function is used by fairly generic consumers to get all the
58 * channels registered as having this consumer.
59 */
60struct iio_channel *iio_channel_get_all(struct device *dev);
61
62/**
63 * iio_channel_release_all() - reverse iio_channel_get_all
64 * @chan:		Array of channels to be released.
65 */
66void iio_channel_release_all(struct iio_channel *chan);
67
68struct iio_cb_buffer;
69/**
70 * iio_channel_get_all_cb() - register callback for triggered capture
71 * @dev:		Pointer to client device.
72 * @cb:			Callback function.
73 * @private:		Private data passed to callback.
74 *
75 * NB right now we have no ability to mux data from multiple devices.
76 * So if the channels requested come from different devices this will
77 * fail.
78 */
79struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
80					     int (*cb)(const void *data,
81						       void *private),
82					     void *private);
83/**
84 * iio_channel_release_all_cb() - release and unregister the callback.
85 * @cb_buffer:		The callback buffer that was allocated.
86 */
87void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
88
89/**
90 * iio_channel_start_all_cb() - start the flow of data through callback.
91 * @cb_buff:		The callback buffer we are starting.
92 */
93int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
94
95/**
96 * iio_channel_stop_all_cb() - stop the flow of data through the callback.
97 * @cb_buff:		The callback buffer we are stopping.
98 */
99void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
100
101/**
102 * iio_channel_cb_get_channels() - get access to the underlying channels.
103 * @cb_buff:		The callback buffer from whom we want the channel
104 *			information.
105 *
106 * This function allows one to obtain information about the channels.
107 * Whilst this may allow direct reading if all buffers are disabled, the
108 * primary aim is to allow drivers that are consuming a channel to query
109 * things like scaling of the channel.
110 */
111struct iio_channel
112*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
113
114/**
115 * iio_read_channel_raw() - read from a given channel
116 * @chan:		The channel being queried.
117 * @val:		Value read back.
118 *
119 * Note raw reads from iio channels are in adc counts and hence
120 * scale will need to be applied if standard units required.
121 */
122int iio_read_channel_raw(struct iio_channel *chan,
123			 int *val);
124
125/**
126 * iio_read_channel_average_raw() - read from a given channel
127 * @chan:		The channel being queried.
128 * @val:		Value read back.
129 *
130 * Note raw reads from iio channels are in adc counts and hence
131 * scale will need to be applied if standard units required.
132 *
133 * In opposit to the normal iio_read_channel_raw this function
134 * returns the average of multiple reads.
135 */
136int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
137
138/**
139 * iio_read_channel_processed() - read processed value from a given channel
140 * @chan:		The channel being queried.
141 * @val:		Value read back.
142 *
143 * Returns an error code or 0.
144 *
145 * This function will read a processed value from a channel. A processed value
146 * means that this value will have the correct unit and not some device internal
147 * representation. If the device does not support reporting a processed value
148 * the function will query the raw value and the channels scale and offset and
149 * do the appropriate transformation.
150 */
151int iio_read_channel_processed(struct iio_channel *chan, int *val);
152
153/**
154 * iio_get_channel_type() - get the type of a channel
155 * @channel:		The channel being queried.
156 * @type:		The type of the channel.
157 *
158 * returns the enum iio_chan_type of the channel
159 */
160int iio_get_channel_type(struct iio_channel *channel,
161			 enum iio_chan_type *type);
162
163/**
164 * iio_read_channel_scale() - read the scale value for a channel
165 * @chan:		The channel being queried.
166 * @val:		First part of value read back.
167 * @val2:		Second part of value read back.
168 *
169 * Note returns a description of what is in val and val2, such
170 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
171 * + val2/1e6
172 */
173int iio_read_channel_scale(struct iio_channel *chan, int *val,
174			   int *val2);
175
176/**
177 * iio_convert_raw_to_processed() - Converts a raw value to a processed value
178 * @chan:		The channel being queried
179 * @raw:		The raw IIO to convert
180 * @processed:		The result of the conversion
181 * @scale:		Scale factor to apply during the conversion
182 *
183 * Returns an error code or 0.
184 *
185 * This function converts a raw value to processed value for a specific channel.
186 * A raw value is the device internal representation of a sample and the value
187 * returned by iio_read_channel_raw, so the unit of that value is device
188 * depended. A processed value on the other hand is value has a normed unit
189 * according with the IIO specification.
190 *
191 * The scale factor allows to increase the precession of the returned value. For
192 * a scale factor of 1 the function will return the result in the normal IIO
193 * unit for the channel type. E.g. millivolt for voltage channels, if you want
194 * nanovolts instead pass 1000 as the scale factor.
195 */
196int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
197	int *processed, unsigned int scale);
198
199#endif
200