2 * Industrial I/O in kernel consumer interface
4 * Copyright (c) 2011 Jonathan Cameron
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.
10 #ifndef _IIO_INKERN_CONSUMER_H_
11 #define _IIO_INKERN_CONSUMER_H_
13 #include <linux/types.h>
14 #include <linux/iio/types.h>
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.
27 struct iio_dev *indio_dev;
28 const struct iio_chan_spec *channel;
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
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'
42 struct iio_channel *iio_channel_get(struct device *dev,
43 const char *consumer_channel);
46 * iio_channel_release() - release channels obtained via iio_channel_get
47 * @chan: The channel to be released.
49 void iio_channel_release(struct iio_channel *chan);
52 * iio_channel_get_all() - get all channels associated with a client
53 * @dev: Pointer to consumer device.
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.
60 struct iio_channel *iio_channel_get_all(struct device *dev);
63 * iio_channel_release_all() - reverse iio_channel_get_all
64 * @chan: Array of channels to be released.
66 void iio_channel_release_all(struct iio_channel *chan);
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.
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
79 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
80 int (*cb)(const void *data,
84 * iio_channel_release_all_cb() - release and unregister the callback.
85 * @cb_buffer: The callback buffer that was allocated.
87 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
90 * iio_channel_start_all_cb() - start the flow of data through callback.
91 * @cb_buff: The callback buffer we are starting.
93 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
96 * iio_channel_stop_all_cb() - stop the flow of data through the callback.
97 * @cb_buff: The callback buffer we are stopping.
99 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
102 * iio_channel_cb_get_channels() - get access to the underlying channels.
103 * @cb_buffer: The callback buffer from whom we want the channel
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.
112 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
115 * iio_read_channel_raw() - read from a given channel
116 * @chan: The channel being queried.
117 * @val: Value read back.
119 * Note raw reads from iio channels are in adc counts and hence
120 * scale will need to be applied if standard units required.
122 int iio_read_channel_raw(struct iio_channel *chan,
126 * iio_read_channel_average_raw() - read from a given channel
127 * @chan: The channel being queried.
128 * @val: Value read back.
130 * Note raw reads from iio channels are in adc counts and hence
131 * scale will need to be applied if standard units required.
133 * In opposit to the normal iio_read_channel_raw this function
134 * returns the average of multiple reads.
136 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
139 * iio_read_channel_processed() - read processed value from a given channel
140 * @chan: The channel being queried.
141 * @val: Value read back.
143 * Returns an error code or 0.
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.
151 int iio_read_channel_processed(struct iio_channel *chan, int *val);
154 * iio_write_channel_raw() - write to a given channel
155 * @chan: The channel being queried.
156 * @val: Value being written.
158 * Note raw writes to iio channels are in dac counts and hence
159 * scale will need to be applied if standard units required.
161 int iio_write_channel_raw(struct iio_channel *chan, int val);
164 * iio_get_channel_type() - get the type of a channel
165 * @channel: The channel being queried.
166 * @type: The type of the channel.
168 * returns the enum iio_chan_type of the channel
170 int iio_get_channel_type(struct iio_channel *channel,
171 enum iio_chan_type *type);
174 * iio_read_channel_scale() - read the scale value for a channel
175 * @chan: The channel being queried.
176 * @val: First part of value read back.
177 * @val2: Second part of value read back.
179 * Note returns a description of what is in val and val2, such
180 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
183 int iio_read_channel_scale(struct iio_channel *chan, int *val,
187 * iio_convert_raw_to_processed() - Converts a raw value to a processed value
188 * @chan: The channel being queried
189 * @raw: The raw IIO to convert
190 * @processed: The result of the conversion
191 * @scale: Scale factor to apply during the conversion
193 * Returns an error code or 0.
195 * This function converts a raw value to processed value for a specific channel.
196 * A raw value is the device internal representation of a sample and the value
197 * returned by iio_read_channel_raw, so the unit of that value is device
198 * depended. A processed value on the other hand is value has a normed unit
199 * according with the IIO specification.
201 * The scale factor allows to increase the precession of the returned value. For
202 * a scale factor of 1 the function will return the result in the normal IIO
203 * unit for the channel type. E.g. millivolt for voltage channels, if you want
204 * nanovolts instead pass 1000000 as the scale factor.
206 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
207 int *processed, unsigned int scale);