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