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; 18 19/** 20 * struct iio_channel - everything needed for a consumer to use a channel 21 * @indio_dev: Device on which the channel exists. 22 * @channel: Full description of the channel. 23 * @data: Data about the channel used by consumer. 24 */ 25struct iio_channel { 26 struct iio_dev *indio_dev; 27 const struct iio_chan_spec *channel; 28 void *data; 29}; 30 31/** 32 * iio_channel_get() - get description of all that is needed to access channel. 33 * @name: Unique name of the device as provided in the iio_map 34 * with which the desired provider to consumer mapping 35 * was registered. 36 * @consumer_channel: Unique name to identify the channel on the consumer 37 * side. This typically describes the channels use within 38 * the consumer. E.g. 'battery_voltage' 39 */ 40struct iio_channel *iio_channel_get(const char *name, 41 const char *consumer_channel); 42 43/** 44 * iio_channel_release() - release channels obtained via iio_channel_get 45 * @chan: The channel to be released. 46 */ 47void iio_channel_release(struct iio_channel *chan); 48 49/** 50 * iio_channel_get_all() - get all channels associated with a client 51 * @name: name of consumer device. 52 * 53 * Returns an array of iio_channel structures terminated with one with 54 * null iio_dev pointer. 55 * This function is used by fairly generic consumers to get all the 56 * channels registered as having this consumer. 57 */ 58struct iio_channel *iio_channel_get_all(const char *name); 59 60/** 61 * iio_channel_release_all() - reverse iio_channel_get_all 62 * @chan: Array of channels to be released. 63 */ 64void iio_channel_release_all(struct iio_channel *chan); 65 66struct iio_cb_buffer; 67/** 68 * iio_channel_get_all_cb() - register callback for triggered capture 69 * @name: Name of client device. 70 * @cb: Callback function. 71 * @private: Private data passed to callback. 72 * 73 * NB right now we have no ability to mux data from multiple devices. 74 * So if the channels requested come from different devices this will 75 * fail. 76 */ 77struct iio_cb_buffer *iio_channel_get_all_cb(const char *name, 78 int (*cb)(u8 *data, 79 void *private), 80 void *private); 81/** 82 * iio_channel_release_all_cb() - release and unregister the callback. 83 * @cb_buffer: The callback buffer that was allocated. 84 */ 85void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer); 86 87/** 88 * iio_channel_start_all_cb() - start the flow of data through callback. 89 * @cb_buff: The callback buffer we are starting. 90 */ 91int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff); 92 93/** 94 * iio_channel_stop_all_cb() - stop the flow of data through the callback. 95 * @cb_buff: The callback buffer we are stopping. 96 */ 97void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff); 98 99/** 100 * iio_channel_cb_get_channels() - get access to the underlying channels. 101 * @cb_buff: The callback buffer from whom we want the channel 102 * information. 103 * 104 * This function allows one to obtain information about the channels. 105 * Whilst this may allow direct reading if all buffers are disabled, the 106 * primary aim is to allow drivers that are consuming a channel to query 107 * things like scaling of the channel. 108 */ 109struct iio_channel 110*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer); 111 112/** 113 * iio_read_channel_raw() - read from a given channel 114 * @chan: The channel being queried. 115 * @val: Value read back. 116 * 117 * Note raw reads from iio channels are in adc counts and hence 118 * scale will need to be applied if standard units required. 119 */ 120int iio_read_channel_raw(struct iio_channel *chan, 121 int *val); 122 123/** 124 * iio_read_channel_processed() - read processed value from a given channel 125 * @chan: The channel being queried. 126 * @val: Value read back. 127 * 128 * Returns an error code or 0. 129 * 130 * This function will read a processed value from a channel. A processed value 131 * means that this value will have the correct unit and not some device internal 132 * representation. If the device does not support reporting a processed value 133 * the function will query the raw value and the channels scale and offset and 134 * do the appropriate transformation. 135 */ 136int iio_read_channel_processed(struct iio_channel *chan, int *val); 137 138/** 139 * iio_get_channel_type() - get the type of a channel 140 * @channel: The channel being queried. 141 * @type: The type of the channel. 142 * 143 * returns the enum iio_chan_type of the channel 144 */ 145int iio_get_channel_type(struct iio_channel *channel, 146 enum iio_chan_type *type); 147 148/** 149 * iio_read_channel_scale() - read the scale value for a channel 150 * @chan: The channel being queried. 151 * @val: First part of value read back. 152 * @val2: Second part of value read back. 153 * 154 * Note returns a description of what is in val and val2, such 155 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val 156 * + val2/1e6 157 */ 158int iio_read_channel_scale(struct iio_channel *chan, int *val, 159 int *val2); 160 161/** 162 * iio_convert_raw_to_processed() - Converts a raw value to a processed value 163 * @chan: The channel being queried 164 * @raw: The raw IIO to convert 165 * @processed: The result of the conversion 166 * @scale: Scale factor to apply during the conversion 167 * 168 * Returns an error code or 0. 169 * 170 * This function converts a raw value to processed value for a specific channel. 171 * A raw value is the device internal representation of a sample and the value 172 * returned by iio_read_channel_raw, so the unit of that value is device 173 * depended. A processed value on the other hand is value has a normed unit 174 * according with the IIO specification. 175 * 176 * The scale factor allows to increase the precession of the returned value. For 177 * a scale factor of 1 the function will return the result in the normal IIO 178 * unit for the channel type. E.g. millivolt for voltage channels, if you want 179 * nanovolts instead pass 1000 as the scale factor. 180 */ 181int iio_convert_raw_to_processed(struct iio_channel *chan, int raw, 182 int *processed, unsigned int scale); 183 184#endif 185