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 14 struct iio_dev; 15 struct 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 */ 22 struct 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 */ 36 struct 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 */ 43 void 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 */ 54 struct 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 */ 60 void 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 */ 70 int 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 */ 86 int 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 */ 95 int 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 */ 108 int 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 */ 131 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw, 132 int *processed, unsigned int scale); 133 134 #endif 135