include/linux/iio/consumer.h

   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