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
  13 #include <linux/types.h>
  14 #include <linux/iio/types.h>
  15
  16 struct iio_dev;
  17 struct iio_chan_spec;
  18 struct 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  */
  26 struct 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  */
  42 struct 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  */
  49 void 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  */
  60 struct 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  */
  66 void iio_channel_release_all(struct iio_channel *chan);
  67
  68 struct 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  */
  79 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
  80                                              int (*cb)(u8 *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  */
  87 void 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  */
  93 int 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  */
  99 void 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  */
 111 struct 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  */
 122 int iio_read_channel_raw(struct iio_channel *chan,
 123                          int *val);
 124
 125 /**
 126  * iio_read_channel_processed() - read processed value from a given channel
 127  * @chan:               The channel being queried.
 128  * @val:                Value read back.
 129  *
 130  * Returns an error code or 0.
 131  *
 132  * This function will read a processed value from a channel. A processed value
 133  * means that this value will have the correct unit and not some device internal
 134  * representation. If the device does not support reporting a processed value
 135  * the function will query the raw value and the channels scale and offset and
 136  * do the appropriate transformation.
 137  */
 138 int iio_read_channel_processed(struct iio_channel *chan, int *val);
 139
 140 /**
 141  * iio_get_channel_type() - get the type of a channel
 142  * @channel:            The channel being queried.
 143  * @type:               The type of the channel.
 144  *
 145  * returns the enum iio_chan_type of the channel
 146  */
 147 int iio_get_channel_type(struct iio_channel *channel,
 148                          enum iio_chan_type *type);
 149
 150 /**
 151  * iio_read_channel_scale() - read the scale value for a channel
 152  * @chan:               The channel being queried.
 153  * @val:                First part of value read back.
 154  * @val2:               Second part of value read back.
 155  *
 156  * Note returns a description of what is in val and val2, such
 157  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 158  * + val2/1e6
 159  */
 160 int iio_read_channel_scale(struct iio_channel *chan, int *val,
 161                            int *val2);
 162
 163 /**
 164  * iio_convert_raw_to_processed() - Converts a raw value to a processed value
 165  * @chan:               The channel being queried
 166  * @raw:                The raw IIO to convert
 167  * @processed:          The result of the conversion
 168  * @scale:              Scale factor to apply during the conversion
 169  *
 170  * Returns an error code or 0.
 171  *
 172  * This function converts a raw value to processed value for a specific channel.
 173  * A raw value is the device internal representation of a sample and the value
 174  * returned by iio_read_channel_raw, so the unit of that value is device
 175  * depended. A processed value on the other hand is value has a normed unit
 176  * according with the IIO specification.
 177  *
 178  * The scale factor allows to increase the precession of the returned value. For
 179  * a scale factor of 1 the function will return the result in the normal IIO
 180  * unit for the channel type. E.g. millivolt for voltage channels, if you want
 181  * nanovolts instead pass 1000 as the scale factor.
 182  */
 183 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 184         int *processed, unsigned int scale);
 185
 186 #endif