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  * devm_iio_channel_get() - Resource managed version of iio_channel_get().
  53  * @dev:                Pointer to consumer device. Device name must match
  54  *                      the name of the device as provided in the iio_map
  55  *                      with which the desired provider to consumer mapping
  56  *                      was registered.
  57  * @consumer_channel:   Unique name to identify the channel on the consumer
  58  *                      side. This typically describes the channels use within
  59  *                      the consumer. E.g. 'battery_voltage'
  60  *
  61  * Returns a pointer to negative errno if it is not able to get the iio channel
  62  * otherwise returns valid pointer for iio channel.
  63  *
  64  * The allocated iio channel is automatically released when the device is
  65  * unbound.
  66  */
  67 struct iio_channel *devm_iio_channel_get(struct device *dev,
  68                                          const char *consumer_channel);
  69 /**
  70  * devm_iio_channel_release() - Resource managed version of
  71  *                              iio_channel_release().
  72  * @dev:                Pointer to consumer device for which resource
  73  *                      is allocared.
  74  * @chan:               The channel to be released.
  75  */
  76 void devm_iio_channel_release(struct device *dev, struct iio_channel *chan);
  77
  78 /**
  79  * iio_channel_get_all() - get all channels associated with a client
  80  * @dev:                Pointer to consumer device.
  81  *
  82  * Returns an array of iio_channel structures terminated with one with
  83  * null iio_dev pointer.
  84  * This function is used by fairly generic consumers to get all the
  85  * channels registered as having this consumer.
  86  */
  87 struct iio_channel *iio_channel_get_all(struct device *dev);
  88
  89 /**
  90  * iio_channel_release_all() - reverse iio_channel_get_all
  91  * @chan:               Array of channels to be released.
  92  */
  93 void iio_channel_release_all(struct iio_channel *chan);
  94
  95 /**
  96  * devm_iio_channel_get_all() - Resource managed version of
  97  *                              iio_channel_get_all().
  98  * @dev: Pointer to consumer device.
  99  *
 100  * Returns a pointer to negative errno if it is not able to get the iio channel
 101  * otherwise returns an array of iio_channel structures terminated with one with
 102  * null iio_dev pointer.
 103  *
 104  * This function is used by fairly generic consumers to get all the
 105  * channels registered as having this consumer.
 106  *
 107  * The allocated iio channels are automatically released when the device is
 108  * unbounded.
 109  */
 110 struct iio_channel *devm_iio_channel_get_all(struct device *dev);
 111
 112 /**
 113  * devm_iio_channel_release_all() - Resource managed version of
 114  *                                  iio_channel_release_all().
 115  * @dev:                Pointer to consumer device for which resource
 116  *                      is allocared.
 117  * @chan:               Array channel to be released.
 118  */
 119 void devm_iio_channel_release_all(struct device *dev, struct iio_channel *chan);
 120
 121 struct iio_cb_buffer;
 122 /**
 123  * iio_channel_get_all_cb() - register callback for triggered capture
 124  * @dev:                Pointer to client device.
 125  * @cb:                 Callback function.
 126  * @private:            Private data passed to callback.
 127  *
 128  * NB right now we have no ability to mux data from multiple devices.
 129  * So if the channels requested come from different devices this will
 130  * fail.
 131  */
 132 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
 133                                              int (*cb)(const void *data,
 134                                                        void *private),
 135                                              void *private);
 136 /**
 137  * iio_channel_release_all_cb() - release and unregister the callback.
 138  * @cb_buffer:          The callback buffer that was allocated.
 139  */
 140 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
 141
 142 /**
 143  * iio_channel_start_all_cb() - start the flow of data through callback.
 144  * @cb_buff:            The callback buffer we are starting.
 145  */
 146 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
 147
 148 /**
 149  * iio_channel_stop_all_cb() - stop the flow of data through the callback.
 150  * @cb_buff:            The callback buffer we are stopping.
 151  */
 152 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
 153
 154 /**
 155  * iio_channel_cb_get_channels() - get access to the underlying channels.
 156  * @cb_buffer:          The callback buffer from whom we want the channel
 157  *                      information.
 158  *
 159  * This function allows one to obtain information about the channels.
 160  * Whilst this may allow direct reading if all buffers are disabled, the
 161  * primary aim is to allow drivers that are consuming a channel to query
 162  * things like scaling of the channel.
 163  */
 164 struct iio_channel
 165 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
 166
 167 /**
 168  * iio_read_channel_raw() - read from a given channel
 169  * @chan:               The channel being queried.
 170  * @val:                Value read back.
 171  *
 172  * Note raw reads from iio channels are in adc counts and hence
 173  * scale will need to be applied if standard units required.
 174  */
 175 int iio_read_channel_raw(struct iio_channel *chan,
 176                          int *val);
 177
 178 /**
 179  * iio_read_channel_average_raw() - read from a given channel
 180  * @chan:               The channel being queried.
 181  * @val:                Value read back.
 182  *
 183  * Note raw reads from iio channels are in adc counts and hence
 184  * scale will need to be applied if standard units required.
 185  *
 186  * In opposit to the normal iio_read_channel_raw this function
 187  * returns the average of multiple reads.
 188  */
 189 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
 190
 191 /**
 192  * iio_read_channel_processed() - read processed value from a given channel
 193  * @chan:               The channel being queried.
 194  * @val:                Value read back.
 195  *
 196  * Returns an error code or 0.
 197  *
 198  * This function will read a processed value from a channel. A processed value
 199  * means that this value will have the correct unit and not some device internal
 200  * representation. If the device does not support reporting a processed value
 201  * the function will query the raw value and the channels scale and offset and
 202  * do the appropriate transformation.
 203  */
 204 int iio_read_channel_processed(struct iio_channel *chan, int *val);
 205
 206 /**
 207  * iio_write_channel_raw() - write to a given channel
 208  * @chan:               The channel being queried.
 209  * @val:                Value being written.
 210  *
 211  * Note raw writes to iio channels are in dac counts and hence
 212  * scale will need to be applied if standard units required.
 213  */
 214 int iio_write_channel_raw(struct iio_channel *chan, int val);
 215
 216 /**
 217  * iio_get_channel_type() - get the type of a channel
 218  * @channel:            The channel being queried.
 219  * @type:               The type of the channel.
 220  *
 221  * returns the enum iio_chan_type of the channel
 222  */
 223 int iio_get_channel_type(struct iio_channel *channel,
 224                          enum iio_chan_type *type);
 225
 226 /**
 227  * iio_read_channel_scale() - read the scale value for a channel
 228  * @chan:               The channel being queried.
 229  * @val:                First part of value read back.
 230  * @val2:               Second part of value read back.
 231  *
 232  * Note returns a description of what is in val and val2, such
 233  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 234  * + val2/1e6
 235  */
 236 int iio_read_channel_scale(struct iio_channel *chan, int *val,
 237                            int *val2);
 238
 239 /**
 240  * iio_convert_raw_to_processed() - Converts a raw value to a processed value
 241  * @chan:               The channel being queried
 242  * @raw:                The raw IIO to convert
 243  * @processed:          The result of the conversion
 244  * @scale:              Scale factor to apply during the conversion
 245  *
 246  * Returns an error code or 0.
 247  *
 248  * This function converts a raw value to processed value for a specific channel.
 249  * A raw value is the device internal representation of a sample and the value
 250  * returned by iio_read_channel_raw, so the unit of that value is device
 251  * depended. A processed value on the other hand is value has a normed unit
 252  * according with the IIO specification.
 253  *
 254  * The scale factor allows to increase the precession of the returned value. For
 255  * a scale factor of 1 the function will return the result in the normal IIO
 256  * unit for the channel type. E.g. millivolt for voltage channels, if you want
 257  * nanovolts instead pass 1000000 as the scale factor.
 258  */
 259 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 260         int *processed, unsigned int scale);
 261
 262 #endif