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_channel_cb_get_iio_dev() - get access to the underlying device.
 169  * @cb_buffer:          The callback buffer from whom we want the device
 170  *                      information.
 171  *
 172  * This function allows one to obtain information about the device.
 173  * The primary aim is to allow drivers that are consuming a device to query
 174  * things like current trigger.
 175  */
 176 struct iio_dev
 177 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
 178
 179 /**
 180  * iio_read_channel_raw() - read from a given channel
 181  * @chan:               The channel being queried.
 182  * @val:                Value read back.
 183  *
 184  * Note raw reads from iio channels are in adc counts and hence
 185  * scale will need to be applied if standard units required.
 186  */
 187 int iio_read_channel_raw(struct iio_channel *chan,
 188                          int *val);
 189
 190 /**
 191  * iio_read_channel_average_raw() - read from a given channel
 192  * @chan:               The channel being queried.
 193  * @val:                Value read back.
 194  *
 195  * Note raw reads from iio channels are in adc counts and hence
 196  * scale will need to be applied if standard units required.
 197  *
 198  * In opposit to the normal iio_read_channel_raw this function
 199  * returns the average of multiple reads.
 200  */
 201 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
 202
 203 /**
 204  * iio_read_channel_processed() - read processed value from a given channel
 205  * @chan:               The channel being queried.
 206  * @val:                Value read back.
 207  *
 208  * Returns an error code or 0.
 209  *
 210  * This function will read a processed value from a channel. A processed value
 211  * means that this value will have the correct unit and not some device internal
 212  * representation. If the device does not support reporting a processed value
 213  * the function will query the raw value and the channels scale and offset and
 214  * do the appropriate transformation.
 215  */
 216 int iio_read_channel_processed(struct iio_channel *chan, int *val);
 217
 218 /**
 219  * iio_write_channel_raw() - write to a given channel
 220  * @chan:               The channel being queried.
 221  * @val:                Value being written.
 222  *
 223  * Note raw writes to iio channels are in dac counts and hence
 224  * scale will need to be applied if standard units required.
 225  */
 226 int iio_write_channel_raw(struct iio_channel *chan, int val);
 227
 228 /**
 229  * iio_read_max_channel_raw() - read maximum available raw value from a given
 230  *                              channel, i.e. the maximum possible value.
 231  * @chan:               The channel being queried.
 232  * @val:                Value read back.
 233  *
 234  * Note raw reads from iio channels are in adc counts and hence
 235  * scale will need to be applied if standard units are required.
 236  */
 237 int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
 238
 239 /**
 240  * iio_read_avail_channel_raw() - read available raw values from a given channel
 241  * @chan:               The channel being queried.
 242  * @vals:               Available values read back.
 243  * @length:             Number of entries in vals.
 244  *
 245  * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
 246  *
 247  * For ranges, three vals are always returned; min, step and max.
 248  * For lists, all the possible values are enumerated.
 249  *
 250  * Note raw available values from iio channels are in adc counts and
 251  * hence scale will need to be applied if standard units are required.
 252  */
 253 int iio_read_avail_channel_raw(struct iio_channel *chan,
 254                                const int **vals, int *length);
 255
 256 /**
 257  * iio_get_channel_type() - get the type of a channel
 258  * @channel:            The channel being queried.
 259  * @type:               The type of the channel.
 260  *
 261  * returns the enum iio_chan_type of the channel
 262  */
 263 int iio_get_channel_type(struct iio_channel *channel,
 264                          enum iio_chan_type *type);
 265
 266 /**
 267  * iio_read_channel_offset() - read the offset value for a channel
 268  * @chan:               The channel being queried.
 269  * @val:                First part of value read back.
 270  * @val2:               Second part of value read back.
 271  *
 272  * Note returns a description of what is in val and val2, such
 273  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 274  * + val2/1e6
 275  */
 276 int iio_read_channel_offset(struct iio_channel *chan, int *val,
 277                            int *val2);
 278
 279 /**
 280  * iio_read_channel_scale() - read the scale value for a channel
 281  * @chan:               The channel being queried.
 282  * @val:                First part of value read back.
 283  * @val2:               Second part of value read back.
 284  *
 285  * Note returns a description of what is in val and val2, such
 286  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 287  * + val2/1e6
 288  */
 289 int iio_read_channel_scale(struct iio_channel *chan, int *val,
 290                            int *val2);
 291
 292 /**
 293  * iio_convert_raw_to_processed() - Converts a raw value to a processed value
 294  * @chan:               The channel being queried
 295  * @raw:                The raw IIO to convert
 296  * @processed:          The result of the conversion
 297  * @scale:              Scale factor to apply during the conversion
 298  *
 299  * Returns an error code or 0.
 300  *
 301  * This function converts a raw value to processed value for a specific channel.
 302  * A raw value is the device internal representation of a sample and the value
 303  * returned by iio_read_channel_raw, so the unit of that value is device
 304  * depended. A processed value on the other hand is value has a normed unit
 305  * according with the IIO specification.
 306  *
 307  * The scale factor allows to increase the precession of the returned value. For
 308  * a scale factor of 1 the function will return the result in the normal IIO
 309  * unit for the channel type. E.g. millivolt for voltage channels, if you want
 310  * nanovolts instead pass 1000000 as the scale factor.
 311  */
 312 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 313         int *processed, unsigned int scale);
 314
 315 /**
 316  * iio_get_channel_ext_info_count() - get number of ext_info attributes
 317  *                                    connected to the channel.
 318  * @chan:               The channel being queried
 319  *
 320  * Returns the number of ext_info attributes
 321  */
 322 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
 323
 324 /**
 325  * iio_read_channel_ext_info() - read ext_info attribute from a given channel
 326  * @chan:               The channel being queried.
 327  * @attr:               The ext_info attribute to read.
 328  * @buf:                Where to store the attribute value. Assumed to hold
 329  *                      at least PAGE_SIZE bytes.
 330  *
 331  * Returns the number of bytes written to buf (perhaps w/o zero termination;
 332  * it need not even be a string), or an error code.
 333  */
 334 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
 335                                   const char *attr, char *buf);
 336
 337 /**
 338  * iio_write_channel_ext_info() - write ext_info attribute from a given channel
 339  * @chan:               The channel being queried.
 340  * @attr:               The ext_info attribute to read.
 341  * @buf:                The new attribute value. Strings needs to be zero-
 342  *                      terminated, but the terminator should not be included
 343  *                      in the below len.
 344  * @len:                The size of the new attribute value.
 345  *
 346  * Returns the number of accepted bytes, which should be the same as len.
 347  * An error code can also be returned.
 348  */
 349 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
 350                                    const char *buf, size_t len);
 351
 352 #endif