include/linux/iio/consumer.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Industrial I/O in kernel consumer interface
   4  *
   5  * Copyright (c) 2011 Jonathan Cameron
   6  */
   7 #ifndef _IIO_INKERN_CONSUMER_H_
   8 #define _IIO_INKERN_CONSUMER_H_
   9
  10 #include <linux/types.h>
  11 #include <linux/iio/types.h>
  12
  13 struct iio_dev;
  14 struct iio_chan_spec;
  15 struct device;
  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  * @data:               Data about the channel used by consumer.
  22  */
  23 struct iio_channel {
  24         struct iio_dev *indio_dev;
  25         const struct iio_chan_spec *channel;
  26         void *data;
  27 };
  28
  29 /**
  30  * iio_channel_get() - get description of all that is needed to access channel.
  31  * @dev:                Pointer to consumer device. Device name must match
  32  *                      the name of the device as provided in the iio_map
  33  *                      with which the desired provider to consumer mapping
  34  *                      was registered.
  35  * @consumer_channel:   Unique name to identify the channel on the consumer
  36  *                      side. This typically describes the channels use within
  37  *                      the consumer. E.g. 'battery_voltage'
  38  */
  39 struct iio_channel *iio_channel_get(struct device *dev,
  40                                     const char *consumer_channel);
  41
  42 /**
  43  * iio_channel_release() - release channels obtained via iio_channel_get
  44  * @chan:               The channel to be released.
  45  */
  46 void iio_channel_release(struct iio_channel *chan);
  47
  48 /**
  49  * devm_iio_channel_get() - Resource managed version of iio_channel_get().
  50  * @dev:                Pointer to consumer device. Device name must match
  51  *                      the name of the device as provided in the iio_map
  52  *                      with which the desired provider to consumer mapping
  53  *                      was registered.
  54  * @consumer_channel:   Unique name to identify the channel on the consumer
  55  *                      side. This typically describes the channels use within
  56  *                      the consumer. E.g. 'battery_voltage'
  57  *
  58  * Returns a pointer to negative errno if it is not able to get the iio channel
  59  * otherwise returns valid pointer for iio channel.
  60  *
  61  * The allocated iio channel is automatically released when the device is
  62  * unbound.
  63  */
  64 struct iio_channel *devm_iio_channel_get(struct device *dev,
  65                                          const char *consumer_channel);
  66 /**
  67  * devm_iio_channel_release() - Resource managed version of
  68  *                              iio_channel_release().
  69  * @dev:                Pointer to consumer device for which resource
  70  *                      is allocared.
  71  * @chan:               The channel to be released.
  72  */
  73 void devm_iio_channel_release(struct device *dev, struct iio_channel *chan);
  74
  75 /**
  76  * iio_channel_get_all() - get all channels associated with a client
  77  * @dev:                Pointer to consumer device.
  78  *
  79  * Returns an array of iio_channel structures terminated with one with
  80  * null iio_dev pointer.
  81  * This function is used by fairly generic consumers to get all the
  82  * channels registered as having this consumer.
  83  */
  84 struct iio_channel *iio_channel_get_all(struct device *dev);
  85
  86 /**
  87  * iio_channel_release_all() - reverse iio_channel_get_all
  88  * @chan:               Array of channels to be released.
  89  */
  90 void iio_channel_release_all(struct iio_channel *chan);
  91
  92 /**
  93  * devm_iio_channel_get_all() - Resource managed version of
  94  *                              iio_channel_get_all().
  95  * @dev: Pointer to consumer device.
  96  *
  97  * Returns a pointer to negative errno if it is not able to get the iio channel
  98  * otherwise returns an array of iio_channel structures terminated with one with
  99  * null iio_dev pointer.
 100  *
 101  * This function is used by fairly generic consumers to get all the
 102  * channels registered as having this consumer.
 103  *
 104  * The allocated iio channels are automatically released when the device is
 105  * unbounded.
 106  */
 107 struct iio_channel *devm_iio_channel_get_all(struct device *dev);
 108
 109 /**
 110  * devm_iio_channel_release_all() - Resource managed version of
 111  *                                  iio_channel_release_all().
 112  * @dev:                Pointer to consumer device for which resource
 113  *                      is allocared.
 114  * @chan:               Array channel to be released.
 115  */
 116 void devm_iio_channel_release_all(struct device *dev, struct iio_channel *chan);
 117
 118 struct iio_cb_buffer;
 119 /**
 120  * iio_channel_get_all_cb() - register callback for triggered capture
 121  * @dev:                Pointer to client device.
 122  * @cb:                 Callback function.
 123  * @private:            Private data passed to callback.
 124  *
 125  * NB right now we have no ability to mux data from multiple devices.
 126  * So if the channels requested come from different devices this will
 127  * fail.
 128  */
 129 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
 130                                              int (*cb)(const void *data,
 131                                                        void *private),
 132                                              void *private);
 133 /**
 134  * iio_channel_cb_set_buffer_watermark() - set the buffer watermark.
 135  * @cb_buffer:          The callback buffer from whom we want the channel
 136  *                      information.
 137  * @watermark: buffer watermark in bytes.
 138  *
 139  * This function allows to configure the buffer watermark.
 140  */
 141 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buffer,
 142                                         size_t watermark);
 143
 144 /**
 145  * iio_channel_release_all_cb() - release and unregister the callback.
 146  * @cb_buffer:          The callback buffer that was allocated.
 147  */
 148 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
 149
 150 /**
 151  * iio_channel_start_all_cb() - start the flow of data through callback.
 152  * @cb_buff:            The callback buffer we are starting.
 153  */
 154 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
 155
 156 /**
 157  * iio_channel_stop_all_cb() - stop the flow of data through the callback.
 158  * @cb_buff:            The callback buffer we are stopping.
 159  */
 160 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
 161
 162 /**
 163  * iio_channel_cb_get_channels() - get access to the underlying channels.
 164  * @cb_buffer:          The callback buffer from whom we want the channel
 165  *                      information.
 166  *
 167  * This function allows one to obtain information about the channels.
 168  * Whilst this may allow direct reading if all buffers are disabled, the
 169  * primary aim is to allow drivers that are consuming a channel to query
 170  * things like scaling of the channel.
 171  */
 172 struct iio_channel
 173 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
 174
 175 /**
 176  * iio_channel_cb_get_iio_dev() - get access to the underlying device.
 177  * @cb_buffer:          The callback buffer from whom we want the device
 178  *                      information.
 179  *
 180  * This function allows one to obtain information about the device.
 181  * The primary aim is to allow drivers that are consuming a device to query
 182  * things like current trigger.
 183  */
 184 struct iio_dev
 185 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
 186
 187 /**
 188  * iio_read_channel_raw() - read from a given channel
 189  * @chan:               The channel being queried.
 190  * @val:                Value read back.
 191  *
 192  * Note raw reads from iio channels are in adc counts and hence
 193  * scale will need to be applied if standard units required.
 194  */
 195 int iio_read_channel_raw(struct iio_channel *chan,
 196                          int *val);
 197
 198 /**
 199  * iio_read_channel_average_raw() - read from a given channel
 200  * @chan:               The channel being queried.
 201  * @val:                Value read back.
 202  *
 203  * Note raw reads from iio channels are in adc counts and hence
 204  * scale will need to be applied if standard units required.
 205  *
 206  * In opposit to the normal iio_read_channel_raw this function
 207  * returns the average of multiple reads.
 208  */
 209 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
 210
 211 /**
 212  * iio_read_channel_processed() - read processed value from a given channel
 213  * @chan:               The channel being queried.
 214  * @val:                Value read back.
 215  *
 216  * Returns an error code or 0.
 217  *
 218  * This function will read a processed value from a channel. A processed value
 219  * means that this value will have the correct unit and not some device internal
 220  * representation. If the device does not support reporting a processed value
 221  * the function will query the raw value and the channels scale and offset and
 222  * do the appropriate transformation.
 223  */
 224 int iio_read_channel_processed(struct iio_channel *chan, int *val);
 225
 226 /**
 227  * iio_write_channel_attribute() - Write values to the device attribute.
 228  * @chan:       The channel being queried.
 229  * @val:        Value being written.
 230  * @val2:       Value being written.val2 use depends on attribute type.
 231  * @attribute:  info attribute to be read.
 232  *
 233  * Returns an error code or 0.
 234  */
 235 int iio_write_channel_attribute(struct iio_channel *chan, int val,
 236                                 int val2, enum iio_chan_info_enum attribute);
 237
 238 /**
 239  * iio_read_channel_attribute() - Read values from the device attribute.
 240  * @chan:       The channel being queried.
 241  * @val:        Value being written.
 242  * @val2:       Value being written.Val2 use depends on attribute type.
 243  * @attribute:  info attribute to be written.
 244  *
 245  * Returns an error code if failed. Else returns a description of what is in val
 246  * and val2, such as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 247  * + val2/1e6
 248  */
 249 int iio_read_channel_attribute(struct iio_channel *chan, int *val,
 250                                int *val2, enum iio_chan_info_enum attribute);
 251
 252 /**
 253  * iio_write_channel_raw() - write to a given channel
 254  * @chan:               The channel being queried.
 255  * @val:                Value being written.
 256  *
 257  * Note raw writes to iio channels are in dac counts and hence
 258  * scale will need to be applied if standard units required.
 259  */
 260 int iio_write_channel_raw(struct iio_channel *chan, int val);
 261
 262 /**
 263  * iio_read_max_channel_raw() - read maximum available raw value from a given
 264  *                              channel, i.e. the maximum possible value.
 265  * @chan:               The channel being queried.
 266  * @val:                Value read back.
 267  *
 268  * Note raw reads from iio channels are in adc counts and hence
 269  * scale will need to be applied if standard units are required.
 270  */
 271 int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
 272
 273 /**
 274  * iio_read_avail_channel_raw() - read available raw values from a given channel
 275  * @chan:               The channel being queried.
 276  * @vals:               Available values read back.
 277  * @length:             Number of entries in vals.
 278  *
 279  * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
 280  *
 281  * For ranges, three vals are always returned; min, step and max.
 282  * For lists, all the possible values are enumerated.
 283  *
 284  * Note raw available values from iio channels are in adc counts and
 285  * hence scale will need to be applied if standard units are required.
 286  */
 287 int iio_read_avail_channel_raw(struct iio_channel *chan,
 288                                const int **vals, int *length);
 289
 290 /**
 291  * iio_read_avail_channel_attribute() - read available channel attribute values
 292  * @chan:               The channel being queried.
 293  * @vals:               Available values read back.
 294  * @type:               Type of values read back.
 295  * @length:             Number of entries in vals.
 296  * @attribute:          info attribute to be read back.
 297  *
 298  * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
 299  */
 300 int iio_read_avail_channel_attribute(struct iio_channel *chan,
 301                                      const int **vals, int *type, int *length,
 302                                      enum iio_chan_info_enum attribute);
 303
 304 /**
 305  * iio_get_channel_type() - get the type of a channel
 306  * @channel:            The channel being queried.
 307  * @type:               The type of the channel.
 308  *
 309  * returns the enum iio_chan_type of the channel
 310  */
 311 int iio_get_channel_type(struct iio_channel *channel,
 312                          enum iio_chan_type *type);
 313
 314 /**
 315  * iio_read_channel_offset() - read the offset value for a channel
 316  * @chan:               The channel being queried.
 317  * @val:                First part of value read back.
 318  * @val2:               Second part of value read back.
 319  *
 320  * Note returns a description of what is in val and val2, such
 321  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 322  * + val2/1e6
 323  */
 324 int iio_read_channel_offset(struct iio_channel *chan, int *val,
 325                            int *val2);
 326
 327 /**
 328  * iio_read_channel_scale() - read the scale value for a channel
 329  * @chan:               The channel being queried.
 330  * @val:                First part of value read back.
 331  * @val2:               Second part of value read back.
 332  *
 333  * Note returns a description of what is in val and val2, such
 334  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
 335  * + val2/1e6
 336  */
 337 int iio_read_channel_scale(struct iio_channel *chan, int *val,
 338                            int *val2);
 339
 340 /**
 341  * iio_convert_raw_to_processed() - Converts a raw value to a processed value
 342  * @chan:               The channel being queried
 343  * @raw:                The raw IIO to convert
 344  * @processed:          The result of the conversion
 345  * @scale:              Scale factor to apply during the conversion
 346  *
 347  * Returns an error code or 0.
 348  *
 349  * This function converts a raw value to processed value for a specific channel.
 350  * A raw value is the device internal representation of a sample and the value
 351  * returned by iio_read_channel_raw, so the unit of that value is device
 352  * depended. A processed value on the other hand is value has a normed unit
 353  * according with the IIO specification.
 354  *
 355  * The scale factor allows to increase the precession of the returned value. For
 356  * a scale factor of 1 the function will return the result in the normal IIO
 357  * unit for the channel type. E.g. millivolt for voltage channels, if you want
 358  * nanovolts instead pass 1000000 as the scale factor.
 359  */
 360 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 361         int *processed, unsigned int scale);
 362
 363 /**
 364  * iio_get_channel_ext_info_count() - get number of ext_info attributes
 365  *                                    connected to the channel.
 366  * @chan:               The channel being queried
 367  *
 368  * Returns the number of ext_info attributes
 369  */
 370 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
 371
 372 /**
 373  * iio_read_channel_ext_info() - read ext_info attribute from a given channel
 374  * @chan:               The channel being queried.
 375  * @attr:               The ext_info attribute to read.
 376  * @buf:                Where to store the attribute value. Assumed to hold
 377  *                      at least PAGE_SIZE bytes.
 378  *
 379  * Returns the number of bytes written to buf (perhaps w/o zero termination;
 380  * it need not even be a string), or an error code.
 381  */
 382 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
 383                                   const char *attr, char *buf);
 384
 385 /**
 386  * iio_write_channel_ext_info() - write ext_info attribute from a given channel
 387  * @chan:               The channel being queried.
 388  * @attr:               The ext_info attribute to read.
 389  * @buf:                The new attribute value. Strings needs to be zero-
 390  *                      terminated, but the terminator should not be included
 391  *                      in the below len.
 392  * @len:                The size of the new attribute value.
 393  *
 394  * Returns the number of accepted bytes, which should be the same as len.
 395  * An error code can also be returned.
 396  */
 397 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
 398                                    const char *buf, size_t len);
 399
 400 #endif