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 401
