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_cb_set_buffer_watermark() - set the buffer watermark. 138 * @cb_buffer: The callback buffer from whom we want the channel 139 * information. 140 * @watermark: buffer watermark in bytes. 141 * 142 * This function allows to configure the buffer watermark. 143 */ 144 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buffer, 145 size_t watermark); 146 147 /** 148 * iio_channel_release_all_cb() - release and unregister the callback. 149 * @cb_buffer: The callback buffer that was allocated. 150 */ 151 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer); 152 153 /** 154 * iio_channel_start_all_cb() - start the flow of data through callback. 155 * @cb_buff: The callback buffer we are starting. 156 */ 157 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff); 158 159 /** 160 * iio_channel_stop_all_cb() - stop the flow of data through the callback. 161 * @cb_buff: The callback buffer we are stopping. 162 */ 163 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff); 164 165 /** 166 * iio_channel_cb_get_channels() - get access to the underlying channels. 167 * @cb_buffer: The callback buffer from whom we want the channel 168 * information. 169 * 170 * This function allows one to obtain information about the channels. 171 * Whilst this may allow direct reading if all buffers are disabled, the 172 * primary aim is to allow drivers that are consuming a channel to query 173 * things like scaling of the channel. 174 */ 175 struct iio_channel 176 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer); 177 178 /** 179 * iio_channel_cb_get_iio_dev() - get access to the underlying device. 180 * @cb_buffer: The callback buffer from whom we want the device 181 * information. 182 * 183 * This function allows one to obtain information about the device. 184 * The primary aim is to allow drivers that are consuming a device to query 185 * things like current trigger. 186 */ 187 struct iio_dev 188 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer); 189 190 /** 191 * iio_read_channel_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 int iio_read_channel_raw(struct iio_channel *chan, 199 int *val); 200 201 /** 202 * iio_read_channel_average_raw() - read from a given channel 203 * @chan: The channel being queried. 204 * @val: Value read back. 205 * 206 * Note raw reads from iio channels are in adc counts and hence 207 * scale will need to be applied if standard units required. 208 * 209 * In opposit to the normal iio_read_channel_raw this function 210 * returns the average of multiple reads. 211 */ 212 int iio_read_channel_average_raw(struct iio_channel *chan, int *val); 213 214 /** 215 * iio_read_channel_processed() - read processed value from a given channel 216 * @chan: The channel being queried. 217 * @val: Value read back. 218 * 219 * Returns an error code or 0. 220 * 221 * This function will read a processed value from a channel. A processed value 222 * means that this value will have the correct unit and not some device internal 223 * representation. If the device does not support reporting a processed value 224 * the function will query the raw value and the channels scale and offset and 225 * do the appropriate transformation. 226 */ 227 int iio_read_channel_processed(struct iio_channel *chan, int *val); 228 229 /** 230 * iio_write_channel_attribute() - Write values to the device attribute. 231 * @chan: The channel being queried. 232 * @val: Value being written. 233 * @val2: Value being written.val2 use depends on attribute type. 234 * @attribute: info attribute to be read. 235 * 236 * Returns an error code or 0. 237 */ 238 int iio_write_channel_attribute(struct iio_channel *chan, int val, 239 int val2, enum iio_chan_info_enum attribute); 240 241 /** 242 * iio_read_channel_attribute() - Read values from the device attribute. 243 * @chan: The channel being queried. 244 * @val: Value being written. 245 * @val2: Value being written.Val2 use depends on attribute type. 246 * @attribute: info attribute to be written. 247 * 248 * Returns an error code if failed. Else returns a description of what is in val 249 * and val2, such as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val 250 * + val2/1e6 251 */ 252 int iio_read_channel_attribute(struct iio_channel *chan, int *val, 253 int *val2, enum iio_chan_info_enum attribute); 254 255 /** 256 * iio_write_channel_raw() - write to a given channel 257 * @chan: The channel being queried. 258 * @val: Value being written. 259 * 260 * Note raw writes to iio channels are in dac counts and hence 261 * scale will need to be applied if standard units required. 262 */ 263 int iio_write_channel_raw(struct iio_channel *chan, int val); 264 265 /** 266 * iio_read_max_channel_raw() - read maximum available raw value from a given 267 * channel, i.e. the maximum possible value. 268 * @chan: The channel being queried. 269 * @val: Value read back. 270 * 271 * Note raw reads from iio channels are in adc counts and hence 272 * scale will need to be applied if standard units are required. 273 */ 274 int iio_read_max_channel_raw(struct iio_channel *chan, int *val); 275 276 /** 277 * iio_read_avail_channel_raw() - read available raw values from a given channel 278 * @chan: The channel being queried. 279 * @vals: Available values read back. 280 * @length: Number of entries in vals. 281 * 282 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST. 283 * 284 * For ranges, three vals are always returned; min, step and max. 285 * For lists, all the possible values are enumerated. 286 * 287 * Note raw available values from iio channels are in adc counts and 288 * hence scale will need to be applied if standard units are required. 289 */ 290 int iio_read_avail_channel_raw(struct iio_channel *chan, 291 const int **vals, int *length); 292 293 /** 294 * iio_get_channel_type() - get the type of a channel 295 * @channel: The channel being queried. 296 * @type: The type of the channel. 297 * 298 * returns the enum iio_chan_type of the channel 299 */ 300 int iio_get_channel_type(struct iio_channel *channel, 301 enum iio_chan_type *type); 302 303 /** 304 * iio_read_channel_offset() - read the offset value for a channel 305 * @chan: The channel being queried. 306 * @val: First part of value read back. 307 * @val2: Second part of value read back. 308 * 309 * Note returns a description of what is in val and val2, such 310 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val 311 * + val2/1e6 312 */ 313 int iio_read_channel_offset(struct iio_channel *chan, int *val, 314 int *val2); 315 316 /** 317 * iio_read_channel_scale() - read the scale value for a channel 318 * @chan: The channel being queried. 319 * @val: First part of value read back. 320 * @val2: Second part of value read back. 321 * 322 * Note returns a description of what is in val and val2, such 323 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val 324 * + val2/1e6 325 */ 326 int iio_read_channel_scale(struct iio_channel *chan, int *val, 327 int *val2); 328 329 /** 330 * iio_convert_raw_to_processed() - Converts a raw value to a processed value 331 * @chan: The channel being queried 332 * @raw: The raw IIO to convert 333 * @processed: The result of the conversion 334 * @scale: Scale factor to apply during the conversion 335 * 336 * Returns an error code or 0. 337 * 338 * This function converts a raw value to processed value for a specific channel. 339 * A raw value is the device internal representation of a sample and the value 340 * returned by iio_read_channel_raw, so the unit of that value is device 341 * depended. A processed value on the other hand is value has a normed unit 342 * according with the IIO specification. 343 * 344 * The scale factor allows to increase the precession of the returned value. For 345 * a scale factor of 1 the function will return the result in the normal IIO 346 * unit for the channel type. E.g. millivolt for voltage channels, if you want 347 * nanovolts instead pass 1000000 as the scale factor. 348 */ 349 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw, 350 int *processed, unsigned int scale); 351 352 /** 353 * iio_get_channel_ext_info_count() - get number of ext_info attributes 354 * connected to the channel. 355 * @chan: The channel being queried 356 * 357 * Returns the number of ext_info attributes 358 */ 359 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan); 360 361 /** 362 * iio_read_channel_ext_info() - read ext_info attribute from a given channel 363 * @chan: The channel being queried. 364 * @attr: The ext_info attribute to read. 365 * @buf: Where to store the attribute value. Assumed to hold 366 * at least PAGE_SIZE bytes. 367 * 368 * Returns the number of bytes written to buf (perhaps w/o zero termination; 369 * it need not even be a string), or an error code. 370 */ 371 ssize_t iio_read_channel_ext_info(struct iio_channel *chan, 372 const char *attr, char *buf); 373 374 /** 375 * iio_write_channel_ext_info() - write ext_info attribute from a given channel 376 * @chan: The channel being queried. 377 * @attr: The ext_info attribute to read. 378 * @buf: The new attribute value. Strings needs to be zero- 379 * terminated, but the terminator should not be included 380 * in the below len. 381 * @len: The size of the new attribute value. 382 * 383 * Returns the number of accepted bytes, which should be the same as len. 384 * An error code can also be returned. 385 */ 386 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr, 387 const char *buf, size_t len); 388 389 #endif 390
