1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Industrial I/O in kernel consumer interface
5 * Copyright (c) 2011 Jonathan Cameron
7 #ifndef _IIO_INKERN_CONSUMER_H_
8 #define _IIO_INKERN_CONSUMER_H_
10 #include <linux/types.h>
11 #include <linux/iio/types.h>
19 * struct iio_channel - everything needed for a consumer to use a channel
20 * @indio_dev: Device on which the channel exists.
21 * @channel: Full description of the channel.
22 * @data: Data about the channel used by consumer.
25 struct iio_dev *indio_dev;
26 const struct iio_chan_spec *channel;
31 * iio_channel_get() - get description of all that is needed to access channel.
32 * @dev: Pointer to consumer device. Device name must match
33 * the name of the device as provided in the iio_map
34 * with which the desired provider to consumer mapping
36 * @consumer_channel: Unique name to identify the channel on the consumer
37 * side. This typically describes the channels use within
38 * the consumer. E.g. 'battery_voltage'
40 struct iio_channel *iio_channel_get(struct device *dev,
41 const char *consumer_channel);
44 * iio_channel_release() - release channels obtained via iio_channel_get
45 * @chan: The channel to be released.
47 void iio_channel_release(struct iio_channel *chan);
50 * devm_iio_channel_get() - Resource managed version of iio_channel_get().
51 * @dev: Pointer to consumer device. Device name must match
52 * the name of the device as provided in the iio_map
53 * with which the desired provider to consumer mapping
55 * @consumer_channel: Unique name to identify the channel on the consumer
56 * side. This typically describes the channels use within
57 * the consumer. E.g. 'battery_voltage'
59 * Returns a pointer to negative errno if it is not able to get the iio channel
60 * otherwise returns valid pointer for iio channel.
62 * The allocated iio channel is automatically released when the device is
65 struct iio_channel *devm_iio_channel_get(struct device *dev,
66 const char *consumer_channel);
68 * iio_channel_get_all() - get all channels associated with a client
69 * @dev: Pointer to consumer device.
71 * Returns an array of iio_channel structures terminated with one with
72 * null iio_dev pointer.
73 * This function is used by fairly generic consumers to get all the
74 * channels registered as having this consumer.
76 struct iio_channel *iio_channel_get_all(struct device *dev);
79 * iio_channel_release_all() - reverse iio_channel_get_all
80 * @chan: Array of channels to be released.
82 void iio_channel_release_all(struct iio_channel *chan);
85 * devm_iio_channel_get_all() - Resource managed version of
86 * iio_channel_get_all().
87 * @dev: Pointer to consumer device.
89 * Returns a pointer to negative errno if it is not able to get the iio channel
90 * otherwise returns an array of iio_channel structures terminated with one with
91 * null iio_dev pointer.
93 * This function is used by fairly generic consumers to get all the
94 * channels registered as having this consumer.
96 * The allocated iio channels are automatically released when the device is
99 struct iio_channel *devm_iio_channel_get_all(struct device *dev);
102 * fwnode_iio_channel_get_by_name() - get description of all that is needed to access channel.
103 * @fwnode: Pointer to consumer Firmware node
104 * @consumer_channel: Unique name to identify the channel on the consumer
105 * side. This typically describes the channels use within
106 * the consumer. E.g. 'battery_voltage'
108 struct iio_channel *fwnode_iio_channel_get_by_name(struct fwnode_handle *fwnode,
112 * devm_fwnode_iio_channel_get_by_name() - Resource managed version of
113 * fwnode_iio_channel_get_by_name().
114 * @dev: Pointer to consumer device.
115 * @fwnode: Pointer to consumer Firmware node
116 * @consumer_channel: Unique name to identify the channel on the consumer
117 * side. This typically describes the channels use within
118 * the consumer. E.g. 'battery_voltage'
120 * Returns a pointer to negative errno if it is not able to get the iio channel
121 * otherwise returns valid pointer for iio channel.
123 * The allocated iio channel is automatically released when the device is
126 struct iio_channel *devm_fwnode_iio_channel_get_by_name(struct device *dev,
127 struct fwnode_handle *fwnode,
128 const char *consumer_channel);
130 struct iio_cb_buffer;
132 * iio_channel_get_all_cb() - register callback for triggered capture
133 * @dev: Pointer to client device.
134 * @cb: Callback function.
135 * @private: Private data passed to callback.
137 * NB right now we have no ability to mux data from multiple devices.
138 * So if the channels requested come from different devices this will
141 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
142 int (*cb)(const void *data,
146 * iio_channel_cb_set_buffer_watermark() - set the buffer watermark.
147 * @cb_buffer: The callback buffer from whom we want the channel
149 * @watermark: buffer watermark in bytes.
151 * This function allows to configure the buffer watermark.
153 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buffer,
157 * iio_channel_release_all_cb() - release and unregister the callback.
158 * @cb_buffer: The callback buffer that was allocated.
160 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
163 * iio_channel_start_all_cb() - start the flow of data through callback.
164 * @cb_buff: The callback buffer we are starting.
166 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
169 * iio_channel_stop_all_cb() - stop the flow of data through the callback.
170 * @cb_buff: The callback buffer we are stopping.
172 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
175 * iio_channel_cb_get_channels() - get access to the underlying channels.
176 * @cb_buffer: The callback buffer from whom we want the channel
179 * This function allows one to obtain information about the channels.
180 * Whilst this may allow direct reading if all buffers are disabled, the
181 * primary aim is to allow drivers that are consuming a channel to query
182 * things like scaling of the channel.
185 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
188 * iio_channel_cb_get_iio_dev() - get access to the underlying device.
189 * @cb_buffer: The callback buffer from whom we want the device
192 * This function allows one to obtain information about the device.
193 * The primary aim is to allow drivers that are consuming a device to query
194 * things like current trigger.
197 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
200 * iio_read_channel_raw() - read from a given channel
201 * @chan: The channel being queried.
202 * @val: Value read back.
204 * Note, if standard units are required, raw reads from iio channels
205 * need the offset (default 0) and scale (default 1) to be applied
206 * as (raw + offset) * scale.
208 int iio_read_channel_raw(struct iio_channel *chan,
212 * iio_read_channel_average_raw() - read from a given channel
213 * @chan: The channel being queried.
214 * @val: Value read back.
216 * Note, if standard units are required, raw reads from iio channels
217 * need the offset (default 0) and scale (default 1) to be applied
218 * as (raw + offset) * scale.
220 * In opposit to the normal iio_read_channel_raw this function
221 * returns the average of multiple reads.
223 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
226 * iio_read_channel_processed() - read processed value from a given channel
227 * @chan: The channel being queried.
228 * @val: Value read back.
230 * Returns an error code or 0.
232 * This function will read a processed value from a channel. A processed value
233 * means that this value will have the correct unit and not some device internal
234 * representation. If the device does not support reporting a processed value
235 * the function will query the raw value and the channels scale and offset and
236 * do the appropriate transformation.
238 int iio_read_channel_processed(struct iio_channel *chan, int *val);
241 * iio_read_channel_processed_scale() - read and scale a processed value
242 * @chan: The channel being queried.
243 * @val: Value read back.
244 * @scale: Scale factor to apply during the conversion
246 * Returns an error code or 0.
248 * This function will read a processed value from a channel. This will work
249 * like @iio_read_channel_processed() but also scale with an additional
250 * scale factor while attempting to minimize any precision loss.
252 int iio_read_channel_processed_scale(struct iio_channel *chan, int *val,
256 * iio_write_channel_attribute() - Write values to the device attribute.
257 * @chan: The channel being queried.
258 * @val: Value being written.
259 * @val2: Value being written.val2 use depends on attribute type.
260 * @attribute: info attribute to be read.
262 * Returns an error code or 0.
264 int iio_write_channel_attribute(struct iio_channel *chan, int val,
265 int val2, enum iio_chan_info_enum attribute);
268 * iio_read_channel_attribute() - Read values from the device attribute.
269 * @chan: The channel being queried.
270 * @val: Value being written.
271 * @val2: Value being written.Val2 use depends on attribute type.
272 * @attribute: info attribute to be written.
274 * Returns an error code if failed. Else returns a description of what is in val
275 * and val2, such as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
278 int iio_read_channel_attribute(struct iio_channel *chan, int *val,
279 int *val2, enum iio_chan_info_enum attribute);
282 * iio_write_channel_raw() - write to a given channel
283 * @chan: The channel being queried.
284 * @val: Value being written.
286 * Note that for raw writes to iio channels, if the value provided is
287 * in standard units, the affect of the scale and offset must be removed
288 * as (value / scale) - offset.
290 int iio_write_channel_raw(struct iio_channel *chan, int val);
293 * iio_read_max_channel_raw() - read maximum available raw value from a given
294 * channel, i.e. the maximum possible value.
295 * @chan: The channel being queried.
296 * @val: Value read back.
298 * Note, if standard units are required, raw reads from iio channels
299 * need the offset (default 0) and scale (default 1) to be applied
300 * as (raw + offset) * scale.
302 int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
305 * iio_read_min_channel_raw() - read minimum available raw value from a given
306 * channel, i.e. the minimum possible value.
307 * @chan: The channel being queried.
308 * @val: Value read back.
310 * Note, if standard units are required, raw reads from iio channels
311 * need the offset (default 0) and scale (default 1) to be applied
312 * as (raw + offset) * scale.
314 int iio_read_min_channel_raw(struct iio_channel *chan, int *val);
317 * iio_read_avail_channel_raw() - read available raw values from a given channel
318 * @chan: The channel being queried.
319 * @vals: Available values read back.
320 * @length: Number of entries in vals.
322 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
324 * For ranges, three vals are always returned; min, step and max.
325 * For lists, all the possible values are enumerated.
327 * Note, if standard units are required, raw available values from iio
328 * channels need the offset (default 0) and scale (default 1) to be applied
329 * as (raw + offset) * scale.
331 int iio_read_avail_channel_raw(struct iio_channel *chan,
332 const int **vals, int *length);
335 * iio_read_avail_channel_attribute() - read available channel attribute values
336 * @chan: The channel being queried.
337 * @vals: Available values read back.
338 * @type: Type of values read back.
339 * @length: Number of entries in vals.
340 * @attribute: info attribute to be read back.
342 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
344 int iio_read_avail_channel_attribute(struct iio_channel *chan,
345 const int **vals, int *type, int *length,
346 enum iio_chan_info_enum attribute);
349 * iio_get_channel_type() - get the type of a channel
350 * @channel: The channel being queried.
351 * @type: The type of the channel.
353 * returns the enum iio_chan_type of the channel
355 int iio_get_channel_type(struct iio_channel *channel,
356 enum iio_chan_type *type);
359 * iio_read_channel_offset() - read the offset value for a channel
360 * @chan: The channel being queried.
361 * @val: First part of value read back.
362 * @val2: Second part of value read back.
364 * Note returns a description of what is in val and val2, such
365 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
368 int iio_read_channel_offset(struct iio_channel *chan, int *val,
372 * iio_read_channel_scale() - read the scale value for a channel
373 * @chan: The channel being queried.
374 * @val: First part of value read back.
375 * @val2: Second part of value read back.
377 * Note returns a description of what is in val and val2, such
378 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
381 int iio_read_channel_scale(struct iio_channel *chan, int *val,
385 * iio_convert_raw_to_processed() - Converts a raw value to a processed value
386 * @chan: The channel being queried
387 * @raw: The raw IIO to convert
388 * @processed: The result of the conversion
389 * @scale: Scale factor to apply during the conversion
391 * Returns an error code or 0.
393 * This function converts a raw value to processed value for a specific channel.
394 * A raw value is the device internal representation of a sample and the value
395 * returned by iio_read_channel_raw, so the unit of that value is device
396 * depended. A processed value on the other hand is value has a normed unit
397 * according with the IIO specification.
399 * The scale factor allows to increase the precession of the returned value. For
400 * a scale factor of 1 the function will return the result in the normal IIO
401 * unit for the channel type. E.g. millivolt for voltage channels, if you want
402 * nanovolts instead pass 1000000 as the scale factor.
404 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
405 int *processed, unsigned int scale);
408 * iio_get_channel_ext_info_count() - get number of ext_info attributes
409 * connected to the channel.
410 * @chan: The channel being queried
412 * Returns the number of ext_info attributes
414 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
417 * iio_read_channel_ext_info() - read ext_info attribute from a given channel
418 * @chan: The channel being queried.
419 * @attr: The ext_info attribute to read.
420 * @buf: Where to store the attribute value. Assumed to hold
421 * at least PAGE_SIZE bytes.
423 * Returns the number of bytes written to buf (perhaps w/o zero termination;
424 * it need not even be a string), or an error code.
426 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
427 const char *attr, char *buf);
430 * iio_write_channel_ext_info() - write ext_info attribute from a given channel
431 * @chan: The channel being queried.
432 * @attr: The ext_info attribute to read.
433 * @buf: The new attribute value. Strings needs to be zero-
434 * terminated, but the terminator should not be included
436 * @len: The size of the new attribute value.
438 * Returns the number of accepted bytes, which should be the same as len.
439 * An error code can also be returned.
441 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
442 const char *buf, size_t len);