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 * of_iio_channel_get_by_name() - get description of all that is needed to access channel.
103 * @np: Pointer to consumer device tree 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'
109 struct iio_channel *of_iio_channel_get_by_name(struct device_node *np, const char *name);
111 static inline struct iio_channel *
112 of_iio_channel_get_by_name(struct device_node *np, const char *name)
119 * devm_of_iio_channel_get_by_name() - Resource managed version of of_iio_channel_get_by_name().
120 * @dev: Pointer to consumer device.
121 * @np: Pointer to consumer device tree node
122 * @consumer_channel: Unique name to identify the channel on the consumer
123 * side. This typically describes the channels use within
124 * the consumer. E.g. 'battery_voltage'
126 * Returns a pointer to negative errno if it is not able to get the iio channel
127 * otherwise returns valid pointer for iio channel.
129 * The allocated iio channel is automatically released when the device is
132 struct iio_channel *devm_of_iio_channel_get_by_name(struct device *dev,
133 struct device_node *np,
134 const char *consumer_channel);
136 struct iio_cb_buffer;
138 * iio_channel_get_all_cb() - register callback for triggered capture
139 * @dev: Pointer to client device.
140 * @cb: Callback function.
141 * @private: Private data passed to callback.
143 * NB right now we have no ability to mux data from multiple devices.
144 * So if the channels requested come from different devices this will
147 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
148 int (*cb)(const void *data,
152 * iio_channel_cb_set_buffer_watermark() - set the buffer watermark.
153 * @cb_buffer: The callback buffer from whom we want the channel
155 * @watermark: buffer watermark in bytes.
157 * This function allows to configure the buffer watermark.
159 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buffer,
163 * iio_channel_release_all_cb() - release and unregister the callback.
164 * @cb_buffer: The callback buffer that was allocated.
166 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
169 * iio_channel_start_all_cb() - start the flow of data through callback.
170 * @cb_buff: The callback buffer we are starting.
172 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
175 * iio_channel_stop_all_cb() - stop the flow of data through the callback.
176 * @cb_buff: The callback buffer we are stopping.
178 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
181 * iio_channel_cb_get_channels() - get access to the underlying channels.
182 * @cb_buffer: The callback buffer from whom we want the channel
185 * This function allows one to obtain information about the channels.
186 * Whilst this may allow direct reading if all buffers are disabled, the
187 * primary aim is to allow drivers that are consuming a channel to query
188 * things like scaling of the channel.
191 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
194 * iio_channel_cb_get_iio_dev() - get access to the underlying device.
195 * @cb_buffer: The callback buffer from whom we want the device
198 * This function allows one to obtain information about the device.
199 * The primary aim is to allow drivers that are consuming a device to query
200 * things like current trigger.
203 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
206 * iio_read_channel_raw() - read from a given channel
207 * @chan: The channel being queried.
208 * @val: Value read back.
210 * Note raw reads from iio channels are in adc counts and hence
211 * scale will need to be applied if standard units required.
213 int iio_read_channel_raw(struct iio_channel *chan,
217 * iio_read_channel_average_raw() - read from a given channel
218 * @chan: The channel being queried.
219 * @val: Value read back.
221 * Note raw reads from iio channels are in adc counts and hence
222 * scale will need to be applied if standard units required.
224 * In opposit to the normal iio_read_channel_raw this function
225 * returns the average of multiple reads.
227 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
230 * iio_read_channel_processed() - read processed value from a given channel
231 * @chan: The channel being queried.
232 * @val: Value read back.
234 * Returns an error code or 0.
236 * This function will read a processed value from a channel. A processed value
237 * means that this value will have the correct unit and not some device internal
238 * representation. If the device does not support reporting a processed value
239 * the function will query the raw value and the channels scale and offset and
240 * do the appropriate transformation.
242 int iio_read_channel_processed(struct iio_channel *chan, int *val);
245 * iio_read_channel_processed_scale() - read and scale a processed value
246 * @chan: The channel being queried.
247 * @val: Value read back.
248 * @scale: Scale factor to apply during the conversion
250 * Returns an error code or 0.
252 * This function will read a processed value from a channel. This will work
253 * like @iio_read_channel_processed() but also scale with an additional
254 * scale factor while attempting to minimize any precision loss.
256 int iio_read_channel_processed_scale(struct iio_channel *chan, int *val,
260 * iio_write_channel_attribute() - Write values to the device attribute.
261 * @chan: The channel being queried.
262 * @val: Value being written.
263 * @val2: Value being written.val2 use depends on attribute type.
264 * @attribute: info attribute to be read.
266 * Returns an error code or 0.
268 int iio_write_channel_attribute(struct iio_channel *chan, int val,
269 int val2, enum iio_chan_info_enum attribute);
272 * iio_read_channel_attribute() - Read values from the device attribute.
273 * @chan: The channel being queried.
274 * @val: Value being written.
275 * @val2: Value being written.Val2 use depends on attribute type.
276 * @attribute: info attribute to be written.
278 * Returns an error code if failed. Else returns a description of what is in val
279 * and val2, such as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
282 int iio_read_channel_attribute(struct iio_channel *chan, int *val,
283 int *val2, enum iio_chan_info_enum attribute);
286 * iio_write_channel_raw() - write to a given channel
287 * @chan: The channel being queried.
288 * @val: Value being written.
290 * Note raw writes to iio channels are in dac counts and hence
291 * scale will need to be applied if standard units required.
293 int iio_write_channel_raw(struct iio_channel *chan, int val);
296 * iio_read_max_channel_raw() - read maximum available raw value from a given
297 * channel, i.e. the maximum possible value.
298 * @chan: The channel being queried.
299 * @val: Value read back.
301 * Note raw reads from iio channels are in adc counts and hence
302 * scale will need to be applied if standard units are required.
304 int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
307 * iio_read_avail_channel_raw() - read available raw values from a given channel
308 * @chan: The channel being queried.
309 * @vals: Available values read back.
310 * @length: Number of entries in vals.
312 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
314 * For ranges, three vals are always returned; min, step and max.
315 * For lists, all the possible values are enumerated.
317 * Note raw available values from iio channels are in adc counts and
318 * hence scale will need to be applied if standard units are required.
320 int iio_read_avail_channel_raw(struct iio_channel *chan,
321 const int **vals, int *length);
324 * iio_read_avail_channel_attribute() - read available channel attribute values
325 * @chan: The channel being queried.
326 * @vals: Available values read back.
327 * @type: Type of values read back.
328 * @length: Number of entries in vals.
329 * @attribute: info attribute to be read back.
331 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
333 int iio_read_avail_channel_attribute(struct iio_channel *chan,
334 const int **vals, int *type, int *length,
335 enum iio_chan_info_enum attribute);
338 * iio_get_channel_type() - get the type of a channel
339 * @channel: The channel being queried.
340 * @type: The type of the channel.
342 * returns the enum iio_chan_type of the channel
344 int iio_get_channel_type(struct iio_channel *channel,
345 enum iio_chan_type *type);
348 * iio_read_channel_offset() - read the offset value for a channel
349 * @chan: The channel being queried.
350 * @val: First part of value read back.
351 * @val2: Second part of value read back.
353 * Note returns a description of what is in val and val2, such
354 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
357 int iio_read_channel_offset(struct iio_channel *chan, int *val,
361 * iio_read_channel_scale() - read the scale value for a channel
362 * @chan: The channel being queried.
363 * @val: First part of value read back.
364 * @val2: Second part of value read back.
366 * Note returns a description of what is in val and val2, such
367 * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
370 int iio_read_channel_scale(struct iio_channel *chan, int *val,
374 * iio_convert_raw_to_processed() - Converts a raw value to a processed value
375 * @chan: The channel being queried
376 * @raw: The raw IIO to convert
377 * @processed: The result of the conversion
378 * @scale: Scale factor to apply during the conversion
380 * Returns an error code or 0.
382 * This function converts a raw value to processed value for a specific channel.
383 * A raw value is the device internal representation of a sample and the value
384 * returned by iio_read_channel_raw, so the unit of that value is device
385 * depended. A processed value on the other hand is value has a normed unit
386 * according with the IIO specification.
388 * The scale factor allows to increase the precession of the returned value. For
389 * a scale factor of 1 the function will return the result in the normal IIO
390 * unit for the channel type. E.g. millivolt for voltage channels, if you want
391 * nanovolts instead pass 1000000 as the scale factor.
393 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
394 int *processed, unsigned int scale);
397 * iio_get_channel_ext_info_count() - get number of ext_info attributes
398 * connected to the channel.
399 * @chan: The channel being queried
401 * Returns the number of ext_info attributes
403 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
406 * iio_read_channel_ext_info() - read ext_info attribute from a given channel
407 * @chan: The channel being queried.
408 * @attr: The ext_info attribute to read.
409 * @buf: Where to store the attribute value. Assumed to hold
410 * at least PAGE_SIZE bytes.
412 * Returns the number of bytes written to buf (perhaps w/o zero termination;
413 * it need not even be a string), or an error code.
415 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
416 const char *attr, char *buf);
419 * iio_write_channel_ext_info() - write ext_info attribute from a given channel
420 * @chan: The channel being queried.
421 * @attr: The ext_info attribute to read.
422 * @buf: The new attribute value. Strings needs to be zero-
423 * terminated, but the terminator should not be included
425 * @len: The size of the new attribute value.
427 * Returns the number of accepted bytes, which should be the same as len.
428 * An error code can also be returned.
430 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
431 const char *buf, size_t len);