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 struct fwnode_handle;
17 
18 /**
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.
23  */
24 struct iio_channel {
25 	struct iio_dev *indio_dev;
26 	const struct iio_chan_spec *channel;
27 	void *data;
28 };
29 
30 /**
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
35  *			was registered.
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'
39  */
40 struct iio_channel *iio_channel_get(struct device *dev,
41 				    const char *consumer_channel);
42 
43 /**
44  * iio_channel_release() - release channels obtained via iio_channel_get
45  * @chan:		The channel to be released.
46  */
47 void iio_channel_release(struct iio_channel *chan);
48 
49 /**
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
54  *			was registered.
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'
58  *
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.
61  *
62  * The allocated iio channel is automatically released when the device is
63  * unbound.
64  */
65 struct iio_channel *devm_iio_channel_get(struct device *dev,
66 					 const char *consumer_channel);
67 /**
68  * iio_channel_get_all() - get all channels associated with a client
69  * @dev:		Pointer to consumer device.
70  *
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.
75  */
76 struct iio_channel *iio_channel_get_all(struct device *dev);
77 
78 /**
79  * iio_channel_release_all() - reverse iio_channel_get_all
80  * @chan:		Array of channels to be released.
81  */
82 void iio_channel_release_all(struct iio_channel *chan);
83 
84 /**
85  * devm_iio_channel_get_all() - Resource managed version of
86  *				iio_channel_get_all().
87  * @dev: Pointer to consumer device.
88  *
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.
92  *
93  * This function is used by fairly generic consumers to get all the
94  * channels registered as having this consumer.
95  *
96  * The allocated iio channels are automatically released when the device is
97  * unbounded.
98  */
99 struct iio_channel *devm_iio_channel_get_all(struct device *dev);
100 
101 /**
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'
107  */
108 struct iio_channel *fwnode_iio_channel_get_by_name(struct fwnode_handle *fwnode,
109 						   const char *name);
110 
111 /**
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'
119  *
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.
122  *
123  * The allocated iio channel is automatically released when the device is
124  * unbound.
125  */
126 struct iio_channel *devm_fwnode_iio_channel_get_by_name(struct device *dev,
127 							struct fwnode_handle *fwnode,
128 							const char *consumer_channel);
129 
130 struct iio_cb_buffer;
131 /**
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.
136  *
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
139  * fail.
140  */
141 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
142 					     int (*cb)(const void *data,
143 						       void *private),
144 					     void *private);
145 /**
146  * iio_channel_cb_set_buffer_watermark() - set the buffer watermark.
147  * @cb_buffer:		The callback buffer from whom we want the channel
148  *			information.
149  * @watermark: buffer watermark in bytes.
150  *
151  * This function allows to configure the buffer watermark.
152  */
153 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buffer,
154 					size_t watermark);
155 
156 /**
157  * iio_channel_release_all_cb() - release and unregister the callback.
158  * @cb_buffer:		The callback buffer that was allocated.
159  */
160 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
161 
162 /**
163  * iio_channel_start_all_cb() - start the flow of data through callback.
164  * @cb_buff:		The callback buffer we are starting.
165  */
166 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
167 
168 /**
169  * iio_channel_stop_all_cb() - stop the flow of data through the callback.
170  * @cb_buff:		The callback buffer we are stopping.
171  */
172 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
173 
174 /**
175  * iio_channel_cb_get_channels() - get access to the underlying channels.
176  * @cb_buffer:		The callback buffer from whom we want the channel
177  *			information.
178  *
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.
183  */
184 struct iio_channel
185 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
186 
187 /**
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
190  *			information.
191  *
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.
195  */
196 struct iio_dev
197 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
198 
199 /**
200  * iio_read_channel_raw() - read from a given channel
201  * @chan:		The channel being queried.
202  * @val:		Value read back.
203  *
204  * Note raw reads from iio channels are in adc counts and hence
205  * scale will need to be applied if standard units required.
206  */
207 int iio_read_channel_raw(struct iio_channel *chan,
208 			 int *val);
209 
210 /**
211  * iio_read_channel_average_raw() - read from a given channel
212  * @chan:		The channel being queried.
213  * @val:		Value read back.
214  *
215  * Note raw reads from iio channels are in adc counts and hence
216  * scale will need to be applied if standard units required.
217  *
218  * In opposit to the normal iio_read_channel_raw this function
219  * returns the average of multiple reads.
220  */
221 int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
222 
223 /**
224  * iio_read_channel_processed() - read processed value from a given channel
225  * @chan:		The channel being queried.
226  * @val:		Value read back.
227  *
228  * Returns an error code or 0.
229  *
230  * This function will read a processed value from a channel. A processed value
231  * means that this value will have the correct unit and not some device internal
232  * representation. If the device does not support reporting a processed value
233  * the function will query the raw value and the channels scale and offset and
234  * do the appropriate transformation.
235  */
236 int iio_read_channel_processed(struct iio_channel *chan, int *val);
237 
238 /**
239  * iio_read_channel_processed_scale() - read and scale a processed value
240  * @chan:		The channel being queried.
241  * @val:		Value read back.
242  * @scale:		Scale factor to apply during the conversion
243  *
244  * Returns an error code or 0.
245  *
246  * This function will read a processed value from a channel. This will work
247  * like @iio_read_channel_processed() but also scale with an additional
248  * scale factor while attempting to minimize any precision loss.
249  */
250 int iio_read_channel_processed_scale(struct iio_channel *chan, int *val,
251 				     unsigned int scale);
252 
253 /**
254  * iio_write_channel_attribute() - Write values to the device attribute.
255  * @chan:	The channel being queried.
256  * @val:	Value being written.
257  * @val2:	Value being written.val2 use depends on attribute type.
258  * @attribute:	info attribute to be read.
259  *
260  * Returns an error code or 0.
261  */
262 int iio_write_channel_attribute(struct iio_channel *chan, int val,
263 				int val2, enum iio_chan_info_enum attribute);
264 
265 /**
266  * iio_read_channel_attribute() - Read values from the device attribute.
267  * @chan:	The channel being queried.
268  * @val:	Value being written.
269  * @val2:	Value being written.Val2 use depends on attribute type.
270  * @attribute:	info attribute to be written.
271  *
272  * Returns an error code if failed. Else returns a description of what is in val
273  * and val2, such as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
274  * + val2/1e6
275  */
276 int iio_read_channel_attribute(struct iio_channel *chan, int *val,
277 			       int *val2, enum iio_chan_info_enum attribute);
278 
279 /**
280  * iio_write_channel_raw() - write to a given channel
281  * @chan:		The channel being queried.
282  * @val:		Value being written.
283  *
284  * Note raw writes to iio channels are in dac counts and hence
285  * scale will need to be applied if standard units required.
286  */
287 int iio_write_channel_raw(struct iio_channel *chan, int val);
288 
289 /**
290  * iio_read_max_channel_raw() - read maximum available raw value from a given
291  *				channel, i.e. the maximum possible value.
292  * @chan:		The channel being queried.
293  * @val:		Value read back.
294  *
295  * Note raw reads from iio channels are in adc counts and hence
296  * scale will need to be applied if standard units are required.
297  */
298 int iio_read_max_channel_raw(struct iio_channel *chan, int *val);
299 
300 /**
301  * iio_read_avail_channel_raw() - read available raw values from a given channel
302  * @chan:		The channel being queried.
303  * @vals:		Available values read back.
304  * @length:		Number of entries in vals.
305  *
306  * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
307  *
308  * For ranges, three vals are always returned; min, step and max.
309  * For lists, all the possible values are enumerated.
310  *
311  * Note raw available values from iio channels are in adc counts and
312  * hence scale will need to be applied if standard units are required.
313  */
314 int iio_read_avail_channel_raw(struct iio_channel *chan,
315 			       const int **vals, int *length);
316 
317 /**
318  * iio_read_avail_channel_attribute() - read available channel attribute values
319  * @chan:		The channel being queried.
320  * @vals:		Available values read back.
321  * @type:		Type of values read back.
322  * @length:		Number of entries in vals.
323  * @attribute:		info attribute to be read back.
324  *
325  * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
326  */
327 int iio_read_avail_channel_attribute(struct iio_channel *chan,
328 				     const int **vals, int *type, int *length,
329 				     enum iio_chan_info_enum attribute);
330 
331 /**
332  * iio_get_channel_type() - get the type of a channel
333  * @channel:		The channel being queried.
334  * @type:		The type of the channel.
335  *
336  * returns the enum iio_chan_type of the channel
337  */
338 int iio_get_channel_type(struct iio_channel *channel,
339 			 enum iio_chan_type *type);
340 
341 /**
342  * iio_read_channel_offset() - read the offset value for a channel
343  * @chan:		The channel being queried.
344  * @val:		First part of value read back.
345  * @val2:		Second part of value read back.
346  *
347  * Note returns a description of what is in val and val2, such
348  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
349  * + val2/1e6
350  */
351 int iio_read_channel_offset(struct iio_channel *chan, int *val,
352 			   int *val2);
353 
354 /**
355  * iio_read_channel_scale() - read the scale value for a channel
356  * @chan:		The channel being queried.
357  * @val:		First part of value read back.
358  * @val2:		Second part of value read back.
359  *
360  * Note returns a description of what is in val and val2, such
361  * as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
362  * + val2/1e6
363  */
364 int iio_read_channel_scale(struct iio_channel *chan, int *val,
365 			   int *val2);
366 
367 /**
368  * iio_convert_raw_to_processed() - Converts a raw value to a processed value
369  * @chan:		The channel being queried
370  * @raw:		The raw IIO to convert
371  * @processed:		The result of the conversion
372  * @scale:		Scale factor to apply during the conversion
373  *
374  * Returns an error code or 0.
375  *
376  * This function converts a raw value to processed value for a specific channel.
377  * A raw value is the device internal representation of a sample and the value
378  * returned by iio_read_channel_raw, so the unit of that value is device
379  * depended. A processed value on the other hand is value has a normed unit
380  * according with the IIO specification.
381  *
382  * The scale factor allows to increase the precession of the returned value. For
383  * a scale factor of 1 the function will return the result in the normal IIO
384  * unit for the channel type. E.g. millivolt for voltage channels, if you want
385  * nanovolts instead pass 1000000 as the scale factor.
386  */
387 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
388 	int *processed, unsigned int scale);
389 
390 /**
391  * iio_get_channel_ext_info_count() - get number of ext_info attributes
392  *				      connected to the channel.
393  * @chan:		The channel being queried
394  *
395  * Returns the number of ext_info attributes
396  */
397 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
398 
399 /**
400  * iio_read_channel_ext_info() - read ext_info attribute from a given channel
401  * @chan:		The channel being queried.
402  * @attr:		The ext_info attribute to read.
403  * @buf:		Where to store the attribute value. Assumed to hold
404  *			at least PAGE_SIZE bytes.
405  *
406  * Returns the number of bytes written to buf (perhaps w/o zero termination;
407  * it need not even be a string), or an error code.
408  */
409 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
410 				  const char *attr, char *buf);
411 
412 /**
413  * iio_write_channel_ext_info() - write ext_info attribute from a given channel
414  * @chan:		The channel being queried.
415  * @attr:		The ext_info attribute to read.
416  * @buf:		The new attribute value. Strings needs to be zero-
417  *			terminated, but the terminator should not be included
418  *			in the below len.
419  * @len:		The size of the new attribute value.
420  *
421  * Returns the number of accepted bytes, which should be the same as len.
422  * An error code can also be returned.
423  */
424 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
425 				   const char *buf, size_t len);
426 
427 #endif
428