xref: /linux/include/linux/iio/iio.h (revision 25aee3debe0464f6c680173041fa3de30ec9ff54)
1 
2 /* The industrial I/O core
3  *
4  * Copyright (c) 2008 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 _INDUSTRIAL_IO_H_
11 #define _INDUSTRIAL_IO_H_
12 
13 #include <linux/device.h>
14 #include <linux/cdev.h>
15 #include <linux/iio/types.h>
16 /* IIO TODO LIST */
17 /*
18  * Provide means of adjusting timer accuracy.
19  * Currently assumes nano seconds.
20  */
21 
22 enum iio_chan_info_enum {
23 	IIO_CHAN_INFO_RAW = 0,
24 	IIO_CHAN_INFO_PROCESSED,
25 	IIO_CHAN_INFO_SCALE,
26 	IIO_CHAN_INFO_OFFSET,
27 	IIO_CHAN_INFO_CALIBSCALE,
28 	IIO_CHAN_INFO_CALIBBIAS,
29 	IIO_CHAN_INFO_PEAK,
30 	IIO_CHAN_INFO_PEAK_SCALE,
31 	IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW,
32 	IIO_CHAN_INFO_AVERAGE_RAW,
33 	IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY,
34 	IIO_CHAN_INFO_SAMP_FREQ,
35 	IIO_CHAN_INFO_FREQUENCY,
36 	IIO_CHAN_INFO_PHASE,
37 	IIO_CHAN_INFO_HARDWAREGAIN,
38 };
39 
40 #define IIO_CHAN_INFO_SHARED_BIT(type) BIT(type*2)
41 #define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
42 
43 #define IIO_CHAN_INFO_RAW_SEPARATE_BIT			\
44 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_RAW)
45 #define IIO_CHAN_INFO_PROCESSED_SEPARATE_BIT			\
46 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PROCESSED)
47 #define IIO_CHAN_INFO_SCALE_SEPARATE_BIT		\
48 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_SCALE)
49 #define IIO_CHAN_INFO_SCALE_SHARED_BIT			\
50 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_SCALE)
51 #define IIO_CHAN_INFO_OFFSET_SEPARATE_BIT			\
52 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_OFFSET)
53 #define IIO_CHAN_INFO_OFFSET_SHARED_BIT			\
54 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_OFFSET)
55 #define IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT			\
56 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBSCALE)
57 #define IIO_CHAN_INFO_CALIBSCALE_SHARED_BIT			\
58 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_CALIBSCALE)
59 #define IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT			\
60 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBBIAS)
61 #define IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT			\
62 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_CALIBBIAS)
63 #define IIO_CHAN_INFO_PEAK_SEPARATE_BIT			\
64 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PEAK)
65 #define IIO_CHAN_INFO_PEAK_SHARED_BIT			\
66 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PEAK)
67 #define IIO_CHAN_INFO_PEAKSCALE_SEPARATE_BIT			\
68 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PEAKSCALE)
69 #define IIO_CHAN_INFO_PEAKSCALE_SHARED_BIT			\
70 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PEAKSCALE)
71 #define IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW_SEPARATE_BIT	\
72 	IIO_CHAN_INFO_SEPARATE_BIT(				\
73 		IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW)
74 #define IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW_SHARED_BIT	\
75 	IIO_CHAN_INFO_SHARED_BIT(				\
76 		IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW)
77 #define IIO_CHAN_INFO_AVERAGE_RAW_SEPARATE_BIT			\
78 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_AVERAGE_RAW)
79 #define IIO_CHAN_INFO_AVERAGE_RAW_SHARED_BIT			\
80 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_AVERAGE_RAW)
81 #define IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY_SHARED_BIT \
82 	IIO_CHAN_INFO_SHARED_BIT(			       \
83 		IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)
84 #define IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY_SEPARATE_BIT \
85 	IIO_CHAN_INFO_SEPARATE_BIT(			       \
86 		IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)
87 #define IIO_CHAN_INFO_SAMP_FREQ_SEPARATE_BIT		\
88 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_SAMP_FREQ)
89 #define IIO_CHAN_INFO_SAMP_FREQ_SHARED_BIT			\
90 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_SAMP_FREQ)
91 #define IIO_CHAN_INFO_FREQUENCY_SEPARATE_BIT			\
92 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_FREQUENCY)
93 #define IIO_CHAN_INFO_FREQUENCY_SHARED_BIT			\
94 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_FREQUENCY)
95 #define IIO_CHAN_INFO_PHASE_SEPARATE_BIT			\
96 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PHASE)
97 #define IIO_CHAN_INFO_PHASE_SHARED_BIT			\
98 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PHASE)
99 #define IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT			\
100 	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_HARDWAREGAIN)
101 #define IIO_CHAN_INFO_HARDWAREGAIN_SHARED_BIT			\
102 	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_HARDWAREGAIN)
103 
104 enum iio_endian {
105 	IIO_CPU,
106 	IIO_BE,
107 	IIO_LE,
108 };
109 
110 struct iio_chan_spec;
111 struct iio_dev;
112 
113 /**
114  * struct iio_chan_spec_ext_info - Extended channel info attribute
115  * @name:	Info attribute name
116  * @shared:	Whether this attribute is shared between all channels.
117  * @read:	Read callback for this info attribute, may be NULL.
118  * @write:	Write callback for this info attribute, may be NULL.
119  * @private:	Data private to the driver.
120  */
121 struct iio_chan_spec_ext_info {
122 	const char *name;
123 	bool shared;
124 	ssize_t (*read)(struct iio_dev *, uintptr_t private,
125 			struct iio_chan_spec const *, char *buf);
126 	ssize_t (*write)(struct iio_dev *, uintptr_t private,
127 			 struct iio_chan_spec const *, const char *buf,
128 			 size_t len);
129 	uintptr_t private;
130 };
131 
132 /**
133  * struct iio_enum - Enum channel info attribute
134  * @items:	An array of strings.
135  * @num_items:	Length of the item array.
136  * @set:	Set callback function, may be NULL.
137  * @get:	Get callback function, may be NULL.
138  *
139  * The iio_enum struct can be used to implement enum style channel attributes.
140  * Enum style attributes are those which have a set of strings which map to
141  * unsigned integer values. The IIO enum helper code takes care of mapping
142  * between value and string as well as generating a "_available" file which
143  * contains a list of all available items. The set callback will be called when
144  * the attribute is updated. The last parameter is the index to the newly
145  * activated item. The get callback will be used to query the currently active
146  * item and is supposed to return the index for it.
147  */
148 struct iio_enum {
149 	const char * const *items;
150 	unsigned int num_items;
151 	int (*set)(struct iio_dev *, const struct iio_chan_spec *, unsigned int);
152 	int (*get)(struct iio_dev *, const struct iio_chan_spec *);
153 };
154 
155 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
156 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
157 ssize_t iio_enum_read(struct iio_dev *indio_dev,
158 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
159 ssize_t iio_enum_write(struct iio_dev *indio_dev,
160 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
161 	size_t len);
162 
163 /**
164  * IIO_ENUM() - Initialize enum extended channel attribute
165  * @_name:	Attribute name
166  * @_shared:	Whether the attribute is shared between all channels
167  * @_e:		Pointer to a iio_enum struct
168  *
169  * This should usually be used together with IIO_ENUM_AVAILABLE()
170  */
171 #define IIO_ENUM(_name, _shared, _e) \
172 { \
173 	.name = (_name), \
174 	.shared = (_shared), \
175 	.read = iio_enum_read, \
176 	.write = iio_enum_write, \
177 	.private = (uintptr_t)(_e), \
178 }
179 
180 /**
181  * IIO_ENUM_AVAILABLE() - Initialize enum available extended channel attribute
182  * @_name:	Attribute name ("_available" will be appended to the name)
183  * @_e:		Pointer to a iio_enum struct
184  *
185  * Creates a read only attribute which list all the available enum items in a
186  * space separated list. This should usually be used together with IIO_ENUM()
187  */
188 #define IIO_ENUM_AVAILABLE(_name, _e) \
189 { \
190 	.name = (_name "_available"), \
191 	.shared = true, \
192 	.read = iio_enum_available_read, \
193 	.private = (uintptr_t)(_e), \
194 }
195 
196 /**
197  * struct iio_chan_spec - specification of a single channel
198  * @type:		What type of measurement is the channel making.
199  * @channel:		What number do we wish to assign the channel.
200  * @channel2:		If there is a second number for a differential
201  *			channel then this is it. If modified is set then the
202  *			value here specifies the modifier.
203  * @address:		Driver specific identifier.
204  * @scan_index:		Monotonic index to give ordering in scans when read
205  *			from a buffer.
206  * @scan_type:		Sign:		's' or 'u' to specify signed or unsigned
207  *			realbits:	Number of valid bits of data
208  *			storage_bits:	Realbits + padding
209  *			shift:		Shift right by this before masking out
210  *					realbits.
211  *			endianness:	little or big endian
212  * @info_mask:		What information is to be exported about this channel.
213  *			This includes calibbias, scale etc.
214  * @event_mask:		What events can this channel produce.
215  * @ext_info:		Array of extended info attributes for this channel.
216  *			The array is NULL terminated, the last element should
217  *			have its name field set to NULL.
218  * @extend_name:	Allows labeling of channel attributes with an
219  *			informative name. Note this has no effect codes etc,
220  *			unlike modifiers.
221  * @datasheet_name:	A name used in in-kernel mapping of channels. It should
222  *			correspond to the first name that the channel is referred
223  *			to by in the datasheet (e.g. IND), or the nearest
224  *			possible compound name (e.g. IND-INC).
225  * @modified:		Does a modifier apply to this channel. What these are
226  *			depends on the channel type.  Modifier is set in
227  *			channel2. Examples are IIO_MOD_X for axial sensors about
228  *			the 'x' axis.
229  * @indexed:		Specify the channel has a numerical index. If not,
230  *			the channel index number will be suppressed for sysfs
231  *			attributes but not for event codes.
232  * @differential:	Channel is differential.
233  */
234 struct iio_chan_spec {
235 	enum iio_chan_type	type;
236 	int			channel;
237 	int			channel2;
238 	unsigned long		address;
239 	int			scan_index;
240 	struct {
241 		char	sign;
242 		u8	realbits;
243 		u8	storagebits;
244 		u8	shift;
245 		enum iio_endian endianness;
246 	} scan_type;
247 	long			info_mask;
248 	long			event_mask;
249 	const struct iio_chan_spec_ext_info *ext_info;
250 	const char		*extend_name;
251 	const char		*datasheet_name;
252 	unsigned		modified:1;
253 	unsigned		indexed:1;
254 	unsigned		output:1;
255 	unsigned		differential:1;
256 };
257 
258 #define IIO_ST(si, rb, sb, sh)						\
259 	{ .sign = si, .realbits = rb, .storagebits = sb, .shift = sh }
260 
261 #define IIO_CHAN_SOFT_TIMESTAMP(_si)					\
262 	{ .type = IIO_TIMESTAMP, .channel = -1,				\
263 			.scan_index = _si, .scan_type = IIO_ST('s', 64, 64, 0) }
264 
265 /**
266  * iio_get_time_ns() - utility function to get a time stamp for events etc
267  **/
268 static inline s64 iio_get_time_ns(void)
269 {
270 	struct timespec ts;
271 	/*
272 	 * calls getnstimeofday.
273 	 * If hrtimers then up to ns accurate, if not microsecond.
274 	 */
275 	ktime_get_real_ts(&ts);
276 
277 	return timespec_to_ns(&ts);
278 }
279 
280 /* Device operating modes */
281 #define INDIO_DIRECT_MODE		0x01
282 #define INDIO_BUFFER_TRIGGERED		0x02
283 #define INDIO_BUFFER_HARDWARE		0x08
284 
285 #define INDIO_ALL_BUFFER_MODES					\
286 	(INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE)
287 
288 struct iio_trigger; /* forward declaration */
289 struct iio_dev;
290 
291 /**
292  * struct iio_info - constant information about device
293  * @driver_module:	module structure used to ensure correct
294  *			ownership of chrdevs etc
295  * @event_attrs:	event control attributes
296  * @attrs:		general purpose device attributes
297  * @read_raw:		function to request a value from the device.
298  *			mask specifies which value. Note 0 means a reading of
299  *			the channel in question.  Return value will specify the
300  *			type of value returned by the device. val and val2 will
301  *			contain the elements making up the returned value.
302  * @write_raw:		function to write a value to the device.
303  *			Parameters are the same as for read_raw.
304  * @write_raw_get_fmt:	callback function to query the expected
305  *			format/precision. If not set by the driver, write_raw
306  *			returns IIO_VAL_INT_PLUS_MICRO.
307  * @read_event_config:	find out if the event is enabled.
308  * @write_event_config:	set if the event is enabled.
309  * @read_event_value:	read a value associated with the event. Meaning
310  *			is event dependant. event_code specifies which event.
311  * @write_event_value:	write the value associated with the event.
312  *			Meaning is event dependent.
313  * @validate_trigger:	function to validate the trigger when the
314  *			current trigger gets changed.
315  **/
316 struct iio_info {
317 	struct module			*driver_module;
318 	struct attribute_group		*event_attrs;
319 	const struct attribute_group	*attrs;
320 
321 	int (*read_raw)(struct iio_dev *indio_dev,
322 			struct iio_chan_spec const *chan,
323 			int *val,
324 			int *val2,
325 			long mask);
326 
327 	int (*write_raw)(struct iio_dev *indio_dev,
328 			 struct iio_chan_spec const *chan,
329 			 int val,
330 			 int val2,
331 			 long mask);
332 
333 	int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
334 			 struct iio_chan_spec const *chan,
335 			 long mask);
336 
337 	int (*read_event_config)(struct iio_dev *indio_dev,
338 				 u64 event_code);
339 
340 	int (*write_event_config)(struct iio_dev *indio_dev,
341 				  u64 event_code,
342 				  int state);
343 
344 	int (*read_event_value)(struct iio_dev *indio_dev,
345 				u64 event_code,
346 				int *val);
347 	int (*write_event_value)(struct iio_dev *indio_dev,
348 				 u64 event_code,
349 				 int val);
350 	int (*validate_trigger)(struct iio_dev *indio_dev,
351 				struct iio_trigger *trig);
352 	int (*update_scan_mode)(struct iio_dev *indio_dev,
353 				const unsigned long *scan_mask);
354 	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
355 				  unsigned reg, unsigned writeval,
356 				  unsigned *readval);
357 };
358 
359 /**
360  * struct iio_buffer_setup_ops - buffer setup related callbacks
361  * @preenable:		[DRIVER] function to run prior to marking buffer enabled
362  * @postenable:		[DRIVER] function to run after marking buffer enabled
363  * @predisable:		[DRIVER] function to run prior to marking buffer
364  *			disabled
365  * @postdisable:	[DRIVER] function to run after marking buffer disabled
366  * @validate_scan_mask: [DRIVER] function callback to check whether a given
367  *			scan mask is valid for the device.
368  */
369 struct iio_buffer_setup_ops {
370 	int				(*preenable)(struct iio_dev *);
371 	int				(*postenable)(struct iio_dev *);
372 	int				(*predisable)(struct iio_dev *);
373 	int				(*postdisable)(struct iio_dev *);
374 	bool (*validate_scan_mask)(struct iio_dev *indio_dev,
375 				   const unsigned long *scan_mask);
376 };
377 
378 /**
379  * struct iio_dev - industrial I/O device
380  * @id:			[INTERN] used to identify device internally
381  * @modes:		[DRIVER] operating modes supported by device
382  * @currentmode:	[DRIVER] current operating mode
383  * @dev:		[DRIVER] device structure, should be assigned a parent
384  *			and owner
385  * @event_interface:	[INTERN] event chrdevs associated with interrupt lines
386  * @buffer:		[DRIVER] any buffer present
387  * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
388  * @mlock:		[INTERN] lock used to prevent simultaneous device state
389  *			changes
390  * @available_scan_masks: [DRIVER] optional array of allowed bitmasks
391  * @masklength:		[INTERN] the length of the mask established from
392  *			channels
393  * @active_scan_mask:	[INTERN] union of all scan masks requested by buffers
394  * @scan_timestamp:	[INTERN] set if any buffers have requested timestamp
395  * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
396  * @trig:		[INTERN] current device trigger (buffer modes)
397  * @pollfunc:		[DRIVER] function run on trigger being received
398  * @channels:		[DRIVER] channel specification structure table
399  * @num_channels:	[DRIVER] number of channels specified in @channels.
400  * @channel_attr_list:	[INTERN] keep track of automatically created channel
401  *			attributes
402  * @chan_attr_group:	[INTERN] group for all attrs in base directory
403  * @name:		[DRIVER] name of the device.
404  * @info:		[DRIVER] callbacks and constant info from driver
405  * @info_exist_lock:	[INTERN] lock to prevent use during removal
406  * @setup_ops:		[DRIVER] callbacks to call before and after buffer
407  *			enable/disable
408  * @chrdev:		[INTERN] associated character device
409  * @groups:		[INTERN] attribute groups
410  * @groupcounter:	[INTERN] index of next attribute group
411  * @flags:		[INTERN] file ops related flags including busy flag.
412  * @debugfs_dentry:	[INTERN] device specific debugfs dentry.
413  * @cached_reg_addr:	[INTERN] cached register address for debugfs reads.
414  */
415 struct iio_dev {
416 	int				id;
417 
418 	int				modes;
419 	int				currentmode;
420 	struct device			dev;
421 
422 	struct iio_event_interface	*event_interface;
423 
424 	struct iio_buffer		*buffer;
425 	int				scan_bytes;
426 	struct mutex			mlock;
427 
428 	const unsigned long		*available_scan_masks;
429 	unsigned			masklength;
430 	const unsigned long		*active_scan_mask;
431 	bool				scan_timestamp;
432 	unsigned			scan_index_timestamp;
433 	struct iio_trigger		*trig;
434 	struct iio_poll_func		*pollfunc;
435 
436 	struct iio_chan_spec const	*channels;
437 	int				num_channels;
438 
439 	struct list_head		channel_attr_list;
440 	struct attribute_group		chan_attr_group;
441 	const char			*name;
442 	const struct iio_info		*info;
443 	struct mutex			info_exist_lock;
444 	const struct iio_buffer_setup_ops	*setup_ops;
445 	struct cdev			chrdev;
446 #define IIO_MAX_GROUPS 6
447 	const struct attribute_group	*groups[IIO_MAX_GROUPS + 1];
448 	int				groupcounter;
449 
450 	unsigned long			flags;
451 #if defined(CONFIG_DEBUG_FS)
452 	struct dentry			*debugfs_dentry;
453 	unsigned			cached_reg_addr;
454 #endif
455 };
456 
457 /**
458  * iio_find_channel_from_si() - get channel from its scan index
459  * @indio_dev:		device
460  * @si:			scan index to match
461  */
462 const struct iio_chan_spec
463 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si);
464 
465 /**
466  * iio_device_register() - register a device with the IIO subsystem
467  * @indio_dev:		Device structure filled by the device driver
468  **/
469 int iio_device_register(struct iio_dev *indio_dev);
470 
471 /**
472  * iio_device_unregister() - unregister a device from the IIO subsystem
473  * @indio_dev:		Device structure representing the device.
474  **/
475 void iio_device_unregister(struct iio_dev *indio_dev);
476 
477 /**
478  * iio_push_event() - try to add event to the list for userspace reading
479  * @indio_dev:		IIO device structure
480  * @ev_code:		What event
481  * @timestamp:		When the event occurred
482  **/
483 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);
484 
485 extern struct bus_type iio_bus_type;
486 
487 /**
488  * iio_device_put() - reference counted deallocation of struct device
489  * @indio_dev: 		IIO device structure containing the device
490  **/
491 static inline void iio_device_put(struct iio_dev *indio_dev)
492 {
493 	if (indio_dev)
494 		put_device(&indio_dev->dev);
495 };
496 
497 /**
498  * dev_to_iio_dev() - Get IIO device struct from a device struct
499  * @dev: 		The device embedded in the IIO device
500  *
501  * Note: The device must be a IIO device, otherwise the result is undefined.
502  */
503 static inline struct iio_dev *dev_to_iio_dev(struct device *dev)
504 {
505 	return container_of(dev, struct iio_dev, dev);
506 }
507 
508 /**
509  * iio_device_get() - increment reference count for the device
510  * @indio_dev: 		IIO device structure
511  *
512  * Returns: The passed IIO device
513  **/
514 static inline struct iio_dev *iio_device_get(struct iio_dev *indio_dev)
515 {
516 	return indio_dev ? dev_to_iio_dev(get_device(&indio_dev->dev)) : NULL;
517 }
518 
519 /* Can we make this smaller? */
520 #define IIO_ALIGN L1_CACHE_BYTES
521 /**
522  * iio_device_alloc() - allocate an iio_dev from a driver
523  * @sizeof_priv: 	Space to allocate for private structure.
524  **/
525 struct iio_dev *iio_device_alloc(int sizeof_priv);
526 
527 static inline void *iio_priv(const struct iio_dev *indio_dev)
528 {
529 	return (char *)indio_dev + ALIGN(sizeof(struct iio_dev), IIO_ALIGN);
530 }
531 
532 static inline struct iio_dev *iio_priv_to_dev(void *priv)
533 {
534 	return (struct iio_dev *)((char *)priv -
535 				  ALIGN(sizeof(struct iio_dev), IIO_ALIGN));
536 }
537 
538 /**
539  * iio_device_free() - free an iio_dev from a driver
540  * @indio_dev: 		the iio_dev associated with the device
541  **/
542 void iio_device_free(struct iio_dev *indio_dev);
543 
544 /**
545  * iio_buffer_enabled() - helper function to test if the buffer is enabled
546  * @indio_dev:		IIO device structure for device
547  **/
548 static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
549 {
550 	return indio_dev->currentmode
551 		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
552 };
553 
554 /**
555  * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
556  * @indio_dev:		IIO device structure for device
557  **/
558 #if defined(CONFIG_DEBUG_FS)
559 static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
560 {
561 	return indio_dev->debugfs_dentry;
562 };
563 #else
564 static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
565 {
566 	return NULL;
567 };
568 #endif
569 
570 #endif /* _INDUSTRIAL_IO_H_ */
571