1 /* The industrial I/O core
2  *
3  * Copyright (c) 2008 Jonathan Cameron
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 as published by
7  * the Free Software Foundation.
8  *
9  * Based on elements of hwmon and input subsystems.
10  */
11 
12 #define pr_fmt(fmt) "iio-core: " fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/idr.h>
17 #include <linux/kdev_t.h>
18 #include <linux/err.h>
19 #include <linux/device.h>
20 #include <linux/fs.h>
21 #include <linux/poll.h>
22 #include <linux/sched.h>
23 #include <linux/wait.h>
24 #include <linux/cdev.h>
25 #include <linux/slab.h>
26 #include <linux/anon_inodes.h>
27 #include <linux/debugfs.h>
28 #include <linux/iio/iio.h>
29 #include "iio_core.h"
30 #include "iio_core_trigger.h"
31 #include <linux/iio/sysfs.h>
32 #include <linux/iio/events.h>
33 #include <linux/iio/buffer.h>
34 
35 /* IDA to assign each registered device a unique id */
36 static DEFINE_IDA(iio_ida);
37 
38 static dev_t iio_devt;
39 
40 #define IIO_DEV_MAX 256
41 struct bus_type iio_bus_type = {
42 	.name = "iio",
43 };
44 EXPORT_SYMBOL(iio_bus_type);
45 
46 static struct dentry *iio_debugfs_dentry;
47 
48 static const char * const iio_direction[] = {
49 	[0] = "in",
50 	[1] = "out",
51 };
52 
53 static const char * const iio_chan_type_name_spec[] = {
54 	[IIO_VOLTAGE] = "voltage",
55 	[IIO_CURRENT] = "current",
56 	[IIO_POWER] = "power",
57 	[IIO_ACCEL] = "accel",
58 	[IIO_ANGL_VEL] = "anglvel",
59 	[IIO_MAGN] = "magn",
60 	[IIO_LIGHT] = "illuminance",
61 	[IIO_INTENSITY] = "intensity",
62 	[IIO_PROXIMITY] = "proximity",
63 	[IIO_TEMP] = "temp",
64 	[IIO_INCLI] = "incli",
65 	[IIO_ROT] = "rot",
66 	[IIO_ANGL] = "angl",
67 	[IIO_TIMESTAMP] = "timestamp",
68 	[IIO_CAPACITANCE] = "capacitance",
69 	[IIO_ALTVOLTAGE] = "altvoltage",
70 	[IIO_CCT] = "cct",
71 	[IIO_PRESSURE] = "pressure",
72 	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
73 	[IIO_ACTIVITY] = "activity",
74 	[IIO_STEPS] = "steps",
75 	[IIO_ENERGY] = "energy",
76 	[IIO_DISTANCE] = "distance",
77 	[IIO_VELOCITY] = "velocity",
78 	[IIO_CONCENTRATION] = "concentration",
79 	[IIO_RESISTANCE] = "resistance",
80 	[IIO_PH] = "ph",
81 };
82 
83 static const char * const iio_modifier_names[] = {
84 	[IIO_MOD_X] = "x",
85 	[IIO_MOD_Y] = "y",
86 	[IIO_MOD_Z] = "z",
87 	[IIO_MOD_X_AND_Y] = "x&y",
88 	[IIO_MOD_X_AND_Z] = "x&z",
89 	[IIO_MOD_Y_AND_Z] = "y&z",
90 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
91 	[IIO_MOD_X_OR_Y] = "x|y",
92 	[IIO_MOD_X_OR_Z] = "x|z",
93 	[IIO_MOD_Y_OR_Z] = "y|z",
94 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
95 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
96 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
97 	[IIO_MOD_LIGHT_BOTH] = "both",
98 	[IIO_MOD_LIGHT_IR] = "ir",
99 	[IIO_MOD_LIGHT_CLEAR] = "clear",
100 	[IIO_MOD_LIGHT_RED] = "red",
101 	[IIO_MOD_LIGHT_GREEN] = "green",
102 	[IIO_MOD_LIGHT_BLUE] = "blue",
103 	[IIO_MOD_QUATERNION] = "quaternion",
104 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
105 	[IIO_MOD_TEMP_OBJECT] = "object",
106 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
107 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
108 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
109 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
110 	[IIO_MOD_RUNNING] = "running",
111 	[IIO_MOD_JOGGING] = "jogging",
112 	[IIO_MOD_WALKING] = "walking",
113 	[IIO_MOD_STILL] = "still",
114 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
115 	[IIO_MOD_I] = "i",
116 	[IIO_MOD_Q] = "q",
117 	[IIO_MOD_CO2] = "co2",
118 	[IIO_MOD_VOC] = "voc",
119 };
120 
121 /* relies on pairs of these shared then separate */
122 static const char * const iio_chan_info_postfix[] = {
123 	[IIO_CHAN_INFO_RAW] = "raw",
124 	[IIO_CHAN_INFO_PROCESSED] = "input",
125 	[IIO_CHAN_INFO_SCALE] = "scale",
126 	[IIO_CHAN_INFO_OFFSET] = "offset",
127 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
128 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
129 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
130 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
131 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
132 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
133 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
134 	= "filter_low_pass_3db_frequency",
135 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
136 	= "filter_high_pass_3db_frequency",
137 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
138 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
139 	[IIO_CHAN_INFO_PHASE] = "phase",
140 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
141 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
142 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
143 	[IIO_CHAN_INFO_ENABLE] = "en",
144 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
145 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
146 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
147 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
148 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
149 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
150 };
151 
152 /**
153  * iio_find_channel_from_si() - get channel from its scan index
154  * @indio_dev:		device
155  * @si:			scan index to match
156  */
157 const struct iio_chan_spec
158 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
159 {
160 	int i;
161 
162 	for (i = 0; i < indio_dev->num_channels; i++)
163 		if (indio_dev->channels[i].scan_index == si)
164 			return &indio_dev->channels[i];
165 	return NULL;
166 }
167 
168 /* This turns up an awful lot */
169 ssize_t iio_read_const_attr(struct device *dev,
170 			    struct device_attribute *attr,
171 			    char *buf)
172 {
173 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
174 }
175 EXPORT_SYMBOL(iio_read_const_attr);
176 
177 static int __init iio_init(void)
178 {
179 	int ret;
180 
181 	/* Register sysfs bus */
182 	ret  = bus_register(&iio_bus_type);
183 	if (ret < 0) {
184 		pr_err("could not register bus type\n");
185 		goto error_nothing;
186 	}
187 
188 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
189 	if (ret < 0) {
190 		pr_err("failed to allocate char dev region\n");
191 		goto error_unregister_bus_type;
192 	}
193 
194 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
195 
196 	return 0;
197 
198 error_unregister_bus_type:
199 	bus_unregister(&iio_bus_type);
200 error_nothing:
201 	return ret;
202 }
203 
204 static void __exit iio_exit(void)
205 {
206 	if (iio_devt)
207 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
208 	bus_unregister(&iio_bus_type);
209 	debugfs_remove(iio_debugfs_dentry);
210 }
211 
212 #if defined(CONFIG_DEBUG_FS)
213 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
214 			      size_t count, loff_t *ppos)
215 {
216 	struct iio_dev *indio_dev = file->private_data;
217 	char buf[20];
218 	unsigned val = 0;
219 	ssize_t len;
220 	int ret;
221 
222 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
223 						  indio_dev->cached_reg_addr,
224 						  0, &val);
225 	if (ret)
226 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
227 
228 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
229 
230 	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
231 }
232 
233 static ssize_t iio_debugfs_write_reg(struct file *file,
234 		     const char __user *userbuf, size_t count, loff_t *ppos)
235 {
236 	struct iio_dev *indio_dev = file->private_data;
237 	unsigned reg, val;
238 	char buf[80];
239 	int ret;
240 
241 	count = min_t(size_t, count, (sizeof(buf)-1));
242 	if (copy_from_user(buf, userbuf, count))
243 		return -EFAULT;
244 
245 	buf[count] = 0;
246 
247 	ret = sscanf(buf, "%i %i", &reg, &val);
248 
249 	switch (ret) {
250 	case 1:
251 		indio_dev->cached_reg_addr = reg;
252 		break;
253 	case 2:
254 		indio_dev->cached_reg_addr = reg;
255 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
256 							  val, NULL);
257 		if (ret) {
258 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
259 				__func__);
260 			return ret;
261 		}
262 		break;
263 	default:
264 		return -EINVAL;
265 	}
266 
267 	return count;
268 }
269 
270 static const struct file_operations iio_debugfs_reg_fops = {
271 	.open = simple_open,
272 	.read = iio_debugfs_read_reg,
273 	.write = iio_debugfs_write_reg,
274 };
275 
276 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
277 {
278 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
279 }
280 
281 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
282 {
283 	struct dentry *d;
284 
285 	if (indio_dev->info->debugfs_reg_access == NULL)
286 		return 0;
287 
288 	if (!iio_debugfs_dentry)
289 		return 0;
290 
291 	indio_dev->debugfs_dentry =
292 		debugfs_create_dir(dev_name(&indio_dev->dev),
293 				   iio_debugfs_dentry);
294 	if (indio_dev->debugfs_dentry == NULL) {
295 		dev_warn(indio_dev->dev.parent,
296 			 "Failed to create debugfs directory\n");
297 		return -EFAULT;
298 	}
299 
300 	d = debugfs_create_file("direct_reg_access", 0644,
301 				indio_dev->debugfs_dentry,
302 				indio_dev, &iio_debugfs_reg_fops);
303 	if (!d) {
304 		iio_device_unregister_debugfs(indio_dev);
305 		return -ENOMEM;
306 	}
307 
308 	return 0;
309 }
310 #else
311 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
312 {
313 	return 0;
314 }
315 
316 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
317 {
318 }
319 #endif /* CONFIG_DEBUG_FS */
320 
321 static ssize_t iio_read_channel_ext_info(struct device *dev,
322 				     struct device_attribute *attr,
323 				     char *buf)
324 {
325 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
326 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
327 	const struct iio_chan_spec_ext_info *ext_info;
328 
329 	ext_info = &this_attr->c->ext_info[this_attr->address];
330 
331 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
332 }
333 
334 static ssize_t iio_write_channel_ext_info(struct device *dev,
335 				     struct device_attribute *attr,
336 				     const char *buf,
337 					 size_t len)
338 {
339 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
340 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
341 	const struct iio_chan_spec_ext_info *ext_info;
342 
343 	ext_info = &this_attr->c->ext_info[this_attr->address];
344 
345 	return ext_info->write(indio_dev, ext_info->private,
346 			       this_attr->c, buf, len);
347 }
348 
349 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
350 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
351 {
352 	const struct iio_enum *e = (const struct iio_enum *)priv;
353 	unsigned int i;
354 	size_t len = 0;
355 
356 	if (!e->num_items)
357 		return 0;
358 
359 	for (i = 0; i < e->num_items; ++i)
360 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
361 
362 	/* replace last space with a newline */
363 	buf[len - 1] = '\n';
364 
365 	return len;
366 }
367 EXPORT_SYMBOL_GPL(iio_enum_available_read);
368 
369 ssize_t iio_enum_read(struct iio_dev *indio_dev,
370 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
371 {
372 	const struct iio_enum *e = (const struct iio_enum *)priv;
373 	int i;
374 
375 	if (!e->get)
376 		return -EINVAL;
377 
378 	i = e->get(indio_dev, chan);
379 	if (i < 0)
380 		return i;
381 	else if (i >= e->num_items)
382 		return -EINVAL;
383 
384 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
385 }
386 EXPORT_SYMBOL_GPL(iio_enum_read);
387 
388 ssize_t iio_enum_write(struct iio_dev *indio_dev,
389 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
390 	size_t len)
391 {
392 	const struct iio_enum *e = (const struct iio_enum *)priv;
393 	unsigned int i;
394 	int ret;
395 
396 	if (!e->set)
397 		return -EINVAL;
398 
399 	for (i = 0; i < e->num_items; i++) {
400 		if (sysfs_streq(buf, e->items[i]))
401 			break;
402 	}
403 
404 	if (i == e->num_items)
405 		return -EINVAL;
406 
407 	ret = e->set(indio_dev, chan, i);
408 	return ret ? ret : len;
409 }
410 EXPORT_SYMBOL_GPL(iio_enum_write);
411 
412 /**
413  * iio_format_value() - Formats a IIO value into its string representation
414  * @buf:	The buffer to which the formatted value gets written
415  * @type:	One of the IIO_VAL_... constants. This decides how the val
416  *		and val2 parameters are formatted.
417  * @size:	Number of IIO value entries contained in vals
418  * @vals:	Pointer to the values, exact meaning depends on the
419  *		type parameter.
420  *
421  * Return: 0 by default, a negative number on failure or the
422  *	   total number of characters written for a type that belongs
423  *	   to the IIO_VAL_... constant.
424  */
425 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
426 {
427 	unsigned long long tmp;
428 	bool scale_db = false;
429 
430 	switch (type) {
431 	case IIO_VAL_INT:
432 		return sprintf(buf, "%d\n", vals[0]);
433 	case IIO_VAL_INT_PLUS_MICRO_DB:
434 		scale_db = true;
435 	case IIO_VAL_INT_PLUS_MICRO:
436 		if (vals[1] < 0)
437 			return sprintf(buf, "-%d.%06u%s\n", abs(vals[0]),
438 				       -vals[1], scale_db ? " dB" : "");
439 		else
440 			return sprintf(buf, "%d.%06u%s\n", vals[0], vals[1],
441 				scale_db ? " dB" : "");
442 	case IIO_VAL_INT_PLUS_NANO:
443 		if (vals[1] < 0)
444 			return sprintf(buf, "-%d.%09u\n", abs(vals[0]),
445 				       -vals[1]);
446 		else
447 			return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
448 	case IIO_VAL_FRACTIONAL:
449 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
450 		vals[1] = do_div(tmp, 1000000000LL);
451 		vals[0] = tmp;
452 		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
453 	case IIO_VAL_FRACTIONAL_LOG2:
454 		tmp = (s64)vals[0] * 1000000000LL >> vals[1];
455 		vals[1] = do_div(tmp, 1000000000LL);
456 		vals[0] = tmp;
457 		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
458 	case IIO_VAL_INT_MULTIPLE:
459 	{
460 		int i;
461 		int len = 0;
462 
463 		for (i = 0; i < size; ++i)
464 			len += snprintf(&buf[len], PAGE_SIZE - len, "%d ",
465 								vals[i]);
466 		len += snprintf(&buf[len], PAGE_SIZE - len, "\n");
467 		return len;
468 	}
469 	default:
470 		return 0;
471 	}
472 }
473 EXPORT_SYMBOL_GPL(iio_format_value);
474 
475 static ssize_t iio_read_channel_info(struct device *dev,
476 				     struct device_attribute *attr,
477 				     char *buf)
478 {
479 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
480 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
481 	int vals[INDIO_MAX_RAW_ELEMENTS];
482 	int ret;
483 	int val_len = 2;
484 
485 	if (indio_dev->info->read_raw_multi)
486 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
487 							INDIO_MAX_RAW_ELEMENTS,
488 							vals, &val_len,
489 							this_attr->address);
490 	else
491 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
492 				    &vals[0], &vals[1], this_attr->address);
493 
494 	if (ret < 0)
495 		return ret;
496 
497 	return iio_format_value(buf, ret, val_len, vals);
498 }
499 
500 /**
501  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
502  * @str: The string to parse
503  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
504  * @integer: The integer part of the number
505  * @fract: The fractional part of the number
506  *
507  * Returns 0 on success, or a negative error code if the string could not be
508  * parsed.
509  */
510 int iio_str_to_fixpoint(const char *str, int fract_mult,
511 	int *integer, int *fract)
512 {
513 	int i = 0, f = 0;
514 	bool integer_part = true, negative = false;
515 
516 	if (fract_mult == 0) {
517 		*fract = 0;
518 
519 		return kstrtoint(str, 0, integer);
520 	}
521 
522 	if (str[0] == '-') {
523 		negative = true;
524 		str++;
525 	} else if (str[0] == '+') {
526 		str++;
527 	}
528 
529 	while (*str) {
530 		if ('0' <= *str && *str <= '9') {
531 			if (integer_part) {
532 				i = i * 10 + *str - '0';
533 			} else {
534 				f += fract_mult * (*str - '0');
535 				fract_mult /= 10;
536 			}
537 		} else if (*str == '\n') {
538 			if (*(str + 1) == '\0')
539 				break;
540 			else
541 				return -EINVAL;
542 		} else if (*str == '.' && integer_part) {
543 			integer_part = false;
544 		} else {
545 			return -EINVAL;
546 		}
547 		str++;
548 	}
549 
550 	if (negative) {
551 		if (i)
552 			i = -i;
553 		else
554 			f = -f;
555 	}
556 
557 	*integer = i;
558 	*fract = f;
559 
560 	return 0;
561 }
562 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
563 
564 static ssize_t iio_write_channel_info(struct device *dev,
565 				      struct device_attribute *attr,
566 				      const char *buf,
567 				      size_t len)
568 {
569 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
570 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
571 	int ret, fract_mult = 100000;
572 	int integer, fract;
573 
574 	/* Assumes decimal - precision based on number of digits */
575 	if (!indio_dev->info->write_raw)
576 		return -EINVAL;
577 
578 	if (indio_dev->info->write_raw_get_fmt)
579 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
580 			this_attr->c, this_attr->address)) {
581 		case IIO_VAL_INT:
582 			fract_mult = 0;
583 			break;
584 		case IIO_VAL_INT_PLUS_MICRO:
585 			fract_mult = 100000;
586 			break;
587 		case IIO_VAL_INT_PLUS_NANO:
588 			fract_mult = 100000000;
589 			break;
590 		default:
591 			return -EINVAL;
592 		}
593 
594 	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
595 	if (ret)
596 		return ret;
597 
598 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
599 					 integer, fract, this_attr->address);
600 	if (ret)
601 		return ret;
602 
603 	return len;
604 }
605 
606 static
607 int __iio_device_attr_init(struct device_attribute *dev_attr,
608 			   const char *postfix,
609 			   struct iio_chan_spec const *chan,
610 			   ssize_t (*readfunc)(struct device *dev,
611 					       struct device_attribute *attr,
612 					       char *buf),
613 			   ssize_t (*writefunc)(struct device *dev,
614 						struct device_attribute *attr,
615 						const char *buf,
616 						size_t len),
617 			   enum iio_shared_by shared_by)
618 {
619 	int ret = 0;
620 	char *name = NULL;
621 	char *full_postfix;
622 	sysfs_attr_init(&dev_attr->attr);
623 
624 	/* Build up postfix of <extend_name>_<modifier>_postfix */
625 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
626 		if (chan->extend_name)
627 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
628 						 iio_modifier_names[chan
629 								    ->channel2],
630 						 chan->extend_name,
631 						 postfix);
632 		else
633 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
634 						 iio_modifier_names[chan
635 								    ->channel2],
636 						 postfix);
637 	} else {
638 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
639 			full_postfix = kstrdup(postfix, GFP_KERNEL);
640 		else
641 			full_postfix = kasprintf(GFP_KERNEL,
642 						 "%s_%s",
643 						 chan->extend_name,
644 						 postfix);
645 	}
646 	if (full_postfix == NULL)
647 		return -ENOMEM;
648 
649 	if (chan->differential) { /* Differential can not have modifier */
650 		switch (shared_by) {
651 		case IIO_SHARED_BY_ALL:
652 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
653 			break;
654 		case IIO_SHARED_BY_DIR:
655 			name = kasprintf(GFP_KERNEL, "%s_%s",
656 						iio_direction[chan->output],
657 						full_postfix);
658 			break;
659 		case IIO_SHARED_BY_TYPE:
660 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
661 					    iio_direction[chan->output],
662 					    iio_chan_type_name_spec[chan->type],
663 					    iio_chan_type_name_spec[chan->type],
664 					    full_postfix);
665 			break;
666 		case IIO_SEPARATE:
667 			if (!chan->indexed) {
668 				WARN(1, "Differential channels must be indexed\n");
669 				ret = -EINVAL;
670 				goto error_free_full_postfix;
671 			}
672 			name = kasprintf(GFP_KERNEL,
673 					    "%s_%s%d-%s%d_%s",
674 					    iio_direction[chan->output],
675 					    iio_chan_type_name_spec[chan->type],
676 					    chan->channel,
677 					    iio_chan_type_name_spec[chan->type],
678 					    chan->channel2,
679 					    full_postfix);
680 			break;
681 		}
682 	} else { /* Single ended */
683 		switch (shared_by) {
684 		case IIO_SHARED_BY_ALL:
685 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
686 			break;
687 		case IIO_SHARED_BY_DIR:
688 			name = kasprintf(GFP_KERNEL, "%s_%s",
689 						iio_direction[chan->output],
690 						full_postfix);
691 			break;
692 		case IIO_SHARED_BY_TYPE:
693 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
694 					    iio_direction[chan->output],
695 					    iio_chan_type_name_spec[chan->type],
696 					    full_postfix);
697 			break;
698 
699 		case IIO_SEPARATE:
700 			if (chan->indexed)
701 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
702 						    iio_direction[chan->output],
703 						    iio_chan_type_name_spec[chan->type],
704 						    chan->channel,
705 						    full_postfix);
706 			else
707 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
708 						    iio_direction[chan->output],
709 						    iio_chan_type_name_spec[chan->type],
710 						    full_postfix);
711 			break;
712 		}
713 	}
714 	if (name == NULL) {
715 		ret = -ENOMEM;
716 		goto error_free_full_postfix;
717 	}
718 	dev_attr->attr.name = name;
719 
720 	if (readfunc) {
721 		dev_attr->attr.mode |= S_IRUGO;
722 		dev_attr->show = readfunc;
723 	}
724 
725 	if (writefunc) {
726 		dev_attr->attr.mode |= S_IWUSR;
727 		dev_attr->store = writefunc;
728 	}
729 
730 error_free_full_postfix:
731 	kfree(full_postfix);
732 
733 	return ret;
734 }
735 
736 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
737 {
738 	kfree(dev_attr->attr.name);
739 }
740 
741 int __iio_add_chan_devattr(const char *postfix,
742 			   struct iio_chan_spec const *chan,
743 			   ssize_t (*readfunc)(struct device *dev,
744 					       struct device_attribute *attr,
745 					       char *buf),
746 			   ssize_t (*writefunc)(struct device *dev,
747 						struct device_attribute *attr,
748 						const char *buf,
749 						size_t len),
750 			   u64 mask,
751 			   enum iio_shared_by shared_by,
752 			   struct device *dev,
753 			   struct list_head *attr_list)
754 {
755 	int ret;
756 	struct iio_dev_attr *iio_attr, *t;
757 
758 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
759 	if (iio_attr == NULL)
760 		return -ENOMEM;
761 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
762 				     postfix, chan,
763 				     readfunc, writefunc, shared_by);
764 	if (ret)
765 		goto error_iio_dev_attr_free;
766 	iio_attr->c = chan;
767 	iio_attr->address = mask;
768 	list_for_each_entry(t, attr_list, l)
769 		if (strcmp(t->dev_attr.attr.name,
770 			   iio_attr->dev_attr.attr.name) == 0) {
771 			if (shared_by == IIO_SEPARATE)
772 				dev_err(dev, "tried to double register : %s\n",
773 					t->dev_attr.attr.name);
774 			ret = -EBUSY;
775 			goto error_device_attr_deinit;
776 		}
777 	list_add(&iio_attr->l, attr_list);
778 
779 	return 0;
780 
781 error_device_attr_deinit:
782 	__iio_device_attr_deinit(&iio_attr->dev_attr);
783 error_iio_dev_attr_free:
784 	kfree(iio_attr);
785 	return ret;
786 }
787 
788 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
789 					 struct iio_chan_spec const *chan,
790 					 enum iio_shared_by shared_by,
791 					 const long *infomask)
792 {
793 	int i, ret, attrcount = 0;
794 
795 	for_each_set_bit(i, infomask, sizeof(infomask)*8) {
796 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
797 			return -EINVAL;
798 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
799 					     chan,
800 					     &iio_read_channel_info,
801 					     &iio_write_channel_info,
802 					     i,
803 					     shared_by,
804 					     &indio_dev->dev,
805 					     &indio_dev->channel_attr_list);
806 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
807 			continue;
808 		else if (ret < 0)
809 			return ret;
810 		attrcount++;
811 	}
812 
813 	return attrcount;
814 }
815 
816 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
817 					struct iio_chan_spec const *chan)
818 {
819 	int ret, attrcount = 0;
820 	const struct iio_chan_spec_ext_info *ext_info;
821 
822 	if (chan->channel < 0)
823 		return 0;
824 	ret = iio_device_add_info_mask_type(indio_dev, chan,
825 					    IIO_SEPARATE,
826 					    &chan->info_mask_separate);
827 	if (ret < 0)
828 		return ret;
829 	attrcount += ret;
830 
831 	ret = iio_device_add_info_mask_type(indio_dev, chan,
832 					    IIO_SHARED_BY_TYPE,
833 					    &chan->info_mask_shared_by_type);
834 	if (ret < 0)
835 		return ret;
836 	attrcount += ret;
837 
838 	ret = iio_device_add_info_mask_type(indio_dev, chan,
839 					    IIO_SHARED_BY_DIR,
840 					    &chan->info_mask_shared_by_dir);
841 	if (ret < 0)
842 		return ret;
843 	attrcount += ret;
844 
845 	ret = iio_device_add_info_mask_type(indio_dev, chan,
846 					    IIO_SHARED_BY_ALL,
847 					    &chan->info_mask_shared_by_all);
848 	if (ret < 0)
849 		return ret;
850 	attrcount += ret;
851 
852 	if (chan->ext_info) {
853 		unsigned int i = 0;
854 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
855 			ret = __iio_add_chan_devattr(ext_info->name,
856 					chan,
857 					ext_info->read ?
858 					    &iio_read_channel_ext_info : NULL,
859 					ext_info->write ?
860 					    &iio_write_channel_ext_info : NULL,
861 					i,
862 					ext_info->shared,
863 					&indio_dev->dev,
864 					&indio_dev->channel_attr_list);
865 			i++;
866 			if (ret == -EBUSY && ext_info->shared)
867 				continue;
868 
869 			if (ret)
870 				return ret;
871 
872 			attrcount++;
873 		}
874 	}
875 
876 	return attrcount;
877 }
878 
879 /**
880  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
881  * @attr_list: List of IIO device attributes
882  *
883  * This function frees the memory allocated for each of the IIO device
884  * attributes in the list.
885  */
886 void iio_free_chan_devattr_list(struct list_head *attr_list)
887 {
888 	struct iio_dev_attr *p, *n;
889 
890 	list_for_each_entry_safe(p, n, attr_list, l) {
891 		kfree(p->dev_attr.attr.name);
892 		list_del(&p->l);
893 		kfree(p);
894 	}
895 }
896 
897 static ssize_t iio_show_dev_name(struct device *dev,
898 				 struct device_attribute *attr,
899 				 char *buf)
900 {
901 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
902 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
903 }
904 
905 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
906 
907 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
908 {
909 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
910 	struct iio_dev_attr *p;
911 	struct attribute **attr;
912 
913 	/* First count elements in any existing group */
914 	if (indio_dev->info->attrs) {
915 		attr = indio_dev->info->attrs->attrs;
916 		while (*attr++ != NULL)
917 			attrcount_orig++;
918 	}
919 	attrcount = attrcount_orig;
920 	/*
921 	 * New channel registration method - relies on the fact a group does
922 	 * not need to be initialized if its name is NULL.
923 	 */
924 	if (indio_dev->channels)
925 		for (i = 0; i < indio_dev->num_channels; i++) {
926 			ret = iio_device_add_channel_sysfs(indio_dev,
927 							   &indio_dev
928 							   ->channels[i]);
929 			if (ret < 0)
930 				goto error_clear_attrs;
931 			attrcount += ret;
932 		}
933 
934 	if (indio_dev->name)
935 		attrcount++;
936 
937 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
938 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
939 						   GFP_KERNEL);
940 	if (indio_dev->chan_attr_group.attrs == NULL) {
941 		ret = -ENOMEM;
942 		goto error_clear_attrs;
943 	}
944 	/* Copy across original attributes */
945 	if (indio_dev->info->attrs)
946 		memcpy(indio_dev->chan_attr_group.attrs,
947 		       indio_dev->info->attrs->attrs,
948 		       sizeof(indio_dev->chan_attr_group.attrs[0])
949 		       *attrcount_orig);
950 	attrn = attrcount_orig;
951 	/* Add all elements from the list. */
952 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
953 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
954 	if (indio_dev->name)
955 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
956 
957 	indio_dev->groups[indio_dev->groupcounter++] =
958 		&indio_dev->chan_attr_group;
959 
960 	return 0;
961 
962 error_clear_attrs:
963 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
964 
965 	return ret;
966 }
967 
968 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
969 {
970 
971 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
972 	kfree(indio_dev->chan_attr_group.attrs);
973 	indio_dev->chan_attr_group.attrs = NULL;
974 }
975 
976 static void iio_dev_release(struct device *device)
977 {
978 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
979 	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
980 		iio_device_unregister_trigger_consumer(indio_dev);
981 	iio_device_unregister_eventset(indio_dev);
982 	iio_device_unregister_sysfs(indio_dev);
983 
984 	iio_buffer_put(indio_dev->buffer);
985 
986 	ida_simple_remove(&iio_ida, indio_dev->id);
987 	kfree(indio_dev);
988 }
989 
990 struct device_type iio_device_type = {
991 	.name = "iio_device",
992 	.release = iio_dev_release,
993 };
994 
995 /**
996  * iio_device_alloc() - allocate an iio_dev from a driver
997  * @sizeof_priv:	Space to allocate for private structure.
998  **/
999 struct iio_dev *iio_device_alloc(int sizeof_priv)
1000 {
1001 	struct iio_dev *dev;
1002 	size_t alloc_size;
1003 
1004 	alloc_size = sizeof(struct iio_dev);
1005 	if (sizeof_priv) {
1006 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1007 		alloc_size += sizeof_priv;
1008 	}
1009 	/* ensure 32-byte alignment of whole construct ? */
1010 	alloc_size += IIO_ALIGN - 1;
1011 
1012 	dev = kzalloc(alloc_size, GFP_KERNEL);
1013 
1014 	if (dev) {
1015 		dev->dev.groups = dev->groups;
1016 		dev->dev.type = &iio_device_type;
1017 		dev->dev.bus = &iio_bus_type;
1018 		device_initialize(&dev->dev);
1019 		dev_set_drvdata(&dev->dev, (void *)dev);
1020 		mutex_init(&dev->mlock);
1021 		mutex_init(&dev->info_exist_lock);
1022 		INIT_LIST_HEAD(&dev->channel_attr_list);
1023 
1024 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1025 		if (dev->id < 0) {
1026 			/* cannot use a dev_err as the name isn't available */
1027 			pr_err("failed to get device id\n");
1028 			kfree(dev);
1029 			return NULL;
1030 		}
1031 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1032 		INIT_LIST_HEAD(&dev->buffer_list);
1033 	}
1034 
1035 	return dev;
1036 }
1037 EXPORT_SYMBOL(iio_device_alloc);
1038 
1039 /**
1040  * iio_device_free() - free an iio_dev from a driver
1041  * @dev:		the iio_dev associated with the device
1042  **/
1043 void iio_device_free(struct iio_dev *dev)
1044 {
1045 	if (dev)
1046 		put_device(&dev->dev);
1047 }
1048 EXPORT_SYMBOL(iio_device_free);
1049 
1050 static void devm_iio_device_release(struct device *dev, void *res)
1051 {
1052 	iio_device_free(*(struct iio_dev **)res);
1053 }
1054 
1055 static int devm_iio_device_match(struct device *dev, void *res, void *data)
1056 {
1057 	struct iio_dev **r = res;
1058 	if (!r || !*r) {
1059 		WARN_ON(!r || !*r);
1060 		return 0;
1061 	}
1062 	return *r == data;
1063 }
1064 
1065 /**
1066  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1067  * @dev:		Device to allocate iio_dev for
1068  * @sizeof_priv:	Space to allocate for private structure.
1069  *
1070  * Managed iio_device_alloc. iio_dev allocated with this function is
1071  * automatically freed on driver detach.
1072  *
1073  * If an iio_dev allocated with this function needs to be freed separately,
1074  * devm_iio_device_free() must be used.
1075  *
1076  * RETURNS:
1077  * Pointer to allocated iio_dev on success, NULL on failure.
1078  */
1079 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1080 {
1081 	struct iio_dev **ptr, *iio_dev;
1082 
1083 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1084 			   GFP_KERNEL);
1085 	if (!ptr)
1086 		return NULL;
1087 
1088 	iio_dev = iio_device_alloc(sizeof_priv);
1089 	if (iio_dev) {
1090 		*ptr = iio_dev;
1091 		devres_add(dev, ptr);
1092 	} else {
1093 		devres_free(ptr);
1094 	}
1095 
1096 	return iio_dev;
1097 }
1098 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1099 
1100 /**
1101  * devm_iio_device_free - Resource-managed iio_device_free()
1102  * @dev:		Device this iio_dev belongs to
1103  * @iio_dev:		the iio_dev associated with the device
1104  *
1105  * Free iio_dev allocated with devm_iio_device_alloc().
1106  */
1107 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1108 {
1109 	int rc;
1110 
1111 	rc = devres_release(dev, devm_iio_device_release,
1112 			    devm_iio_device_match, iio_dev);
1113 	WARN_ON(rc);
1114 }
1115 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1116 
1117 /**
1118  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1119  * @inode:	Inode structure for identifying the device in the file system
1120  * @filp:	File structure for iio device used to keep and later access
1121  *		private data
1122  *
1123  * Return: 0 on success or -EBUSY if the device is already opened
1124  **/
1125 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1126 {
1127 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1128 						struct iio_dev, chrdev);
1129 
1130 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1131 		return -EBUSY;
1132 
1133 	iio_device_get(indio_dev);
1134 
1135 	filp->private_data = indio_dev;
1136 
1137 	return 0;
1138 }
1139 
1140 /**
1141  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1142  * @inode:	Inode structure pointer for the char device
1143  * @filp:	File structure pointer for the char device
1144  *
1145  * Return: 0 for successful release
1146  */
1147 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1148 {
1149 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1150 						struct iio_dev, chrdev);
1151 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1152 	iio_device_put(indio_dev);
1153 
1154 	return 0;
1155 }
1156 
1157 /* Somewhat of a cross file organization violation - ioctls here are actually
1158  * event related */
1159 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1160 {
1161 	struct iio_dev *indio_dev = filp->private_data;
1162 	int __user *ip = (int __user *)arg;
1163 	int fd;
1164 
1165 	if (!indio_dev->info)
1166 		return -ENODEV;
1167 
1168 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1169 		fd = iio_event_getfd(indio_dev);
1170 		if (fd < 0)
1171 			return fd;
1172 		if (copy_to_user(ip, &fd, sizeof(fd)))
1173 			return -EFAULT;
1174 		return 0;
1175 	}
1176 	return -EINVAL;
1177 }
1178 
1179 static const struct file_operations iio_buffer_fileops = {
1180 	.read = iio_buffer_read_first_n_outer_addr,
1181 	.release = iio_chrdev_release,
1182 	.open = iio_chrdev_open,
1183 	.poll = iio_buffer_poll_addr,
1184 	.owner = THIS_MODULE,
1185 	.llseek = noop_llseek,
1186 	.unlocked_ioctl = iio_ioctl,
1187 	.compat_ioctl = iio_ioctl,
1188 };
1189 
1190 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1191 {
1192 	int i, j;
1193 	const struct iio_chan_spec *channels = indio_dev->channels;
1194 
1195 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1196 		return 0;
1197 
1198 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1199 		if (channels[i].scan_index < 0)
1200 			continue;
1201 		for (j = i + 1; j < indio_dev->num_channels; j++)
1202 			if (channels[i].scan_index == channels[j].scan_index) {
1203 				dev_err(&indio_dev->dev,
1204 					"Duplicate scan index %d\n",
1205 					channels[i].scan_index);
1206 				return -EINVAL;
1207 			}
1208 	}
1209 
1210 	return 0;
1211 }
1212 
1213 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1214 
1215 /**
1216  * iio_device_register() - register a device with the IIO subsystem
1217  * @indio_dev:		Device structure filled by the device driver
1218  **/
1219 int iio_device_register(struct iio_dev *indio_dev)
1220 {
1221 	int ret;
1222 
1223 	/* If the calling driver did not initialize of_node, do it here */
1224 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1225 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1226 
1227 	ret = iio_check_unique_scan_index(indio_dev);
1228 	if (ret < 0)
1229 		return ret;
1230 
1231 	/* configure elements for the chrdev */
1232 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1233 
1234 	ret = iio_device_register_debugfs(indio_dev);
1235 	if (ret) {
1236 		dev_err(indio_dev->dev.parent,
1237 			"Failed to register debugfs interfaces\n");
1238 		return ret;
1239 	}
1240 
1241 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1242 	if (ret) {
1243 		dev_err(indio_dev->dev.parent,
1244 			"Failed to create buffer sysfs interfaces\n");
1245 		goto error_unreg_debugfs;
1246 	}
1247 
1248 	ret = iio_device_register_sysfs(indio_dev);
1249 	if (ret) {
1250 		dev_err(indio_dev->dev.parent,
1251 			"Failed to register sysfs interfaces\n");
1252 		goto error_buffer_free_sysfs;
1253 	}
1254 	ret = iio_device_register_eventset(indio_dev);
1255 	if (ret) {
1256 		dev_err(indio_dev->dev.parent,
1257 			"Failed to register event set\n");
1258 		goto error_free_sysfs;
1259 	}
1260 	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
1261 		iio_device_register_trigger_consumer(indio_dev);
1262 
1263 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1264 		indio_dev->setup_ops == NULL)
1265 		indio_dev->setup_ops = &noop_ring_setup_ops;
1266 
1267 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1268 	indio_dev->chrdev.owner = indio_dev->info->driver_module;
1269 	indio_dev->chrdev.kobj.parent = &indio_dev->dev.kobj;
1270 	ret = cdev_add(&indio_dev->chrdev, indio_dev->dev.devt, 1);
1271 	if (ret < 0)
1272 		goto error_unreg_eventset;
1273 
1274 	ret = device_add(&indio_dev->dev);
1275 	if (ret < 0)
1276 		goto error_cdev_del;
1277 
1278 	return 0;
1279 error_cdev_del:
1280 	cdev_del(&indio_dev->chrdev);
1281 error_unreg_eventset:
1282 	iio_device_unregister_eventset(indio_dev);
1283 error_free_sysfs:
1284 	iio_device_unregister_sysfs(indio_dev);
1285 error_buffer_free_sysfs:
1286 	iio_buffer_free_sysfs_and_mask(indio_dev);
1287 error_unreg_debugfs:
1288 	iio_device_unregister_debugfs(indio_dev);
1289 	return ret;
1290 }
1291 EXPORT_SYMBOL(iio_device_register);
1292 
1293 /**
1294  * iio_device_unregister() - unregister a device from the IIO subsystem
1295  * @indio_dev:		Device structure representing the device.
1296  **/
1297 void iio_device_unregister(struct iio_dev *indio_dev)
1298 {
1299 	mutex_lock(&indio_dev->info_exist_lock);
1300 
1301 	device_del(&indio_dev->dev);
1302 
1303 	if (indio_dev->chrdev.dev)
1304 		cdev_del(&indio_dev->chrdev);
1305 	iio_device_unregister_debugfs(indio_dev);
1306 
1307 	iio_disable_all_buffers(indio_dev);
1308 
1309 	indio_dev->info = NULL;
1310 
1311 	iio_device_wakeup_eventset(indio_dev);
1312 	iio_buffer_wakeup_poll(indio_dev);
1313 
1314 	mutex_unlock(&indio_dev->info_exist_lock);
1315 
1316 	iio_buffer_free_sysfs_and_mask(indio_dev);
1317 }
1318 EXPORT_SYMBOL(iio_device_unregister);
1319 
1320 static void devm_iio_device_unreg(struct device *dev, void *res)
1321 {
1322 	iio_device_unregister(*(struct iio_dev **)res);
1323 }
1324 
1325 /**
1326  * devm_iio_device_register - Resource-managed iio_device_register()
1327  * @dev:	Device to allocate iio_dev for
1328  * @indio_dev:	Device structure filled by the device driver
1329  *
1330  * Managed iio_device_register.  The IIO device registered with this
1331  * function is automatically unregistered on driver detach. This function
1332  * calls iio_device_register() internally. Refer to that function for more
1333  * information.
1334  *
1335  * If an iio_dev registered with this function needs to be unregistered
1336  * separately, devm_iio_device_unregister() must be used.
1337  *
1338  * RETURNS:
1339  * 0 on success, negative error number on failure.
1340  */
1341 int devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev)
1342 {
1343 	struct iio_dev **ptr;
1344 	int ret;
1345 
1346 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1347 	if (!ptr)
1348 		return -ENOMEM;
1349 
1350 	*ptr = indio_dev;
1351 	ret = iio_device_register(indio_dev);
1352 	if (!ret)
1353 		devres_add(dev, ptr);
1354 	else
1355 		devres_free(ptr);
1356 
1357 	return ret;
1358 }
1359 EXPORT_SYMBOL_GPL(devm_iio_device_register);
1360 
1361 /**
1362  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1363  * @dev:	Device this iio_dev belongs to
1364  * @indio_dev:	the iio_dev associated with the device
1365  *
1366  * Unregister iio_dev registered with devm_iio_device_register().
1367  */
1368 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1369 {
1370 	int rc;
1371 
1372 	rc = devres_release(dev, devm_iio_device_unreg,
1373 			    devm_iio_device_match, indio_dev);
1374 	WARN_ON(rc);
1375 }
1376 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1377 
1378 subsys_initcall(iio_init);
1379 module_exit(iio_exit);
1380 
1381 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1382 MODULE_DESCRIPTION("Industrial I/O core");
1383 MODULE_LICENSE("GPL");
1384