xref: /linux/drivers/iio/industrialio-core.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * The industrial I/O core
4  *
5  * Copyright (c) 2008 Jonathan Cameron
6  *
7  * Based on elements of hwmon and input subsystems.
8  */
9 
10 #define pr_fmt(fmt) "iio-core: " fmt
11 
12 #include <linux/anon_inodes.h>
13 #include <linux/cdev.h>
14 #include <linux/cleanup.h>
15 #include <linux/debugfs.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/fs.h>
19 #include <linux/idr.h>
20 #include <linux/kdev_t.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/poll.h>
25 #include <linux/property.h>
26 #include <linux/sched.h>
27 #include <linux/slab.h>
28 #include <linux/wait.h>
29 
30 #include <linux/iio/buffer.h>
31 #include <linux/iio/buffer_impl.h>
32 #include <linux/iio/events.h>
33 #include <linux/iio/iio-opaque.h>
34 #include <linux/iio/iio.h>
35 #include <linux/iio/sysfs.h>
36 
37 #include "iio_core.h"
38 #include "iio_core_trigger.h"
39 
40 /* IDA to assign each registered device a unique id */
41 static DEFINE_IDA(iio_ida);
42 
43 static dev_t iio_devt;
44 
45 #define IIO_DEV_MAX 256
46 const struct bus_type iio_bus_type = {
47 	.name = "iio",
48 };
49 EXPORT_SYMBOL(iio_bus_type);
50 
51 static struct dentry *iio_debugfs_dentry;
52 
53 static const char * const iio_direction[] = {
54 	[0] = "in",
55 	[1] = "out",
56 };
57 
58 static const char * const iio_chan_type_name_spec[] = {
59 	[IIO_VOLTAGE] = "voltage",
60 	[IIO_CURRENT] = "current",
61 	[IIO_POWER] = "power",
62 	[IIO_ACCEL] = "accel",
63 	[IIO_ANGL_VEL] = "anglvel",
64 	[IIO_MAGN] = "magn",
65 	[IIO_LIGHT] = "illuminance",
66 	[IIO_INTENSITY] = "intensity",
67 	[IIO_PROXIMITY] = "proximity",
68 	[IIO_TEMP] = "temp",
69 	[IIO_INCLI] = "incli",
70 	[IIO_ROT] = "rot",
71 	[IIO_ANGL] = "angl",
72 	[IIO_TIMESTAMP] = "timestamp",
73 	[IIO_CAPACITANCE] = "capacitance",
74 	[IIO_ALTVOLTAGE] = "altvoltage",
75 	[IIO_CCT] = "cct",
76 	[IIO_PRESSURE] = "pressure",
77 	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
78 	[IIO_ACTIVITY] = "activity",
79 	[IIO_STEPS] = "steps",
80 	[IIO_ENERGY] = "energy",
81 	[IIO_DISTANCE] = "distance",
82 	[IIO_VELOCITY] = "velocity",
83 	[IIO_CONCENTRATION] = "concentration",
84 	[IIO_RESISTANCE] = "resistance",
85 	[IIO_PH] = "ph",
86 	[IIO_UVINDEX] = "uvindex",
87 	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
88 	[IIO_COUNT] = "count",
89 	[IIO_INDEX] = "index",
90 	[IIO_GRAVITY]  = "gravity",
91 	[IIO_POSITIONRELATIVE]  = "positionrelative",
92 	[IIO_PHASE] = "phase",
93 	[IIO_MASSCONCENTRATION] = "massconcentration",
94 	[IIO_DELTA_ANGL] = "deltaangl",
95 	[IIO_DELTA_VELOCITY] = "deltavelocity",
96 	[IIO_COLORTEMP] = "colortemp",
97 	[IIO_CHROMATICITY] = "chromaticity",
98 	[IIO_ATTENTION] = "attention",
99 };
100 
101 static const char * const iio_modifier_names[] = {
102 	[IIO_MOD_X] = "x",
103 	[IIO_MOD_Y] = "y",
104 	[IIO_MOD_Z] = "z",
105 	[IIO_MOD_X_AND_Y] = "x&y",
106 	[IIO_MOD_X_AND_Z] = "x&z",
107 	[IIO_MOD_Y_AND_Z] = "y&z",
108 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
109 	[IIO_MOD_X_OR_Y] = "x|y",
110 	[IIO_MOD_X_OR_Z] = "x|z",
111 	[IIO_MOD_Y_OR_Z] = "y|z",
112 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
113 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
114 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
115 	[IIO_MOD_LIGHT_BOTH] = "both",
116 	[IIO_MOD_LIGHT_IR] = "ir",
117 	[IIO_MOD_LIGHT_CLEAR] = "clear",
118 	[IIO_MOD_LIGHT_RED] = "red",
119 	[IIO_MOD_LIGHT_GREEN] = "green",
120 	[IIO_MOD_LIGHT_BLUE] = "blue",
121 	[IIO_MOD_LIGHT_UV] = "uv",
122 	[IIO_MOD_LIGHT_UVA] = "uva",
123 	[IIO_MOD_LIGHT_UVB] = "uvb",
124 	[IIO_MOD_LIGHT_DUV] = "duv",
125 	[IIO_MOD_QUATERNION] = "quaternion",
126 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
127 	[IIO_MOD_TEMP_OBJECT] = "object",
128 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
129 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
130 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
131 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
132 	[IIO_MOD_RUNNING] = "running",
133 	[IIO_MOD_JOGGING] = "jogging",
134 	[IIO_MOD_WALKING] = "walking",
135 	[IIO_MOD_STILL] = "still",
136 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
137 	[IIO_MOD_I] = "i",
138 	[IIO_MOD_Q] = "q",
139 	[IIO_MOD_CO2] = "co2",
140 	[IIO_MOD_VOC] = "voc",
141 	[IIO_MOD_PM1] = "pm1",
142 	[IIO_MOD_PM2P5] = "pm2p5",
143 	[IIO_MOD_PM4] = "pm4",
144 	[IIO_MOD_PM10] = "pm10",
145 	[IIO_MOD_ETHANOL] = "ethanol",
146 	[IIO_MOD_H2] = "h2",
147 	[IIO_MOD_O2] = "o2",
148 	[IIO_MOD_LINEAR_X] = "linear_x",
149 	[IIO_MOD_LINEAR_Y] = "linear_y",
150 	[IIO_MOD_LINEAR_Z] = "linear_z",
151 	[IIO_MOD_PITCH] = "pitch",
152 	[IIO_MOD_YAW] = "yaw",
153 	[IIO_MOD_ROLL] = "roll",
154 };
155 
156 /* relies on pairs of these shared then separate */
157 static const char * const iio_chan_info_postfix[] = {
158 	[IIO_CHAN_INFO_RAW] = "raw",
159 	[IIO_CHAN_INFO_PROCESSED] = "input",
160 	[IIO_CHAN_INFO_SCALE] = "scale",
161 	[IIO_CHAN_INFO_OFFSET] = "offset",
162 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
163 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
164 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
165 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
166 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
167 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
168 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
169 	= "filter_low_pass_3db_frequency",
170 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
171 	= "filter_high_pass_3db_frequency",
172 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
173 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
174 	[IIO_CHAN_INFO_PHASE] = "phase",
175 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
176 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
177 	[IIO_CHAN_INFO_HYSTERESIS_RELATIVE] = "hysteresis_relative",
178 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
179 	[IIO_CHAN_INFO_ENABLE] = "en",
180 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
181 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
182 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
183 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
184 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
185 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
186 	[IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
187 	[IIO_CHAN_INFO_CALIBAMBIENT] = "calibambient",
188 	[IIO_CHAN_INFO_ZEROPOINT] = "zeropoint",
189 	[IIO_CHAN_INFO_TROUGH] = "trough_raw",
190 };
191 /**
192  * iio_device_id() - query the unique ID for the device
193  * @indio_dev:		Device structure whose ID is being queried
194  *
195  * The IIO device ID is a unique index used for example for the naming
196  * of the character device /dev/iio\:device[ID].
197  *
198  * Returns: Unique ID for the device.
199  */
200 int iio_device_id(struct iio_dev *indio_dev)
201 {
202 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
203 
204 	return iio_dev_opaque->id;
205 }
206 EXPORT_SYMBOL_GPL(iio_device_id);
207 
208 /**
209  * iio_buffer_enabled() - helper function to test if the buffer is enabled
210  * @indio_dev:		IIO device structure for device
211  *
212  * Returns: True, if the buffer is enabled.
213  */
214 bool iio_buffer_enabled(struct iio_dev *indio_dev)
215 {
216 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
217 
218 	return iio_dev_opaque->currentmode & INDIO_ALL_BUFFER_MODES;
219 }
220 EXPORT_SYMBOL_GPL(iio_buffer_enabled);
221 
222 #if defined(CONFIG_DEBUG_FS)
223 /*
224  * There's also a CONFIG_DEBUG_FS guard in include/linux/iio/iio.h for
225  * iio_get_debugfs_dentry() to make it inline if CONFIG_DEBUG_FS is undefined
226  */
227 struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
228 {
229 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
230 
231 	return iio_dev_opaque->debugfs_dentry;
232 }
233 EXPORT_SYMBOL_GPL(iio_get_debugfs_dentry);
234 #endif
235 
236 /**
237  * iio_find_channel_from_si() - get channel from its scan index
238  * @indio_dev:		device
239  * @si:			scan index to match
240  *
241  * Returns:
242  * Constant pointer to iio_chan_spec, if scan index matches, NULL on failure.
243  */
244 const struct iio_chan_spec
245 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
246 {
247 	int i;
248 
249 	for (i = 0; i < indio_dev->num_channels; i++)
250 		if (indio_dev->channels[i].scan_index == si)
251 			return &indio_dev->channels[i];
252 	return NULL;
253 }
254 
255 /* This turns up an awful lot */
256 ssize_t iio_read_const_attr(struct device *dev,
257 			    struct device_attribute *attr,
258 			    char *buf)
259 {
260 	return sysfs_emit(buf, "%s\n", to_iio_const_attr(attr)->string);
261 }
262 EXPORT_SYMBOL(iio_read_const_attr);
263 
264 /**
265  * iio_device_set_clock() - Set current timestamping clock for the device
266  * @indio_dev: IIO device structure containing the device
267  * @clock_id: timestamping clock POSIX identifier to set.
268  *
269  * Returns: 0 on success, or a negative error code.
270  */
271 int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
272 {
273 	int ret;
274 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
275 	const struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
276 
277 	ret = mutex_lock_interruptible(&iio_dev_opaque->mlock);
278 	if (ret)
279 		return ret;
280 	if ((ev_int && iio_event_enabled(ev_int)) ||
281 	    iio_buffer_enabled(indio_dev)) {
282 		mutex_unlock(&iio_dev_opaque->mlock);
283 		return -EBUSY;
284 	}
285 	iio_dev_opaque->clock_id = clock_id;
286 	mutex_unlock(&iio_dev_opaque->mlock);
287 
288 	return 0;
289 }
290 EXPORT_SYMBOL(iio_device_set_clock);
291 
292 /**
293  * iio_device_get_clock() - Retrieve current timestamping clock for the device
294  * @indio_dev: IIO device structure containing the device
295  *
296  * Returns: Clock ID of the current timestamping clock for the device.
297  */
298 clockid_t iio_device_get_clock(const struct iio_dev *indio_dev)
299 {
300 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
301 
302 	return iio_dev_opaque->clock_id;
303 }
304 EXPORT_SYMBOL(iio_device_get_clock);
305 
306 /**
307  * iio_get_time_ns() - utility function to get a time stamp for events etc
308  * @indio_dev: device
309  *
310  * Returns: Timestamp of the event in nanoseconds.
311  */
312 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
313 {
314 	struct timespec64 tp;
315 
316 	switch (iio_device_get_clock(indio_dev)) {
317 	case CLOCK_REALTIME:
318 		return ktime_get_real_ns();
319 	case CLOCK_MONOTONIC:
320 		return ktime_get_ns();
321 	case CLOCK_MONOTONIC_RAW:
322 		return ktime_get_raw_ns();
323 	case CLOCK_REALTIME_COARSE:
324 		return ktime_to_ns(ktime_get_coarse_real());
325 	case CLOCK_MONOTONIC_COARSE:
326 		ktime_get_coarse_ts64(&tp);
327 		return timespec64_to_ns(&tp);
328 	case CLOCK_BOOTTIME:
329 		return ktime_get_boottime_ns();
330 	case CLOCK_TAI:
331 		return ktime_get_clocktai_ns();
332 	default:
333 		BUG();
334 	}
335 }
336 EXPORT_SYMBOL(iio_get_time_ns);
337 
338 static int __init iio_init(void)
339 {
340 	int ret;
341 
342 	/* Register sysfs bus */
343 	ret  = bus_register(&iio_bus_type);
344 	if (ret < 0) {
345 		pr_err("could not register bus type\n");
346 		goto error_nothing;
347 	}
348 
349 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
350 	if (ret < 0) {
351 		pr_err("failed to allocate char dev region\n");
352 		goto error_unregister_bus_type;
353 	}
354 
355 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
356 
357 	return 0;
358 
359 error_unregister_bus_type:
360 	bus_unregister(&iio_bus_type);
361 error_nothing:
362 	return ret;
363 }
364 
365 static void __exit iio_exit(void)
366 {
367 	if (iio_devt)
368 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
369 	bus_unregister(&iio_bus_type);
370 	debugfs_remove(iio_debugfs_dentry);
371 }
372 
373 #if defined(CONFIG_DEBUG_FS)
374 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
375 			      size_t count, loff_t *ppos)
376 {
377 	struct iio_dev *indio_dev = file->private_data;
378 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
379 	unsigned int val = 0;
380 	int ret;
381 
382 	if (*ppos > 0)
383 		return simple_read_from_buffer(userbuf, count, ppos,
384 					       iio_dev_opaque->read_buf,
385 					       iio_dev_opaque->read_buf_len);
386 
387 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
388 						  iio_dev_opaque->cached_reg_addr,
389 						  0, &val);
390 	if (ret) {
391 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
392 		return ret;
393 	}
394 
395 	iio_dev_opaque->read_buf_len = snprintf(iio_dev_opaque->read_buf,
396 						sizeof(iio_dev_opaque->read_buf),
397 						"0x%X\n", val);
398 
399 	return simple_read_from_buffer(userbuf, count, ppos,
400 				       iio_dev_opaque->read_buf,
401 				       iio_dev_opaque->read_buf_len);
402 }
403 
404 static ssize_t iio_debugfs_write_reg(struct file *file,
405 		     const char __user *userbuf, size_t count, loff_t *ppos)
406 {
407 	struct iio_dev *indio_dev = file->private_data;
408 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
409 	unsigned int reg, val;
410 	char buf[80];
411 	int ret;
412 
413 	count = min(count, sizeof(buf) - 1);
414 	if (copy_from_user(buf, userbuf, count))
415 		return -EFAULT;
416 
417 	buf[count] = 0;
418 
419 	ret = sscanf(buf, "%i %i", &reg, &val);
420 
421 	switch (ret) {
422 	case 1:
423 		iio_dev_opaque->cached_reg_addr = reg;
424 		break;
425 	case 2:
426 		iio_dev_opaque->cached_reg_addr = reg;
427 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
428 							  val, NULL);
429 		if (ret) {
430 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
431 				__func__);
432 			return ret;
433 		}
434 		break;
435 	default:
436 		return -EINVAL;
437 	}
438 
439 	return count;
440 }
441 
442 static const struct file_operations iio_debugfs_reg_fops = {
443 	.open = simple_open,
444 	.read = iio_debugfs_read_reg,
445 	.write = iio_debugfs_write_reg,
446 };
447 
448 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
449 {
450 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
451 
452 	debugfs_remove_recursive(iio_dev_opaque->debugfs_dentry);
453 }
454 
455 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
456 {
457 	struct iio_dev_opaque *iio_dev_opaque;
458 
459 	if (indio_dev->info->debugfs_reg_access == NULL)
460 		return;
461 
462 	if (!iio_debugfs_dentry)
463 		return;
464 
465 	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
466 
467 	iio_dev_opaque->debugfs_dentry =
468 		debugfs_create_dir(dev_name(&indio_dev->dev),
469 				   iio_debugfs_dentry);
470 
471 	debugfs_create_file("direct_reg_access", 0644,
472 			    iio_dev_opaque->debugfs_dentry, indio_dev,
473 			    &iio_debugfs_reg_fops);
474 }
475 #else
476 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
477 {
478 }
479 
480 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
481 {
482 }
483 #endif /* CONFIG_DEBUG_FS */
484 
485 static ssize_t iio_read_channel_ext_info(struct device *dev,
486 				     struct device_attribute *attr,
487 				     char *buf)
488 {
489 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
490 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
491 	const struct iio_chan_spec_ext_info *ext_info;
492 
493 	ext_info = &this_attr->c->ext_info[this_attr->address];
494 
495 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
496 }
497 
498 static ssize_t iio_write_channel_ext_info(struct device *dev,
499 				     struct device_attribute *attr,
500 				     const char *buf, size_t len)
501 {
502 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
503 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
504 	const struct iio_chan_spec_ext_info *ext_info;
505 
506 	ext_info = &this_attr->c->ext_info[this_attr->address];
507 
508 	return ext_info->write(indio_dev, ext_info->private,
509 			       this_attr->c, buf, len);
510 }
511 
512 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
513 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
514 {
515 	const struct iio_enum *e = (const struct iio_enum *)priv;
516 	unsigned int i;
517 	size_t len = 0;
518 
519 	if (!e->num_items)
520 		return 0;
521 
522 	for (i = 0; i < e->num_items; ++i) {
523 		if (!e->items[i])
524 			continue;
525 		len += sysfs_emit_at(buf, len, "%s ", e->items[i]);
526 	}
527 
528 	/* replace last space with a newline */
529 	buf[len - 1] = '\n';
530 
531 	return len;
532 }
533 EXPORT_SYMBOL_GPL(iio_enum_available_read);
534 
535 ssize_t iio_enum_read(struct iio_dev *indio_dev,
536 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
537 {
538 	const struct iio_enum *e = (const struct iio_enum *)priv;
539 	int i;
540 
541 	if (!e->get)
542 		return -EINVAL;
543 
544 	i = e->get(indio_dev, chan);
545 	if (i < 0)
546 		return i;
547 	if (i >= e->num_items || !e->items[i])
548 		return -EINVAL;
549 
550 	return sysfs_emit(buf, "%s\n", e->items[i]);
551 }
552 EXPORT_SYMBOL_GPL(iio_enum_read);
553 
554 ssize_t iio_enum_write(struct iio_dev *indio_dev,
555 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
556 	size_t len)
557 {
558 	const struct iio_enum *e = (const struct iio_enum *)priv;
559 	int ret;
560 
561 	if (!e->set)
562 		return -EINVAL;
563 
564 	ret = __sysfs_match_string(e->items, e->num_items, buf);
565 	if (ret < 0)
566 		return ret;
567 
568 	ret = e->set(indio_dev, chan, ret);
569 	return ret ? ret : len;
570 }
571 EXPORT_SYMBOL_GPL(iio_enum_write);
572 
573 static const struct iio_mount_matrix iio_mount_idmatrix = {
574 	.rotation = {
575 		"1", "0", "0",
576 		"0", "1", "0",
577 		"0", "0", "1"
578 	}
579 };
580 
581 static int iio_setup_mount_idmatrix(const struct device *dev,
582 				    struct iio_mount_matrix *matrix)
583 {
584 	*matrix = iio_mount_idmatrix;
585 	dev_info(dev, "mounting matrix not found: using identity...\n");
586 	return 0;
587 }
588 
589 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
590 			      const struct iio_chan_spec *chan, char *buf)
591 {
592 	const struct iio_mount_matrix *mtx;
593 
594 	mtx = ((iio_get_mount_matrix_t *)priv)(indio_dev, chan);
595 	if (IS_ERR(mtx))
596 		return PTR_ERR(mtx);
597 
598 	if (!mtx)
599 		mtx = &iio_mount_idmatrix;
600 
601 	return sysfs_emit(buf, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
602 			  mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
603 			  mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
604 			  mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
605 }
606 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
607 
608 /**
609  * iio_read_mount_matrix() - retrieve iio device mounting matrix from
610  *                           device "mount-matrix" property
611  * @dev:	device the mounting matrix property is assigned to
612  * @matrix:	where to store retrieved matrix
613  *
614  * If device is assigned no mounting matrix property, a default 3x3 identity
615  * matrix will be filled in.
616  *
617  * Returns: 0 if success, or a negative error code on failure.
618  */
619 int iio_read_mount_matrix(struct device *dev, struct iio_mount_matrix *matrix)
620 {
621 	size_t len = ARRAY_SIZE(iio_mount_idmatrix.rotation);
622 	int err;
623 
624 	err = device_property_read_string_array(dev, "mount-matrix", matrix->rotation, len);
625 	if (err == len)
626 		return 0;
627 
628 	if (err >= 0)
629 		/* Invalid number of matrix entries. */
630 		return -EINVAL;
631 
632 	if (err != -EINVAL)
633 		/* Invalid matrix declaration format. */
634 		return err;
635 
636 	/* Matrix was not declared at all: fallback to identity. */
637 	return iio_setup_mount_idmatrix(dev, matrix);
638 }
639 EXPORT_SYMBOL(iio_read_mount_matrix);
640 
641 static ssize_t __iio_format_value(char *buf, size_t offset, unsigned int type,
642 				  int size, const int *vals)
643 {
644 	int tmp0, tmp1;
645 	s64 tmp2;
646 	bool scale_db = false;
647 
648 	switch (type) {
649 	case IIO_VAL_INT:
650 		return sysfs_emit_at(buf, offset, "%d", vals[0]);
651 	case IIO_VAL_INT_PLUS_MICRO_DB:
652 		scale_db = true;
653 		fallthrough;
654 	case IIO_VAL_INT_PLUS_MICRO:
655 		if (vals[1] < 0)
656 			return sysfs_emit_at(buf, offset, "-%d.%06u%s",
657 					     abs(vals[0]), -vals[1],
658 					     scale_db ? " dB" : "");
659 		else
660 			return sysfs_emit_at(buf, offset, "%d.%06u%s", vals[0],
661 					     vals[1], scale_db ? " dB" : "");
662 	case IIO_VAL_INT_PLUS_NANO:
663 		if (vals[1] < 0)
664 			return sysfs_emit_at(buf, offset, "-%d.%09u",
665 					     abs(vals[0]), -vals[1]);
666 		else
667 			return sysfs_emit_at(buf, offset, "%d.%09u", vals[0],
668 					     vals[1]);
669 	case IIO_VAL_FRACTIONAL:
670 		tmp2 = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
671 		tmp0 = (int)div_s64_rem(tmp2, 1000000000, &tmp1);
672 		if ((tmp2 < 0) && (tmp0 == 0))
673 			return sysfs_emit_at(buf, offset, "-0.%09u", abs(tmp1));
674 		else
675 			return sysfs_emit_at(buf, offset, "%d.%09u", tmp0,
676 					     abs(tmp1));
677 	case IIO_VAL_FRACTIONAL_LOG2:
678 		tmp2 = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
679 		tmp0 = (int)div_s64_rem(tmp2, 1000000000LL, &tmp1);
680 		if (tmp0 == 0 && tmp2 < 0)
681 			return sysfs_emit_at(buf, offset, "-0.%09u", abs(tmp1));
682 		else
683 			return sysfs_emit_at(buf, offset, "%d.%09u", tmp0,
684 					     abs(tmp1));
685 	case IIO_VAL_INT_MULTIPLE:
686 	{
687 		int i;
688 		int l = 0;
689 
690 		for (i = 0; i < size; ++i)
691 			l += sysfs_emit_at(buf, offset + l, "%d ", vals[i]);
692 		return l;
693 	}
694 	case IIO_VAL_CHAR:
695 		return sysfs_emit_at(buf, offset, "%c", (char)vals[0]);
696 	case IIO_VAL_INT_64:
697 		tmp2 = (s64)((((u64)vals[1]) << 32) | (u32)vals[0]);
698 		return sysfs_emit_at(buf, offset, "%lld", tmp2);
699 	default:
700 		return 0;
701 	}
702 }
703 
704 /**
705  * iio_format_value() - Formats a IIO value into its string representation
706  * @buf:	The buffer to which the formatted value gets written
707  *		which is assumed to be big enough (i.e. PAGE_SIZE).
708  * @type:	One of the IIO_VAL_* constants. This decides how the val
709  *		and val2 parameters are formatted.
710  * @size:	Number of IIO value entries contained in vals
711  * @vals:	Pointer to the values, exact meaning depends on the
712  *		type parameter.
713  *
714  * Returns:
715  * 0 by default, a negative number on failure or the total number of characters
716  * written for a type that belongs to the IIO_VAL_* constant.
717  */
718 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
719 {
720 	ssize_t len;
721 
722 	len = __iio_format_value(buf, 0, type, size, vals);
723 	if (len >= PAGE_SIZE - 1)
724 		return -EFBIG;
725 
726 	return len + sysfs_emit_at(buf, len, "\n");
727 }
728 EXPORT_SYMBOL_GPL(iio_format_value);
729 
730 ssize_t do_iio_read_channel_label(struct iio_dev *indio_dev,
731 				  const struct iio_chan_spec *c,
732 				  char *buf)
733 {
734 	if (indio_dev->info->read_label)
735 		return indio_dev->info->read_label(indio_dev, c, buf);
736 
737 	if (c->extend_name)
738 		return sysfs_emit(buf, "%s\n", c->extend_name);
739 
740 	return -EINVAL;
741 }
742 
743 static ssize_t iio_read_channel_label(struct device *dev,
744 				      struct device_attribute *attr,
745 				      char *buf)
746 {
747 	return do_iio_read_channel_label(dev_to_iio_dev(dev),
748 					 to_iio_dev_attr(attr)->c, buf);
749 }
750 
751 static ssize_t iio_read_channel_info(struct device *dev,
752 				     struct device_attribute *attr,
753 				     char *buf)
754 {
755 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
756 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
757 	int vals[INDIO_MAX_RAW_ELEMENTS];
758 	int ret;
759 	int val_len = 2;
760 
761 	if (indio_dev->info->read_raw_multi)
762 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
763 							INDIO_MAX_RAW_ELEMENTS,
764 							vals, &val_len,
765 							this_attr->address);
766 	else if (indio_dev->info->read_raw)
767 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
768 				    &vals[0], &vals[1], this_attr->address);
769 	else
770 		return -EINVAL;
771 
772 	if (ret < 0)
773 		return ret;
774 
775 	return iio_format_value(buf, ret, val_len, vals);
776 }
777 
778 static ssize_t iio_format_list(char *buf, const int *vals, int type, int length,
779 			       const char *prefix, const char *suffix)
780 {
781 	ssize_t len;
782 	int stride;
783 	int i;
784 
785 	switch (type) {
786 	case IIO_VAL_INT:
787 		stride = 1;
788 		break;
789 	default:
790 		stride = 2;
791 		break;
792 	}
793 
794 	len = sysfs_emit(buf, prefix);
795 
796 	for (i = 0; i <= length - stride; i += stride) {
797 		if (i != 0) {
798 			len += sysfs_emit_at(buf, len, " ");
799 			if (len >= PAGE_SIZE)
800 				return -EFBIG;
801 		}
802 
803 		len += __iio_format_value(buf, len, type, stride, &vals[i]);
804 		if (len >= PAGE_SIZE)
805 			return -EFBIG;
806 	}
807 
808 	len += sysfs_emit_at(buf, len, "%s\n", suffix);
809 
810 	return len;
811 }
812 
813 static ssize_t iio_format_avail_list(char *buf, const int *vals,
814 				     int type, int length)
815 {
816 
817 	return iio_format_list(buf, vals, type, length, "", "");
818 }
819 
820 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
821 {
822 	int length;
823 
824 	/*
825 	 * length refers to the array size , not the number of elements.
826 	 * The purpose is to print the range [min , step ,max] so length should
827 	 * be 3 in case of int, and 6 for other types.
828 	 */
829 	switch (type) {
830 	case IIO_VAL_INT:
831 		length = 3;
832 		break;
833 	default:
834 		length = 6;
835 		break;
836 	}
837 
838 	return iio_format_list(buf, vals, type, length, "[", "]");
839 }
840 
841 static ssize_t iio_read_channel_info_avail(struct device *dev,
842 					   struct device_attribute *attr,
843 					   char *buf)
844 {
845 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
846 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
847 	const int *vals;
848 	int ret;
849 	int length;
850 	int type;
851 
852 	if (!indio_dev->info->read_avail)
853 		return -EINVAL;
854 
855 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
856 					  &vals, &type, &length,
857 					  this_attr->address);
858 
859 	if (ret < 0)
860 		return ret;
861 	switch (ret) {
862 	case IIO_AVAIL_LIST:
863 		return iio_format_avail_list(buf, vals, type, length);
864 	case IIO_AVAIL_RANGE:
865 		return iio_format_avail_range(buf, vals, type);
866 	default:
867 		return -EINVAL;
868 	}
869 }
870 
871 /**
872  * __iio_str_to_fixpoint() - Parse a fixed-point number from a string
873  * @str: The string to parse
874  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
875  * @integer: The integer part of the number
876  * @fract: The fractional part of the number
877  * @scale_db: True if this should parse as dB
878  *
879  * Returns:
880  * 0 on success, or a negative error code if the string could not be parsed.
881  */
882 static int __iio_str_to_fixpoint(const char *str, int fract_mult,
883 				 int *integer, int *fract, bool scale_db)
884 {
885 	int i = 0, f = 0;
886 	bool integer_part = true, negative = false;
887 
888 	if (fract_mult == 0) {
889 		*fract = 0;
890 
891 		return kstrtoint(str, 0, integer);
892 	}
893 
894 	if (str[0] == '-') {
895 		negative = true;
896 		str++;
897 	} else if (str[0] == '+') {
898 		str++;
899 	}
900 
901 	while (*str) {
902 		if ('0' <= *str && *str <= '9') {
903 			if (integer_part) {
904 				i = i * 10 + *str - '0';
905 			} else {
906 				f += fract_mult * (*str - '0');
907 				fract_mult /= 10;
908 			}
909 		} else if (*str == '\n') {
910 			if (*(str + 1) == '\0')
911 				break;
912 			return -EINVAL;
913 		} else if (!strncmp(str, " dB", sizeof(" dB") - 1) && scale_db) {
914 			/* Ignore the dB suffix */
915 			str += sizeof(" dB") - 1;
916 			continue;
917 		} else if (!strncmp(str, "dB", sizeof("dB") - 1) && scale_db) {
918 			/* Ignore the dB suffix */
919 			str += sizeof("dB") - 1;
920 			continue;
921 		} else if (*str == '.' && integer_part) {
922 			integer_part = false;
923 		} else {
924 			return -EINVAL;
925 		}
926 		str++;
927 	}
928 
929 	if (negative) {
930 		if (i)
931 			i = -i;
932 		else
933 			f = -f;
934 	}
935 
936 	*integer = i;
937 	*fract = f;
938 
939 	return 0;
940 }
941 
942 /**
943  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
944  * @str: The string to parse
945  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
946  * @integer: The integer part of the number
947  * @fract: The fractional part of the number
948  *
949  * Returns:
950  * 0 on success, or a negative error code if the string could not be parsed.
951  */
952 int iio_str_to_fixpoint(const char *str, int fract_mult,
953 			int *integer, int *fract)
954 {
955 	return __iio_str_to_fixpoint(str, fract_mult, integer, fract, false);
956 }
957 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
958 
959 static ssize_t iio_write_channel_info(struct device *dev,
960 				      struct device_attribute *attr,
961 				      const char *buf,
962 				      size_t len)
963 {
964 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
965 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
966 	int ret, fract_mult = 100000;
967 	int integer, fract = 0;
968 	bool is_char = false;
969 	bool scale_db = false;
970 
971 	/* Assumes decimal - precision based on number of digits */
972 	if (!indio_dev->info->write_raw)
973 		return -EINVAL;
974 
975 	if (indio_dev->info->write_raw_get_fmt)
976 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
977 			this_attr->c, this_attr->address)) {
978 		case IIO_VAL_INT:
979 			fract_mult = 0;
980 			break;
981 		case IIO_VAL_INT_PLUS_MICRO_DB:
982 			scale_db = true;
983 			fallthrough;
984 		case IIO_VAL_INT_PLUS_MICRO:
985 			fract_mult = 100000;
986 			break;
987 		case IIO_VAL_INT_PLUS_NANO:
988 			fract_mult = 100000000;
989 			break;
990 		case IIO_VAL_CHAR:
991 			is_char = true;
992 			break;
993 		default:
994 			return -EINVAL;
995 		}
996 
997 	if (is_char) {
998 		char ch;
999 
1000 		if (sscanf(buf, "%c", &ch) != 1)
1001 			return -EINVAL;
1002 		integer = ch;
1003 	} else {
1004 		ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
1005 					    scale_db);
1006 		if (ret)
1007 			return ret;
1008 	}
1009 
1010 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
1011 					 integer, fract, this_attr->address);
1012 	if (ret)
1013 		return ret;
1014 
1015 	return len;
1016 }
1017 
1018 static
1019 int __iio_device_attr_init(struct device_attribute *dev_attr,
1020 			   const char *postfix,
1021 			   struct iio_chan_spec const *chan,
1022 			   ssize_t (*readfunc)(struct device *dev,
1023 					       struct device_attribute *attr,
1024 					       char *buf),
1025 			   ssize_t (*writefunc)(struct device *dev,
1026 						struct device_attribute *attr,
1027 						const char *buf,
1028 						size_t len),
1029 			   enum iio_shared_by shared_by)
1030 {
1031 	int ret = 0;
1032 	char *name = NULL;
1033 	char *full_postfix;
1034 
1035 	sysfs_attr_init(&dev_attr->attr);
1036 
1037 	/* Build up postfix of <extend_name>_<modifier>_postfix */
1038 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
1039 		if (chan->extend_name)
1040 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
1041 						 iio_modifier_names[chan->channel2],
1042 						 chan->extend_name,
1043 						 postfix);
1044 		else
1045 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
1046 						 iio_modifier_names[chan->channel2],
1047 						 postfix);
1048 	} else {
1049 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
1050 			full_postfix = kstrdup(postfix, GFP_KERNEL);
1051 		else
1052 			full_postfix = kasprintf(GFP_KERNEL,
1053 						 "%s_%s",
1054 						 chan->extend_name,
1055 						 postfix);
1056 	}
1057 	if (full_postfix == NULL)
1058 		return -ENOMEM;
1059 
1060 	if (chan->differential) { /* Differential can not have modifier */
1061 		switch (shared_by) {
1062 		case IIO_SHARED_BY_ALL:
1063 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
1064 			break;
1065 		case IIO_SHARED_BY_DIR:
1066 			name = kasprintf(GFP_KERNEL, "%s_%s",
1067 						iio_direction[chan->output],
1068 						full_postfix);
1069 			break;
1070 		case IIO_SHARED_BY_TYPE:
1071 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
1072 					    iio_direction[chan->output],
1073 					    iio_chan_type_name_spec[chan->type],
1074 					    iio_chan_type_name_spec[chan->type],
1075 					    full_postfix);
1076 			break;
1077 		case IIO_SEPARATE:
1078 			if (!chan->indexed) {
1079 				WARN(1, "Differential channels must be indexed\n");
1080 				ret = -EINVAL;
1081 				goto error_free_full_postfix;
1082 			}
1083 			name = kasprintf(GFP_KERNEL,
1084 					    "%s_%s%d-%s%d_%s",
1085 					    iio_direction[chan->output],
1086 					    iio_chan_type_name_spec[chan->type],
1087 					    chan->channel,
1088 					    iio_chan_type_name_spec[chan->type],
1089 					    chan->channel2,
1090 					    full_postfix);
1091 			break;
1092 		}
1093 	} else { /* Single ended */
1094 		switch (shared_by) {
1095 		case IIO_SHARED_BY_ALL:
1096 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
1097 			break;
1098 		case IIO_SHARED_BY_DIR:
1099 			name = kasprintf(GFP_KERNEL, "%s_%s",
1100 						iio_direction[chan->output],
1101 						full_postfix);
1102 			break;
1103 		case IIO_SHARED_BY_TYPE:
1104 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1105 					    iio_direction[chan->output],
1106 					    iio_chan_type_name_spec[chan->type],
1107 					    full_postfix);
1108 			break;
1109 
1110 		case IIO_SEPARATE:
1111 			if (chan->indexed)
1112 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
1113 						    iio_direction[chan->output],
1114 						    iio_chan_type_name_spec[chan->type],
1115 						    chan->channel,
1116 						    full_postfix);
1117 			else
1118 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1119 						    iio_direction[chan->output],
1120 						    iio_chan_type_name_spec[chan->type],
1121 						    full_postfix);
1122 			break;
1123 		}
1124 	}
1125 	if (name == NULL) {
1126 		ret = -ENOMEM;
1127 		goto error_free_full_postfix;
1128 	}
1129 	dev_attr->attr.name = name;
1130 
1131 	if (readfunc) {
1132 		dev_attr->attr.mode |= 0444;
1133 		dev_attr->show = readfunc;
1134 	}
1135 
1136 	if (writefunc) {
1137 		dev_attr->attr.mode |= 0200;
1138 		dev_attr->store = writefunc;
1139 	}
1140 
1141 error_free_full_postfix:
1142 	kfree(full_postfix);
1143 
1144 	return ret;
1145 }
1146 
1147 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1148 {
1149 	kfree(dev_attr->attr.name);
1150 }
1151 
1152 int __iio_add_chan_devattr(const char *postfix,
1153 			   struct iio_chan_spec const *chan,
1154 			   ssize_t (*readfunc)(struct device *dev,
1155 					       struct device_attribute *attr,
1156 					       char *buf),
1157 			   ssize_t (*writefunc)(struct device *dev,
1158 						struct device_attribute *attr,
1159 						const char *buf,
1160 						size_t len),
1161 			   u64 mask,
1162 			   enum iio_shared_by shared_by,
1163 			   struct device *dev,
1164 			   struct iio_buffer *buffer,
1165 			   struct list_head *attr_list)
1166 {
1167 	int ret;
1168 	struct iio_dev_attr *iio_attr, *t;
1169 
1170 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1171 	if (iio_attr == NULL)
1172 		return -ENOMEM;
1173 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1174 				     postfix, chan,
1175 				     readfunc, writefunc, shared_by);
1176 	if (ret)
1177 		goto error_iio_dev_attr_free;
1178 	iio_attr->c = chan;
1179 	iio_attr->address = mask;
1180 	iio_attr->buffer = buffer;
1181 	list_for_each_entry(t, attr_list, l)
1182 		if (strcmp(t->dev_attr.attr.name,
1183 			   iio_attr->dev_attr.attr.name) == 0) {
1184 			if (shared_by == IIO_SEPARATE)
1185 				dev_err(dev, "tried to double register : %s\n",
1186 					t->dev_attr.attr.name);
1187 			ret = -EBUSY;
1188 			goto error_device_attr_deinit;
1189 		}
1190 	list_add(&iio_attr->l, attr_list);
1191 
1192 	return 0;
1193 
1194 error_device_attr_deinit:
1195 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1196 error_iio_dev_attr_free:
1197 	kfree(iio_attr);
1198 	return ret;
1199 }
1200 
1201 static int iio_device_add_channel_label(struct iio_dev *indio_dev,
1202 					 struct iio_chan_spec const *chan)
1203 {
1204 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1205 	int ret;
1206 
1207 	if (!indio_dev->info->read_label && !chan->extend_name)
1208 		return 0;
1209 
1210 	ret = __iio_add_chan_devattr("label",
1211 				     chan,
1212 				     &iio_read_channel_label,
1213 				     NULL,
1214 				     0,
1215 				     IIO_SEPARATE,
1216 				     &indio_dev->dev,
1217 				     NULL,
1218 				     &iio_dev_opaque->channel_attr_list);
1219 	if (ret < 0)
1220 		return ret;
1221 
1222 	return 1;
1223 }
1224 
1225 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1226 					 struct iio_chan_spec const *chan,
1227 					 enum iio_shared_by shared_by,
1228 					 const long *infomask)
1229 {
1230 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1231 	int i, ret, attrcount = 0;
1232 
1233 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1234 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1235 			return -EINVAL;
1236 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1237 					     chan,
1238 					     &iio_read_channel_info,
1239 					     &iio_write_channel_info,
1240 					     i,
1241 					     shared_by,
1242 					     &indio_dev->dev,
1243 					     NULL,
1244 					     &iio_dev_opaque->channel_attr_list);
1245 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1246 			continue;
1247 		if (ret < 0)
1248 			return ret;
1249 		attrcount++;
1250 	}
1251 
1252 	return attrcount;
1253 }
1254 
1255 static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
1256 					       struct iio_chan_spec const *chan,
1257 					       enum iio_shared_by shared_by,
1258 					       const long *infomask)
1259 {
1260 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1261 	int i, ret, attrcount = 0;
1262 	char *avail_postfix;
1263 
1264 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1265 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1266 			return -EINVAL;
1267 		avail_postfix = kasprintf(GFP_KERNEL,
1268 					  "%s_available",
1269 					  iio_chan_info_postfix[i]);
1270 		if (!avail_postfix)
1271 			return -ENOMEM;
1272 
1273 		ret = __iio_add_chan_devattr(avail_postfix,
1274 					     chan,
1275 					     &iio_read_channel_info_avail,
1276 					     NULL,
1277 					     i,
1278 					     shared_by,
1279 					     &indio_dev->dev,
1280 					     NULL,
1281 					     &iio_dev_opaque->channel_attr_list);
1282 		kfree(avail_postfix);
1283 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1284 			continue;
1285 		if (ret < 0)
1286 			return ret;
1287 		attrcount++;
1288 	}
1289 
1290 	return attrcount;
1291 }
1292 
1293 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1294 					struct iio_chan_spec const *chan)
1295 {
1296 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1297 	int ret, attrcount = 0;
1298 	const struct iio_chan_spec_ext_info *ext_info;
1299 
1300 	if (chan->channel < 0)
1301 		return 0;
1302 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1303 					    IIO_SEPARATE,
1304 					    &chan->info_mask_separate);
1305 	if (ret < 0)
1306 		return ret;
1307 	attrcount += ret;
1308 
1309 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1310 						  IIO_SEPARATE,
1311 						  &chan->info_mask_separate_available);
1312 	if (ret < 0)
1313 		return ret;
1314 	attrcount += ret;
1315 
1316 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1317 					    IIO_SHARED_BY_TYPE,
1318 					    &chan->info_mask_shared_by_type);
1319 	if (ret < 0)
1320 		return ret;
1321 	attrcount += ret;
1322 
1323 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1324 						  IIO_SHARED_BY_TYPE,
1325 						  &chan->info_mask_shared_by_type_available);
1326 	if (ret < 0)
1327 		return ret;
1328 	attrcount += ret;
1329 
1330 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1331 					    IIO_SHARED_BY_DIR,
1332 					    &chan->info_mask_shared_by_dir);
1333 	if (ret < 0)
1334 		return ret;
1335 	attrcount += ret;
1336 
1337 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1338 						  IIO_SHARED_BY_DIR,
1339 						  &chan->info_mask_shared_by_dir_available);
1340 	if (ret < 0)
1341 		return ret;
1342 	attrcount += ret;
1343 
1344 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1345 					    IIO_SHARED_BY_ALL,
1346 					    &chan->info_mask_shared_by_all);
1347 	if (ret < 0)
1348 		return ret;
1349 	attrcount += ret;
1350 
1351 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1352 						  IIO_SHARED_BY_ALL,
1353 						  &chan->info_mask_shared_by_all_available);
1354 	if (ret < 0)
1355 		return ret;
1356 	attrcount += ret;
1357 
1358 	ret = iio_device_add_channel_label(indio_dev, chan);
1359 	if (ret < 0)
1360 		return ret;
1361 	attrcount += ret;
1362 
1363 	if (chan->ext_info) {
1364 		unsigned int i = 0;
1365 
1366 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1367 			ret = __iio_add_chan_devattr(ext_info->name,
1368 					chan,
1369 					ext_info->read ?
1370 					    &iio_read_channel_ext_info : NULL,
1371 					ext_info->write ?
1372 					    &iio_write_channel_ext_info : NULL,
1373 					i,
1374 					ext_info->shared,
1375 					&indio_dev->dev,
1376 					NULL,
1377 					&iio_dev_opaque->channel_attr_list);
1378 			i++;
1379 			if (ret == -EBUSY && ext_info->shared)
1380 				continue;
1381 
1382 			if (ret)
1383 				return ret;
1384 
1385 			attrcount++;
1386 		}
1387 	}
1388 
1389 	return attrcount;
1390 }
1391 
1392 /**
1393  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1394  * @attr_list: List of IIO device attributes
1395  *
1396  * This function frees the memory allocated for each of the IIO device
1397  * attributes in the list.
1398  */
1399 void iio_free_chan_devattr_list(struct list_head *attr_list)
1400 {
1401 	struct iio_dev_attr *p, *n;
1402 
1403 	list_for_each_entry_safe(p, n, attr_list, l) {
1404 		kfree_const(p->dev_attr.attr.name);
1405 		list_del(&p->l);
1406 		kfree(p);
1407 	}
1408 }
1409 
1410 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
1411 			 char *buf)
1412 {
1413 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1414 
1415 	return sysfs_emit(buf, "%s\n", indio_dev->name);
1416 }
1417 
1418 static DEVICE_ATTR_RO(name);
1419 
1420 static ssize_t label_show(struct device *dev, struct device_attribute *attr,
1421 			  char *buf)
1422 {
1423 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1424 
1425 	return sysfs_emit(buf, "%s\n", indio_dev->label);
1426 }
1427 
1428 static DEVICE_ATTR_RO(label);
1429 
1430 static const char * const clock_names[] = {
1431 	[CLOCK_REALTIME]	 	= "realtime",
1432 	[CLOCK_MONOTONIC]	 	= "monotonic",
1433 	[CLOCK_PROCESS_CPUTIME_ID]	= "process_cputime_id",
1434 	[CLOCK_THREAD_CPUTIME_ID]	= "thread_cputime_id",
1435 	[CLOCK_MONOTONIC_RAW]	 	= "monotonic_raw",
1436 	[CLOCK_REALTIME_COARSE]	 	= "realtime_coarse",
1437 	[CLOCK_MONOTONIC_COARSE] 	= "monotonic_coarse",
1438 	[CLOCK_BOOTTIME]	 	= "boottime",
1439 	[CLOCK_REALTIME_ALARM]		= "realtime_alarm",
1440 	[CLOCK_BOOTTIME_ALARM]		= "boottime_alarm",
1441 	[CLOCK_SGI_CYCLE]		= "sgi_cycle",
1442 	[CLOCK_TAI]		 	= "tai",
1443 };
1444 
1445 static ssize_t current_timestamp_clock_show(struct device *dev,
1446 					    struct device_attribute *attr,
1447 					    char *buf)
1448 {
1449 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1450 	const clockid_t clk = iio_device_get_clock(indio_dev);
1451 
1452 	switch (clk) {
1453 	case CLOCK_REALTIME:
1454 	case CLOCK_MONOTONIC:
1455 	case CLOCK_MONOTONIC_RAW:
1456 	case CLOCK_REALTIME_COARSE:
1457 	case CLOCK_MONOTONIC_COARSE:
1458 	case CLOCK_BOOTTIME:
1459 	case CLOCK_TAI:
1460 		break;
1461 	default:
1462 		BUG();
1463 	}
1464 
1465 	return sysfs_emit(buf, "%s\n", clock_names[clk]);
1466 }
1467 
1468 static ssize_t current_timestamp_clock_store(struct device *dev,
1469 					     struct device_attribute *attr,
1470 					     const char *buf, size_t len)
1471 {
1472 	clockid_t clk;
1473 	int ret;
1474 
1475 	ret = sysfs_match_string(clock_names, buf);
1476 	if (ret < 0)
1477 		return ret;
1478 	clk = ret;
1479 
1480 	switch (clk) {
1481 	case CLOCK_REALTIME:
1482 	case CLOCK_MONOTONIC:
1483 	case CLOCK_MONOTONIC_RAW:
1484 	case CLOCK_REALTIME_COARSE:
1485 	case CLOCK_MONOTONIC_COARSE:
1486 	case CLOCK_BOOTTIME:
1487 	case CLOCK_TAI:
1488 		break;
1489 	default:
1490 		return -EINVAL;
1491 	}
1492 
1493 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1494 	if (ret)
1495 		return ret;
1496 
1497 	return len;
1498 }
1499 
1500 int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
1501 				    const struct attribute_group *group)
1502 {
1503 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1504 	const struct attribute_group **new, **old = iio_dev_opaque->groups;
1505 	unsigned int cnt = iio_dev_opaque->groupcounter;
1506 
1507 	new = krealloc_array(old, cnt + 2, sizeof(*new), GFP_KERNEL);
1508 	if (!new)
1509 		return -ENOMEM;
1510 
1511 	new[iio_dev_opaque->groupcounter++] = group;
1512 	new[iio_dev_opaque->groupcounter] = NULL;
1513 
1514 	iio_dev_opaque->groups = new;
1515 
1516 	return 0;
1517 }
1518 
1519 static DEVICE_ATTR_RW(current_timestamp_clock);
1520 
1521 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1522 {
1523 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1524 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1525 	struct iio_dev_attr *p;
1526 	struct attribute **attr, *clk = NULL;
1527 
1528 	/* First count elements in any existing group */
1529 	if (indio_dev->info->attrs) {
1530 		attr = indio_dev->info->attrs->attrs;
1531 		while (*attr++ != NULL)
1532 			attrcount_orig++;
1533 	}
1534 	attrcount = attrcount_orig;
1535 	/*
1536 	 * New channel registration method - relies on the fact a group does
1537 	 * not need to be initialized if its name is NULL.
1538 	 */
1539 	if (indio_dev->channels)
1540 		for (i = 0; i < indio_dev->num_channels; i++) {
1541 			const struct iio_chan_spec *chan =
1542 				&indio_dev->channels[i];
1543 
1544 			if (chan->type == IIO_TIMESTAMP)
1545 				clk = &dev_attr_current_timestamp_clock.attr;
1546 
1547 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1548 			if (ret < 0)
1549 				goto error_clear_attrs;
1550 			attrcount += ret;
1551 		}
1552 
1553 	if (iio_dev_opaque->event_interface)
1554 		clk = &dev_attr_current_timestamp_clock.attr;
1555 
1556 	if (indio_dev->name)
1557 		attrcount++;
1558 	if (indio_dev->label)
1559 		attrcount++;
1560 	if (clk)
1561 		attrcount++;
1562 
1563 	iio_dev_opaque->chan_attr_group.attrs =
1564 		kcalloc(attrcount + 1,
1565 			sizeof(iio_dev_opaque->chan_attr_group.attrs[0]),
1566 			GFP_KERNEL);
1567 	if (iio_dev_opaque->chan_attr_group.attrs == NULL) {
1568 		ret = -ENOMEM;
1569 		goto error_clear_attrs;
1570 	}
1571 	/* Copy across original attributes, and point to original binary attributes */
1572 	if (indio_dev->info->attrs) {
1573 		memcpy(iio_dev_opaque->chan_attr_group.attrs,
1574 		       indio_dev->info->attrs->attrs,
1575 		       sizeof(iio_dev_opaque->chan_attr_group.attrs[0])
1576 		       *attrcount_orig);
1577 		iio_dev_opaque->chan_attr_group.is_visible =
1578 			indio_dev->info->attrs->is_visible;
1579 		iio_dev_opaque->chan_attr_group.bin_attrs =
1580 			indio_dev->info->attrs->bin_attrs;
1581 	}
1582 	attrn = attrcount_orig;
1583 	/* Add all elements from the list. */
1584 	list_for_each_entry(p, &iio_dev_opaque->channel_attr_list, l)
1585 		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1586 	if (indio_dev->name)
1587 		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1588 	if (indio_dev->label)
1589 		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &dev_attr_label.attr;
1590 	if (clk)
1591 		iio_dev_opaque->chan_attr_group.attrs[attrn++] = clk;
1592 
1593 	ret = iio_device_register_sysfs_group(indio_dev,
1594 					      &iio_dev_opaque->chan_attr_group);
1595 	if (ret)
1596 		goto error_free_chan_attrs;
1597 
1598 	return 0;
1599 
1600 error_free_chan_attrs:
1601 	kfree(iio_dev_opaque->chan_attr_group.attrs);
1602 	iio_dev_opaque->chan_attr_group.attrs = NULL;
1603 error_clear_attrs:
1604 	iio_free_chan_devattr_list(&iio_dev_opaque->channel_attr_list);
1605 
1606 	return ret;
1607 }
1608 
1609 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1610 {
1611 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1612 
1613 	iio_free_chan_devattr_list(&iio_dev_opaque->channel_attr_list);
1614 	kfree(iio_dev_opaque->chan_attr_group.attrs);
1615 	iio_dev_opaque->chan_attr_group.attrs = NULL;
1616 	kfree(iio_dev_opaque->groups);
1617 	iio_dev_opaque->groups = NULL;
1618 }
1619 
1620 static void iio_dev_release(struct device *device)
1621 {
1622 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1623 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1624 
1625 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1626 		iio_device_unregister_trigger_consumer(indio_dev);
1627 	iio_device_unregister_eventset(indio_dev);
1628 	iio_device_unregister_sysfs(indio_dev);
1629 
1630 	iio_device_detach_buffers(indio_dev);
1631 
1632 	lockdep_unregister_key(&iio_dev_opaque->mlock_key);
1633 
1634 	ida_free(&iio_ida, iio_dev_opaque->id);
1635 	kfree(iio_dev_opaque);
1636 }
1637 
1638 const struct device_type iio_device_type = {
1639 	.name = "iio_device",
1640 	.release = iio_dev_release,
1641 };
1642 
1643 /**
1644  * iio_device_alloc() - allocate an iio_dev from a driver
1645  * @parent:		Parent device.
1646  * @sizeof_priv:	Space to allocate for private structure.
1647  *
1648  * Returns:
1649  * Pointer to allocated iio_dev on success, NULL on failure.
1650  */
1651 struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
1652 {
1653 	struct iio_dev_opaque *iio_dev_opaque;
1654 	struct iio_dev *indio_dev;
1655 	size_t alloc_size;
1656 
1657 	if (sizeof_priv)
1658 		alloc_size = ALIGN(sizeof(*iio_dev_opaque), IIO_DMA_MINALIGN) + sizeof_priv;
1659 	else
1660 		alloc_size = sizeof(*iio_dev_opaque);
1661 
1662 	iio_dev_opaque = kzalloc(alloc_size, GFP_KERNEL);
1663 	if (!iio_dev_opaque)
1664 		return NULL;
1665 
1666 	indio_dev = &iio_dev_opaque->indio_dev;
1667 
1668 	if (sizeof_priv)
1669 		ACCESS_PRIVATE(indio_dev, priv) = (char *)iio_dev_opaque +
1670 			ALIGN(sizeof(*iio_dev_opaque), IIO_DMA_MINALIGN);
1671 
1672 	indio_dev->dev.parent = parent;
1673 	indio_dev->dev.type = &iio_device_type;
1674 	indio_dev->dev.bus = &iio_bus_type;
1675 	device_initialize(&indio_dev->dev);
1676 	mutex_init(&iio_dev_opaque->mlock);
1677 	mutex_init(&iio_dev_opaque->info_exist_lock);
1678 	INIT_LIST_HEAD(&iio_dev_opaque->channel_attr_list);
1679 
1680 	iio_dev_opaque->id = ida_alloc(&iio_ida, GFP_KERNEL);
1681 	if (iio_dev_opaque->id < 0) {
1682 		/* cannot use a dev_err as the name isn't available */
1683 		pr_err("failed to get device id\n");
1684 		kfree(iio_dev_opaque);
1685 		return NULL;
1686 	}
1687 
1688 	if (dev_set_name(&indio_dev->dev, "iio:device%d", iio_dev_opaque->id)) {
1689 		ida_free(&iio_ida, iio_dev_opaque->id);
1690 		kfree(iio_dev_opaque);
1691 		return NULL;
1692 	}
1693 
1694 	INIT_LIST_HEAD(&iio_dev_opaque->buffer_list);
1695 	INIT_LIST_HEAD(&iio_dev_opaque->ioctl_handlers);
1696 
1697 	lockdep_register_key(&iio_dev_opaque->mlock_key);
1698 	lockdep_set_class(&iio_dev_opaque->mlock, &iio_dev_opaque->mlock_key);
1699 
1700 	return indio_dev;
1701 }
1702 EXPORT_SYMBOL(iio_device_alloc);
1703 
1704 /**
1705  * iio_device_free() - free an iio_dev from a driver
1706  * @dev:		the iio_dev associated with the device
1707  */
1708 void iio_device_free(struct iio_dev *dev)
1709 {
1710 	if (dev)
1711 		put_device(&dev->dev);
1712 }
1713 EXPORT_SYMBOL(iio_device_free);
1714 
1715 static void devm_iio_device_release(void *iio_dev)
1716 {
1717 	iio_device_free(iio_dev);
1718 }
1719 
1720 /**
1721  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1722  * @parent:		Device to allocate iio_dev for, and parent for this IIO device
1723  * @sizeof_priv:	Space to allocate for private structure.
1724  *
1725  * Managed iio_device_alloc. iio_dev allocated with this function is
1726  * automatically freed on driver detach.
1727  *
1728  * Returns:
1729  * Pointer to allocated iio_dev on success, NULL on failure.
1730  */
1731 struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv)
1732 {
1733 	struct iio_dev *iio_dev;
1734 	int ret;
1735 
1736 	iio_dev = iio_device_alloc(parent, sizeof_priv);
1737 	if (!iio_dev)
1738 		return NULL;
1739 
1740 	ret = devm_add_action_or_reset(parent, devm_iio_device_release,
1741 				       iio_dev);
1742 	if (ret)
1743 		return NULL;
1744 
1745 	return iio_dev;
1746 }
1747 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1748 
1749 /**
1750  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1751  * @inode:	Inode structure for identifying the device in the file system
1752  * @filp:	File structure for iio device used to keep and later access
1753  *		private data
1754  *
1755  * Returns: 0 on success or -EBUSY if the device is already opened
1756  */
1757 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1758 {
1759 	struct iio_dev_opaque *iio_dev_opaque =
1760 		container_of(inode->i_cdev, struct iio_dev_opaque, chrdev);
1761 	struct iio_dev *indio_dev = &iio_dev_opaque->indio_dev;
1762 	struct iio_dev_buffer_pair *ib;
1763 
1764 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags))
1765 		return -EBUSY;
1766 
1767 	iio_device_get(indio_dev);
1768 
1769 	ib = kmalloc(sizeof(*ib), GFP_KERNEL);
1770 	if (!ib) {
1771 		iio_device_put(indio_dev);
1772 		clear_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags);
1773 		return -ENOMEM;
1774 	}
1775 
1776 	ib->indio_dev = indio_dev;
1777 	ib->buffer = indio_dev->buffer;
1778 
1779 	filp->private_data = ib;
1780 
1781 	return 0;
1782 }
1783 
1784 /**
1785  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1786  * @inode:	Inode structure pointer for the char device
1787  * @filp:	File structure pointer for the char device
1788  *
1789  * Returns: 0 for successful release.
1790  */
1791 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1792 {
1793 	struct iio_dev_buffer_pair *ib = filp->private_data;
1794 	struct iio_dev_opaque *iio_dev_opaque =
1795 		container_of(inode->i_cdev, struct iio_dev_opaque, chrdev);
1796 	struct iio_dev *indio_dev = &iio_dev_opaque->indio_dev;
1797 
1798 	kfree(ib);
1799 	clear_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags);
1800 	iio_device_put(indio_dev);
1801 
1802 	return 0;
1803 }
1804 
1805 void iio_device_ioctl_handler_register(struct iio_dev *indio_dev,
1806 				       struct iio_ioctl_handler *h)
1807 {
1808 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1809 
1810 	list_add_tail(&h->entry, &iio_dev_opaque->ioctl_handlers);
1811 }
1812 
1813 void iio_device_ioctl_handler_unregister(struct iio_ioctl_handler *h)
1814 {
1815 	list_del(&h->entry);
1816 }
1817 
1818 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1819 {
1820 	struct iio_dev_buffer_pair *ib = filp->private_data;
1821 	struct iio_dev *indio_dev = ib->indio_dev;
1822 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1823 	struct iio_ioctl_handler *h;
1824 	int ret;
1825 
1826 	guard(mutex)(&iio_dev_opaque->info_exist_lock);
1827 	/*
1828 	 * The NULL check here is required to prevent crashing when a device
1829 	 * is being removed while userspace would still have open file handles
1830 	 * to try to access this device.
1831 	 */
1832 	if (!indio_dev->info)
1833 		return -ENODEV;
1834 
1835 	list_for_each_entry(h, &iio_dev_opaque->ioctl_handlers, entry) {
1836 		ret = h->ioctl(indio_dev, filp, cmd, arg);
1837 		if (ret != IIO_IOCTL_UNHANDLED)
1838 			return ret;
1839 	}
1840 
1841 	return -ENODEV;
1842 }
1843 
1844 static const struct file_operations iio_buffer_fileops = {
1845 	.owner = THIS_MODULE,
1846 	.llseek = noop_llseek,
1847 	.read = iio_buffer_read_outer_addr,
1848 	.write = iio_buffer_write_outer_addr,
1849 	.poll = iio_buffer_poll_addr,
1850 	.unlocked_ioctl = iio_ioctl,
1851 	.compat_ioctl = compat_ptr_ioctl,
1852 	.open = iio_chrdev_open,
1853 	.release = iio_chrdev_release,
1854 };
1855 
1856 static const struct file_operations iio_event_fileops = {
1857 	.owner = THIS_MODULE,
1858 	.llseek = noop_llseek,
1859 	.unlocked_ioctl = iio_ioctl,
1860 	.compat_ioctl = compat_ptr_ioctl,
1861 	.open = iio_chrdev_open,
1862 	.release = iio_chrdev_release,
1863 };
1864 
1865 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1866 {
1867 	int i, j;
1868 	const struct iio_chan_spec *channels = indio_dev->channels;
1869 
1870 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1871 		return 0;
1872 
1873 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1874 		if (channels[i].scan_index < 0)
1875 			continue;
1876 		for (j = i + 1; j < indio_dev->num_channels; j++)
1877 			if (channels[i].scan_index == channels[j].scan_index) {
1878 				dev_err(&indio_dev->dev,
1879 					"Duplicate scan index %d\n",
1880 					channels[i].scan_index);
1881 				return -EINVAL;
1882 			}
1883 	}
1884 
1885 	return 0;
1886 }
1887 
1888 static int iio_check_extended_name(const struct iio_dev *indio_dev)
1889 {
1890 	unsigned int i;
1891 
1892 	if (!indio_dev->info->read_label)
1893 		return 0;
1894 
1895 	for (i = 0; i < indio_dev->num_channels; i++) {
1896 		if (indio_dev->channels[i].extend_name) {
1897 			dev_err(&indio_dev->dev,
1898 				"Cannot use labels and extend_name at the same time\n");
1899 			return -EINVAL;
1900 		}
1901 	}
1902 
1903 	return 0;
1904 }
1905 
1906 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1907 
1908 static void iio_sanity_check_avail_scan_masks(struct iio_dev *indio_dev)
1909 {
1910 	unsigned int num_masks, masklength, longs_per_mask;
1911 	const unsigned long *av_masks;
1912 	int i;
1913 
1914 	av_masks = indio_dev->available_scan_masks;
1915 	masklength = iio_get_masklength(indio_dev);
1916 	longs_per_mask = BITS_TO_LONGS(masklength);
1917 
1918 	/*
1919 	 * The code determining how many available_scan_masks is in the array
1920 	 * will be assuming the end of masks when first long with all bits
1921 	 * zeroed is encountered. This is incorrect for masks where mask
1922 	 * consists of more than one long, and where some of the available masks
1923 	 * has long worth of bits zeroed (but has subsequent bit(s) set). This
1924 	 * is a safety measure against bug where array of masks is terminated by
1925 	 * a single zero while mask width is greater than width of a long.
1926 	 */
1927 	if (longs_per_mask > 1)
1928 		dev_warn(indio_dev->dev.parent,
1929 			 "multi long available scan masks not fully supported\n");
1930 
1931 	if (bitmap_empty(av_masks, masklength))
1932 		dev_warn(indio_dev->dev.parent, "empty scan mask\n");
1933 
1934 	for (num_masks = 0; *av_masks; num_masks++)
1935 		av_masks += longs_per_mask;
1936 
1937 	if (num_masks < 2)
1938 		return;
1939 
1940 	av_masks = indio_dev->available_scan_masks;
1941 
1942 	/*
1943 	 * Go through all the masks from first to one before the last, and see
1944 	 * that no mask found later from the available_scan_masks array is a
1945 	 * subset of mask found earlier. If this happens, then the mask found
1946 	 * later will never get used because scanning the array is stopped when
1947 	 * the first suitable mask is found. Drivers should order the array of
1948 	 * available masks in the order of preference (presumably the least
1949 	 * costy to access masks first).
1950 	 */
1951 	for (i = 0; i < num_masks - 1; i++) {
1952 		const unsigned long *mask1;
1953 		int j;
1954 
1955 		mask1 = av_masks + i * longs_per_mask;
1956 		for (j = i + 1; j < num_masks; j++) {
1957 			const unsigned long *mask2;
1958 
1959 			mask2 = av_masks + j * longs_per_mask;
1960 			if (bitmap_subset(mask2, mask1, masklength))
1961 				dev_warn(indio_dev->dev.parent,
1962 					 "available_scan_mask %d subset of %d. Never used\n",
1963 					 j, i);
1964 		}
1965 	}
1966 }
1967 
1968 /**
1969  * iio_active_scan_mask_index - Get index of the active scan mask inside the
1970  * available scan masks array
1971  * @indio_dev: the IIO device containing the active and available scan masks
1972  *
1973  * Returns: the index or -EINVAL if  active_scan_mask is not set
1974  */
1975 int iio_active_scan_mask_index(struct iio_dev *indio_dev)
1976 
1977 {
1978 	const unsigned long *av_masks;
1979 	unsigned int masklength = iio_get_masklength(indio_dev);
1980 	int i = 0;
1981 
1982 	if (!indio_dev->active_scan_mask)
1983 		return -EINVAL;
1984 
1985 	/*
1986 	 * As in iio_scan_mask_match and iio_sanity_check_avail_scan_masks,
1987 	 * the condition here do not handle multi-long masks correctly.
1988 	 * It only checks the first long to be zero, and will use such mask
1989 	 * as a terminator even if there was bits set after the first long.
1990 	 *
1991 	 * This should be fine since the available_scan_mask has already been
1992 	 * sanity tested using iio_sanity_check_avail_scan_masks.
1993 	 *
1994 	 * See iio_scan_mask_match and iio_sanity_check_avail_scan_masks for
1995 	 * more details
1996 	 */
1997 	av_masks = indio_dev->available_scan_masks;
1998 	while (*av_masks) {
1999 		if (indio_dev->active_scan_mask == av_masks)
2000 			return i;
2001 		av_masks += BITS_TO_LONGS(masklength);
2002 		i++;
2003 	}
2004 
2005 	dev_warn(indio_dev->dev.parent,
2006 		 "active scan mask is not part of the available scan masks\n");
2007 	return -EINVAL;
2008 }
2009 EXPORT_SYMBOL_GPL(iio_active_scan_mask_index);
2010 
2011 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
2012 {
2013 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2014 	struct fwnode_handle *fwnode = NULL;
2015 	int ret;
2016 
2017 	if (!indio_dev->info)
2018 		return -EINVAL;
2019 
2020 	iio_dev_opaque->driver_module = this_mod;
2021 
2022 	/* If the calling driver did not initialize firmware node, do it here */
2023 	if (dev_fwnode(&indio_dev->dev))
2024 		fwnode = dev_fwnode(&indio_dev->dev);
2025 	/* The default dummy IIO device has no parent */
2026 	else if (indio_dev->dev.parent)
2027 		fwnode = dev_fwnode(indio_dev->dev.parent);
2028 	device_set_node(&indio_dev->dev, fwnode);
2029 
2030 	fwnode_property_read_string(fwnode, "label", &indio_dev->label);
2031 
2032 	ret = iio_check_unique_scan_index(indio_dev);
2033 	if (ret < 0)
2034 		return ret;
2035 
2036 	ret = iio_check_extended_name(indio_dev);
2037 	if (ret < 0)
2038 		return ret;
2039 
2040 	iio_device_register_debugfs(indio_dev);
2041 
2042 	ret = iio_buffers_alloc_sysfs_and_mask(indio_dev);
2043 	if (ret) {
2044 		dev_err(indio_dev->dev.parent,
2045 			"Failed to create buffer sysfs interfaces\n");
2046 		goto error_unreg_debugfs;
2047 	}
2048 
2049 	if (indio_dev->available_scan_masks)
2050 		iio_sanity_check_avail_scan_masks(indio_dev);
2051 
2052 	ret = iio_device_register_sysfs(indio_dev);
2053 	if (ret) {
2054 		dev_err(indio_dev->dev.parent,
2055 			"Failed to register sysfs interfaces\n");
2056 		goto error_buffer_free_sysfs;
2057 	}
2058 	ret = iio_device_register_eventset(indio_dev);
2059 	if (ret) {
2060 		dev_err(indio_dev->dev.parent,
2061 			"Failed to register event set\n");
2062 		goto error_free_sysfs;
2063 	}
2064 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
2065 		iio_device_register_trigger_consumer(indio_dev);
2066 
2067 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
2068 		indio_dev->setup_ops == NULL)
2069 		indio_dev->setup_ops = &noop_ring_setup_ops;
2070 
2071 	if (iio_dev_opaque->attached_buffers_cnt)
2072 		cdev_init(&iio_dev_opaque->chrdev, &iio_buffer_fileops);
2073 	else if (iio_dev_opaque->event_interface)
2074 		cdev_init(&iio_dev_opaque->chrdev, &iio_event_fileops);
2075 
2076 	if (iio_dev_opaque->attached_buffers_cnt || iio_dev_opaque->event_interface) {
2077 		indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), iio_dev_opaque->id);
2078 		iio_dev_opaque->chrdev.owner = this_mod;
2079 	}
2080 
2081 	/* assign device groups now; they should be all registered now */
2082 	indio_dev->dev.groups = iio_dev_opaque->groups;
2083 
2084 	ret = cdev_device_add(&iio_dev_opaque->chrdev, &indio_dev->dev);
2085 	if (ret < 0)
2086 		goto error_unreg_eventset;
2087 
2088 	return 0;
2089 
2090 error_unreg_eventset:
2091 	iio_device_unregister_eventset(indio_dev);
2092 error_free_sysfs:
2093 	iio_device_unregister_sysfs(indio_dev);
2094 error_buffer_free_sysfs:
2095 	iio_buffers_free_sysfs_and_mask(indio_dev);
2096 error_unreg_debugfs:
2097 	iio_device_unregister_debugfs(indio_dev);
2098 	return ret;
2099 }
2100 EXPORT_SYMBOL(__iio_device_register);
2101 
2102 /**
2103  * iio_device_unregister() - unregister a device from the IIO subsystem
2104  * @indio_dev:		Device structure representing the device.
2105  */
2106 void iio_device_unregister(struct iio_dev *indio_dev)
2107 {
2108 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2109 
2110 	cdev_device_del(&iio_dev_opaque->chrdev, &indio_dev->dev);
2111 
2112 	scoped_guard(mutex, &iio_dev_opaque->info_exist_lock) {
2113 		iio_device_unregister_debugfs(indio_dev);
2114 
2115 		iio_disable_all_buffers(indio_dev);
2116 
2117 		indio_dev->info = NULL;
2118 
2119 		iio_device_wakeup_eventset(indio_dev);
2120 		iio_buffer_wakeup_poll(indio_dev);
2121 	}
2122 
2123 	iio_buffers_free_sysfs_and_mask(indio_dev);
2124 }
2125 EXPORT_SYMBOL(iio_device_unregister);
2126 
2127 static void devm_iio_device_unreg(void *indio_dev)
2128 {
2129 	iio_device_unregister(indio_dev);
2130 }
2131 
2132 int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
2133 			       struct module *this_mod)
2134 {
2135 	int ret;
2136 
2137 	ret = __iio_device_register(indio_dev, this_mod);
2138 	if (ret)
2139 		return ret;
2140 
2141 	return devm_add_action_or_reset(dev, devm_iio_device_unreg, indio_dev);
2142 }
2143 EXPORT_SYMBOL_GPL(__devm_iio_device_register);
2144 
2145 /**
2146  * iio_device_claim_direct_mode - Keep device in direct mode
2147  * @indio_dev:	the iio_dev associated with the device
2148  *
2149  * If the device is in direct mode it is guaranteed to stay
2150  * that way until iio_device_release_direct_mode() is called.
2151  *
2152  * Use with iio_device_release_direct_mode()
2153  *
2154  * Returns: 0 on success, -EBUSY on failure.
2155  */
2156 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
2157 {
2158 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2159 
2160 	mutex_lock(&iio_dev_opaque->mlock);
2161 
2162 	if (iio_buffer_enabled(indio_dev)) {
2163 		mutex_unlock(&iio_dev_opaque->mlock);
2164 		return -EBUSY;
2165 	}
2166 	return 0;
2167 }
2168 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
2169 
2170 /**
2171  * iio_device_release_direct_mode - releases claim on direct mode
2172  * @indio_dev:	the iio_dev associated with the device
2173  *
2174  * Release the claim. Device is no longer guaranteed to stay
2175  * in direct mode.
2176  *
2177  * Use with iio_device_claim_direct_mode()
2178  */
2179 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
2180 {
2181 	mutex_unlock(&to_iio_dev_opaque(indio_dev)->mlock);
2182 }
2183 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
2184 
2185 /**
2186  * iio_device_claim_buffer_mode - Keep device in buffer mode
2187  * @indio_dev:	the iio_dev associated with the device
2188  *
2189  * If the device is in buffer mode it is guaranteed to stay
2190  * that way until iio_device_release_buffer_mode() is called.
2191  *
2192  * Use with iio_device_release_buffer_mode().
2193  *
2194  * Returns: 0 on success, -EBUSY on failure.
2195  */
2196 int iio_device_claim_buffer_mode(struct iio_dev *indio_dev)
2197 {
2198 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2199 
2200 	mutex_lock(&iio_dev_opaque->mlock);
2201 
2202 	if (iio_buffer_enabled(indio_dev))
2203 		return 0;
2204 
2205 	mutex_unlock(&iio_dev_opaque->mlock);
2206 	return -EBUSY;
2207 }
2208 EXPORT_SYMBOL_GPL(iio_device_claim_buffer_mode);
2209 
2210 /**
2211  * iio_device_release_buffer_mode - releases claim on buffer mode
2212  * @indio_dev:	the iio_dev associated with the device
2213  *
2214  * Release the claim. Device is no longer guaranteed to stay
2215  * in buffer mode.
2216  *
2217  * Use with iio_device_claim_buffer_mode().
2218  */
2219 void iio_device_release_buffer_mode(struct iio_dev *indio_dev)
2220 {
2221 	mutex_unlock(&to_iio_dev_opaque(indio_dev)->mlock);
2222 }
2223 EXPORT_SYMBOL_GPL(iio_device_release_buffer_mode);
2224 
2225 /**
2226  * iio_device_get_current_mode() - helper function providing read-only access to
2227  *				   the opaque @currentmode variable
2228  * @indio_dev:			   IIO device structure for device
2229  */
2230 int iio_device_get_current_mode(struct iio_dev *indio_dev)
2231 {
2232 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2233 
2234 	return iio_dev_opaque->currentmode;
2235 }
2236 EXPORT_SYMBOL_GPL(iio_device_get_current_mode);
2237 
2238 subsys_initcall(iio_init);
2239 module_exit(iio_exit);
2240 
2241 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
2242 MODULE_DESCRIPTION("Industrial I/O core");
2243 MODULE_LICENSE("GPL");
2244