1 // SPDX-License-Identifier: GPL-2.0-only
2 /* The industrial I/O core
3  *
4  * Copyright (c) 2008 Jonathan Cameron
5  *
6  * Based on elements of hwmon and input subsystems.
7  */
8 
9 #define pr_fmt(fmt) "iio-core: " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/idr.h>
14 #include <linux/kdev_t.h>
15 #include <linux/err.h>
16 #include <linux/device.h>
17 #include <linux/fs.h>
18 #include <linux/poll.h>
19 #include <linux/property.h>
20 #include <linux/sched.h>
21 #include <linux/wait.h>
22 #include <linux/cdev.h>
23 #include <linux/slab.h>
24 #include <linux/anon_inodes.h>
25 #include <linux/debugfs.h>
26 #include <linux/mutex.h>
27 #include <linux/iio/iio.h>
28 #include "iio_core.h"
29 #include "iio_core_trigger.h"
30 #include <linux/iio/sysfs.h>
31 #include <linux/iio/events.h>
32 #include <linux/iio/buffer.h>
33 #include <linux/iio/buffer_impl.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 	[IIO_UVINDEX] = "uvindex",
82 	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
83 	[IIO_COUNT] = "count",
84 	[IIO_INDEX] = "index",
85 	[IIO_GRAVITY]  = "gravity",
86 	[IIO_POSITIONRELATIVE]  = "positionrelative",
87 	[IIO_PHASE] = "phase",
88 	[IIO_MASSCONCENTRATION] = "massconcentration",
89 };
90 
91 static const char * const iio_modifier_names[] = {
92 	[IIO_MOD_X] = "x",
93 	[IIO_MOD_Y] = "y",
94 	[IIO_MOD_Z] = "z",
95 	[IIO_MOD_X_AND_Y] = "x&y",
96 	[IIO_MOD_X_AND_Z] = "x&z",
97 	[IIO_MOD_Y_AND_Z] = "y&z",
98 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
99 	[IIO_MOD_X_OR_Y] = "x|y",
100 	[IIO_MOD_X_OR_Z] = "x|z",
101 	[IIO_MOD_Y_OR_Z] = "y|z",
102 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
103 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
104 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
105 	[IIO_MOD_LIGHT_BOTH] = "both",
106 	[IIO_MOD_LIGHT_IR] = "ir",
107 	[IIO_MOD_LIGHT_CLEAR] = "clear",
108 	[IIO_MOD_LIGHT_RED] = "red",
109 	[IIO_MOD_LIGHT_GREEN] = "green",
110 	[IIO_MOD_LIGHT_BLUE] = "blue",
111 	[IIO_MOD_LIGHT_UV] = "uv",
112 	[IIO_MOD_LIGHT_DUV] = "duv",
113 	[IIO_MOD_QUATERNION] = "quaternion",
114 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
115 	[IIO_MOD_TEMP_OBJECT] = "object",
116 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
117 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
118 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
119 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
120 	[IIO_MOD_RUNNING] = "running",
121 	[IIO_MOD_JOGGING] = "jogging",
122 	[IIO_MOD_WALKING] = "walking",
123 	[IIO_MOD_STILL] = "still",
124 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
125 	[IIO_MOD_I] = "i",
126 	[IIO_MOD_Q] = "q",
127 	[IIO_MOD_CO2] = "co2",
128 	[IIO_MOD_VOC] = "voc",
129 	[IIO_MOD_PM1] = "pm1",
130 	[IIO_MOD_PM2P5] = "pm2p5",
131 	[IIO_MOD_PM4] = "pm4",
132 	[IIO_MOD_PM10] = "pm10",
133 };
134 
135 /* relies on pairs of these shared then separate */
136 static const char * const iio_chan_info_postfix[] = {
137 	[IIO_CHAN_INFO_RAW] = "raw",
138 	[IIO_CHAN_INFO_PROCESSED] = "input",
139 	[IIO_CHAN_INFO_SCALE] = "scale",
140 	[IIO_CHAN_INFO_OFFSET] = "offset",
141 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
142 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
143 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
144 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
145 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
146 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
147 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
148 	= "filter_low_pass_3db_frequency",
149 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
150 	= "filter_high_pass_3db_frequency",
151 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
152 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
153 	[IIO_CHAN_INFO_PHASE] = "phase",
154 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
155 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
156 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
157 	[IIO_CHAN_INFO_ENABLE] = "en",
158 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
159 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
160 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
161 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
162 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
163 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
164 	[IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
165 };
166 
167 /**
168  * iio_find_channel_from_si() - get channel from its scan index
169  * @indio_dev:		device
170  * @si:			scan index to match
171  */
172 const struct iio_chan_spec
173 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
174 {
175 	int i;
176 
177 	for (i = 0; i < indio_dev->num_channels; i++)
178 		if (indio_dev->channels[i].scan_index == si)
179 			return &indio_dev->channels[i];
180 	return NULL;
181 }
182 
183 /* This turns up an awful lot */
184 ssize_t iio_read_const_attr(struct device *dev,
185 			    struct device_attribute *attr,
186 			    char *buf)
187 {
188 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
189 }
190 EXPORT_SYMBOL(iio_read_const_attr);
191 
192 static int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
193 {
194 	int ret;
195 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
196 
197 	ret = mutex_lock_interruptible(&indio_dev->mlock);
198 	if (ret)
199 		return ret;
200 	if ((ev_int && iio_event_enabled(ev_int)) ||
201 	    iio_buffer_enabled(indio_dev)) {
202 		mutex_unlock(&indio_dev->mlock);
203 		return -EBUSY;
204 	}
205 	indio_dev->clock_id = clock_id;
206 	mutex_unlock(&indio_dev->mlock);
207 
208 	return 0;
209 }
210 
211 /**
212  * iio_get_time_ns() - utility function to get a time stamp for events etc
213  * @indio_dev: device
214  */
215 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
216 {
217 	struct timespec64 tp;
218 
219 	switch (iio_device_get_clock(indio_dev)) {
220 	case CLOCK_REALTIME:
221 		return ktime_get_real_ns();
222 	case CLOCK_MONOTONIC:
223 		return ktime_get_ns();
224 	case CLOCK_MONOTONIC_RAW:
225 		return ktime_get_raw_ns();
226 	case CLOCK_REALTIME_COARSE:
227 		return ktime_to_ns(ktime_get_coarse_real());
228 	case CLOCK_MONOTONIC_COARSE:
229 		ktime_get_coarse_ts64(&tp);
230 		return timespec64_to_ns(&tp);
231 	case CLOCK_BOOTTIME:
232 		return ktime_get_boottime_ns();
233 	case CLOCK_TAI:
234 		return ktime_get_clocktai_ns();
235 	default:
236 		BUG();
237 	}
238 }
239 EXPORT_SYMBOL(iio_get_time_ns);
240 
241 /**
242  * iio_get_time_res() - utility function to get time stamp clock resolution in
243  *                      nano seconds.
244  * @indio_dev: device
245  */
246 unsigned int iio_get_time_res(const struct iio_dev *indio_dev)
247 {
248 	switch (iio_device_get_clock(indio_dev)) {
249 	case CLOCK_REALTIME:
250 	case CLOCK_MONOTONIC:
251 	case CLOCK_MONOTONIC_RAW:
252 	case CLOCK_BOOTTIME:
253 	case CLOCK_TAI:
254 		return hrtimer_resolution;
255 	case CLOCK_REALTIME_COARSE:
256 	case CLOCK_MONOTONIC_COARSE:
257 		return LOW_RES_NSEC;
258 	default:
259 		BUG();
260 	}
261 }
262 EXPORT_SYMBOL(iio_get_time_res);
263 
264 static int __init iio_init(void)
265 {
266 	int ret;
267 
268 	/* Register sysfs bus */
269 	ret  = bus_register(&iio_bus_type);
270 	if (ret < 0) {
271 		pr_err("could not register bus type\n");
272 		goto error_nothing;
273 	}
274 
275 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
276 	if (ret < 0) {
277 		pr_err("failed to allocate char dev region\n");
278 		goto error_unregister_bus_type;
279 	}
280 
281 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
282 
283 	return 0;
284 
285 error_unregister_bus_type:
286 	bus_unregister(&iio_bus_type);
287 error_nothing:
288 	return ret;
289 }
290 
291 static void __exit iio_exit(void)
292 {
293 	if (iio_devt)
294 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
295 	bus_unregister(&iio_bus_type);
296 	debugfs_remove(iio_debugfs_dentry);
297 }
298 
299 #if defined(CONFIG_DEBUG_FS)
300 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
301 			      size_t count, loff_t *ppos)
302 {
303 	struct iio_dev *indio_dev = file->private_data;
304 	unsigned val = 0;
305 	int ret;
306 
307 	if (*ppos > 0)
308 		return simple_read_from_buffer(userbuf, count, ppos,
309 					       indio_dev->read_buf,
310 					       indio_dev->read_buf_len);
311 
312 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
313 						  indio_dev->cached_reg_addr,
314 						  0, &val);
315 	if (ret) {
316 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
317 		return ret;
318 	}
319 
320 	indio_dev->read_buf_len = snprintf(indio_dev->read_buf,
321 					   sizeof(indio_dev->read_buf),
322 					   "0x%X\n", val);
323 
324 	return simple_read_from_buffer(userbuf, count, ppos,
325 				       indio_dev->read_buf,
326 				       indio_dev->read_buf_len);
327 }
328 
329 static ssize_t iio_debugfs_write_reg(struct file *file,
330 		     const char __user *userbuf, size_t count, loff_t *ppos)
331 {
332 	struct iio_dev *indio_dev = file->private_data;
333 	unsigned reg, val;
334 	char buf[80];
335 	int ret;
336 
337 	count = min_t(size_t, count, (sizeof(buf)-1));
338 	if (copy_from_user(buf, userbuf, count))
339 		return -EFAULT;
340 
341 	buf[count] = 0;
342 
343 	ret = sscanf(buf, "%i %i", &reg, &val);
344 
345 	switch (ret) {
346 	case 1:
347 		indio_dev->cached_reg_addr = reg;
348 		break;
349 	case 2:
350 		indio_dev->cached_reg_addr = reg;
351 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
352 							  val, NULL);
353 		if (ret) {
354 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
355 				__func__);
356 			return ret;
357 		}
358 		break;
359 	default:
360 		return -EINVAL;
361 	}
362 
363 	return count;
364 }
365 
366 static const struct file_operations iio_debugfs_reg_fops = {
367 	.open = simple_open,
368 	.read = iio_debugfs_read_reg,
369 	.write = iio_debugfs_write_reg,
370 };
371 
372 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
373 {
374 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
375 }
376 
377 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
378 {
379 	if (indio_dev->info->debugfs_reg_access == NULL)
380 		return;
381 
382 	if (!iio_debugfs_dentry)
383 		return;
384 
385 	indio_dev->debugfs_dentry =
386 		debugfs_create_dir(dev_name(&indio_dev->dev),
387 				   iio_debugfs_dentry);
388 
389 	debugfs_create_file("direct_reg_access", 0644,
390 			    indio_dev->debugfs_dentry, indio_dev,
391 			    &iio_debugfs_reg_fops);
392 }
393 #else
394 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
395 {
396 }
397 
398 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
399 {
400 }
401 #endif /* CONFIG_DEBUG_FS */
402 
403 static ssize_t iio_read_channel_ext_info(struct device *dev,
404 				     struct device_attribute *attr,
405 				     char *buf)
406 {
407 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
408 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
409 	const struct iio_chan_spec_ext_info *ext_info;
410 
411 	ext_info = &this_attr->c->ext_info[this_attr->address];
412 
413 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
414 }
415 
416 static ssize_t iio_write_channel_ext_info(struct device *dev,
417 				     struct device_attribute *attr,
418 				     const char *buf,
419 					 size_t len)
420 {
421 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
422 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
423 	const struct iio_chan_spec_ext_info *ext_info;
424 
425 	ext_info = &this_attr->c->ext_info[this_attr->address];
426 
427 	return ext_info->write(indio_dev, ext_info->private,
428 			       this_attr->c, buf, len);
429 }
430 
431 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
432 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
433 {
434 	const struct iio_enum *e = (const struct iio_enum *)priv;
435 	unsigned int i;
436 	size_t len = 0;
437 
438 	if (!e->num_items)
439 		return 0;
440 
441 	for (i = 0; i < e->num_items; ++i)
442 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
443 
444 	/* replace last space with a newline */
445 	buf[len - 1] = '\n';
446 
447 	return len;
448 }
449 EXPORT_SYMBOL_GPL(iio_enum_available_read);
450 
451 ssize_t iio_enum_read(struct iio_dev *indio_dev,
452 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
453 {
454 	const struct iio_enum *e = (const struct iio_enum *)priv;
455 	int i;
456 
457 	if (!e->get)
458 		return -EINVAL;
459 
460 	i = e->get(indio_dev, chan);
461 	if (i < 0)
462 		return i;
463 	else if (i >= e->num_items)
464 		return -EINVAL;
465 
466 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
467 }
468 EXPORT_SYMBOL_GPL(iio_enum_read);
469 
470 ssize_t iio_enum_write(struct iio_dev *indio_dev,
471 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
472 	size_t len)
473 {
474 	const struct iio_enum *e = (const struct iio_enum *)priv;
475 	int ret;
476 
477 	if (!e->set)
478 		return -EINVAL;
479 
480 	ret = __sysfs_match_string(e->items, e->num_items, buf);
481 	if (ret < 0)
482 		return ret;
483 
484 	ret = e->set(indio_dev, chan, ret);
485 	return ret ? ret : len;
486 }
487 EXPORT_SYMBOL_GPL(iio_enum_write);
488 
489 static const struct iio_mount_matrix iio_mount_idmatrix = {
490 	.rotation = {
491 		"1", "0", "0",
492 		"0", "1", "0",
493 		"0", "0", "1"
494 	}
495 };
496 
497 static int iio_setup_mount_idmatrix(const struct device *dev,
498 				    struct iio_mount_matrix *matrix)
499 {
500 	*matrix = iio_mount_idmatrix;
501 	dev_info(dev, "mounting matrix not found: using identity...\n");
502 	return 0;
503 }
504 
505 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
506 			      const struct iio_chan_spec *chan, char *buf)
507 {
508 	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
509 					      priv)(indio_dev, chan);
510 
511 	if (IS_ERR(mtx))
512 		return PTR_ERR(mtx);
513 
514 	if (!mtx)
515 		mtx = &iio_mount_idmatrix;
516 
517 	return snprintf(buf, PAGE_SIZE, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
518 			mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
519 			mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
520 			mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
521 }
522 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
523 
524 /**
525  * iio_read_mount_matrix() - retrieve iio device mounting matrix from
526  *                           device "mount-matrix" property
527  * @dev:	device the mounting matrix property is assigned to
528  * @propname:	device specific mounting matrix property name
529  * @matrix:	where to store retrieved matrix
530  *
531  * If device is assigned no mounting matrix property, a default 3x3 identity
532  * matrix will be filled in.
533  *
534  * Return: 0 if success, or a negative error code on failure.
535  */
536 int iio_read_mount_matrix(struct device *dev, const char *propname,
537 			  struct iio_mount_matrix *matrix)
538 {
539 	size_t len = ARRAY_SIZE(iio_mount_idmatrix.rotation);
540 	int err;
541 
542 	err = device_property_read_string_array(dev, propname,
543 						matrix->rotation, len);
544 	if (err == len)
545 		return 0;
546 
547 	if (err >= 0)
548 		/* Invalid number of matrix entries. */
549 		return -EINVAL;
550 
551 	if (err != -EINVAL)
552 		/* Invalid matrix declaration format. */
553 		return err;
554 
555 	/* Matrix was not declared at all: fallback to identity. */
556 	return iio_setup_mount_idmatrix(dev, matrix);
557 }
558 EXPORT_SYMBOL(iio_read_mount_matrix);
559 
560 static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
561 				  int size, const int *vals)
562 {
563 	unsigned long long tmp;
564 	int tmp0, tmp1;
565 	bool scale_db = false;
566 
567 	switch (type) {
568 	case IIO_VAL_INT:
569 		return snprintf(buf, len, "%d", vals[0]);
570 	case IIO_VAL_INT_PLUS_MICRO_DB:
571 		scale_db = true;
572 		/* fall through */
573 	case IIO_VAL_INT_PLUS_MICRO:
574 		if (vals[1] < 0)
575 			return snprintf(buf, len, "-%d.%06u%s", abs(vals[0]),
576 					-vals[1], scale_db ? " dB" : "");
577 		else
578 			return snprintf(buf, len, "%d.%06u%s", vals[0], vals[1],
579 					scale_db ? " dB" : "");
580 	case IIO_VAL_INT_PLUS_NANO:
581 		if (vals[1] < 0)
582 			return snprintf(buf, len, "-%d.%09u", abs(vals[0]),
583 					-vals[1]);
584 		else
585 			return snprintf(buf, len, "%d.%09u", vals[0], vals[1]);
586 	case IIO_VAL_FRACTIONAL:
587 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
588 		tmp1 = vals[1];
589 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
590 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
591 	case IIO_VAL_FRACTIONAL_LOG2:
592 		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
593 		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
594 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
595 	case IIO_VAL_INT_MULTIPLE:
596 	{
597 		int i;
598 		int l = 0;
599 
600 		for (i = 0; i < size; ++i) {
601 			l += snprintf(&buf[l], len - l, "%d ", vals[i]);
602 			if (l >= len)
603 				break;
604 		}
605 		return l;
606 	}
607 	case IIO_VAL_CHAR:
608 		return snprintf(buf, len, "%c", (char)vals[0]);
609 	default:
610 		return 0;
611 	}
612 }
613 
614 /**
615  * iio_format_value() - Formats a IIO value into its string representation
616  * @buf:	The buffer to which the formatted value gets written
617  *		which is assumed to be big enough (i.e. PAGE_SIZE).
618  * @type:	One of the IIO_VAL_* constants. This decides how the val
619  *		and val2 parameters are formatted.
620  * @size:	Number of IIO value entries contained in vals
621  * @vals:	Pointer to the values, exact meaning depends on the
622  *		type parameter.
623  *
624  * Return: 0 by default, a negative number on failure or the
625  *	   total number of characters written for a type that belongs
626  *	   to the IIO_VAL_* constant.
627  */
628 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
629 {
630 	ssize_t len;
631 
632 	len = __iio_format_value(buf, PAGE_SIZE, type, size, vals);
633 	if (len >= PAGE_SIZE - 1)
634 		return -EFBIG;
635 
636 	return len + sprintf(buf + len, "\n");
637 }
638 EXPORT_SYMBOL_GPL(iio_format_value);
639 
640 static ssize_t iio_read_channel_info(struct device *dev,
641 				     struct device_attribute *attr,
642 				     char *buf)
643 {
644 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
645 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
646 	int vals[INDIO_MAX_RAW_ELEMENTS];
647 	int ret;
648 	int val_len = 2;
649 
650 	if (indio_dev->info->read_raw_multi)
651 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
652 							INDIO_MAX_RAW_ELEMENTS,
653 							vals, &val_len,
654 							this_attr->address);
655 	else
656 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
657 				    &vals[0], &vals[1], this_attr->address);
658 
659 	if (ret < 0)
660 		return ret;
661 
662 	return iio_format_value(buf, ret, val_len, vals);
663 }
664 
665 static ssize_t iio_format_avail_list(char *buf, const int *vals,
666 				     int type, int length)
667 {
668 	int i;
669 	ssize_t len = 0;
670 
671 	switch (type) {
672 	case IIO_VAL_INT:
673 		for (i = 0; i < length; i++) {
674 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
675 						  type, 1, &vals[i]);
676 			if (len >= PAGE_SIZE)
677 				return -EFBIG;
678 			if (i < length - 1)
679 				len += snprintf(buf + len, PAGE_SIZE - len,
680 						" ");
681 			else
682 				len += snprintf(buf + len, PAGE_SIZE - len,
683 						"\n");
684 			if (len >= PAGE_SIZE)
685 				return -EFBIG;
686 		}
687 		break;
688 	default:
689 		for (i = 0; i < length / 2; i++) {
690 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
691 						  type, 2, &vals[i * 2]);
692 			if (len >= PAGE_SIZE)
693 				return -EFBIG;
694 			if (i < length / 2 - 1)
695 				len += snprintf(buf + len, PAGE_SIZE - len,
696 						" ");
697 			else
698 				len += snprintf(buf + len, PAGE_SIZE - len,
699 						"\n");
700 			if (len >= PAGE_SIZE)
701 				return -EFBIG;
702 		}
703 	}
704 
705 	return len;
706 }
707 
708 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
709 {
710 	int i;
711 	ssize_t len;
712 
713 	len = snprintf(buf, PAGE_SIZE, "[");
714 	switch (type) {
715 	case IIO_VAL_INT:
716 		for (i = 0; i < 3; i++) {
717 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
718 						  type, 1, &vals[i]);
719 			if (len >= PAGE_SIZE)
720 				return -EFBIG;
721 			if (i < 2)
722 				len += snprintf(buf + len, PAGE_SIZE - len,
723 						" ");
724 			else
725 				len += snprintf(buf + len, PAGE_SIZE - len,
726 						"]\n");
727 			if (len >= PAGE_SIZE)
728 				return -EFBIG;
729 		}
730 		break;
731 	default:
732 		for (i = 0; i < 3; i++) {
733 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
734 						  type, 2, &vals[i * 2]);
735 			if (len >= PAGE_SIZE)
736 				return -EFBIG;
737 			if (i < 2)
738 				len += snprintf(buf + len, PAGE_SIZE - len,
739 						" ");
740 			else
741 				len += snprintf(buf + len, PAGE_SIZE - len,
742 						"]\n");
743 			if (len >= PAGE_SIZE)
744 				return -EFBIG;
745 		}
746 	}
747 
748 	return len;
749 }
750 
751 static ssize_t iio_read_channel_info_avail(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 	const int *vals;
758 	int ret;
759 	int length;
760 	int type;
761 
762 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
763 					  &vals, &type, &length,
764 					  this_attr->address);
765 
766 	if (ret < 0)
767 		return ret;
768 	switch (ret) {
769 	case IIO_AVAIL_LIST:
770 		return iio_format_avail_list(buf, vals, type, length);
771 	case IIO_AVAIL_RANGE:
772 		return iio_format_avail_range(buf, vals, type);
773 	default:
774 		return -EINVAL;
775 	}
776 }
777 
778 /**
779  * __iio_str_to_fixpoint() - Parse a fixed-point number from a string
780  * @str: The string to parse
781  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
782  * @integer: The integer part of the number
783  * @fract: The fractional part of the number
784  * @scale_db: True if this should parse as dB
785  *
786  * Returns 0 on success, or a negative error code if the string could not be
787  * parsed.
788  */
789 static int __iio_str_to_fixpoint(const char *str, int fract_mult,
790 				 int *integer, int *fract, bool scale_db)
791 {
792 	int i = 0, f = 0;
793 	bool integer_part = true, negative = false;
794 
795 	if (fract_mult == 0) {
796 		*fract = 0;
797 
798 		return kstrtoint(str, 0, integer);
799 	}
800 
801 	if (str[0] == '-') {
802 		negative = true;
803 		str++;
804 	} else if (str[0] == '+') {
805 		str++;
806 	}
807 
808 	while (*str) {
809 		if ('0' <= *str && *str <= '9') {
810 			if (integer_part) {
811 				i = i * 10 + *str - '0';
812 			} else {
813 				f += fract_mult * (*str - '0');
814 				fract_mult /= 10;
815 			}
816 		} else if (*str == '\n') {
817 			if (*(str + 1) == '\0')
818 				break;
819 			else
820 				return -EINVAL;
821 		} else if (!strncmp(str, " dB", sizeof(" dB") - 1) && scale_db) {
822 			/* Ignore the dB suffix */
823 			str += sizeof(" dB") - 1;
824 			continue;
825 		} else if (!strncmp(str, "dB", sizeof("dB") - 1) && scale_db) {
826 			/* Ignore the dB suffix */
827 			str += sizeof("dB") - 1;
828 			continue;
829 		} else if (*str == '.' && integer_part) {
830 			integer_part = false;
831 		} else {
832 			return -EINVAL;
833 		}
834 		str++;
835 	}
836 
837 	if (negative) {
838 		if (i)
839 			i = -i;
840 		else
841 			f = -f;
842 	}
843 
844 	*integer = i;
845 	*fract = f;
846 
847 	return 0;
848 }
849 
850 /**
851  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
852  * @str: The string to parse
853  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
854  * @integer: The integer part of the number
855  * @fract: The fractional part of the number
856  *
857  * Returns 0 on success, or a negative error code if the string could not be
858  * parsed.
859  */
860 int iio_str_to_fixpoint(const char *str, int fract_mult,
861 			int *integer, int *fract)
862 {
863 	return __iio_str_to_fixpoint(str, fract_mult, integer, fract, false);
864 }
865 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
866 
867 static ssize_t iio_write_channel_info(struct device *dev,
868 				      struct device_attribute *attr,
869 				      const char *buf,
870 				      size_t len)
871 {
872 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
873 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
874 	int ret, fract_mult = 100000;
875 	int integer, fract = 0;
876 	bool is_char = false;
877 	bool scale_db = false;
878 
879 	/* Assumes decimal - precision based on number of digits */
880 	if (!indio_dev->info->write_raw)
881 		return -EINVAL;
882 
883 	if (indio_dev->info->write_raw_get_fmt)
884 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
885 			this_attr->c, this_attr->address)) {
886 		case IIO_VAL_INT:
887 			fract_mult = 0;
888 			break;
889 		case IIO_VAL_INT_PLUS_MICRO_DB:
890 			scale_db = true;
891 			/* fall through */
892 		case IIO_VAL_INT_PLUS_MICRO:
893 			fract_mult = 100000;
894 			break;
895 		case IIO_VAL_INT_PLUS_NANO:
896 			fract_mult = 100000000;
897 			break;
898 		case IIO_VAL_CHAR:
899 			is_char = true;
900 			break;
901 		default:
902 			return -EINVAL;
903 		}
904 
905 	if (is_char) {
906 		char ch;
907 
908 		if (sscanf(buf, "%c", &ch) != 1)
909 			return -EINVAL;
910 		integer = ch;
911 	} else {
912 		ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
913 		if (ret)
914 			return ret;
915 	}
916 	ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
917 				    scale_db);
918 	if (ret)
919 		return ret;
920 
921 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
922 					 integer, fract, this_attr->address);
923 	if (ret)
924 		return ret;
925 
926 	return len;
927 }
928 
929 static
930 int __iio_device_attr_init(struct device_attribute *dev_attr,
931 			   const char *postfix,
932 			   struct iio_chan_spec const *chan,
933 			   ssize_t (*readfunc)(struct device *dev,
934 					       struct device_attribute *attr,
935 					       char *buf),
936 			   ssize_t (*writefunc)(struct device *dev,
937 						struct device_attribute *attr,
938 						const char *buf,
939 						size_t len),
940 			   enum iio_shared_by shared_by)
941 {
942 	int ret = 0;
943 	char *name = NULL;
944 	char *full_postfix;
945 	sysfs_attr_init(&dev_attr->attr);
946 
947 	/* Build up postfix of <extend_name>_<modifier>_postfix */
948 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
949 		if (chan->extend_name)
950 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
951 						 iio_modifier_names[chan
952 								    ->channel2],
953 						 chan->extend_name,
954 						 postfix);
955 		else
956 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
957 						 iio_modifier_names[chan
958 								    ->channel2],
959 						 postfix);
960 	} else {
961 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
962 			full_postfix = kstrdup(postfix, GFP_KERNEL);
963 		else
964 			full_postfix = kasprintf(GFP_KERNEL,
965 						 "%s_%s",
966 						 chan->extend_name,
967 						 postfix);
968 	}
969 	if (full_postfix == NULL)
970 		return -ENOMEM;
971 
972 	if (chan->differential) { /* Differential can not have modifier */
973 		switch (shared_by) {
974 		case IIO_SHARED_BY_ALL:
975 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
976 			break;
977 		case IIO_SHARED_BY_DIR:
978 			name = kasprintf(GFP_KERNEL, "%s_%s",
979 						iio_direction[chan->output],
980 						full_postfix);
981 			break;
982 		case IIO_SHARED_BY_TYPE:
983 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
984 					    iio_direction[chan->output],
985 					    iio_chan_type_name_spec[chan->type],
986 					    iio_chan_type_name_spec[chan->type],
987 					    full_postfix);
988 			break;
989 		case IIO_SEPARATE:
990 			if (!chan->indexed) {
991 				WARN(1, "Differential channels must be indexed\n");
992 				ret = -EINVAL;
993 				goto error_free_full_postfix;
994 			}
995 			name = kasprintf(GFP_KERNEL,
996 					    "%s_%s%d-%s%d_%s",
997 					    iio_direction[chan->output],
998 					    iio_chan_type_name_spec[chan->type],
999 					    chan->channel,
1000 					    iio_chan_type_name_spec[chan->type],
1001 					    chan->channel2,
1002 					    full_postfix);
1003 			break;
1004 		}
1005 	} else { /* Single ended */
1006 		switch (shared_by) {
1007 		case IIO_SHARED_BY_ALL:
1008 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
1009 			break;
1010 		case IIO_SHARED_BY_DIR:
1011 			name = kasprintf(GFP_KERNEL, "%s_%s",
1012 						iio_direction[chan->output],
1013 						full_postfix);
1014 			break;
1015 		case IIO_SHARED_BY_TYPE:
1016 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1017 					    iio_direction[chan->output],
1018 					    iio_chan_type_name_spec[chan->type],
1019 					    full_postfix);
1020 			break;
1021 
1022 		case IIO_SEPARATE:
1023 			if (chan->indexed)
1024 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
1025 						    iio_direction[chan->output],
1026 						    iio_chan_type_name_spec[chan->type],
1027 						    chan->channel,
1028 						    full_postfix);
1029 			else
1030 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1031 						    iio_direction[chan->output],
1032 						    iio_chan_type_name_spec[chan->type],
1033 						    full_postfix);
1034 			break;
1035 		}
1036 	}
1037 	if (name == NULL) {
1038 		ret = -ENOMEM;
1039 		goto error_free_full_postfix;
1040 	}
1041 	dev_attr->attr.name = name;
1042 
1043 	if (readfunc) {
1044 		dev_attr->attr.mode |= S_IRUGO;
1045 		dev_attr->show = readfunc;
1046 	}
1047 
1048 	if (writefunc) {
1049 		dev_attr->attr.mode |= S_IWUSR;
1050 		dev_attr->store = writefunc;
1051 	}
1052 
1053 error_free_full_postfix:
1054 	kfree(full_postfix);
1055 
1056 	return ret;
1057 }
1058 
1059 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1060 {
1061 	kfree(dev_attr->attr.name);
1062 }
1063 
1064 int __iio_add_chan_devattr(const char *postfix,
1065 			   struct iio_chan_spec const *chan,
1066 			   ssize_t (*readfunc)(struct device *dev,
1067 					       struct device_attribute *attr,
1068 					       char *buf),
1069 			   ssize_t (*writefunc)(struct device *dev,
1070 						struct device_attribute *attr,
1071 						const char *buf,
1072 						size_t len),
1073 			   u64 mask,
1074 			   enum iio_shared_by shared_by,
1075 			   struct device *dev,
1076 			   struct list_head *attr_list)
1077 {
1078 	int ret;
1079 	struct iio_dev_attr *iio_attr, *t;
1080 
1081 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1082 	if (iio_attr == NULL)
1083 		return -ENOMEM;
1084 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1085 				     postfix, chan,
1086 				     readfunc, writefunc, shared_by);
1087 	if (ret)
1088 		goto error_iio_dev_attr_free;
1089 	iio_attr->c = chan;
1090 	iio_attr->address = mask;
1091 	list_for_each_entry(t, attr_list, l)
1092 		if (strcmp(t->dev_attr.attr.name,
1093 			   iio_attr->dev_attr.attr.name) == 0) {
1094 			if (shared_by == IIO_SEPARATE)
1095 				dev_err(dev, "tried to double register : %s\n",
1096 					t->dev_attr.attr.name);
1097 			ret = -EBUSY;
1098 			goto error_device_attr_deinit;
1099 		}
1100 	list_add(&iio_attr->l, attr_list);
1101 
1102 	return 0;
1103 
1104 error_device_attr_deinit:
1105 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1106 error_iio_dev_attr_free:
1107 	kfree(iio_attr);
1108 	return ret;
1109 }
1110 
1111 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1112 					 struct iio_chan_spec const *chan,
1113 					 enum iio_shared_by shared_by,
1114 					 const long *infomask)
1115 {
1116 	int i, ret, attrcount = 0;
1117 
1118 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1119 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1120 			return -EINVAL;
1121 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1122 					     chan,
1123 					     &iio_read_channel_info,
1124 					     &iio_write_channel_info,
1125 					     i,
1126 					     shared_by,
1127 					     &indio_dev->dev,
1128 					     &indio_dev->channel_attr_list);
1129 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1130 			continue;
1131 		else if (ret < 0)
1132 			return ret;
1133 		attrcount++;
1134 	}
1135 
1136 	return attrcount;
1137 }
1138 
1139 static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
1140 					       struct iio_chan_spec const *chan,
1141 					       enum iio_shared_by shared_by,
1142 					       const long *infomask)
1143 {
1144 	int i, ret, attrcount = 0;
1145 	char *avail_postfix;
1146 
1147 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1148 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1149 			return -EINVAL;
1150 		avail_postfix = kasprintf(GFP_KERNEL,
1151 					  "%s_available",
1152 					  iio_chan_info_postfix[i]);
1153 		if (!avail_postfix)
1154 			return -ENOMEM;
1155 
1156 		ret = __iio_add_chan_devattr(avail_postfix,
1157 					     chan,
1158 					     &iio_read_channel_info_avail,
1159 					     NULL,
1160 					     i,
1161 					     shared_by,
1162 					     &indio_dev->dev,
1163 					     &indio_dev->channel_attr_list);
1164 		kfree(avail_postfix);
1165 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1166 			continue;
1167 		else if (ret < 0)
1168 			return ret;
1169 		attrcount++;
1170 	}
1171 
1172 	return attrcount;
1173 }
1174 
1175 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1176 					struct iio_chan_spec const *chan)
1177 {
1178 	int ret, attrcount = 0;
1179 	const struct iio_chan_spec_ext_info *ext_info;
1180 
1181 	if (chan->channel < 0)
1182 		return 0;
1183 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1184 					    IIO_SEPARATE,
1185 					    &chan->info_mask_separate);
1186 	if (ret < 0)
1187 		return ret;
1188 	attrcount += ret;
1189 
1190 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1191 						  IIO_SEPARATE,
1192 						  &chan->
1193 						  info_mask_separate_available);
1194 	if (ret < 0)
1195 		return ret;
1196 	attrcount += ret;
1197 
1198 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1199 					    IIO_SHARED_BY_TYPE,
1200 					    &chan->info_mask_shared_by_type);
1201 	if (ret < 0)
1202 		return ret;
1203 	attrcount += ret;
1204 
1205 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1206 						  IIO_SHARED_BY_TYPE,
1207 						  &chan->
1208 						  info_mask_shared_by_type_available);
1209 	if (ret < 0)
1210 		return ret;
1211 	attrcount += ret;
1212 
1213 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1214 					    IIO_SHARED_BY_DIR,
1215 					    &chan->info_mask_shared_by_dir);
1216 	if (ret < 0)
1217 		return ret;
1218 	attrcount += ret;
1219 
1220 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1221 						  IIO_SHARED_BY_DIR,
1222 						  &chan->info_mask_shared_by_dir_available);
1223 	if (ret < 0)
1224 		return ret;
1225 	attrcount += ret;
1226 
1227 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1228 					    IIO_SHARED_BY_ALL,
1229 					    &chan->info_mask_shared_by_all);
1230 	if (ret < 0)
1231 		return ret;
1232 	attrcount += ret;
1233 
1234 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1235 						  IIO_SHARED_BY_ALL,
1236 						  &chan->info_mask_shared_by_all_available);
1237 	if (ret < 0)
1238 		return ret;
1239 	attrcount += ret;
1240 
1241 	if (chan->ext_info) {
1242 		unsigned int i = 0;
1243 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1244 			ret = __iio_add_chan_devattr(ext_info->name,
1245 					chan,
1246 					ext_info->read ?
1247 					    &iio_read_channel_ext_info : NULL,
1248 					ext_info->write ?
1249 					    &iio_write_channel_ext_info : NULL,
1250 					i,
1251 					ext_info->shared,
1252 					&indio_dev->dev,
1253 					&indio_dev->channel_attr_list);
1254 			i++;
1255 			if (ret == -EBUSY && ext_info->shared)
1256 				continue;
1257 
1258 			if (ret)
1259 				return ret;
1260 
1261 			attrcount++;
1262 		}
1263 	}
1264 
1265 	return attrcount;
1266 }
1267 
1268 /**
1269  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1270  * @attr_list: List of IIO device attributes
1271  *
1272  * This function frees the memory allocated for each of the IIO device
1273  * attributes in the list.
1274  */
1275 void iio_free_chan_devattr_list(struct list_head *attr_list)
1276 {
1277 	struct iio_dev_attr *p, *n;
1278 
1279 	list_for_each_entry_safe(p, n, attr_list, l) {
1280 		kfree(p->dev_attr.attr.name);
1281 		list_del(&p->l);
1282 		kfree(p);
1283 	}
1284 }
1285 
1286 static ssize_t iio_show_dev_name(struct device *dev,
1287 				 struct device_attribute *attr,
1288 				 char *buf)
1289 {
1290 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1291 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1292 }
1293 
1294 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1295 
1296 static ssize_t iio_show_dev_label(struct device *dev,
1297 				 struct device_attribute *attr,
1298 				 char *buf)
1299 {
1300 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1301 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->label);
1302 }
1303 
1304 static DEVICE_ATTR(label, S_IRUGO, iio_show_dev_label, NULL);
1305 
1306 static ssize_t iio_show_timestamp_clock(struct device *dev,
1307 					struct device_attribute *attr,
1308 					char *buf)
1309 {
1310 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1311 	const clockid_t clk = iio_device_get_clock(indio_dev);
1312 	const char *name;
1313 	ssize_t sz;
1314 
1315 	switch (clk) {
1316 	case CLOCK_REALTIME:
1317 		name = "realtime\n";
1318 		sz = sizeof("realtime\n");
1319 		break;
1320 	case CLOCK_MONOTONIC:
1321 		name = "monotonic\n";
1322 		sz = sizeof("monotonic\n");
1323 		break;
1324 	case CLOCK_MONOTONIC_RAW:
1325 		name = "monotonic_raw\n";
1326 		sz = sizeof("monotonic_raw\n");
1327 		break;
1328 	case CLOCK_REALTIME_COARSE:
1329 		name = "realtime_coarse\n";
1330 		sz = sizeof("realtime_coarse\n");
1331 		break;
1332 	case CLOCK_MONOTONIC_COARSE:
1333 		name = "monotonic_coarse\n";
1334 		sz = sizeof("monotonic_coarse\n");
1335 		break;
1336 	case CLOCK_BOOTTIME:
1337 		name = "boottime\n";
1338 		sz = sizeof("boottime\n");
1339 		break;
1340 	case CLOCK_TAI:
1341 		name = "tai\n";
1342 		sz = sizeof("tai\n");
1343 		break;
1344 	default:
1345 		BUG();
1346 	}
1347 
1348 	memcpy(buf, name, sz);
1349 	return sz;
1350 }
1351 
1352 static ssize_t iio_store_timestamp_clock(struct device *dev,
1353 					 struct device_attribute *attr,
1354 					 const char *buf, size_t len)
1355 {
1356 	clockid_t clk;
1357 	int ret;
1358 
1359 	if (sysfs_streq(buf, "realtime"))
1360 		clk = CLOCK_REALTIME;
1361 	else if (sysfs_streq(buf, "monotonic"))
1362 		clk = CLOCK_MONOTONIC;
1363 	else if (sysfs_streq(buf, "monotonic_raw"))
1364 		clk = CLOCK_MONOTONIC_RAW;
1365 	else if (sysfs_streq(buf, "realtime_coarse"))
1366 		clk = CLOCK_REALTIME_COARSE;
1367 	else if (sysfs_streq(buf, "monotonic_coarse"))
1368 		clk = CLOCK_MONOTONIC_COARSE;
1369 	else if (sysfs_streq(buf, "boottime"))
1370 		clk = CLOCK_BOOTTIME;
1371 	else if (sysfs_streq(buf, "tai"))
1372 		clk = CLOCK_TAI;
1373 	else
1374 		return -EINVAL;
1375 
1376 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1377 	if (ret)
1378 		return ret;
1379 
1380 	return len;
1381 }
1382 
1383 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1384 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1385 
1386 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1387 {
1388 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1389 	struct iio_dev_attr *p;
1390 	struct attribute **attr, *clk = NULL;
1391 
1392 	/* First count elements in any existing group */
1393 	if (indio_dev->info->attrs) {
1394 		attr = indio_dev->info->attrs->attrs;
1395 		while (*attr++ != NULL)
1396 			attrcount_orig++;
1397 	}
1398 	attrcount = attrcount_orig;
1399 	/*
1400 	 * New channel registration method - relies on the fact a group does
1401 	 * not need to be initialized if its name is NULL.
1402 	 */
1403 	if (indio_dev->channels)
1404 		for (i = 0; i < indio_dev->num_channels; i++) {
1405 			const struct iio_chan_spec *chan =
1406 				&indio_dev->channels[i];
1407 
1408 			if (chan->type == IIO_TIMESTAMP)
1409 				clk = &dev_attr_current_timestamp_clock.attr;
1410 
1411 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1412 			if (ret < 0)
1413 				goto error_clear_attrs;
1414 			attrcount += ret;
1415 		}
1416 
1417 	if (indio_dev->event_interface)
1418 		clk = &dev_attr_current_timestamp_clock.attr;
1419 
1420 	if (indio_dev->name)
1421 		attrcount++;
1422 	if (indio_dev->label)
1423 		attrcount++;
1424 	if (clk)
1425 		attrcount++;
1426 
1427 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1428 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1429 						   GFP_KERNEL);
1430 	if (indio_dev->chan_attr_group.attrs == NULL) {
1431 		ret = -ENOMEM;
1432 		goto error_clear_attrs;
1433 	}
1434 	/* Copy across original attributes */
1435 	if (indio_dev->info->attrs)
1436 		memcpy(indio_dev->chan_attr_group.attrs,
1437 		       indio_dev->info->attrs->attrs,
1438 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1439 		       *attrcount_orig);
1440 	attrn = attrcount_orig;
1441 	/* Add all elements from the list. */
1442 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1443 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1444 	if (indio_dev->name)
1445 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1446 	if (indio_dev->label)
1447 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_label.attr;
1448 	if (clk)
1449 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1450 
1451 	indio_dev->groups[indio_dev->groupcounter++] =
1452 		&indio_dev->chan_attr_group;
1453 
1454 	return 0;
1455 
1456 error_clear_attrs:
1457 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1458 
1459 	return ret;
1460 }
1461 
1462 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1463 {
1464 
1465 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1466 	kfree(indio_dev->chan_attr_group.attrs);
1467 	indio_dev->chan_attr_group.attrs = NULL;
1468 }
1469 
1470 static void iio_dev_release(struct device *device)
1471 {
1472 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1473 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1474 		iio_device_unregister_trigger_consumer(indio_dev);
1475 	iio_device_unregister_eventset(indio_dev);
1476 	iio_device_unregister_sysfs(indio_dev);
1477 
1478 	iio_buffer_put(indio_dev->buffer);
1479 
1480 	ida_simple_remove(&iio_ida, indio_dev->id);
1481 	kfree(indio_dev);
1482 }
1483 
1484 struct device_type iio_device_type = {
1485 	.name = "iio_device",
1486 	.release = iio_dev_release,
1487 };
1488 
1489 /**
1490  * iio_device_alloc() - allocate an iio_dev from a driver
1491  * @sizeof_priv:	Space to allocate for private structure.
1492  **/
1493 struct iio_dev *iio_device_alloc(int sizeof_priv)
1494 {
1495 	struct iio_dev *dev;
1496 	size_t alloc_size;
1497 
1498 	alloc_size = sizeof(struct iio_dev);
1499 	if (sizeof_priv) {
1500 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1501 		alloc_size += sizeof_priv;
1502 	}
1503 	/* ensure 32-byte alignment of whole construct ? */
1504 	alloc_size += IIO_ALIGN - 1;
1505 
1506 	dev = kzalloc(alloc_size, GFP_KERNEL);
1507 
1508 	if (dev) {
1509 		dev->dev.groups = dev->groups;
1510 		dev->dev.type = &iio_device_type;
1511 		dev->dev.bus = &iio_bus_type;
1512 		device_initialize(&dev->dev);
1513 		dev_set_drvdata(&dev->dev, (void *)dev);
1514 		mutex_init(&dev->mlock);
1515 		mutex_init(&dev->info_exist_lock);
1516 		INIT_LIST_HEAD(&dev->channel_attr_list);
1517 
1518 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1519 		if (dev->id < 0) {
1520 			/* cannot use a dev_err as the name isn't available */
1521 			pr_err("failed to get device id\n");
1522 			kfree(dev);
1523 			return NULL;
1524 		}
1525 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1526 		INIT_LIST_HEAD(&dev->buffer_list);
1527 	}
1528 
1529 	return dev;
1530 }
1531 EXPORT_SYMBOL(iio_device_alloc);
1532 
1533 /**
1534  * iio_device_free() - free an iio_dev from a driver
1535  * @dev:		the iio_dev associated with the device
1536  **/
1537 void iio_device_free(struct iio_dev *dev)
1538 {
1539 	if (dev)
1540 		put_device(&dev->dev);
1541 }
1542 EXPORT_SYMBOL(iio_device_free);
1543 
1544 static void devm_iio_device_release(struct device *dev, void *res)
1545 {
1546 	iio_device_free(*(struct iio_dev **)res);
1547 }
1548 
1549 int devm_iio_device_match(struct device *dev, void *res, void *data)
1550 {
1551 	struct iio_dev **r = res;
1552 	if (!r || !*r) {
1553 		WARN_ON(!r || !*r);
1554 		return 0;
1555 	}
1556 	return *r == data;
1557 }
1558 EXPORT_SYMBOL_GPL(devm_iio_device_match);
1559 
1560 /**
1561  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1562  * @dev:		Device to allocate iio_dev for
1563  * @sizeof_priv:	Space to allocate for private structure.
1564  *
1565  * Managed iio_device_alloc. iio_dev allocated with this function is
1566  * automatically freed on driver detach.
1567  *
1568  * If an iio_dev allocated with this function needs to be freed separately,
1569  * devm_iio_device_free() must be used.
1570  *
1571  * RETURNS:
1572  * Pointer to allocated iio_dev on success, NULL on failure.
1573  */
1574 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1575 {
1576 	struct iio_dev **ptr, *iio_dev;
1577 
1578 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1579 			   GFP_KERNEL);
1580 	if (!ptr)
1581 		return NULL;
1582 
1583 	iio_dev = iio_device_alloc(sizeof_priv);
1584 	if (iio_dev) {
1585 		*ptr = iio_dev;
1586 		devres_add(dev, ptr);
1587 	} else {
1588 		devres_free(ptr);
1589 	}
1590 
1591 	return iio_dev;
1592 }
1593 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1594 
1595 /**
1596  * devm_iio_device_free - Resource-managed iio_device_free()
1597  * @dev:		Device this iio_dev belongs to
1598  * @iio_dev:		the iio_dev associated with the device
1599  *
1600  * Free iio_dev allocated with devm_iio_device_alloc().
1601  */
1602 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1603 {
1604 	int rc;
1605 
1606 	rc = devres_release(dev, devm_iio_device_release,
1607 			    devm_iio_device_match, iio_dev);
1608 	WARN_ON(rc);
1609 }
1610 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1611 
1612 /**
1613  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1614  * @inode:	Inode structure for identifying the device in the file system
1615  * @filp:	File structure for iio device used to keep and later access
1616  *		private data
1617  *
1618  * Return: 0 on success or -EBUSY if the device is already opened
1619  **/
1620 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1621 {
1622 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1623 						struct iio_dev, chrdev);
1624 
1625 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1626 		return -EBUSY;
1627 
1628 	iio_device_get(indio_dev);
1629 
1630 	filp->private_data = indio_dev;
1631 
1632 	return 0;
1633 }
1634 
1635 /**
1636  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1637  * @inode:	Inode structure pointer for the char device
1638  * @filp:	File structure pointer for the char device
1639  *
1640  * Return: 0 for successful release
1641  */
1642 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1643 {
1644 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1645 						struct iio_dev, chrdev);
1646 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1647 	iio_device_put(indio_dev);
1648 
1649 	return 0;
1650 }
1651 
1652 /* Somewhat of a cross file organization violation - ioctls here are actually
1653  * event related */
1654 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1655 {
1656 	struct iio_dev *indio_dev = filp->private_data;
1657 	int __user *ip = (int __user *)arg;
1658 	int fd;
1659 
1660 	if (!indio_dev->info)
1661 		return -ENODEV;
1662 
1663 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1664 		fd = iio_event_getfd(indio_dev);
1665 		if (fd < 0)
1666 			return fd;
1667 		if (copy_to_user(ip, &fd, sizeof(fd)))
1668 			return -EFAULT;
1669 		return 0;
1670 	}
1671 	return -EINVAL;
1672 }
1673 
1674 static const struct file_operations iio_buffer_fileops = {
1675 	.read = iio_buffer_read_outer_addr,
1676 	.release = iio_chrdev_release,
1677 	.open = iio_chrdev_open,
1678 	.poll = iio_buffer_poll_addr,
1679 	.owner = THIS_MODULE,
1680 	.llseek = noop_llseek,
1681 	.unlocked_ioctl = iio_ioctl,
1682 	.compat_ioctl = compat_ptr_ioctl,
1683 };
1684 
1685 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1686 {
1687 	int i, j;
1688 	const struct iio_chan_spec *channels = indio_dev->channels;
1689 
1690 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1691 		return 0;
1692 
1693 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1694 		if (channels[i].scan_index < 0)
1695 			continue;
1696 		for (j = i + 1; j < indio_dev->num_channels; j++)
1697 			if (channels[i].scan_index == channels[j].scan_index) {
1698 				dev_err(&indio_dev->dev,
1699 					"Duplicate scan index %d\n",
1700 					channels[i].scan_index);
1701 				return -EINVAL;
1702 			}
1703 	}
1704 
1705 	return 0;
1706 }
1707 
1708 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1709 
1710 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
1711 {
1712 	int ret;
1713 
1714 	indio_dev->driver_module = this_mod;
1715 	/* If the calling driver did not initialize of_node, do it here */
1716 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1717 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1718 
1719 	indio_dev->label = of_get_property(indio_dev->dev.of_node, "label",
1720 					   NULL);
1721 
1722 	ret = iio_check_unique_scan_index(indio_dev);
1723 	if (ret < 0)
1724 		return ret;
1725 
1726 	if (!indio_dev->info)
1727 		return -EINVAL;
1728 
1729 	/* configure elements for the chrdev */
1730 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1731 
1732 	iio_device_register_debugfs(indio_dev);
1733 
1734 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1735 	if (ret) {
1736 		dev_err(indio_dev->dev.parent,
1737 			"Failed to create buffer sysfs interfaces\n");
1738 		goto error_unreg_debugfs;
1739 	}
1740 
1741 	ret = iio_device_register_sysfs(indio_dev);
1742 	if (ret) {
1743 		dev_err(indio_dev->dev.parent,
1744 			"Failed to register sysfs interfaces\n");
1745 		goto error_buffer_free_sysfs;
1746 	}
1747 	ret = iio_device_register_eventset(indio_dev);
1748 	if (ret) {
1749 		dev_err(indio_dev->dev.parent,
1750 			"Failed to register event set\n");
1751 		goto error_free_sysfs;
1752 	}
1753 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1754 		iio_device_register_trigger_consumer(indio_dev);
1755 
1756 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1757 		indio_dev->setup_ops == NULL)
1758 		indio_dev->setup_ops = &noop_ring_setup_ops;
1759 
1760 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1761 
1762 	indio_dev->chrdev.owner = this_mod;
1763 
1764 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
1765 	if (ret < 0)
1766 		goto error_unreg_eventset;
1767 
1768 	return 0;
1769 
1770 error_unreg_eventset:
1771 	iio_device_unregister_eventset(indio_dev);
1772 error_free_sysfs:
1773 	iio_device_unregister_sysfs(indio_dev);
1774 error_buffer_free_sysfs:
1775 	iio_buffer_free_sysfs_and_mask(indio_dev);
1776 error_unreg_debugfs:
1777 	iio_device_unregister_debugfs(indio_dev);
1778 	return ret;
1779 }
1780 EXPORT_SYMBOL(__iio_device_register);
1781 
1782 /**
1783  * iio_device_unregister() - unregister a device from the IIO subsystem
1784  * @indio_dev:		Device structure representing the device.
1785  **/
1786 void iio_device_unregister(struct iio_dev *indio_dev)
1787 {
1788 	cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
1789 
1790 	mutex_lock(&indio_dev->info_exist_lock);
1791 
1792 	iio_device_unregister_debugfs(indio_dev);
1793 
1794 	iio_disable_all_buffers(indio_dev);
1795 
1796 	indio_dev->info = NULL;
1797 
1798 	iio_device_wakeup_eventset(indio_dev);
1799 	iio_buffer_wakeup_poll(indio_dev);
1800 
1801 	mutex_unlock(&indio_dev->info_exist_lock);
1802 
1803 	iio_buffer_free_sysfs_and_mask(indio_dev);
1804 }
1805 EXPORT_SYMBOL(iio_device_unregister);
1806 
1807 static void devm_iio_device_unreg(struct device *dev, void *res)
1808 {
1809 	iio_device_unregister(*(struct iio_dev **)res);
1810 }
1811 
1812 int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
1813 			       struct module *this_mod)
1814 {
1815 	struct iio_dev **ptr;
1816 	int ret;
1817 
1818 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1819 	if (!ptr)
1820 		return -ENOMEM;
1821 
1822 	*ptr = indio_dev;
1823 	ret = __iio_device_register(indio_dev, this_mod);
1824 	if (!ret)
1825 		devres_add(dev, ptr);
1826 	else
1827 		devres_free(ptr);
1828 
1829 	return ret;
1830 }
1831 EXPORT_SYMBOL_GPL(__devm_iio_device_register);
1832 
1833 /**
1834  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1835  * @dev:	Device this iio_dev belongs to
1836  * @indio_dev:	the iio_dev associated with the device
1837  *
1838  * Unregister iio_dev registered with devm_iio_device_register().
1839  */
1840 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1841 {
1842 	int rc;
1843 
1844 	rc = devres_release(dev, devm_iio_device_unreg,
1845 			    devm_iio_device_match, indio_dev);
1846 	WARN_ON(rc);
1847 }
1848 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1849 
1850 /**
1851  * iio_device_claim_direct_mode - Keep device in direct mode
1852  * @indio_dev:	the iio_dev associated with the device
1853  *
1854  * If the device is in direct mode it is guaranteed to stay
1855  * that way until iio_device_release_direct_mode() is called.
1856  *
1857  * Use with iio_device_release_direct_mode()
1858  *
1859  * Returns: 0 on success, -EBUSY on failure
1860  */
1861 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1862 {
1863 	mutex_lock(&indio_dev->mlock);
1864 
1865 	if (iio_buffer_enabled(indio_dev)) {
1866 		mutex_unlock(&indio_dev->mlock);
1867 		return -EBUSY;
1868 	}
1869 	return 0;
1870 }
1871 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1872 
1873 /**
1874  * iio_device_release_direct_mode - releases claim on direct mode
1875  * @indio_dev:	the iio_dev associated with the device
1876  *
1877  * Release the claim. Device is no longer guaranteed to stay
1878  * in direct mode.
1879  *
1880  * Use with iio_device_claim_direct_mode()
1881  */
1882 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1883 {
1884 	mutex_unlock(&indio_dev->mlock);
1885 }
1886 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1887 
1888 subsys_initcall(iio_init);
1889 module_exit(iio_exit);
1890 
1891 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1892 MODULE_DESCRIPTION("Industrial I/O core");
1893 MODULE_LICENSE("GPL");
1894