1 /* The industrial I/O core
2  *
3  * Copyright (c) 2008 Jonathan Cameron
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 as published by
7  * the Free Software Foundation.
8  *
9  * Based on elements of hwmon and input subsystems.
10  */
11 
12 #define pr_fmt(fmt) "iio-core: " fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/idr.h>
17 #include <linux/kdev_t.h>
18 #include <linux/err.h>
19 #include <linux/device.h>
20 #include <linux/fs.h>
21 #include <linux/poll.h>
22 #include <linux/sched.h>
23 #include <linux/wait.h>
24 #include <linux/cdev.h>
25 #include <linux/slab.h>
26 #include <linux/anon_inodes.h>
27 #include <linux/debugfs.h>
28 #include <linux/mutex.h>
29 #include <linux/iio/iio.h>
30 #include "iio_core.h"
31 #include "iio_core_trigger.h"
32 #include <linux/iio/sysfs.h>
33 #include <linux/iio/events.h>
34 #include <linux/iio/buffer.h>
35 #include <linux/iio/buffer_impl.h>
36 
37 /* IDA to assign each registered device a unique id */
38 static DEFINE_IDA(iio_ida);
39 
40 static dev_t iio_devt;
41 
42 #define IIO_DEV_MAX 256
43 struct bus_type iio_bus_type = {
44 	.name = "iio",
45 };
46 EXPORT_SYMBOL(iio_bus_type);
47 
48 static struct dentry *iio_debugfs_dentry;
49 
50 static const char * const iio_direction[] = {
51 	[0] = "in",
52 	[1] = "out",
53 };
54 
55 static const char * const iio_chan_type_name_spec[] = {
56 	[IIO_VOLTAGE] = "voltage",
57 	[IIO_CURRENT] = "current",
58 	[IIO_POWER] = "power",
59 	[IIO_ACCEL] = "accel",
60 	[IIO_ANGL_VEL] = "anglvel",
61 	[IIO_MAGN] = "magn",
62 	[IIO_LIGHT] = "illuminance",
63 	[IIO_INTENSITY] = "intensity",
64 	[IIO_PROXIMITY] = "proximity",
65 	[IIO_TEMP] = "temp",
66 	[IIO_INCLI] = "incli",
67 	[IIO_ROT] = "rot",
68 	[IIO_ANGL] = "angl",
69 	[IIO_TIMESTAMP] = "timestamp",
70 	[IIO_CAPACITANCE] = "capacitance",
71 	[IIO_ALTVOLTAGE] = "altvoltage",
72 	[IIO_CCT] = "cct",
73 	[IIO_PRESSURE] = "pressure",
74 	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
75 	[IIO_ACTIVITY] = "activity",
76 	[IIO_STEPS] = "steps",
77 	[IIO_ENERGY] = "energy",
78 	[IIO_DISTANCE] = "distance",
79 	[IIO_VELOCITY] = "velocity",
80 	[IIO_CONCENTRATION] = "concentration",
81 	[IIO_RESISTANCE] = "resistance",
82 	[IIO_PH] = "ph",
83 	[IIO_UVINDEX] = "uvindex",
84 	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
85 	[IIO_COUNT] = "count",
86 	[IIO_INDEX] = "index",
87 	[IIO_GRAVITY]  = "gravity",
88 	[IIO_POSITIONRELATIVE]  = "positionrelative",
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_QUATERNION] = "quaternion",
113 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
114 	[IIO_MOD_TEMP_OBJECT] = "object",
115 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
116 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
117 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
118 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
119 	[IIO_MOD_RUNNING] = "running",
120 	[IIO_MOD_JOGGING] = "jogging",
121 	[IIO_MOD_WALKING] = "walking",
122 	[IIO_MOD_STILL] = "still",
123 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
124 	[IIO_MOD_I] = "i",
125 	[IIO_MOD_Q] = "q",
126 	[IIO_MOD_CO2] = "co2",
127 	[IIO_MOD_VOC] = "voc",
128 };
129 
130 /* relies on pairs of these shared then separate */
131 static const char * const iio_chan_info_postfix[] = {
132 	[IIO_CHAN_INFO_RAW] = "raw",
133 	[IIO_CHAN_INFO_PROCESSED] = "input",
134 	[IIO_CHAN_INFO_SCALE] = "scale",
135 	[IIO_CHAN_INFO_OFFSET] = "offset",
136 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
137 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
138 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
139 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
140 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
141 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
142 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
143 	= "filter_low_pass_3db_frequency",
144 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
145 	= "filter_high_pass_3db_frequency",
146 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
147 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
148 	[IIO_CHAN_INFO_PHASE] = "phase",
149 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
150 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
151 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
152 	[IIO_CHAN_INFO_ENABLE] = "en",
153 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
154 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
155 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
156 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
157 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
158 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
159 };
160 
161 /**
162  * iio_find_channel_from_si() - get channel from its scan index
163  * @indio_dev:		device
164  * @si:			scan index to match
165  */
166 const struct iio_chan_spec
167 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
168 {
169 	int i;
170 
171 	for (i = 0; i < indio_dev->num_channels; i++)
172 		if (indio_dev->channels[i].scan_index == si)
173 			return &indio_dev->channels[i];
174 	return NULL;
175 }
176 
177 /* This turns up an awful lot */
178 ssize_t iio_read_const_attr(struct device *dev,
179 			    struct device_attribute *attr,
180 			    char *buf)
181 {
182 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
183 }
184 EXPORT_SYMBOL(iio_read_const_attr);
185 
186 static int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
187 {
188 	int ret;
189 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
190 
191 	ret = mutex_lock_interruptible(&indio_dev->mlock);
192 	if (ret)
193 		return ret;
194 	if ((ev_int && iio_event_enabled(ev_int)) ||
195 	    iio_buffer_enabled(indio_dev)) {
196 		mutex_unlock(&indio_dev->mlock);
197 		return -EBUSY;
198 	}
199 	indio_dev->clock_id = clock_id;
200 	mutex_unlock(&indio_dev->mlock);
201 
202 	return 0;
203 }
204 
205 /**
206  * iio_get_time_ns() - utility function to get a time stamp for events etc
207  * @indio_dev: device
208  */
209 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
210 {
211 	struct timespec tp;
212 
213 	switch (iio_device_get_clock(indio_dev)) {
214 	case CLOCK_REALTIME:
215 		ktime_get_real_ts(&tp);
216 		break;
217 	case CLOCK_MONOTONIC:
218 		ktime_get_ts(&tp);
219 		break;
220 	case CLOCK_MONOTONIC_RAW:
221 		getrawmonotonic(&tp);
222 		break;
223 	case CLOCK_REALTIME_COARSE:
224 		tp = current_kernel_time();
225 		break;
226 	case CLOCK_MONOTONIC_COARSE:
227 		tp = get_monotonic_coarse();
228 		break;
229 	case CLOCK_BOOTTIME:
230 		get_monotonic_boottime(&tp);
231 		break;
232 	case CLOCK_TAI:
233 		timekeeping_clocktai(&tp);
234 		break;
235 	default:
236 		BUG();
237 	}
238 
239 	return timespec_to_ns(&tp);
240 }
241 EXPORT_SYMBOL(iio_get_time_ns);
242 
243 /**
244  * iio_get_time_res() - utility function to get time stamp clock resolution in
245  *                      nano seconds.
246  * @indio_dev: device
247  */
248 unsigned int iio_get_time_res(const struct iio_dev *indio_dev)
249 {
250 	switch (iio_device_get_clock(indio_dev)) {
251 	case CLOCK_REALTIME:
252 	case CLOCK_MONOTONIC:
253 	case CLOCK_MONOTONIC_RAW:
254 	case CLOCK_BOOTTIME:
255 	case CLOCK_TAI:
256 		return hrtimer_resolution;
257 	case CLOCK_REALTIME_COARSE:
258 	case CLOCK_MONOTONIC_COARSE:
259 		return LOW_RES_NSEC;
260 	default:
261 		BUG();
262 	}
263 }
264 EXPORT_SYMBOL(iio_get_time_res);
265 
266 static int __init iio_init(void)
267 {
268 	int ret;
269 
270 	/* Register sysfs bus */
271 	ret  = bus_register(&iio_bus_type);
272 	if (ret < 0) {
273 		pr_err("could not register bus type\n");
274 		goto error_nothing;
275 	}
276 
277 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
278 	if (ret < 0) {
279 		pr_err("failed to allocate char dev region\n");
280 		goto error_unregister_bus_type;
281 	}
282 
283 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
284 
285 	return 0;
286 
287 error_unregister_bus_type:
288 	bus_unregister(&iio_bus_type);
289 error_nothing:
290 	return ret;
291 }
292 
293 static void __exit iio_exit(void)
294 {
295 	if (iio_devt)
296 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
297 	bus_unregister(&iio_bus_type);
298 	debugfs_remove(iio_debugfs_dentry);
299 }
300 
301 #if defined(CONFIG_DEBUG_FS)
302 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
303 			      size_t count, loff_t *ppos)
304 {
305 	struct iio_dev *indio_dev = file->private_data;
306 	char buf[20];
307 	unsigned val = 0;
308 	ssize_t len;
309 	int ret;
310 
311 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
312 						  indio_dev->cached_reg_addr,
313 						  0, &val);
314 	if (ret) {
315 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
316 		return ret;
317 	}
318 
319 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
320 
321 	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
322 }
323 
324 static ssize_t iio_debugfs_write_reg(struct file *file,
325 		     const char __user *userbuf, size_t count, loff_t *ppos)
326 {
327 	struct iio_dev *indio_dev = file->private_data;
328 	unsigned reg, val;
329 	char buf[80];
330 	int ret;
331 
332 	count = min_t(size_t, count, (sizeof(buf)-1));
333 	if (copy_from_user(buf, userbuf, count))
334 		return -EFAULT;
335 
336 	buf[count] = 0;
337 
338 	ret = sscanf(buf, "%i %i", &reg, &val);
339 
340 	switch (ret) {
341 	case 1:
342 		indio_dev->cached_reg_addr = reg;
343 		break;
344 	case 2:
345 		indio_dev->cached_reg_addr = reg;
346 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
347 							  val, NULL);
348 		if (ret) {
349 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
350 				__func__);
351 			return ret;
352 		}
353 		break;
354 	default:
355 		return -EINVAL;
356 	}
357 
358 	return count;
359 }
360 
361 static const struct file_operations iio_debugfs_reg_fops = {
362 	.open = simple_open,
363 	.read = iio_debugfs_read_reg,
364 	.write = iio_debugfs_write_reg,
365 };
366 
367 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
368 {
369 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
370 }
371 
372 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
373 {
374 	struct dentry *d;
375 
376 	if (indio_dev->info->debugfs_reg_access == NULL)
377 		return 0;
378 
379 	if (!iio_debugfs_dentry)
380 		return 0;
381 
382 	indio_dev->debugfs_dentry =
383 		debugfs_create_dir(dev_name(&indio_dev->dev),
384 				   iio_debugfs_dentry);
385 	if (indio_dev->debugfs_dentry == NULL) {
386 		dev_warn(indio_dev->dev.parent,
387 			 "Failed to create debugfs directory\n");
388 		return -EFAULT;
389 	}
390 
391 	d = debugfs_create_file("direct_reg_access", 0644,
392 				indio_dev->debugfs_dentry,
393 				indio_dev, &iio_debugfs_reg_fops);
394 	if (!d) {
395 		iio_device_unregister_debugfs(indio_dev);
396 		return -ENOMEM;
397 	}
398 
399 	return 0;
400 }
401 #else
402 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
403 {
404 	return 0;
405 }
406 
407 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
408 {
409 }
410 #endif /* CONFIG_DEBUG_FS */
411 
412 static ssize_t iio_read_channel_ext_info(struct device *dev,
413 				     struct device_attribute *attr,
414 				     char *buf)
415 {
416 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
417 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
418 	const struct iio_chan_spec_ext_info *ext_info;
419 
420 	ext_info = &this_attr->c->ext_info[this_attr->address];
421 
422 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
423 }
424 
425 static ssize_t iio_write_channel_ext_info(struct device *dev,
426 				     struct device_attribute *attr,
427 				     const char *buf,
428 					 size_t len)
429 {
430 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
431 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
432 	const struct iio_chan_spec_ext_info *ext_info;
433 
434 	ext_info = &this_attr->c->ext_info[this_attr->address];
435 
436 	return ext_info->write(indio_dev, ext_info->private,
437 			       this_attr->c, buf, len);
438 }
439 
440 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
441 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
442 {
443 	const struct iio_enum *e = (const struct iio_enum *)priv;
444 	unsigned int i;
445 	size_t len = 0;
446 
447 	if (!e->num_items)
448 		return 0;
449 
450 	for (i = 0; i < e->num_items; ++i)
451 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
452 
453 	/* replace last space with a newline */
454 	buf[len - 1] = '\n';
455 
456 	return len;
457 }
458 EXPORT_SYMBOL_GPL(iio_enum_available_read);
459 
460 ssize_t iio_enum_read(struct iio_dev *indio_dev,
461 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
462 {
463 	const struct iio_enum *e = (const struct iio_enum *)priv;
464 	int i;
465 
466 	if (!e->get)
467 		return -EINVAL;
468 
469 	i = e->get(indio_dev, chan);
470 	if (i < 0)
471 		return i;
472 	else if (i >= e->num_items)
473 		return -EINVAL;
474 
475 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
476 }
477 EXPORT_SYMBOL_GPL(iio_enum_read);
478 
479 ssize_t iio_enum_write(struct iio_dev *indio_dev,
480 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
481 	size_t len)
482 {
483 	const struct iio_enum *e = (const struct iio_enum *)priv;
484 	int ret;
485 
486 	if (!e->set)
487 		return -EINVAL;
488 
489 	ret = __sysfs_match_string(e->items, e->num_items, buf);
490 	if (ret < 0)
491 		return ret;
492 
493 	ret = e->set(indio_dev, chan, ret);
494 	return ret ? ret : len;
495 }
496 EXPORT_SYMBOL_GPL(iio_enum_write);
497 
498 static const struct iio_mount_matrix iio_mount_idmatrix = {
499 	.rotation = {
500 		"1", "0", "0",
501 		"0", "1", "0",
502 		"0", "0", "1"
503 	}
504 };
505 
506 static int iio_setup_mount_idmatrix(const struct device *dev,
507 				    struct iio_mount_matrix *matrix)
508 {
509 	*matrix = iio_mount_idmatrix;
510 	dev_info(dev, "mounting matrix not found: using identity...\n");
511 	return 0;
512 }
513 
514 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
515 			      const struct iio_chan_spec *chan, char *buf)
516 {
517 	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
518 					      priv)(indio_dev, chan);
519 
520 	if (IS_ERR(mtx))
521 		return PTR_ERR(mtx);
522 
523 	if (!mtx)
524 		mtx = &iio_mount_idmatrix;
525 
526 	return snprintf(buf, PAGE_SIZE, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
527 			mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
528 			mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
529 			mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
530 }
531 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
532 
533 /**
534  * of_iio_read_mount_matrix() - retrieve iio device mounting matrix from
535  *                              device-tree "mount-matrix" property
536  * @dev:	device the mounting matrix property is assigned to
537  * @propname:	device specific mounting matrix property name
538  * @matrix:	where to store retrieved matrix
539  *
540  * If device is assigned no mounting matrix property, a default 3x3 identity
541  * matrix will be filled in.
542  *
543  * Return: 0 if success, or a negative error code on failure.
544  */
545 #ifdef CONFIG_OF
546 int of_iio_read_mount_matrix(const struct device *dev,
547 			     const char *propname,
548 			     struct iio_mount_matrix *matrix)
549 {
550 	if (dev->of_node) {
551 		int err = of_property_read_string_array(dev->of_node,
552 				propname, matrix->rotation,
553 				ARRAY_SIZE(iio_mount_idmatrix.rotation));
554 
555 		if (err == ARRAY_SIZE(iio_mount_idmatrix.rotation))
556 			return 0;
557 
558 		if (err >= 0)
559 			/* Invalid number of matrix entries. */
560 			return -EINVAL;
561 
562 		if (err != -EINVAL)
563 			/* Invalid matrix declaration format. */
564 			return err;
565 	}
566 
567 	/* Matrix was not declared at all: fallback to identity. */
568 	return iio_setup_mount_idmatrix(dev, matrix);
569 }
570 #else
571 int of_iio_read_mount_matrix(const struct device *dev,
572 			     const char *propname,
573 			     struct iio_mount_matrix *matrix)
574 {
575 	return iio_setup_mount_idmatrix(dev, matrix);
576 }
577 #endif
578 EXPORT_SYMBOL(of_iio_read_mount_matrix);
579 
580 static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
581 				  int size, const int *vals)
582 {
583 	unsigned long long tmp;
584 	int tmp0, tmp1;
585 	bool scale_db = false;
586 
587 	switch (type) {
588 	case IIO_VAL_INT:
589 		return snprintf(buf, len, "%d", vals[0]);
590 	case IIO_VAL_INT_PLUS_MICRO_DB:
591 		scale_db = true;
592 		/* fall through */
593 	case IIO_VAL_INT_PLUS_MICRO:
594 		if (vals[1] < 0)
595 			return snprintf(buf, len, "-%d.%06u%s", abs(vals[0]),
596 					-vals[1], scale_db ? " dB" : "");
597 		else
598 			return snprintf(buf, len, "%d.%06u%s", vals[0], vals[1],
599 					scale_db ? " dB" : "");
600 	case IIO_VAL_INT_PLUS_NANO:
601 		if (vals[1] < 0)
602 			return snprintf(buf, len, "-%d.%09u", abs(vals[0]),
603 					-vals[1]);
604 		else
605 			return snprintf(buf, len, "%d.%09u", vals[0], vals[1]);
606 	case IIO_VAL_FRACTIONAL:
607 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
608 		tmp1 = vals[1];
609 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
610 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
611 	case IIO_VAL_FRACTIONAL_LOG2:
612 		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
613 		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
614 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
615 	case IIO_VAL_INT_MULTIPLE:
616 	{
617 		int i;
618 		int l = 0;
619 
620 		for (i = 0; i < size; ++i) {
621 			l += snprintf(&buf[l], len - l, "%d ", vals[i]);
622 			if (l >= len)
623 				break;
624 		}
625 		return l;
626 	}
627 	default:
628 		return 0;
629 	}
630 }
631 
632 /**
633  * iio_format_value() - Formats a IIO value into its string representation
634  * @buf:	The buffer to which the formatted value gets written
635  *		which is assumed to be big enough (i.e. PAGE_SIZE).
636  * @type:	One of the IIO_VAL_* constants. This decides how the val
637  *		and val2 parameters are formatted.
638  * @size:	Number of IIO value entries contained in vals
639  * @vals:	Pointer to the values, exact meaning depends on the
640  *		type parameter.
641  *
642  * Return: 0 by default, a negative number on failure or the
643  *	   total number of characters written for a type that belongs
644  *	   to the IIO_VAL_* constant.
645  */
646 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
647 {
648 	ssize_t len;
649 
650 	len = __iio_format_value(buf, PAGE_SIZE, type, size, vals);
651 	if (len >= PAGE_SIZE - 1)
652 		return -EFBIG;
653 
654 	return len + sprintf(buf + len, "\n");
655 }
656 EXPORT_SYMBOL_GPL(iio_format_value);
657 
658 static ssize_t iio_read_channel_info(struct device *dev,
659 				     struct device_attribute *attr,
660 				     char *buf)
661 {
662 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
663 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
664 	int vals[INDIO_MAX_RAW_ELEMENTS];
665 	int ret;
666 	int val_len = 2;
667 
668 	if (indio_dev->info->read_raw_multi)
669 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
670 							INDIO_MAX_RAW_ELEMENTS,
671 							vals, &val_len,
672 							this_attr->address);
673 	else
674 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
675 				    &vals[0], &vals[1], this_attr->address);
676 
677 	if (ret < 0)
678 		return ret;
679 
680 	return iio_format_value(buf, ret, val_len, vals);
681 }
682 
683 static ssize_t iio_format_avail_list(char *buf, const int *vals,
684 				     int type, int length)
685 {
686 	int i;
687 	ssize_t len = 0;
688 
689 	switch (type) {
690 	case IIO_VAL_INT:
691 		for (i = 0; i < length; i++) {
692 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
693 						  type, 1, &vals[i]);
694 			if (len >= PAGE_SIZE)
695 				return -EFBIG;
696 			if (i < length - 1)
697 				len += snprintf(buf + len, PAGE_SIZE - len,
698 						" ");
699 			else
700 				len += snprintf(buf + len, PAGE_SIZE - len,
701 						"\n");
702 			if (len >= PAGE_SIZE)
703 				return -EFBIG;
704 		}
705 		break;
706 	default:
707 		for (i = 0; i < length / 2; i++) {
708 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
709 						  type, 2, &vals[i * 2]);
710 			if (len >= PAGE_SIZE)
711 				return -EFBIG;
712 			if (i < length / 2 - 1)
713 				len += snprintf(buf + len, PAGE_SIZE - len,
714 						" ");
715 			else
716 				len += snprintf(buf + len, PAGE_SIZE - len,
717 						"\n");
718 			if (len >= PAGE_SIZE)
719 				return -EFBIG;
720 		}
721 	}
722 
723 	return len;
724 }
725 
726 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
727 {
728 	int i;
729 	ssize_t len;
730 
731 	len = snprintf(buf, PAGE_SIZE, "[");
732 	switch (type) {
733 	case IIO_VAL_INT:
734 		for (i = 0; i < 3; i++) {
735 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
736 						  type, 1, &vals[i]);
737 			if (len >= PAGE_SIZE)
738 				return -EFBIG;
739 			if (i < 2)
740 				len += snprintf(buf + len, PAGE_SIZE - len,
741 						" ");
742 			else
743 				len += snprintf(buf + len, PAGE_SIZE - len,
744 						"]\n");
745 			if (len >= PAGE_SIZE)
746 				return -EFBIG;
747 		}
748 		break;
749 	default:
750 		for (i = 0; i < 3; i++) {
751 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
752 						  type, 2, &vals[i * 2]);
753 			if (len >= PAGE_SIZE)
754 				return -EFBIG;
755 			if (i < 2)
756 				len += snprintf(buf + len, PAGE_SIZE - len,
757 						" ");
758 			else
759 				len += snprintf(buf + len, PAGE_SIZE - len,
760 						"]\n");
761 			if (len >= PAGE_SIZE)
762 				return -EFBIG;
763 		}
764 	}
765 
766 	return len;
767 }
768 
769 static ssize_t iio_read_channel_info_avail(struct device *dev,
770 					   struct device_attribute *attr,
771 					   char *buf)
772 {
773 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
774 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
775 	const int *vals;
776 	int ret;
777 	int length;
778 	int type;
779 
780 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
781 					  &vals, &type, &length,
782 					  this_attr->address);
783 
784 	if (ret < 0)
785 		return ret;
786 	switch (ret) {
787 	case IIO_AVAIL_LIST:
788 		return iio_format_avail_list(buf, vals, type, length);
789 	case IIO_AVAIL_RANGE:
790 		return iio_format_avail_range(buf, vals, type);
791 	default:
792 		return -EINVAL;
793 	}
794 }
795 
796 /**
797  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
798  * @str: The string to parse
799  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
800  * @integer: The integer part of the number
801  * @fract: The fractional part of the number
802  *
803  * Returns 0 on success, or a negative error code if the string could not be
804  * parsed.
805  */
806 int iio_str_to_fixpoint(const char *str, int fract_mult,
807 	int *integer, int *fract)
808 {
809 	int i = 0, f = 0;
810 	bool integer_part = true, negative = false;
811 
812 	if (fract_mult == 0) {
813 		*fract = 0;
814 
815 		return kstrtoint(str, 0, integer);
816 	}
817 
818 	if (str[0] == '-') {
819 		negative = true;
820 		str++;
821 	} else if (str[0] == '+') {
822 		str++;
823 	}
824 
825 	while (*str) {
826 		if ('0' <= *str && *str <= '9') {
827 			if (integer_part) {
828 				i = i * 10 + *str - '0';
829 			} else {
830 				f += fract_mult * (*str - '0');
831 				fract_mult /= 10;
832 			}
833 		} else if (*str == '\n') {
834 			if (*(str + 1) == '\0')
835 				break;
836 			else
837 				return -EINVAL;
838 		} else if (*str == '.' && integer_part) {
839 			integer_part = false;
840 		} else {
841 			return -EINVAL;
842 		}
843 		str++;
844 	}
845 
846 	if (negative) {
847 		if (i)
848 			i = -i;
849 		else
850 			f = -f;
851 	}
852 
853 	*integer = i;
854 	*fract = f;
855 
856 	return 0;
857 }
858 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
859 
860 static ssize_t iio_write_channel_info(struct device *dev,
861 				      struct device_attribute *attr,
862 				      const char *buf,
863 				      size_t len)
864 {
865 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
866 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
867 	int ret, fract_mult = 100000;
868 	int integer, fract;
869 
870 	/* Assumes decimal - precision based on number of digits */
871 	if (!indio_dev->info->write_raw)
872 		return -EINVAL;
873 
874 	if (indio_dev->info->write_raw_get_fmt)
875 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
876 			this_attr->c, this_attr->address)) {
877 		case IIO_VAL_INT:
878 			fract_mult = 0;
879 			break;
880 		case IIO_VAL_INT_PLUS_MICRO:
881 			fract_mult = 100000;
882 			break;
883 		case IIO_VAL_INT_PLUS_NANO:
884 			fract_mult = 100000000;
885 			break;
886 		default:
887 			return -EINVAL;
888 		}
889 
890 	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
891 	if (ret)
892 		return ret;
893 
894 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
895 					 integer, fract, this_attr->address);
896 	if (ret)
897 		return ret;
898 
899 	return len;
900 }
901 
902 static
903 int __iio_device_attr_init(struct device_attribute *dev_attr,
904 			   const char *postfix,
905 			   struct iio_chan_spec const *chan,
906 			   ssize_t (*readfunc)(struct device *dev,
907 					       struct device_attribute *attr,
908 					       char *buf),
909 			   ssize_t (*writefunc)(struct device *dev,
910 						struct device_attribute *attr,
911 						const char *buf,
912 						size_t len),
913 			   enum iio_shared_by shared_by)
914 {
915 	int ret = 0;
916 	char *name = NULL;
917 	char *full_postfix;
918 	sysfs_attr_init(&dev_attr->attr);
919 
920 	/* Build up postfix of <extend_name>_<modifier>_postfix */
921 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
922 		if (chan->extend_name)
923 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
924 						 iio_modifier_names[chan
925 								    ->channel2],
926 						 chan->extend_name,
927 						 postfix);
928 		else
929 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
930 						 iio_modifier_names[chan
931 								    ->channel2],
932 						 postfix);
933 	} else {
934 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
935 			full_postfix = kstrdup(postfix, GFP_KERNEL);
936 		else
937 			full_postfix = kasprintf(GFP_KERNEL,
938 						 "%s_%s",
939 						 chan->extend_name,
940 						 postfix);
941 	}
942 	if (full_postfix == NULL)
943 		return -ENOMEM;
944 
945 	if (chan->differential) { /* Differential can not have modifier */
946 		switch (shared_by) {
947 		case IIO_SHARED_BY_ALL:
948 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
949 			break;
950 		case IIO_SHARED_BY_DIR:
951 			name = kasprintf(GFP_KERNEL, "%s_%s",
952 						iio_direction[chan->output],
953 						full_postfix);
954 			break;
955 		case IIO_SHARED_BY_TYPE:
956 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
957 					    iio_direction[chan->output],
958 					    iio_chan_type_name_spec[chan->type],
959 					    iio_chan_type_name_spec[chan->type],
960 					    full_postfix);
961 			break;
962 		case IIO_SEPARATE:
963 			if (!chan->indexed) {
964 				WARN(1, "Differential channels must be indexed\n");
965 				ret = -EINVAL;
966 				goto error_free_full_postfix;
967 			}
968 			name = kasprintf(GFP_KERNEL,
969 					    "%s_%s%d-%s%d_%s",
970 					    iio_direction[chan->output],
971 					    iio_chan_type_name_spec[chan->type],
972 					    chan->channel,
973 					    iio_chan_type_name_spec[chan->type],
974 					    chan->channel2,
975 					    full_postfix);
976 			break;
977 		}
978 	} else { /* Single ended */
979 		switch (shared_by) {
980 		case IIO_SHARED_BY_ALL:
981 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
982 			break;
983 		case IIO_SHARED_BY_DIR:
984 			name = kasprintf(GFP_KERNEL, "%s_%s",
985 						iio_direction[chan->output],
986 						full_postfix);
987 			break;
988 		case IIO_SHARED_BY_TYPE:
989 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
990 					    iio_direction[chan->output],
991 					    iio_chan_type_name_spec[chan->type],
992 					    full_postfix);
993 			break;
994 
995 		case IIO_SEPARATE:
996 			if (chan->indexed)
997 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
998 						    iio_direction[chan->output],
999 						    iio_chan_type_name_spec[chan->type],
1000 						    chan->channel,
1001 						    full_postfix);
1002 			else
1003 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1004 						    iio_direction[chan->output],
1005 						    iio_chan_type_name_spec[chan->type],
1006 						    full_postfix);
1007 			break;
1008 		}
1009 	}
1010 	if (name == NULL) {
1011 		ret = -ENOMEM;
1012 		goto error_free_full_postfix;
1013 	}
1014 	dev_attr->attr.name = name;
1015 
1016 	if (readfunc) {
1017 		dev_attr->attr.mode |= S_IRUGO;
1018 		dev_attr->show = readfunc;
1019 	}
1020 
1021 	if (writefunc) {
1022 		dev_attr->attr.mode |= S_IWUSR;
1023 		dev_attr->store = writefunc;
1024 	}
1025 
1026 error_free_full_postfix:
1027 	kfree(full_postfix);
1028 
1029 	return ret;
1030 }
1031 
1032 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1033 {
1034 	kfree(dev_attr->attr.name);
1035 }
1036 
1037 int __iio_add_chan_devattr(const char *postfix,
1038 			   struct iio_chan_spec const *chan,
1039 			   ssize_t (*readfunc)(struct device *dev,
1040 					       struct device_attribute *attr,
1041 					       char *buf),
1042 			   ssize_t (*writefunc)(struct device *dev,
1043 						struct device_attribute *attr,
1044 						const char *buf,
1045 						size_t len),
1046 			   u64 mask,
1047 			   enum iio_shared_by shared_by,
1048 			   struct device *dev,
1049 			   struct list_head *attr_list)
1050 {
1051 	int ret;
1052 	struct iio_dev_attr *iio_attr, *t;
1053 
1054 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1055 	if (iio_attr == NULL)
1056 		return -ENOMEM;
1057 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1058 				     postfix, chan,
1059 				     readfunc, writefunc, shared_by);
1060 	if (ret)
1061 		goto error_iio_dev_attr_free;
1062 	iio_attr->c = chan;
1063 	iio_attr->address = mask;
1064 	list_for_each_entry(t, attr_list, l)
1065 		if (strcmp(t->dev_attr.attr.name,
1066 			   iio_attr->dev_attr.attr.name) == 0) {
1067 			if (shared_by == IIO_SEPARATE)
1068 				dev_err(dev, "tried to double register : %s\n",
1069 					t->dev_attr.attr.name);
1070 			ret = -EBUSY;
1071 			goto error_device_attr_deinit;
1072 		}
1073 	list_add(&iio_attr->l, attr_list);
1074 
1075 	return 0;
1076 
1077 error_device_attr_deinit:
1078 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1079 error_iio_dev_attr_free:
1080 	kfree(iio_attr);
1081 	return ret;
1082 }
1083 
1084 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1085 					 struct iio_chan_spec const *chan,
1086 					 enum iio_shared_by shared_by,
1087 					 const long *infomask)
1088 {
1089 	int i, ret, attrcount = 0;
1090 
1091 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1092 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1093 			return -EINVAL;
1094 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1095 					     chan,
1096 					     &iio_read_channel_info,
1097 					     &iio_write_channel_info,
1098 					     i,
1099 					     shared_by,
1100 					     &indio_dev->dev,
1101 					     &indio_dev->channel_attr_list);
1102 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1103 			continue;
1104 		else if (ret < 0)
1105 			return ret;
1106 		attrcount++;
1107 	}
1108 
1109 	return attrcount;
1110 }
1111 
1112 static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
1113 					       struct iio_chan_spec const *chan,
1114 					       enum iio_shared_by shared_by,
1115 					       const long *infomask)
1116 {
1117 	int i, ret, attrcount = 0;
1118 	char *avail_postfix;
1119 
1120 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1121 		avail_postfix = kasprintf(GFP_KERNEL,
1122 					  "%s_available",
1123 					  iio_chan_info_postfix[i]);
1124 		if (!avail_postfix)
1125 			return -ENOMEM;
1126 
1127 		ret = __iio_add_chan_devattr(avail_postfix,
1128 					     chan,
1129 					     &iio_read_channel_info_avail,
1130 					     NULL,
1131 					     i,
1132 					     shared_by,
1133 					     &indio_dev->dev,
1134 					     &indio_dev->channel_attr_list);
1135 		kfree(avail_postfix);
1136 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1137 			continue;
1138 		else if (ret < 0)
1139 			return ret;
1140 		attrcount++;
1141 	}
1142 
1143 	return attrcount;
1144 }
1145 
1146 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1147 					struct iio_chan_spec const *chan)
1148 {
1149 	int ret, attrcount = 0;
1150 	const struct iio_chan_spec_ext_info *ext_info;
1151 
1152 	if (chan->channel < 0)
1153 		return 0;
1154 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1155 					    IIO_SEPARATE,
1156 					    &chan->info_mask_separate);
1157 	if (ret < 0)
1158 		return ret;
1159 	attrcount += ret;
1160 
1161 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1162 						  IIO_SEPARATE,
1163 						  &chan->
1164 						  info_mask_separate_available);
1165 	if (ret < 0)
1166 		return ret;
1167 	attrcount += ret;
1168 
1169 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1170 					    IIO_SHARED_BY_TYPE,
1171 					    &chan->info_mask_shared_by_type);
1172 	if (ret < 0)
1173 		return ret;
1174 	attrcount += ret;
1175 
1176 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1177 						  IIO_SHARED_BY_TYPE,
1178 						  &chan->
1179 						  info_mask_shared_by_type_available);
1180 	if (ret < 0)
1181 		return ret;
1182 	attrcount += ret;
1183 
1184 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1185 					    IIO_SHARED_BY_DIR,
1186 					    &chan->info_mask_shared_by_dir);
1187 	if (ret < 0)
1188 		return ret;
1189 	attrcount += ret;
1190 
1191 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1192 						  IIO_SHARED_BY_DIR,
1193 						  &chan->info_mask_shared_by_dir_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_ALL,
1200 					    &chan->info_mask_shared_by_all);
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_ALL,
1207 						  &chan->info_mask_shared_by_all_available);
1208 	if (ret < 0)
1209 		return ret;
1210 	attrcount += ret;
1211 
1212 	if (chan->ext_info) {
1213 		unsigned int i = 0;
1214 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1215 			ret = __iio_add_chan_devattr(ext_info->name,
1216 					chan,
1217 					ext_info->read ?
1218 					    &iio_read_channel_ext_info : NULL,
1219 					ext_info->write ?
1220 					    &iio_write_channel_ext_info : NULL,
1221 					i,
1222 					ext_info->shared,
1223 					&indio_dev->dev,
1224 					&indio_dev->channel_attr_list);
1225 			i++;
1226 			if (ret == -EBUSY && ext_info->shared)
1227 				continue;
1228 
1229 			if (ret)
1230 				return ret;
1231 
1232 			attrcount++;
1233 		}
1234 	}
1235 
1236 	return attrcount;
1237 }
1238 
1239 /**
1240  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1241  * @attr_list: List of IIO device attributes
1242  *
1243  * This function frees the memory allocated for each of the IIO device
1244  * attributes in the list.
1245  */
1246 void iio_free_chan_devattr_list(struct list_head *attr_list)
1247 {
1248 	struct iio_dev_attr *p, *n;
1249 
1250 	list_for_each_entry_safe(p, n, attr_list, l) {
1251 		kfree(p->dev_attr.attr.name);
1252 		list_del(&p->l);
1253 		kfree(p);
1254 	}
1255 }
1256 
1257 static ssize_t iio_show_dev_name(struct device *dev,
1258 				 struct device_attribute *attr,
1259 				 char *buf)
1260 {
1261 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1262 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1263 }
1264 
1265 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1266 
1267 static ssize_t iio_show_timestamp_clock(struct device *dev,
1268 					struct device_attribute *attr,
1269 					char *buf)
1270 {
1271 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1272 	const clockid_t clk = iio_device_get_clock(indio_dev);
1273 	const char *name;
1274 	ssize_t sz;
1275 
1276 	switch (clk) {
1277 	case CLOCK_REALTIME:
1278 		name = "realtime\n";
1279 		sz = sizeof("realtime\n");
1280 		break;
1281 	case CLOCK_MONOTONIC:
1282 		name = "monotonic\n";
1283 		sz = sizeof("monotonic\n");
1284 		break;
1285 	case CLOCK_MONOTONIC_RAW:
1286 		name = "monotonic_raw\n";
1287 		sz = sizeof("monotonic_raw\n");
1288 		break;
1289 	case CLOCK_REALTIME_COARSE:
1290 		name = "realtime_coarse\n";
1291 		sz = sizeof("realtime_coarse\n");
1292 		break;
1293 	case CLOCK_MONOTONIC_COARSE:
1294 		name = "monotonic_coarse\n";
1295 		sz = sizeof("monotonic_coarse\n");
1296 		break;
1297 	case CLOCK_BOOTTIME:
1298 		name = "boottime\n";
1299 		sz = sizeof("boottime\n");
1300 		break;
1301 	case CLOCK_TAI:
1302 		name = "tai\n";
1303 		sz = sizeof("tai\n");
1304 		break;
1305 	default:
1306 		BUG();
1307 	}
1308 
1309 	memcpy(buf, name, sz);
1310 	return sz;
1311 }
1312 
1313 static ssize_t iio_store_timestamp_clock(struct device *dev,
1314 					 struct device_attribute *attr,
1315 					 const char *buf, size_t len)
1316 {
1317 	clockid_t clk;
1318 	int ret;
1319 
1320 	if (sysfs_streq(buf, "realtime"))
1321 		clk = CLOCK_REALTIME;
1322 	else if (sysfs_streq(buf, "monotonic"))
1323 		clk = CLOCK_MONOTONIC;
1324 	else if (sysfs_streq(buf, "monotonic_raw"))
1325 		clk = CLOCK_MONOTONIC_RAW;
1326 	else if (sysfs_streq(buf, "realtime_coarse"))
1327 		clk = CLOCK_REALTIME_COARSE;
1328 	else if (sysfs_streq(buf, "monotonic_coarse"))
1329 		clk = CLOCK_MONOTONIC_COARSE;
1330 	else if (sysfs_streq(buf, "boottime"))
1331 		clk = CLOCK_BOOTTIME;
1332 	else if (sysfs_streq(buf, "tai"))
1333 		clk = CLOCK_TAI;
1334 	else
1335 		return -EINVAL;
1336 
1337 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1338 	if (ret)
1339 		return ret;
1340 
1341 	return len;
1342 }
1343 
1344 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1345 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1346 
1347 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1348 {
1349 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1350 	struct iio_dev_attr *p;
1351 	struct attribute **attr, *clk = NULL;
1352 
1353 	/* First count elements in any existing group */
1354 	if (indio_dev->info->attrs) {
1355 		attr = indio_dev->info->attrs->attrs;
1356 		while (*attr++ != NULL)
1357 			attrcount_orig++;
1358 	}
1359 	attrcount = attrcount_orig;
1360 	/*
1361 	 * New channel registration method - relies on the fact a group does
1362 	 * not need to be initialized if its name is NULL.
1363 	 */
1364 	if (indio_dev->channels)
1365 		for (i = 0; i < indio_dev->num_channels; i++) {
1366 			const struct iio_chan_spec *chan =
1367 				&indio_dev->channels[i];
1368 
1369 			if (chan->type == IIO_TIMESTAMP)
1370 				clk = &dev_attr_current_timestamp_clock.attr;
1371 
1372 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1373 			if (ret < 0)
1374 				goto error_clear_attrs;
1375 			attrcount += ret;
1376 		}
1377 
1378 	if (indio_dev->event_interface)
1379 		clk = &dev_attr_current_timestamp_clock.attr;
1380 
1381 	if (indio_dev->name)
1382 		attrcount++;
1383 	if (clk)
1384 		attrcount++;
1385 
1386 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1387 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1388 						   GFP_KERNEL);
1389 	if (indio_dev->chan_attr_group.attrs == NULL) {
1390 		ret = -ENOMEM;
1391 		goto error_clear_attrs;
1392 	}
1393 	/* Copy across original attributes */
1394 	if (indio_dev->info->attrs)
1395 		memcpy(indio_dev->chan_attr_group.attrs,
1396 		       indio_dev->info->attrs->attrs,
1397 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1398 		       *attrcount_orig);
1399 	attrn = attrcount_orig;
1400 	/* Add all elements from the list. */
1401 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1402 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1403 	if (indio_dev->name)
1404 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1405 	if (clk)
1406 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1407 
1408 	indio_dev->groups[indio_dev->groupcounter++] =
1409 		&indio_dev->chan_attr_group;
1410 
1411 	return 0;
1412 
1413 error_clear_attrs:
1414 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1415 
1416 	return ret;
1417 }
1418 
1419 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1420 {
1421 
1422 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1423 	kfree(indio_dev->chan_attr_group.attrs);
1424 	indio_dev->chan_attr_group.attrs = NULL;
1425 }
1426 
1427 static void iio_dev_release(struct device *device)
1428 {
1429 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1430 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1431 		iio_device_unregister_trigger_consumer(indio_dev);
1432 	iio_device_unregister_eventset(indio_dev);
1433 	iio_device_unregister_sysfs(indio_dev);
1434 
1435 	iio_buffer_put(indio_dev->buffer);
1436 
1437 	ida_simple_remove(&iio_ida, indio_dev->id);
1438 	kfree(indio_dev);
1439 }
1440 
1441 struct device_type iio_device_type = {
1442 	.name = "iio_device",
1443 	.release = iio_dev_release,
1444 };
1445 
1446 /**
1447  * iio_device_alloc() - allocate an iio_dev from a driver
1448  * @sizeof_priv:	Space to allocate for private structure.
1449  **/
1450 struct iio_dev *iio_device_alloc(int sizeof_priv)
1451 {
1452 	struct iio_dev *dev;
1453 	size_t alloc_size;
1454 
1455 	alloc_size = sizeof(struct iio_dev);
1456 	if (sizeof_priv) {
1457 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1458 		alloc_size += sizeof_priv;
1459 	}
1460 	/* ensure 32-byte alignment of whole construct ? */
1461 	alloc_size += IIO_ALIGN - 1;
1462 
1463 	dev = kzalloc(alloc_size, GFP_KERNEL);
1464 
1465 	if (dev) {
1466 		dev->dev.groups = dev->groups;
1467 		dev->dev.type = &iio_device_type;
1468 		dev->dev.bus = &iio_bus_type;
1469 		device_initialize(&dev->dev);
1470 		dev_set_drvdata(&dev->dev, (void *)dev);
1471 		mutex_init(&dev->mlock);
1472 		mutex_init(&dev->info_exist_lock);
1473 		INIT_LIST_HEAD(&dev->channel_attr_list);
1474 
1475 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1476 		if (dev->id < 0) {
1477 			/* cannot use a dev_err as the name isn't available */
1478 			pr_err("failed to get device id\n");
1479 			kfree(dev);
1480 			return NULL;
1481 		}
1482 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1483 		INIT_LIST_HEAD(&dev->buffer_list);
1484 	}
1485 
1486 	return dev;
1487 }
1488 EXPORT_SYMBOL(iio_device_alloc);
1489 
1490 /**
1491  * iio_device_free() - free an iio_dev from a driver
1492  * @dev:		the iio_dev associated with the device
1493  **/
1494 void iio_device_free(struct iio_dev *dev)
1495 {
1496 	if (dev)
1497 		put_device(&dev->dev);
1498 }
1499 EXPORT_SYMBOL(iio_device_free);
1500 
1501 static void devm_iio_device_release(struct device *dev, void *res)
1502 {
1503 	iio_device_free(*(struct iio_dev **)res);
1504 }
1505 
1506 int devm_iio_device_match(struct device *dev, void *res, void *data)
1507 {
1508 	struct iio_dev **r = res;
1509 	if (!r || !*r) {
1510 		WARN_ON(!r || !*r);
1511 		return 0;
1512 	}
1513 	return *r == data;
1514 }
1515 EXPORT_SYMBOL_GPL(devm_iio_device_match);
1516 
1517 /**
1518  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1519  * @dev:		Device to allocate iio_dev for
1520  * @sizeof_priv:	Space to allocate for private structure.
1521  *
1522  * Managed iio_device_alloc. iio_dev allocated with this function is
1523  * automatically freed on driver detach.
1524  *
1525  * If an iio_dev allocated with this function needs to be freed separately,
1526  * devm_iio_device_free() must be used.
1527  *
1528  * RETURNS:
1529  * Pointer to allocated iio_dev on success, NULL on failure.
1530  */
1531 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1532 {
1533 	struct iio_dev **ptr, *iio_dev;
1534 
1535 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1536 			   GFP_KERNEL);
1537 	if (!ptr)
1538 		return NULL;
1539 
1540 	iio_dev = iio_device_alloc(sizeof_priv);
1541 	if (iio_dev) {
1542 		*ptr = iio_dev;
1543 		devres_add(dev, ptr);
1544 	} else {
1545 		devres_free(ptr);
1546 	}
1547 
1548 	return iio_dev;
1549 }
1550 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1551 
1552 /**
1553  * devm_iio_device_free - Resource-managed iio_device_free()
1554  * @dev:		Device this iio_dev belongs to
1555  * @iio_dev:		the iio_dev associated with the device
1556  *
1557  * Free iio_dev allocated with devm_iio_device_alloc().
1558  */
1559 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1560 {
1561 	int rc;
1562 
1563 	rc = devres_release(dev, devm_iio_device_release,
1564 			    devm_iio_device_match, iio_dev);
1565 	WARN_ON(rc);
1566 }
1567 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1568 
1569 /**
1570  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1571  * @inode:	Inode structure for identifying the device in the file system
1572  * @filp:	File structure for iio device used to keep and later access
1573  *		private data
1574  *
1575  * Return: 0 on success or -EBUSY if the device is already opened
1576  **/
1577 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1578 {
1579 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1580 						struct iio_dev, chrdev);
1581 
1582 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1583 		return -EBUSY;
1584 
1585 	iio_device_get(indio_dev);
1586 
1587 	filp->private_data = indio_dev;
1588 
1589 	return 0;
1590 }
1591 
1592 /**
1593  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1594  * @inode:	Inode structure pointer for the char device
1595  * @filp:	File structure pointer for the char device
1596  *
1597  * Return: 0 for successful release
1598  */
1599 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1600 {
1601 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1602 						struct iio_dev, chrdev);
1603 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1604 	iio_device_put(indio_dev);
1605 
1606 	return 0;
1607 }
1608 
1609 /* Somewhat of a cross file organization violation - ioctls here are actually
1610  * event related */
1611 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1612 {
1613 	struct iio_dev *indio_dev = filp->private_data;
1614 	int __user *ip = (int __user *)arg;
1615 	int fd;
1616 
1617 	if (!indio_dev->info)
1618 		return -ENODEV;
1619 
1620 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1621 		fd = iio_event_getfd(indio_dev);
1622 		if (fd < 0)
1623 			return fd;
1624 		if (copy_to_user(ip, &fd, sizeof(fd)))
1625 			return -EFAULT;
1626 		return 0;
1627 	}
1628 	return -EINVAL;
1629 }
1630 
1631 static const struct file_operations iio_buffer_fileops = {
1632 	.read = iio_buffer_read_first_n_outer_addr,
1633 	.release = iio_chrdev_release,
1634 	.open = iio_chrdev_open,
1635 	.poll = iio_buffer_poll_addr,
1636 	.owner = THIS_MODULE,
1637 	.llseek = noop_llseek,
1638 	.unlocked_ioctl = iio_ioctl,
1639 	.compat_ioctl = iio_ioctl,
1640 };
1641 
1642 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1643 {
1644 	int i, j;
1645 	const struct iio_chan_spec *channels = indio_dev->channels;
1646 
1647 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1648 		return 0;
1649 
1650 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1651 		if (channels[i].scan_index < 0)
1652 			continue;
1653 		for (j = i + 1; j < indio_dev->num_channels; j++)
1654 			if (channels[i].scan_index == channels[j].scan_index) {
1655 				dev_err(&indio_dev->dev,
1656 					"Duplicate scan index %d\n",
1657 					channels[i].scan_index);
1658 				return -EINVAL;
1659 			}
1660 	}
1661 
1662 	return 0;
1663 }
1664 
1665 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1666 
1667 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
1668 {
1669 	int ret;
1670 
1671 	indio_dev->driver_module = this_mod;
1672 	/* If the calling driver did not initialize of_node, do it here */
1673 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1674 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1675 
1676 	ret = iio_check_unique_scan_index(indio_dev);
1677 	if (ret < 0)
1678 		return ret;
1679 
1680 	/* configure elements for the chrdev */
1681 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1682 
1683 	ret = iio_device_register_debugfs(indio_dev);
1684 	if (ret) {
1685 		dev_err(indio_dev->dev.parent,
1686 			"Failed to register debugfs interfaces\n");
1687 		return ret;
1688 	}
1689 
1690 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1691 	if (ret) {
1692 		dev_err(indio_dev->dev.parent,
1693 			"Failed to create buffer sysfs interfaces\n");
1694 		goto error_unreg_debugfs;
1695 	}
1696 
1697 	ret = iio_device_register_sysfs(indio_dev);
1698 	if (ret) {
1699 		dev_err(indio_dev->dev.parent,
1700 			"Failed to register sysfs interfaces\n");
1701 		goto error_buffer_free_sysfs;
1702 	}
1703 	ret = iio_device_register_eventset(indio_dev);
1704 	if (ret) {
1705 		dev_err(indio_dev->dev.parent,
1706 			"Failed to register event set\n");
1707 		goto error_free_sysfs;
1708 	}
1709 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1710 		iio_device_register_trigger_consumer(indio_dev);
1711 
1712 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1713 		indio_dev->setup_ops == NULL)
1714 		indio_dev->setup_ops = &noop_ring_setup_ops;
1715 
1716 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1717 
1718 	indio_dev->chrdev.owner = this_mod;
1719 
1720 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
1721 	if (ret < 0)
1722 		goto error_unreg_eventset;
1723 
1724 	return 0;
1725 
1726 error_unreg_eventset:
1727 	iio_device_unregister_eventset(indio_dev);
1728 error_free_sysfs:
1729 	iio_device_unregister_sysfs(indio_dev);
1730 error_buffer_free_sysfs:
1731 	iio_buffer_free_sysfs_and_mask(indio_dev);
1732 error_unreg_debugfs:
1733 	iio_device_unregister_debugfs(indio_dev);
1734 	return ret;
1735 }
1736 EXPORT_SYMBOL(__iio_device_register);
1737 
1738 /**
1739  * iio_device_unregister() - unregister a device from the IIO subsystem
1740  * @indio_dev:		Device structure representing the device.
1741  **/
1742 void iio_device_unregister(struct iio_dev *indio_dev)
1743 {
1744 	mutex_lock(&indio_dev->info_exist_lock);
1745 
1746 	cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
1747 
1748 	iio_device_unregister_debugfs(indio_dev);
1749 
1750 	iio_disable_all_buffers(indio_dev);
1751 
1752 	indio_dev->info = NULL;
1753 
1754 	iio_device_wakeup_eventset(indio_dev);
1755 	iio_buffer_wakeup_poll(indio_dev);
1756 
1757 	mutex_unlock(&indio_dev->info_exist_lock);
1758 
1759 	iio_buffer_free_sysfs_and_mask(indio_dev);
1760 }
1761 EXPORT_SYMBOL(iio_device_unregister);
1762 
1763 static void devm_iio_device_unreg(struct device *dev, void *res)
1764 {
1765 	iio_device_unregister(*(struct iio_dev **)res);
1766 }
1767 
1768 int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
1769 			       struct module *this_mod)
1770 {
1771 	struct iio_dev **ptr;
1772 	int ret;
1773 
1774 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1775 	if (!ptr)
1776 		return -ENOMEM;
1777 
1778 	*ptr = indio_dev;
1779 	ret = __iio_device_register(indio_dev, this_mod);
1780 	if (!ret)
1781 		devres_add(dev, ptr);
1782 	else
1783 		devres_free(ptr);
1784 
1785 	return ret;
1786 }
1787 EXPORT_SYMBOL_GPL(__devm_iio_device_register);
1788 
1789 /**
1790  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1791  * @dev:	Device this iio_dev belongs to
1792  * @indio_dev:	the iio_dev associated with the device
1793  *
1794  * Unregister iio_dev registered with devm_iio_device_register().
1795  */
1796 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1797 {
1798 	int rc;
1799 
1800 	rc = devres_release(dev, devm_iio_device_unreg,
1801 			    devm_iio_device_match, indio_dev);
1802 	WARN_ON(rc);
1803 }
1804 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1805 
1806 /**
1807  * iio_device_claim_direct_mode - Keep device in direct mode
1808  * @indio_dev:	the iio_dev associated with the device
1809  *
1810  * If the device is in direct mode it is guaranteed to stay
1811  * that way until iio_device_release_direct_mode() is called.
1812  *
1813  * Use with iio_device_release_direct_mode()
1814  *
1815  * Returns: 0 on success, -EBUSY on failure
1816  */
1817 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1818 {
1819 	mutex_lock(&indio_dev->mlock);
1820 
1821 	if (iio_buffer_enabled(indio_dev)) {
1822 		mutex_unlock(&indio_dev->mlock);
1823 		return -EBUSY;
1824 	}
1825 	return 0;
1826 }
1827 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1828 
1829 /**
1830  * iio_device_release_direct_mode - releases claim on direct mode
1831  * @indio_dev:	the iio_dev associated with the device
1832  *
1833  * Release the claim. Device is no longer guaranteed to stay
1834  * in direct mode.
1835  *
1836  * Use with iio_device_claim_direct_mode()
1837  */
1838 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1839 {
1840 	mutex_unlock(&indio_dev->mlock);
1841 }
1842 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1843 
1844 subsys_initcall(iio_init);
1845 module_exit(iio_exit);
1846 
1847 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1848 MODULE_DESCRIPTION("Industrial I/O core");
1849 MODULE_LICENSE("GPL");
1850