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 	[IIO_PHASE] = "phase",
90 	[IIO_MASSCONCENTRATION] = "massconcentration",
91 };
92 
93 static const char * const iio_modifier_names[] = {
94 	[IIO_MOD_X] = "x",
95 	[IIO_MOD_Y] = "y",
96 	[IIO_MOD_Z] = "z",
97 	[IIO_MOD_X_AND_Y] = "x&y",
98 	[IIO_MOD_X_AND_Z] = "x&z",
99 	[IIO_MOD_Y_AND_Z] = "y&z",
100 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
101 	[IIO_MOD_X_OR_Y] = "x|y",
102 	[IIO_MOD_X_OR_Z] = "x|z",
103 	[IIO_MOD_Y_OR_Z] = "y|z",
104 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
105 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
106 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
107 	[IIO_MOD_LIGHT_BOTH] = "both",
108 	[IIO_MOD_LIGHT_IR] = "ir",
109 	[IIO_MOD_LIGHT_CLEAR] = "clear",
110 	[IIO_MOD_LIGHT_RED] = "red",
111 	[IIO_MOD_LIGHT_GREEN] = "green",
112 	[IIO_MOD_LIGHT_BLUE] = "blue",
113 	[IIO_MOD_LIGHT_UV] = "uv",
114 	[IIO_MOD_LIGHT_DUV] = "duv",
115 	[IIO_MOD_QUATERNION] = "quaternion",
116 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
117 	[IIO_MOD_TEMP_OBJECT] = "object",
118 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
119 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
120 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
121 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
122 	[IIO_MOD_RUNNING] = "running",
123 	[IIO_MOD_JOGGING] = "jogging",
124 	[IIO_MOD_WALKING] = "walking",
125 	[IIO_MOD_STILL] = "still",
126 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
127 	[IIO_MOD_I] = "i",
128 	[IIO_MOD_Q] = "q",
129 	[IIO_MOD_CO2] = "co2",
130 	[IIO_MOD_VOC] = "voc",
131 	[IIO_MOD_PM1] = "pm1",
132 	[IIO_MOD_PM2P5] = "pm2p5",
133 	[IIO_MOD_PM4] = "pm4",
134 	[IIO_MOD_PM10] = "pm10",
135 };
136 
137 /* relies on pairs of these shared then separate */
138 static const char * const iio_chan_info_postfix[] = {
139 	[IIO_CHAN_INFO_RAW] = "raw",
140 	[IIO_CHAN_INFO_PROCESSED] = "input",
141 	[IIO_CHAN_INFO_SCALE] = "scale",
142 	[IIO_CHAN_INFO_OFFSET] = "offset",
143 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
144 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
145 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
146 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
147 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
148 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
149 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
150 	= "filter_low_pass_3db_frequency",
151 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
152 	= "filter_high_pass_3db_frequency",
153 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
154 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
155 	[IIO_CHAN_INFO_PHASE] = "phase",
156 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
157 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
158 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
159 	[IIO_CHAN_INFO_ENABLE] = "en",
160 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
161 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
162 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
163 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
164 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
165 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
166 };
167 
168 /**
169  * iio_find_channel_from_si() - get channel from its scan index
170  * @indio_dev:		device
171  * @si:			scan index to match
172  */
173 const struct iio_chan_spec
174 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
175 {
176 	int i;
177 
178 	for (i = 0; i < indio_dev->num_channels; i++)
179 		if (indio_dev->channels[i].scan_index == si)
180 			return &indio_dev->channels[i];
181 	return NULL;
182 }
183 
184 /* This turns up an awful lot */
185 ssize_t iio_read_const_attr(struct device *dev,
186 			    struct device_attribute *attr,
187 			    char *buf)
188 {
189 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
190 }
191 EXPORT_SYMBOL(iio_read_const_attr);
192 
193 static int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
194 {
195 	int ret;
196 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
197 
198 	ret = mutex_lock_interruptible(&indio_dev->mlock);
199 	if (ret)
200 		return ret;
201 	if ((ev_int && iio_event_enabled(ev_int)) ||
202 	    iio_buffer_enabled(indio_dev)) {
203 		mutex_unlock(&indio_dev->mlock);
204 		return -EBUSY;
205 	}
206 	indio_dev->clock_id = clock_id;
207 	mutex_unlock(&indio_dev->mlock);
208 
209 	return 0;
210 }
211 
212 /**
213  * iio_get_time_ns() - utility function to get a time stamp for events etc
214  * @indio_dev: device
215  */
216 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
217 {
218 	struct timespec64 tp;
219 
220 	switch (iio_device_get_clock(indio_dev)) {
221 	case CLOCK_REALTIME:
222 		return ktime_get_real_ns();
223 	case CLOCK_MONOTONIC:
224 		return ktime_get_ns();
225 	case CLOCK_MONOTONIC_RAW:
226 		return ktime_get_raw_ns();
227 	case CLOCK_REALTIME_COARSE:
228 		return ktime_to_ns(ktime_get_coarse_real());
229 	case CLOCK_MONOTONIC_COARSE:
230 		ktime_get_coarse_ts64(&tp);
231 		return timespec64_to_ns(&tp);
232 	case CLOCK_BOOTTIME:
233 		return ktime_get_boot_ns();
234 	case CLOCK_TAI:
235 		return ktime_get_tai_ns();
236 	default:
237 		BUG();
238 	}
239 }
240 EXPORT_SYMBOL(iio_get_time_ns);
241 
242 /**
243  * iio_get_time_res() - utility function to get time stamp clock resolution in
244  *                      nano seconds.
245  * @indio_dev: device
246  */
247 unsigned int iio_get_time_res(const struct iio_dev *indio_dev)
248 {
249 	switch (iio_device_get_clock(indio_dev)) {
250 	case CLOCK_REALTIME:
251 	case CLOCK_MONOTONIC:
252 	case CLOCK_MONOTONIC_RAW:
253 	case CLOCK_BOOTTIME:
254 	case CLOCK_TAI:
255 		return hrtimer_resolution;
256 	case CLOCK_REALTIME_COARSE:
257 	case CLOCK_MONOTONIC_COARSE:
258 		return LOW_RES_NSEC;
259 	default:
260 		BUG();
261 	}
262 }
263 EXPORT_SYMBOL(iio_get_time_res);
264 
265 static int __init iio_init(void)
266 {
267 	int ret;
268 
269 	/* Register sysfs bus */
270 	ret  = bus_register(&iio_bus_type);
271 	if (ret < 0) {
272 		pr_err("could not register bus type\n");
273 		goto error_nothing;
274 	}
275 
276 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
277 	if (ret < 0) {
278 		pr_err("failed to allocate char dev region\n");
279 		goto error_unregister_bus_type;
280 	}
281 
282 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
283 
284 	return 0;
285 
286 error_unregister_bus_type:
287 	bus_unregister(&iio_bus_type);
288 error_nothing:
289 	return ret;
290 }
291 
292 static void __exit iio_exit(void)
293 {
294 	if (iio_devt)
295 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
296 	bus_unregister(&iio_bus_type);
297 	debugfs_remove(iio_debugfs_dentry);
298 }
299 
300 #if defined(CONFIG_DEBUG_FS)
301 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
302 			      size_t count, loff_t *ppos)
303 {
304 	struct iio_dev *indio_dev = file->private_data;
305 	char buf[20];
306 	unsigned val = 0;
307 	ssize_t len;
308 	int ret;
309 
310 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
311 						  indio_dev->cached_reg_addr,
312 						  0, &val);
313 	if (ret) {
314 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
315 		return ret;
316 	}
317 
318 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
319 
320 	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
321 }
322 
323 static ssize_t iio_debugfs_write_reg(struct file *file,
324 		     const char __user *userbuf, size_t count, loff_t *ppos)
325 {
326 	struct iio_dev *indio_dev = file->private_data;
327 	unsigned reg, val;
328 	char buf[80];
329 	int ret;
330 
331 	count = min_t(size_t, count, (sizeof(buf)-1));
332 	if (copy_from_user(buf, userbuf, count))
333 		return -EFAULT;
334 
335 	buf[count] = 0;
336 
337 	ret = sscanf(buf, "%i %i", &reg, &val);
338 
339 	switch (ret) {
340 	case 1:
341 		indio_dev->cached_reg_addr = reg;
342 		break;
343 	case 2:
344 		indio_dev->cached_reg_addr = reg;
345 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
346 							  val, NULL);
347 		if (ret) {
348 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
349 				__func__);
350 			return ret;
351 		}
352 		break;
353 	default:
354 		return -EINVAL;
355 	}
356 
357 	return count;
358 }
359 
360 static const struct file_operations iio_debugfs_reg_fops = {
361 	.open = simple_open,
362 	.read = iio_debugfs_read_reg,
363 	.write = iio_debugfs_write_reg,
364 };
365 
366 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
367 {
368 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
369 }
370 
371 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
372 {
373 	struct dentry *d;
374 
375 	if (indio_dev->info->debugfs_reg_access == NULL)
376 		return 0;
377 
378 	if (!iio_debugfs_dentry)
379 		return 0;
380 
381 	indio_dev->debugfs_dentry =
382 		debugfs_create_dir(dev_name(&indio_dev->dev),
383 				   iio_debugfs_dentry);
384 	if (indio_dev->debugfs_dentry == NULL) {
385 		dev_warn(indio_dev->dev.parent,
386 			 "Failed to create debugfs directory\n");
387 		return -EFAULT;
388 	}
389 
390 	d = debugfs_create_file("direct_reg_access", 0644,
391 				indio_dev->debugfs_dentry,
392 				indio_dev, &iio_debugfs_reg_fops);
393 	if (!d) {
394 		iio_device_unregister_debugfs(indio_dev);
395 		return -ENOMEM;
396 	}
397 
398 	return 0;
399 }
400 #else
401 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
402 {
403 	return 0;
404 }
405 
406 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
407 {
408 }
409 #endif /* CONFIG_DEBUG_FS */
410 
411 static ssize_t iio_read_channel_ext_info(struct device *dev,
412 				     struct device_attribute *attr,
413 				     char *buf)
414 {
415 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
416 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
417 	const struct iio_chan_spec_ext_info *ext_info;
418 
419 	ext_info = &this_attr->c->ext_info[this_attr->address];
420 
421 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
422 }
423 
424 static ssize_t iio_write_channel_ext_info(struct device *dev,
425 				     struct device_attribute *attr,
426 				     const char *buf,
427 					 size_t len)
428 {
429 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
430 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
431 	const struct iio_chan_spec_ext_info *ext_info;
432 
433 	ext_info = &this_attr->c->ext_info[this_attr->address];
434 
435 	return ext_info->write(indio_dev, ext_info->private,
436 			       this_attr->c, buf, len);
437 }
438 
439 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
440 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
441 {
442 	const struct iio_enum *e = (const struct iio_enum *)priv;
443 	unsigned int i;
444 	size_t len = 0;
445 
446 	if (!e->num_items)
447 		return 0;
448 
449 	for (i = 0; i < e->num_items; ++i)
450 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
451 
452 	/* replace last space with a newline */
453 	buf[len - 1] = '\n';
454 
455 	return len;
456 }
457 EXPORT_SYMBOL_GPL(iio_enum_available_read);
458 
459 ssize_t iio_enum_read(struct iio_dev *indio_dev,
460 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
461 {
462 	const struct iio_enum *e = (const struct iio_enum *)priv;
463 	int i;
464 
465 	if (!e->get)
466 		return -EINVAL;
467 
468 	i = e->get(indio_dev, chan);
469 	if (i < 0)
470 		return i;
471 	else if (i >= e->num_items)
472 		return -EINVAL;
473 
474 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
475 }
476 EXPORT_SYMBOL_GPL(iio_enum_read);
477 
478 ssize_t iio_enum_write(struct iio_dev *indio_dev,
479 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
480 	size_t len)
481 {
482 	const struct iio_enum *e = (const struct iio_enum *)priv;
483 	int ret;
484 
485 	if (!e->set)
486 		return -EINVAL;
487 
488 	ret = __sysfs_match_string(e->items, e->num_items, buf);
489 	if (ret < 0)
490 		return ret;
491 
492 	ret = e->set(indio_dev, chan, ret);
493 	return ret ? ret : len;
494 }
495 EXPORT_SYMBOL_GPL(iio_enum_write);
496 
497 static const struct iio_mount_matrix iio_mount_idmatrix = {
498 	.rotation = {
499 		"1", "0", "0",
500 		"0", "1", "0",
501 		"0", "0", "1"
502 	}
503 };
504 
505 static int iio_setup_mount_idmatrix(const struct device *dev,
506 				    struct iio_mount_matrix *matrix)
507 {
508 	*matrix = iio_mount_idmatrix;
509 	dev_info(dev, "mounting matrix not found: using identity...\n");
510 	return 0;
511 }
512 
513 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
514 			      const struct iio_chan_spec *chan, char *buf)
515 {
516 	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
517 					      priv)(indio_dev, chan);
518 
519 	if (IS_ERR(mtx))
520 		return PTR_ERR(mtx);
521 
522 	if (!mtx)
523 		mtx = &iio_mount_idmatrix;
524 
525 	return snprintf(buf, PAGE_SIZE, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
526 			mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
527 			mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
528 			mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
529 }
530 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
531 
532 /**
533  * of_iio_read_mount_matrix() - retrieve iio device mounting matrix from
534  *                              device-tree "mount-matrix" property
535  * @dev:	device the mounting matrix property is assigned to
536  * @propname:	device specific mounting matrix property name
537  * @matrix:	where to store retrieved matrix
538  *
539  * If device is assigned no mounting matrix property, a default 3x3 identity
540  * matrix will be filled in.
541  *
542  * Return: 0 if success, or a negative error code on failure.
543  */
544 #ifdef CONFIG_OF
545 int of_iio_read_mount_matrix(const struct device *dev,
546 			     const char *propname,
547 			     struct iio_mount_matrix *matrix)
548 {
549 	if (dev->of_node) {
550 		int err = of_property_read_string_array(dev->of_node,
551 				propname, matrix->rotation,
552 				ARRAY_SIZE(iio_mount_idmatrix.rotation));
553 
554 		if (err == ARRAY_SIZE(iio_mount_idmatrix.rotation))
555 			return 0;
556 
557 		if (err >= 0)
558 			/* Invalid number of matrix entries. */
559 			return -EINVAL;
560 
561 		if (err != -EINVAL)
562 			/* Invalid matrix declaration format. */
563 			return err;
564 	}
565 
566 	/* Matrix was not declared at all: fallback to identity. */
567 	return iio_setup_mount_idmatrix(dev, matrix);
568 }
569 #else
570 int of_iio_read_mount_matrix(const struct device *dev,
571 			     const char *propname,
572 			     struct iio_mount_matrix *matrix)
573 {
574 	return iio_setup_mount_idmatrix(dev, matrix);
575 }
576 #endif
577 EXPORT_SYMBOL(of_iio_read_mount_matrix);
578 
579 static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
580 				  int size, const int *vals)
581 {
582 	unsigned long long tmp;
583 	int tmp0, tmp1;
584 	bool scale_db = false;
585 
586 	switch (type) {
587 	case IIO_VAL_INT:
588 		return snprintf(buf, len, "%d", vals[0]);
589 	case IIO_VAL_INT_PLUS_MICRO_DB:
590 		scale_db = true;
591 		/* fall through */
592 	case IIO_VAL_INT_PLUS_MICRO:
593 		if (vals[1] < 0)
594 			return snprintf(buf, len, "-%d.%06u%s", abs(vals[0]),
595 					-vals[1], scale_db ? " dB" : "");
596 		else
597 			return snprintf(buf, len, "%d.%06u%s", vals[0], vals[1],
598 					scale_db ? " dB" : "");
599 	case IIO_VAL_INT_PLUS_NANO:
600 		if (vals[1] < 0)
601 			return snprintf(buf, len, "-%d.%09u", abs(vals[0]),
602 					-vals[1]);
603 		else
604 			return snprintf(buf, len, "%d.%09u", vals[0], vals[1]);
605 	case IIO_VAL_FRACTIONAL:
606 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
607 		tmp1 = vals[1];
608 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
609 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
610 	case IIO_VAL_FRACTIONAL_LOG2:
611 		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
612 		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
613 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
614 	case IIO_VAL_INT_MULTIPLE:
615 	{
616 		int i;
617 		int l = 0;
618 
619 		for (i = 0; i < size; ++i) {
620 			l += snprintf(&buf[l], len - l, "%d ", vals[i]);
621 			if (l >= len)
622 				break;
623 		}
624 		return l;
625 	}
626 	default:
627 		return 0;
628 	}
629 }
630 
631 /**
632  * iio_format_value() - Formats a IIO value into its string representation
633  * @buf:	The buffer to which the formatted value gets written
634  *		which is assumed to be big enough (i.e. PAGE_SIZE).
635  * @type:	One of the IIO_VAL_* constants. This decides how the val
636  *		and val2 parameters are formatted.
637  * @size:	Number of IIO value entries contained in vals
638  * @vals:	Pointer to the values, exact meaning depends on the
639  *		type parameter.
640  *
641  * Return: 0 by default, a negative number on failure or the
642  *	   total number of characters written for a type that belongs
643  *	   to the IIO_VAL_* constant.
644  */
645 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
646 {
647 	ssize_t len;
648 
649 	len = __iio_format_value(buf, PAGE_SIZE, type, size, vals);
650 	if (len >= PAGE_SIZE - 1)
651 		return -EFBIG;
652 
653 	return len + sprintf(buf + len, "\n");
654 }
655 EXPORT_SYMBOL_GPL(iio_format_value);
656 
657 static ssize_t iio_read_channel_info(struct device *dev,
658 				     struct device_attribute *attr,
659 				     char *buf)
660 {
661 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
662 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
663 	int vals[INDIO_MAX_RAW_ELEMENTS];
664 	int ret;
665 	int val_len = 2;
666 
667 	if (indio_dev->info->read_raw_multi)
668 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
669 							INDIO_MAX_RAW_ELEMENTS,
670 							vals, &val_len,
671 							this_attr->address);
672 	else
673 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
674 				    &vals[0], &vals[1], this_attr->address);
675 
676 	if (ret < 0)
677 		return ret;
678 
679 	return iio_format_value(buf, ret, val_len, vals);
680 }
681 
682 static ssize_t iio_format_avail_list(char *buf, const int *vals,
683 				     int type, int length)
684 {
685 	int i;
686 	ssize_t len = 0;
687 
688 	switch (type) {
689 	case IIO_VAL_INT:
690 		for (i = 0; i < length; i++) {
691 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
692 						  type, 1, &vals[i]);
693 			if (len >= PAGE_SIZE)
694 				return -EFBIG;
695 			if (i < length - 1)
696 				len += snprintf(buf + len, PAGE_SIZE - len,
697 						" ");
698 			else
699 				len += snprintf(buf + len, PAGE_SIZE - len,
700 						"\n");
701 			if (len >= PAGE_SIZE)
702 				return -EFBIG;
703 		}
704 		break;
705 	default:
706 		for (i = 0; i < length / 2; i++) {
707 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
708 						  type, 2, &vals[i * 2]);
709 			if (len >= PAGE_SIZE)
710 				return -EFBIG;
711 			if (i < length / 2 - 1)
712 				len += snprintf(buf + len, PAGE_SIZE - len,
713 						" ");
714 			else
715 				len += snprintf(buf + len, PAGE_SIZE - len,
716 						"\n");
717 			if (len >= PAGE_SIZE)
718 				return -EFBIG;
719 		}
720 	}
721 
722 	return len;
723 }
724 
725 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
726 {
727 	int i;
728 	ssize_t len;
729 
730 	len = snprintf(buf, PAGE_SIZE, "[");
731 	switch (type) {
732 	case IIO_VAL_INT:
733 		for (i = 0; i < 3; i++) {
734 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
735 						  type, 1, &vals[i]);
736 			if (len >= PAGE_SIZE)
737 				return -EFBIG;
738 			if (i < 2)
739 				len += snprintf(buf + len, PAGE_SIZE - len,
740 						" ");
741 			else
742 				len += snprintf(buf + len, PAGE_SIZE - len,
743 						"]\n");
744 			if (len >= PAGE_SIZE)
745 				return -EFBIG;
746 		}
747 		break;
748 	default:
749 		for (i = 0; i < 3; i++) {
750 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
751 						  type, 2, &vals[i * 2]);
752 			if (len >= PAGE_SIZE)
753 				return -EFBIG;
754 			if (i < 2)
755 				len += snprintf(buf + len, PAGE_SIZE - len,
756 						" ");
757 			else
758 				len += snprintf(buf + len, PAGE_SIZE - len,
759 						"]\n");
760 			if (len >= PAGE_SIZE)
761 				return -EFBIG;
762 		}
763 	}
764 
765 	return len;
766 }
767 
768 static ssize_t iio_read_channel_info_avail(struct device *dev,
769 					   struct device_attribute *attr,
770 					   char *buf)
771 {
772 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
773 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
774 	const int *vals;
775 	int ret;
776 	int length;
777 	int type;
778 
779 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
780 					  &vals, &type, &length,
781 					  this_attr->address);
782 
783 	if (ret < 0)
784 		return ret;
785 	switch (ret) {
786 	case IIO_AVAIL_LIST:
787 		return iio_format_avail_list(buf, vals, type, length);
788 	case IIO_AVAIL_RANGE:
789 		return iio_format_avail_range(buf, vals, type);
790 	default:
791 		return -EINVAL;
792 	}
793 }
794 
795 /**
796  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
797  * @str: The string to parse
798  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
799  * @integer: The integer part of the number
800  * @fract: The fractional part of the number
801  *
802  * Returns 0 on success, or a negative error code if the string could not be
803  * parsed.
804  */
805 int iio_str_to_fixpoint(const char *str, int fract_mult,
806 	int *integer, int *fract)
807 {
808 	int i = 0, f = 0;
809 	bool integer_part = true, negative = false;
810 
811 	if (fract_mult == 0) {
812 		*fract = 0;
813 
814 		return kstrtoint(str, 0, integer);
815 	}
816 
817 	if (str[0] == '-') {
818 		negative = true;
819 		str++;
820 	} else if (str[0] == '+') {
821 		str++;
822 	}
823 
824 	while (*str) {
825 		if ('0' <= *str && *str <= '9') {
826 			if (integer_part) {
827 				i = i * 10 + *str - '0';
828 			} else {
829 				f += fract_mult * (*str - '0');
830 				fract_mult /= 10;
831 			}
832 		} else if (*str == '\n') {
833 			if (*(str + 1) == '\0')
834 				break;
835 			else
836 				return -EINVAL;
837 		} else if (*str == '.' && integer_part) {
838 			integer_part = false;
839 		} else {
840 			return -EINVAL;
841 		}
842 		str++;
843 	}
844 
845 	if (negative) {
846 		if (i)
847 			i = -i;
848 		else
849 			f = -f;
850 	}
851 
852 	*integer = i;
853 	*fract = f;
854 
855 	return 0;
856 }
857 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
858 
859 static ssize_t iio_write_channel_info(struct device *dev,
860 				      struct device_attribute *attr,
861 				      const char *buf,
862 				      size_t len)
863 {
864 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
865 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
866 	int ret, fract_mult = 100000;
867 	int integer, fract;
868 
869 	/* Assumes decimal - precision based on number of digits */
870 	if (!indio_dev->info->write_raw)
871 		return -EINVAL;
872 
873 	if (indio_dev->info->write_raw_get_fmt)
874 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
875 			this_attr->c, this_attr->address)) {
876 		case IIO_VAL_INT:
877 			fract_mult = 0;
878 			break;
879 		case IIO_VAL_INT_PLUS_MICRO:
880 			fract_mult = 100000;
881 			break;
882 		case IIO_VAL_INT_PLUS_NANO:
883 			fract_mult = 100000000;
884 			break;
885 		default:
886 			return -EINVAL;
887 		}
888 
889 	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
890 	if (ret)
891 		return ret;
892 
893 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
894 					 integer, fract, this_attr->address);
895 	if (ret)
896 		return ret;
897 
898 	return len;
899 }
900 
901 static
902 int __iio_device_attr_init(struct device_attribute *dev_attr,
903 			   const char *postfix,
904 			   struct iio_chan_spec const *chan,
905 			   ssize_t (*readfunc)(struct device *dev,
906 					       struct device_attribute *attr,
907 					       char *buf),
908 			   ssize_t (*writefunc)(struct device *dev,
909 						struct device_attribute *attr,
910 						const char *buf,
911 						size_t len),
912 			   enum iio_shared_by shared_by)
913 {
914 	int ret = 0;
915 	char *name = NULL;
916 	char *full_postfix;
917 	sysfs_attr_init(&dev_attr->attr);
918 
919 	/* Build up postfix of <extend_name>_<modifier>_postfix */
920 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
921 		if (chan->extend_name)
922 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
923 						 iio_modifier_names[chan
924 								    ->channel2],
925 						 chan->extend_name,
926 						 postfix);
927 		else
928 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
929 						 iio_modifier_names[chan
930 								    ->channel2],
931 						 postfix);
932 	} else {
933 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
934 			full_postfix = kstrdup(postfix, GFP_KERNEL);
935 		else
936 			full_postfix = kasprintf(GFP_KERNEL,
937 						 "%s_%s",
938 						 chan->extend_name,
939 						 postfix);
940 	}
941 	if (full_postfix == NULL)
942 		return -ENOMEM;
943 
944 	if (chan->differential) { /* Differential can not have modifier */
945 		switch (shared_by) {
946 		case IIO_SHARED_BY_ALL:
947 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
948 			break;
949 		case IIO_SHARED_BY_DIR:
950 			name = kasprintf(GFP_KERNEL, "%s_%s",
951 						iio_direction[chan->output],
952 						full_postfix);
953 			break;
954 		case IIO_SHARED_BY_TYPE:
955 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
956 					    iio_direction[chan->output],
957 					    iio_chan_type_name_spec[chan->type],
958 					    iio_chan_type_name_spec[chan->type],
959 					    full_postfix);
960 			break;
961 		case IIO_SEPARATE:
962 			if (!chan->indexed) {
963 				WARN(1, "Differential channels must be indexed\n");
964 				ret = -EINVAL;
965 				goto error_free_full_postfix;
966 			}
967 			name = kasprintf(GFP_KERNEL,
968 					    "%s_%s%d-%s%d_%s",
969 					    iio_direction[chan->output],
970 					    iio_chan_type_name_spec[chan->type],
971 					    chan->channel,
972 					    iio_chan_type_name_spec[chan->type],
973 					    chan->channel2,
974 					    full_postfix);
975 			break;
976 		}
977 	} else { /* Single ended */
978 		switch (shared_by) {
979 		case IIO_SHARED_BY_ALL:
980 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
981 			break;
982 		case IIO_SHARED_BY_DIR:
983 			name = kasprintf(GFP_KERNEL, "%s_%s",
984 						iio_direction[chan->output],
985 						full_postfix);
986 			break;
987 		case IIO_SHARED_BY_TYPE:
988 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
989 					    iio_direction[chan->output],
990 					    iio_chan_type_name_spec[chan->type],
991 					    full_postfix);
992 			break;
993 
994 		case IIO_SEPARATE:
995 			if (chan->indexed)
996 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
997 						    iio_direction[chan->output],
998 						    iio_chan_type_name_spec[chan->type],
999 						    chan->channel,
1000 						    full_postfix);
1001 			else
1002 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1003 						    iio_direction[chan->output],
1004 						    iio_chan_type_name_spec[chan->type],
1005 						    full_postfix);
1006 			break;
1007 		}
1008 	}
1009 	if (name == NULL) {
1010 		ret = -ENOMEM;
1011 		goto error_free_full_postfix;
1012 	}
1013 	dev_attr->attr.name = name;
1014 
1015 	if (readfunc) {
1016 		dev_attr->attr.mode |= S_IRUGO;
1017 		dev_attr->show = readfunc;
1018 	}
1019 
1020 	if (writefunc) {
1021 		dev_attr->attr.mode |= S_IWUSR;
1022 		dev_attr->store = writefunc;
1023 	}
1024 
1025 error_free_full_postfix:
1026 	kfree(full_postfix);
1027 
1028 	return ret;
1029 }
1030 
1031 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1032 {
1033 	kfree(dev_attr->attr.name);
1034 }
1035 
1036 int __iio_add_chan_devattr(const char *postfix,
1037 			   struct iio_chan_spec const *chan,
1038 			   ssize_t (*readfunc)(struct device *dev,
1039 					       struct device_attribute *attr,
1040 					       char *buf),
1041 			   ssize_t (*writefunc)(struct device *dev,
1042 						struct device_attribute *attr,
1043 						const char *buf,
1044 						size_t len),
1045 			   u64 mask,
1046 			   enum iio_shared_by shared_by,
1047 			   struct device *dev,
1048 			   struct list_head *attr_list)
1049 {
1050 	int ret;
1051 	struct iio_dev_attr *iio_attr, *t;
1052 
1053 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1054 	if (iio_attr == NULL)
1055 		return -ENOMEM;
1056 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1057 				     postfix, chan,
1058 				     readfunc, writefunc, shared_by);
1059 	if (ret)
1060 		goto error_iio_dev_attr_free;
1061 	iio_attr->c = chan;
1062 	iio_attr->address = mask;
1063 	list_for_each_entry(t, attr_list, l)
1064 		if (strcmp(t->dev_attr.attr.name,
1065 			   iio_attr->dev_attr.attr.name) == 0) {
1066 			if (shared_by == IIO_SEPARATE)
1067 				dev_err(dev, "tried to double register : %s\n",
1068 					t->dev_attr.attr.name);
1069 			ret = -EBUSY;
1070 			goto error_device_attr_deinit;
1071 		}
1072 	list_add(&iio_attr->l, attr_list);
1073 
1074 	return 0;
1075 
1076 error_device_attr_deinit:
1077 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1078 error_iio_dev_attr_free:
1079 	kfree(iio_attr);
1080 	return ret;
1081 }
1082 
1083 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1084 					 struct iio_chan_spec const *chan,
1085 					 enum iio_shared_by shared_by,
1086 					 const long *infomask)
1087 {
1088 	int i, ret, attrcount = 0;
1089 
1090 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1091 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1092 			return -EINVAL;
1093 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1094 					     chan,
1095 					     &iio_read_channel_info,
1096 					     &iio_write_channel_info,
1097 					     i,
1098 					     shared_by,
1099 					     &indio_dev->dev,
1100 					     &indio_dev->channel_attr_list);
1101 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1102 			continue;
1103 		else if (ret < 0)
1104 			return ret;
1105 		attrcount++;
1106 	}
1107 
1108 	return attrcount;
1109 }
1110 
1111 static int iio_device_add_info_mask_type_avail(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 	char *avail_postfix;
1118 
1119 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1120 		avail_postfix = kasprintf(GFP_KERNEL,
1121 					  "%s_available",
1122 					  iio_chan_info_postfix[i]);
1123 		if (!avail_postfix)
1124 			return -ENOMEM;
1125 
1126 		ret = __iio_add_chan_devattr(avail_postfix,
1127 					     chan,
1128 					     &iio_read_channel_info_avail,
1129 					     NULL,
1130 					     i,
1131 					     shared_by,
1132 					     &indio_dev->dev,
1133 					     &indio_dev->channel_attr_list);
1134 		kfree(avail_postfix);
1135 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1136 			continue;
1137 		else if (ret < 0)
1138 			return ret;
1139 		attrcount++;
1140 	}
1141 
1142 	return attrcount;
1143 }
1144 
1145 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1146 					struct iio_chan_spec const *chan)
1147 {
1148 	int ret, attrcount = 0;
1149 	const struct iio_chan_spec_ext_info *ext_info;
1150 
1151 	if (chan->channel < 0)
1152 		return 0;
1153 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1154 					    IIO_SEPARATE,
1155 					    &chan->info_mask_separate);
1156 	if (ret < 0)
1157 		return ret;
1158 	attrcount += ret;
1159 
1160 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1161 						  IIO_SEPARATE,
1162 						  &chan->
1163 						  info_mask_separate_available);
1164 	if (ret < 0)
1165 		return ret;
1166 	attrcount += ret;
1167 
1168 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1169 					    IIO_SHARED_BY_TYPE,
1170 					    &chan->info_mask_shared_by_type);
1171 	if (ret < 0)
1172 		return ret;
1173 	attrcount += ret;
1174 
1175 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1176 						  IIO_SHARED_BY_TYPE,
1177 						  &chan->
1178 						  info_mask_shared_by_type_available);
1179 	if (ret < 0)
1180 		return ret;
1181 	attrcount += ret;
1182 
1183 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1184 					    IIO_SHARED_BY_DIR,
1185 					    &chan->info_mask_shared_by_dir);
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_SHARED_BY_DIR,
1192 						  &chan->info_mask_shared_by_dir_available);
1193 	if (ret < 0)
1194 		return ret;
1195 	attrcount += ret;
1196 
1197 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1198 					    IIO_SHARED_BY_ALL,
1199 					    &chan->info_mask_shared_by_all);
1200 	if (ret < 0)
1201 		return ret;
1202 	attrcount += ret;
1203 
1204 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1205 						  IIO_SHARED_BY_ALL,
1206 						  &chan->info_mask_shared_by_all_available);
1207 	if (ret < 0)
1208 		return ret;
1209 	attrcount += ret;
1210 
1211 	if (chan->ext_info) {
1212 		unsigned int i = 0;
1213 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1214 			ret = __iio_add_chan_devattr(ext_info->name,
1215 					chan,
1216 					ext_info->read ?
1217 					    &iio_read_channel_ext_info : NULL,
1218 					ext_info->write ?
1219 					    &iio_write_channel_ext_info : NULL,
1220 					i,
1221 					ext_info->shared,
1222 					&indio_dev->dev,
1223 					&indio_dev->channel_attr_list);
1224 			i++;
1225 			if (ret == -EBUSY && ext_info->shared)
1226 				continue;
1227 
1228 			if (ret)
1229 				return ret;
1230 
1231 			attrcount++;
1232 		}
1233 	}
1234 
1235 	return attrcount;
1236 }
1237 
1238 /**
1239  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1240  * @attr_list: List of IIO device attributes
1241  *
1242  * This function frees the memory allocated for each of the IIO device
1243  * attributes in the list.
1244  */
1245 void iio_free_chan_devattr_list(struct list_head *attr_list)
1246 {
1247 	struct iio_dev_attr *p, *n;
1248 
1249 	list_for_each_entry_safe(p, n, attr_list, l) {
1250 		kfree(p->dev_attr.attr.name);
1251 		list_del(&p->l);
1252 		kfree(p);
1253 	}
1254 }
1255 
1256 static ssize_t iio_show_dev_name(struct device *dev,
1257 				 struct device_attribute *attr,
1258 				 char *buf)
1259 {
1260 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1261 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1262 }
1263 
1264 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1265 
1266 static ssize_t iio_show_timestamp_clock(struct device *dev,
1267 					struct device_attribute *attr,
1268 					char *buf)
1269 {
1270 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1271 	const clockid_t clk = iio_device_get_clock(indio_dev);
1272 	const char *name;
1273 	ssize_t sz;
1274 
1275 	switch (clk) {
1276 	case CLOCK_REALTIME:
1277 		name = "realtime\n";
1278 		sz = sizeof("realtime\n");
1279 		break;
1280 	case CLOCK_MONOTONIC:
1281 		name = "monotonic\n";
1282 		sz = sizeof("monotonic\n");
1283 		break;
1284 	case CLOCK_MONOTONIC_RAW:
1285 		name = "monotonic_raw\n";
1286 		sz = sizeof("monotonic_raw\n");
1287 		break;
1288 	case CLOCK_REALTIME_COARSE:
1289 		name = "realtime_coarse\n";
1290 		sz = sizeof("realtime_coarse\n");
1291 		break;
1292 	case CLOCK_MONOTONIC_COARSE:
1293 		name = "monotonic_coarse\n";
1294 		sz = sizeof("monotonic_coarse\n");
1295 		break;
1296 	case CLOCK_BOOTTIME:
1297 		name = "boottime\n";
1298 		sz = sizeof("boottime\n");
1299 		break;
1300 	case CLOCK_TAI:
1301 		name = "tai\n";
1302 		sz = sizeof("tai\n");
1303 		break;
1304 	default:
1305 		BUG();
1306 	}
1307 
1308 	memcpy(buf, name, sz);
1309 	return sz;
1310 }
1311 
1312 static ssize_t iio_store_timestamp_clock(struct device *dev,
1313 					 struct device_attribute *attr,
1314 					 const char *buf, size_t len)
1315 {
1316 	clockid_t clk;
1317 	int ret;
1318 
1319 	if (sysfs_streq(buf, "realtime"))
1320 		clk = CLOCK_REALTIME;
1321 	else if (sysfs_streq(buf, "monotonic"))
1322 		clk = CLOCK_MONOTONIC;
1323 	else if (sysfs_streq(buf, "monotonic_raw"))
1324 		clk = CLOCK_MONOTONIC_RAW;
1325 	else if (sysfs_streq(buf, "realtime_coarse"))
1326 		clk = CLOCK_REALTIME_COARSE;
1327 	else if (sysfs_streq(buf, "monotonic_coarse"))
1328 		clk = CLOCK_MONOTONIC_COARSE;
1329 	else if (sysfs_streq(buf, "boottime"))
1330 		clk = CLOCK_BOOTTIME;
1331 	else if (sysfs_streq(buf, "tai"))
1332 		clk = CLOCK_TAI;
1333 	else
1334 		return -EINVAL;
1335 
1336 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1337 	if (ret)
1338 		return ret;
1339 
1340 	return len;
1341 }
1342 
1343 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1344 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1345 
1346 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1347 {
1348 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1349 	struct iio_dev_attr *p;
1350 	struct attribute **attr, *clk = NULL;
1351 
1352 	/* First count elements in any existing group */
1353 	if (indio_dev->info->attrs) {
1354 		attr = indio_dev->info->attrs->attrs;
1355 		while (*attr++ != NULL)
1356 			attrcount_orig++;
1357 	}
1358 	attrcount = attrcount_orig;
1359 	/*
1360 	 * New channel registration method - relies on the fact a group does
1361 	 * not need to be initialized if its name is NULL.
1362 	 */
1363 	if (indio_dev->channels)
1364 		for (i = 0; i < indio_dev->num_channels; i++) {
1365 			const struct iio_chan_spec *chan =
1366 				&indio_dev->channels[i];
1367 
1368 			if (chan->type == IIO_TIMESTAMP)
1369 				clk = &dev_attr_current_timestamp_clock.attr;
1370 
1371 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1372 			if (ret < 0)
1373 				goto error_clear_attrs;
1374 			attrcount += ret;
1375 		}
1376 
1377 	if (indio_dev->event_interface)
1378 		clk = &dev_attr_current_timestamp_clock.attr;
1379 
1380 	if (indio_dev->name)
1381 		attrcount++;
1382 	if (clk)
1383 		attrcount++;
1384 
1385 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1386 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1387 						   GFP_KERNEL);
1388 	if (indio_dev->chan_attr_group.attrs == NULL) {
1389 		ret = -ENOMEM;
1390 		goto error_clear_attrs;
1391 	}
1392 	/* Copy across original attributes */
1393 	if (indio_dev->info->attrs)
1394 		memcpy(indio_dev->chan_attr_group.attrs,
1395 		       indio_dev->info->attrs->attrs,
1396 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1397 		       *attrcount_orig);
1398 	attrn = attrcount_orig;
1399 	/* Add all elements from the list. */
1400 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1401 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1402 	if (indio_dev->name)
1403 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1404 	if (clk)
1405 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1406 
1407 	indio_dev->groups[indio_dev->groupcounter++] =
1408 		&indio_dev->chan_attr_group;
1409 
1410 	return 0;
1411 
1412 error_clear_attrs:
1413 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1414 
1415 	return ret;
1416 }
1417 
1418 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1419 {
1420 
1421 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1422 	kfree(indio_dev->chan_attr_group.attrs);
1423 	indio_dev->chan_attr_group.attrs = NULL;
1424 }
1425 
1426 static void iio_dev_release(struct device *device)
1427 {
1428 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1429 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1430 		iio_device_unregister_trigger_consumer(indio_dev);
1431 	iio_device_unregister_eventset(indio_dev);
1432 	iio_device_unregister_sysfs(indio_dev);
1433 
1434 	iio_buffer_put(indio_dev->buffer);
1435 
1436 	ida_simple_remove(&iio_ida, indio_dev->id);
1437 	kfree(indio_dev);
1438 }
1439 
1440 struct device_type iio_device_type = {
1441 	.name = "iio_device",
1442 	.release = iio_dev_release,
1443 };
1444 
1445 /**
1446  * iio_device_alloc() - allocate an iio_dev from a driver
1447  * @sizeof_priv:	Space to allocate for private structure.
1448  **/
1449 struct iio_dev *iio_device_alloc(int sizeof_priv)
1450 {
1451 	struct iio_dev *dev;
1452 	size_t alloc_size;
1453 
1454 	alloc_size = sizeof(struct iio_dev);
1455 	if (sizeof_priv) {
1456 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1457 		alloc_size += sizeof_priv;
1458 	}
1459 	/* ensure 32-byte alignment of whole construct ? */
1460 	alloc_size += IIO_ALIGN - 1;
1461 
1462 	dev = kzalloc(alloc_size, GFP_KERNEL);
1463 
1464 	if (dev) {
1465 		dev->dev.groups = dev->groups;
1466 		dev->dev.type = &iio_device_type;
1467 		dev->dev.bus = &iio_bus_type;
1468 		device_initialize(&dev->dev);
1469 		dev_set_drvdata(&dev->dev, (void *)dev);
1470 		mutex_init(&dev->mlock);
1471 		mutex_init(&dev->info_exist_lock);
1472 		INIT_LIST_HEAD(&dev->channel_attr_list);
1473 
1474 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1475 		if (dev->id < 0) {
1476 			/* cannot use a dev_err as the name isn't available */
1477 			pr_err("failed to get device id\n");
1478 			kfree(dev);
1479 			return NULL;
1480 		}
1481 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1482 		INIT_LIST_HEAD(&dev->buffer_list);
1483 	}
1484 
1485 	return dev;
1486 }
1487 EXPORT_SYMBOL(iio_device_alloc);
1488 
1489 /**
1490  * iio_device_free() - free an iio_dev from a driver
1491  * @dev:		the iio_dev associated with the device
1492  **/
1493 void iio_device_free(struct iio_dev *dev)
1494 {
1495 	if (dev)
1496 		put_device(&dev->dev);
1497 }
1498 EXPORT_SYMBOL(iio_device_free);
1499 
1500 static void devm_iio_device_release(struct device *dev, void *res)
1501 {
1502 	iio_device_free(*(struct iio_dev **)res);
1503 }
1504 
1505 int devm_iio_device_match(struct device *dev, void *res, void *data)
1506 {
1507 	struct iio_dev **r = res;
1508 	if (!r || !*r) {
1509 		WARN_ON(!r || !*r);
1510 		return 0;
1511 	}
1512 	return *r == data;
1513 }
1514 EXPORT_SYMBOL_GPL(devm_iio_device_match);
1515 
1516 /**
1517  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1518  * @dev:		Device to allocate iio_dev for
1519  * @sizeof_priv:	Space to allocate for private structure.
1520  *
1521  * Managed iio_device_alloc. iio_dev allocated with this function is
1522  * automatically freed on driver detach.
1523  *
1524  * If an iio_dev allocated with this function needs to be freed separately,
1525  * devm_iio_device_free() must be used.
1526  *
1527  * RETURNS:
1528  * Pointer to allocated iio_dev on success, NULL on failure.
1529  */
1530 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1531 {
1532 	struct iio_dev **ptr, *iio_dev;
1533 
1534 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1535 			   GFP_KERNEL);
1536 	if (!ptr)
1537 		return NULL;
1538 
1539 	iio_dev = iio_device_alloc(sizeof_priv);
1540 	if (iio_dev) {
1541 		*ptr = iio_dev;
1542 		devres_add(dev, ptr);
1543 	} else {
1544 		devres_free(ptr);
1545 	}
1546 
1547 	return iio_dev;
1548 }
1549 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1550 
1551 /**
1552  * devm_iio_device_free - Resource-managed iio_device_free()
1553  * @dev:		Device this iio_dev belongs to
1554  * @iio_dev:		the iio_dev associated with the device
1555  *
1556  * Free iio_dev allocated with devm_iio_device_alloc().
1557  */
1558 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1559 {
1560 	int rc;
1561 
1562 	rc = devres_release(dev, devm_iio_device_release,
1563 			    devm_iio_device_match, iio_dev);
1564 	WARN_ON(rc);
1565 }
1566 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1567 
1568 /**
1569  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1570  * @inode:	Inode structure for identifying the device in the file system
1571  * @filp:	File structure for iio device used to keep and later access
1572  *		private data
1573  *
1574  * Return: 0 on success or -EBUSY if the device is already opened
1575  **/
1576 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1577 {
1578 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1579 						struct iio_dev, chrdev);
1580 
1581 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1582 		return -EBUSY;
1583 
1584 	iio_device_get(indio_dev);
1585 
1586 	filp->private_data = indio_dev;
1587 
1588 	return 0;
1589 }
1590 
1591 /**
1592  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1593  * @inode:	Inode structure pointer for the char device
1594  * @filp:	File structure pointer for the char device
1595  *
1596  * Return: 0 for successful release
1597  */
1598 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1599 {
1600 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1601 						struct iio_dev, chrdev);
1602 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1603 	iio_device_put(indio_dev);
1604 
1605 	return 0;
1606 }
1607 
1608 /* Somewhat of a cross file organization violation - ioctls here are actually
1609  * event related */
1610 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1611 {
1612 	struct iio_dev *indio_dev = filp->private_data;
1613 	int __user *ip = (int __user *)arg;
1614 	int fd;
1615 
1616 	if (!indio_dev->info)
1617 		return -ENODEV;
1618 
1619 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1620 		fd = iio_event_getfd(indio_dev);
1621 		if (fd < 0)
1622 			return fd;
1623 		if (copy_to_user(ip, &fd, sizeof(fd)))
1624 			return -EFAULT;
1625 		return 0;
1626 	}
1627 	return -EINVAL;
1628 }
1629 
1630 static const struct file_operations iio_buffer_fileops = {
1631 	.read = iio_buffer_read_first_n_outer_addr,
1632 	.release = iio_chrdev_release,
1633 	.open = iio_chrdev_open,
1634 	.poll = iio_buffer_poll_addr,
1635 	.owner = THIS_MODULE,
1636 	.llseek = noop_llseek,
1637 	.unlocked_ioctl = iio_ioctl,
1638 	.compat_ioctl = iio_ioctl,
1639 };
1640 
1641 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1642 {
1643 	int i, j;
1644 	const struct iio_chan_spec *channels = indio_dev->channels;
1645 
1646 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1647 		return 0;
1648 
1649 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1650 		if (channels[i].scan_index < 0)
1651 			continue;
1652 		for (j = i + 1; j < indio_dev->num_channels; j++)
1653 			if (channels[i].scan_index == channels[j].scan_index) {
1654 				dev_err(&indio_dev->dev,
1655 					"Duplicate scan index %d\n",
1656 					channels[i].scan_index);
1657 				return -EINVAL;
1658 			}
1659 	}
1660 
1661 	return 0;
1662 }
1663 
1664 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1665 
1666 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
1667 {
1668 	int ret;
1669 
1670 	indio_dev->driver_module = this_mod;
1671 	/* If the calling driver did not initialize of_node, do it here */
1672 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1673 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1674 
1675 	ret = iio_check_unique_scan_index(indio_dev);
1676 	if (ret < 0)
1677 		return ret;
1678 
1679 	if (!indio_dev->info)
1680 		return -EINVAL;
1681 
1682 	/* configure elements for the chrdev */
1683 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1684 
1685 	ret = iio_device_register_debugfs(indio_dev);
1686 	if (ret) {
1687 		dev_err(indio_dev->dev.parent,
1688 			"Failed to register debugfs interfaces\n");
1689 		return ret;
1690 	}
1691 
1692 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1693 	if (ret) {
1694 		dev_err(indio_dev->dev.parent,
1695 			"Failed to create buffer sysfs interfaces\n");
1696 		goto error_unreg_debugfs;
1697 	}
1698 
1699 	ret = iio_device_register_sysfs(indio_dev);
1700 	if (ret) {
1701 		dev_err(indio_dev->dev.parent,
1702 			"Failed to register sysfs interfaces\n");
1703 		goto error_buffer_free_sysfs;
1704 	}
1705 	ret = iio_device_register_eventset(indio_dev);
1706 	if (ret) {
1707 		dev_err(indio_dev->dev.parent,
1708 			"Failed to register event set\n");
1709 		goto error_free_sysfs;
1710 	}
1711 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1712 		iio_device_register_trigger_consumer(indio_dev);
1713 
1714 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1715 		indio_dev->setup_ops == NULL)
1716 		indio_dev->setup_ops = &noop_ring_setup_ops;
1717 
1718 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1719 
1720 	indio_dev->chrdev.owner = this_mod;
1721 
1722 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
1723 	if (ret < 0)
1724 		goto error_unreg_eventset;
1725 
1726 	return 0;
1727 
1728 error_unreg_eventset:
1729 	iio_device_unregister_eventset(indio_dev);
1730 error_free_sysfs:
1731 	iio_device_unregister_sysfs(indio_dev);
1732 error_buffer_free_sysfs:
1733 	iio_buffer_free_sysfs_and_mask(indio_dev);
1734 error_unreg_debugfs:
1735 	iio_device_unregister_debugfs(indio_dev);
1736 	return ret;
1737 }
1738 EXPORT_SYMBOL(__iio_device_register);
1739 
1740 /**
1741  * iio_device_unregister() - unregister a device from the IIO subsystem
1742  * @indio_dev:		Device structure representing the device.
1743  **/
1744 void iio_device_unregister(struct iio_dev *indio_dev)
1745 {
1746 	mutex_lock(&indio_dev->info_exist_lock);
1747 
1748 	cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
1749 
1750 	iio_device_unregister_debugfs(indio_dev);
1751 
1752 	iio_disable_all_buffers(indio_dev);
1753 
1754 	indio_dev->info = NULL;
1755 
1756 	iio_device_wakeup_eventset(indio_dev);
1757 	iio_buffer_wakeup_poll(indio_dev);
1758 
1759 	mutex_unlock(&indio_dev->info_exist_lock);
1760 
1761 	iio_buffer_free_sysfs_and_mask(indio_dev);
1762 }
1763 EXPORT_SYMBOL(iio_device_unregister);
1764 
1765 static void devm_iio_device_unreg(struct device *dev, void *res)
1766 {
1767 	iio_device_unregister(*(struct iio_dev **)res);
1768 }
1769 
1770 int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
1771 			       struct module *this_mod)
1772 {
1773 	struct iio_dev **ptr;
1774 	int ret;
1775 
1776 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1777 	if (!ptr)
1778 		return -ENOMEM;
1779 
1780 	*ptr = indio_dev;
1781 	ret = __iio_device_register(indio_dev, this_mod);
1782 	if (!ret)
1783 		devres_add(dev, ptr);
1784 	else
1785 		devres_free(ptr);
1786 
1787 	return ret;
1788 }
1789 EXPORT_SYMBOL_GPL(__devm_iio_device_register);
1790 
1791 /**
1792  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1793  * @dev:	Device this iio_dev belongs to
1794  * @indio_dev:	the iio_dev associated with the device
1795  *
1796  * Unregister iio_dev registered with devm_iio_device_register().
1797  */
1798 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1799 {
1800 	int rc;
1801 
1802 	rc = devres_release(dev, devm_iio_device_unreg,
1803 			    devm_iio_device_match, indio_dev);
1804 	WARN_ON(rc);
1805 }
1806 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1807 
1808 /**
1809  * iio_device_claim_direct_mode - Keep device in direct mode
1810  * @indio_dev:	the iio_dev associated with the device
1811  *
1812  * If the device is in direct mode it is guaranteed to stay
1813  * that way until iio_device_release_direct_mode() is called.
1814  *
1815  * Use with iio_device_release_direct_mode()
1816  *
1817  * Returns: 0 on success, -EBUSY on failure
1818  */
1819 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1820 {
1821 	mutex_lock(&indio_dev->mlock);
1822 
1823 	if (iio_buffer_enabled(indio_dev)) {
1824 		mutex_unlock(&indio_dev->mlock);
1825 		return -EBUSY;
1826 	}
1827 	return 0;
1828 }
1829 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1830 
1831 /**
1832  * iio_device_release_direct_mode - releases claim on direct mode
1833  * @indio_dev:	the iio_dev associated with the device
1834  *
1835  * Release the claim. Device is no longer guaranteed to stay
1836  * in direct mode.
1837  *
1838  * Use with iio_device_claim_direct_mode()
1839  */
1840 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1841 {
1842 	mutex_unlock(&indio_dev->mlock);
1843 }
1844 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1845 
1846 subsys_initcall(iio_init);
1847 module_exit(iio_exit);
1848 
1849 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1850 MODULE_DESCRIPTION("Industrial I/O core");
1851 MODULE_LICENSE("GPL");
1852