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 };
89 
90 static const char * const iio_modifier_names[] = {
91 	[IIO_MOD_X] = "x",
92 	[IIO_MOD_Y] = "y",
93 	[IIO_MOD_Z] = "z",
94 	[IIO_MOD_X_AND_Y] = "x&y",
95 	[IIO_MOD_X_AND_Z] = "x&z",
96 	[IIO_MOD_Y_AND_Z] = "y&z",
97 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
98 	[IIO_MOD_X_OR_Y] = "x|y",
99 	[IIO_MOD_X_OR_Z] = "x|z",
100 	[IIO_MOD_Y_OR_Z] = "y|z",
101 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
102 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
103 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
104 	[IIO_MOD_LIGHT_BOTH] = "both",
105 	[IIO_MOD_LIGHT_IR] = "ir",
106 	[IIO_MOD_LIGHT_CLEAR] = "clear",
107 	[IIO_MOD_LIGHT_RED] = "red",
108 	[IIO_MOD_LIGHT_GREEN] = "green",
109 	[IIO_MOD_LIGHT_BLUE] = "blue",
110 	[IIO_MOD_LIGHT_UV] = "uv",
111 	[IIO_MOD_QUATERNION] = "quaternion",
112 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
113 	[IIO_MOD_TEMP_OBJECT] = "object",
114 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
115 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
116 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
117 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
118 	[IIO_MOD_RUNNING] = "running",
119 	[IIO_MOD_JOGGING] = "jogging",
120 	[IIO_MOD_WALKING] = "walking",
121 	[IIO_MOD_STILL] = "still",
122 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
123 	[IIO_MOD_I] = "i",
124 	[IIO_MOD_Q] = "q",
125 	[IIO_MOD_CO2] = "co2",
126 	[IIO_MOD_VOC] = "voc",
127 };
128 
129 /* relies on pairs of these shared then separate */
130 static const char * const iio_chan_info_postfix[] = {
131 	[IIO_CHAN_INFO_RAW] = "raw",
132 	[IIO_CHAN_INFO_PROCESSED] = "input",
133 	[IIO_CHAN_INFO_SCALE] = "scale",
134 	[IIO_CHAN_INFO_OFFSET] = "offset",
135 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
136 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
137 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
138 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
139 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
140 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
141 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
142 	= "filter_low_pass_3db_frequency",
143 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
144 	= "filter_high_pass_3db_frequency",
145 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
146 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
147 	[IIO_CHAN_INFO_PHASE] = "phase",
148 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
149 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
150 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
151 	[IIO_CHAN_INFO_ENABLE] = "en",
152 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
153 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
154 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
155 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
156 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
157 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
158 };
159 
160 /**
161  * iio_find_channel_from_si() - get channel from its scan index
162  * @indio_dev:		device
163  * @si:			scan index to match
164  */
165 const struct iio_chan_spec
166 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
167 {
168 	int i;
169 
170 	for (i = 0; i < indio_dev->num_channels; i++)
171 		if (indio_dev->channels[i].scan_index == si)
172 			return &indio_dev->channels[i];
173 	return NULL;
174 }
175 
176 /* This turns up an awful lot */
177 ssize_t iio_read_const_attr(struct device *dev,
178 			    struct device_attribute *attr,
179 			    char *buf)
180 {
181 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
182 }
183 EXPORT_SYMBOL(iio_read_const_attr);
184 
185 static int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
186 {
187 	int ret;
188 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
189 
190 	ret = mutex_lock_interruptible(&indio_dev->mlock);
191 	if (ret)
192 		return ret;
193 	if ((ev_int && iio_event_enabled(ev_int)) ||
194 	    iio_buffer_enabled(indio_dev)) {
195 		mutex_unlock(&indio_dev->mlock);
196 		return -EBUSY;
197 	}
198 	indio_dev->clock_id = clock_id;
199 	mutex_unlock(&indio_dev->mlock);
200 
201 	return 0;
202 }
203 
204 /**
205  * iio_get_time_ns() - utility function to get a time stamp for events etc
206  * @indio_dev: device
207  */
208 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
209 {
210 	struct timespec tp;
211 
212 	switch (iio_device_get_clock(indio_dev)) {
213 	case CLOCK_REALTIME:
214 		ktime_get_real_ts(&tp);
215 		break;
216 	case CLOCK_MONOTONIC:
217 		ktime_get_ts(&tp);
218 		break;
219 	case CLOCK_MONOTONIC_RAW:
220 		getrawmonotonic(&tp);
221 		break;
222 	case CLOCK_REALTIME_COARSE:
223 		tp = current_kernel_time();
224 		break;
225 	case CLOCK_MONOTONIC_COARSE:
226 		tp = get_monotonic_coarse();
227 		break;
228 	case CLOCK_BOOTTIME:
229 		get_monotonic_boottime(&tp);
230 		break;
231 	case CLOCK_TAI:
232 		timekeeping_clocktai(&tp);
233 		break;
234 	default:
235 		BUG();
236 	}
237 
238 	return timespec_to_ns(&tp);
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 
316 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
317 
318 	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
319 }
320 
321 static ssize_t iio_debugfs_write_reg(struct file *file,
322 		     const char __user *userbuf, size_t count, loff_t *ppos)
323 {
324 	struct iio_dev *indio_dev = file->private_data;
325 	unsigned reg, val;
326 	char buf[80];
327 	int ret;
328 
329 	count = min_t(size_t, count, (sizeof(buf)-1));
330 	if (copy_from_user(buf, userbuf, count))
331 		return -EFAULT;
332 
333 	buf[count] = 0;
334 
335 	ret = sscanf(buf, "%i %i", &reg, &val);
336 
337 	switch (ret) {
338 	case 1:
339 		indio_dev->cached_reg_addr = reg;
340 		break;
341 	case 2:
342 		indio_dev->cached_reg_addr = reg;
343 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
344 							  val, NULL);
345 		if (ret) {
346 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
347 				__func__);
348 			return ret;
349 		}
350 		break;
351 	default:
352 		return -EINVAL;
353 	}
354 
355 	return count;
356 }
357 
358 static const struct file_operations iio_debugfs_reg_fops = {
359 	.open = simple_open,
360 	.read = iio_debugfs_read_reg,
361 	.write = iio_debugfs_write_reg,
362 };
363 
364 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
365 {
366 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
367 }
368 
369 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
370 {
371 	struct dentry *d;
372 
373 	if (indio_dev->info->debugfs_reg_access == NULL)
374 		return 0;
375 
376 	if (!iio_debugfs_dentry)
377 		return 0;
378 
379 	indio_dev->debugfs_dentry =
380 		debugfs_create_dir(dev_name(&indio_dev->dev),
381 				   iio_debugfs_dentry);
382 	if (indio_dev->debugfs_dentry == NULL) {
383 		dev_warn(indio_dev->dev.parent,
384 			 "Failed to create debugfs directory\n");
385 		return -EFAULT;
386 	}
387 
388 	d = debugfs_create_file("direct_reg_access", 0644,
389 				indio_dev->debugfs_dentry,
390 				indio_dev, &iio_debugfs_reg_fops);
391 	if (!d) {
392 		iio_device_unregister_debugfs(indio_dev);
393 		return -ENOMEM;
394 	}
395 
396 	return 0;
397 }
398 #else
399 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
400 {
401 	return 0;
402 }
403 
404 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
405 {
406 }
407 #endif /* CONFIG_DEBUG_FS */
408 
409 static ssize_t iio_read_channel_ext_info(struct device *dev,
410 				     struct device_attribute *attr,
411 				     char *buf)
412 {
413 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
414 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
415 	const struct iio_chan_spec_ext_info *ext_info;
416 
417 	ext_info = &this_attr->c->ext_info[this_attr->address];
418 
419 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
420 }
421 
422 static ssize_t iio_write_channel_ext_info(struct device *dev,
423 				     struct device_attribute *attr,
424 				     const char *buf,
425 					 size_t len)
426 {
427 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
428 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
429 	const struct iio_chan_spec_ext_info *ext_info;
430 
431 	ext_info = &this_attr->c->ext_info[this_attr->address];
432 
433 	return ext_info->write(indio_dev, ext_info->private,
434 			       this_attr->c, buf, len);
435 }
436 
437 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
438 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
439 {
440 	const struct iio_enum *e = (const struct iio_enum *)priv;
441 	unsigned int i;
442 	size_t len = 0;
443 
444 	if (!e->num_items)
445 		return 0;
446 
447 	for (i = 0; i < e->num_items; ++i)
448 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
449 
450 	/* replace last space with a newline */
451 	buf[len - 1] = '\n';
452 
453 	return len;
454 }
455 EXPORT_SYMBOL_GPL(iio_enum_available_read);
456 
457 ssize_t iio_enum_read(struct iio_dev *indio_dev,
458 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
459 {
460 	const struct iio_enum *e = (const struct iio_enum *)priv;
461 	int i;
462 
463 	if (!e->get)
464 		return -EINVAL;
465 
466 	i = e->get(indio_dev, chan);
467 	if (i < 0)
468 		return i;
469 	else if (i >= e->num_items)
470 		return -EINVAL;
471 
472 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
473 }
474 EXPORT_SYMBOL_GPL(iio_enum_read);
475 
476 ssize_t iio_enum_write(struct iio_dev *indio_dev,
477 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
478 	size_t len)
479 {
480 	const struct iio_enum *e = (const struct iio_enum *)priv;
481 	int ret;
482 
483 	if (!e->set)
484 		return -EINVAL;
485 
486 	ret = __sysfs_match_string(e->items, e->num_items, buf);
487 	if (ret < 0)
488 		return ret;
489 
490 	ret = e->set(indio_dev, chan, ret);
491 	return ret ? ret : len;
492 }
493 EXPORT_SYMBOL_GPL(iio_enum_write);
494 
495 static const struct iio_mount_matrix iio_mount_idmatrix = {
496 	.rotation = {
497 		"1", "0", "0",
498 		"0", "1", "0",
499 		"0", "0", "1"
500 	}
501 };
502 
503 static int iio_setup_mount_idmatrix(const struct device *dev,
504 				    struct iio_mount_matrix *matrix)
505 {
506 	*matrix = iio_mount_idmatrix;
507 	dev_info(dev, "mounting matrix not found: using identity...\n");
508 	return 0;
509 }
510 
511 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
512 			      const struct iio_chan_spec *chan, char *buf)
513 {
514 	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
515 					      priv)(indio_dev, chan);
516 
517 	if (IS_ERR(mtx))
518 		return PTR_ERR(mtx);
519 
520 	if (!mtx)
521 		mtx = &iio_mount_idmatrix;
522 
523 	return snprintf(buf, PAGE_SIZE, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
524 			mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
525 			mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
526 			mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
527 }
528 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
529 
530 /**
531  * of_iio_read_mount_matrix() - retrieve iio device mounting matrix from
532  *                              device-tree "mount-matrix" property
533  * @dev:	device the mounting matrix property is assigned to
534  * @propname:	device specific mounting matrix property name
535  * @matrix:	where to store retrieved matrix
536  *
537  * If device is assigned no mounting matrix property, a default 3x3 identity
538  * matrix will be filled in.
539  *
540  * Return: 0 if success, or a negative error code on failure.
541  */
542 #ifdef CONFIG_OF
543 int of_iio_read_mount_matrix(const struct device *dev,
544 			     const char *propname,
545 			     struct iio_mount_matrix *matrix)
546 {
547 	if (dev->of_node) {
548 		int err = of_property_read_string_array(dev->of_node,
549 				propname, matrix->rotation,
550 				ARRAY_SIZE(iio_mount_idmatrix.rotation));
551 
552 		if (err == ARRAY_SIZE(iio_mount_idmatrix.rotation))
553 			return 0;
554 
555 		if (err >= 0)
556 			/* Invalid number of matrix entries. */
557 			return -EINVAL;
558 
559 		if (err != -EINVAL)
560 			/* Invalid matrix declaration format. */
561 			return err;
562 	}
563 
564 	/* Matrix was not declared at all: fallback to identity. */
565 	return iio_setup_mount_idmatrix(dev, matrix);
566 }
567 #else
568 int of_iio_read_mount_matrix(const struct device *dev,
569 			     const char *propname,
570 			     struct iio_mount_matrix *matrix)
571 {
572 	return iio_setup_mount_idmatrix(dev, matrix);
573 }
574 #endif
575 EXPORT_SYMBOL(of_iio_read_mount_matrix);
576 
577 static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
578 				  int size, const int *vals)
579 {
580 	unsigned long long tmp;
581 	int tmp0, tmp1;
582 	bool scale_db = false;
583 
584 	switch (type) {
585 	case IIO_VAL_INT:
586 		return snprintf(buf, len, "%d", vals[0]);
587 	case IIO_VAL_INT_PLUS_MICRO_DB:
588 		scale_db = true;
589 	case IIO_VAL_INT_PLUS_MICRO:
590 		if (vals[1] < 0)
591 			return snprintf(buf, len, "-%d.%06u%s", abs(vals[0]),
592 					-vals[1], scale_db ? " dB" : "");
593 		else
594 			return snprintf(buf, len, "%d.%06u%s", vals[0], vals[1],
595 					scale_db ? " dB" : "");
596 	case IIO_VAL_INT_PLUS_NANO:
597 		if (vals[1] < 0)
598 			return snprintf(buf, len, "-%d.%09u", abs(vals[0]),
599 					-vals[1]);
600 		else
601 			return snprintf(buf, len, "%d.%09u", vals[0], vals[1]);
602 	case IIO_VAL_FRACTIONAL:
603 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
604 		tmp1 = vals[1];
605 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
606 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
607 	case IIO_VAL_FRACTIONAL_LOG2:
608 		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
609 		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
610 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
611 	case IIO_VAL_INT_MULTIPLE:
612 	{
613 		int i;
614 		int l = 0;
615 
616 		for (i = 0; i < size; ++i) {
617 			l += snprintf(&buf[l], len - l, "%d ", vals[i]);
618 			if (l >= len)
619 				break;
620 		}
621 		return l;
622 	}
623 	default:
624 		return 0;
625 	}
626 }
627 
628 /**
629  * iio_format_value() - Formats a IIO value into its string representation
630  * @buf:	The buffer to which the formatted value gets written
631  *		which is assumed to be big enough (i.e. PAGE_SIZE).
632  * @type:	One of the IIO_VAL_... constants. This decides how the val
633  *		and val2 parameters are formatted.
634  * @size:	Number of IIO value entries contained in vals
635  * @vals:	Pointer to the values, exact meaning depends on the
636  *		type parameter.
637  *
638  * Return: 0 by default, a negative number on failure or the
639  *	   total number of characters written for a type that belongs
640  *	   to the IIO_VAL_... constant.
641  */
642 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
643 {
644 	ssize_t len;
645 
646 	len = __iio_format_value(buf, PAGE_SIZE, type, size, vals);
647 	if (len >= PAGE_SIZE - 1)
648 		return -EFBIG;
649 
650 	return len + sprintf(buf + len, "\n");
651 }
652 EXPORT_SYMBOL_GPL(iio_format_value);
653 
654 static ssize_t iio_read_channel_info(struct device *dev,
655 				     struct device_attribute *attr,
656 				     char *buf)
657 {
658 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
659 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
660 	int vals[INDIO_MAX_RAW_ELEMENTS];
661 	int ret;
662 	int val_len = 2;
663 
664 	if (indio_dev->info->read_raw_multi)
665 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
666 							INDIO_MAX_RAW_ELEMENTS,
667 							vals, &val_len,
668 							this_attr->address);
669 	else
670 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
671 				    &vals[0], &vals[1], this_attr->address);
672 
673 	if (ret < 0)
674 		return ret;
675 
676 	return iio_format_value(buf, ret, val_len, vals);
677 }
678 
679 static ssize_t iio_format_avail_list(char *buf, const int *vals,
680 				     int type, int length)
681 {
682 	int i;
683 	ssize_t len = 0;
684 
685 	switch (type) {
686 	case IIO_VAL_INT:
687 		for (i = 0; i < length; i++) {
688 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
689 						  type, 1, &vals[i]);
690 			if (len >= PAGE_SIZE)
691 				return -EFBIG;
692 			if (i < length - 1)
693 				len += snprintf(buf + len, PAGE_SIZE - len,
694 						" ");
695 			else
696 				len += snprintf(buf + len, PAGE_SIZE - len,
697 						"\n");
698 			if (len >= PAGE_SIZE)
699 				return -EFBIG;
700 		}
701 		break;
702 	default:
703 		for (i = 0; i < length / 2; i++) {
704 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
705 						  type, 2, &vals[i * 2]);
706 			if (len >= PAGE_SIZE)
707 				return -EFBIG;
708 			if (i < length / 2 - 1)
709 				len += snprintf(buf + len, PAGE_SIZE - len,
710 						" ");
711 			else
712 				len += snprintf(buf + len, PAGE_SIZE - len,
713 						"\n");
714 			if (len >= PAGE_SIZE)
715 				return -EFBIG;
716 		}
717 	}
718 
719 	return len;
720 }
721 
722 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
723 {
724 	int i;
725 	ssize_t len;
726 
727 	len = snprintf(buf, PAGE_SIZE, "[");
728 	switch (type) {
729 	case IIO_VAL_INT:
730 		for (i = 0; i < 3; i++) {
731 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
732 						  type, 1, &vals[i]);
733 			if (len >= PAGE_SIZE)
734 				return -EFBIG;
735 			if (i < 2)
736 				len += snprintf(buf + len, PAGE_SIZE - len,
737 						" ");
738 			else
739 				len += snprintf(buf + len, PAGE_SIZE - len,
740 						"]\n");
741 			if (len >= PAGE_SIZE)
742 				return -EFBIG;
743 		}
744 		break;
745 	default:
746 		for (i = 0; i < 3; i++) {
747 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
748 						  type, 2, &vals[i * 2]);
749 			if (len >= PAGE_SIZE)
750 				return -EFBIG;
751 			if (i < 2)
752 				len += snprintf(buf + len, PAGE_SIZE - len,
753 						" ");
754 			else
755 				len += snprintf(buf + len, PAGE_SIZE - len,
756 						"]\n");
757 			if (len >= PAGE_SIZE)
758 				return -EFBIG;
759 		}
760 	}
761 
762 	return len;
763 }
764 
765 static ssize_t iio_read_channel_info_avail(struct device *dev,
766 					   struct device_attribute *attr,
767 					   char *buf)
768 {
769 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
770 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
771 	const int *vals;
772 	int ret;
773 	int length;
774 	int type;
775 
776 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
777 					  &vals, &type, &length,
778 					  this_attr->address);
779 
780 	if (ret < 0)
781 		return ret;
782 	switch (ret) {
783 	case IIO_AVAIL_LIST:
784 		return iio_format_avail_list(buf, vals, type, length);
785 	case IIO_AVAIL_RANGE:
786 		return iio_format_avail_range(buf, vals, type);
787 	default:
788 		return -EINVAL;
789 	}
790 }
791 
792 /**
793  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
794  * @str: The string to parse
795  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
796  * @integer: The integer part of the number
797  * @fract: The fractional part of the number
798  *
799  * Returns 0 on success, or a negative error code if the string could not be
800  * parsed.
801  */
802 int iio_str_to_fixpoint(const char *str, int fract_mult,
803 	int *integer, int *fract)
804 {
805 	int i = 0, f = 0;
806 	bool integer_part = true, negative = false;
807 
808 	if (fract_mult == 0) {
809 		*fract = 0;
810 
811 		return kstrtoint(str, 0, integer);
812 	}
813 
814 	if (str[0] == '-') {
815 		negative = true;
816 		str++;
817 	} else if (str[0] == '+') {
818 		str++;
819 	}
820 
821 	while (*str) {
822 		if ('0' <= *str && *str <= '9') {
823 			if (integer_part) {
824 				i = i * 10 + *str - '0';
825 			} else {
826 				f += fract_mult * (*str - '0');
827 				fract_mult /= 10;
828 			}
829 		} else if (*str == '\n') {
830 			if (*(str + 1) == '\0')
831 				break;
832 			else
833 				return -EINVAL;
834 		} else if (*str == '.' && integer_part) {
835 			integer_part = false;
836 		} else {
837 			return -EINVAL;
838 		}
839 		str++;
840 	}
841 
842 	if (negative) {
843 		if (i)
844 			i = -i;
845 		else
846 			f = -f;
847 	}
848 
849 	*integer = i;
850 	*fract = f;
851 
852 	return 0;
853 }
854 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
855 
856 static ssize_t iio_write_channel_info(struct device *dev,
857 				      struct device_attribute *attr,
858 				      const char *buf,
859 				      size_t len)
860 {
861 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
862 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
863 	int ret, fract_mult = 100000;
864 	int integer, fract;
865 
866 	/* Assumes decimal - precision based on number of digits */
867 	if (!indio_dev->info->write_raw)
868 		return -EINVAL;
869 
870 	if (indio_dev->info->write_raw_get_fmt)
871 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
872 			this_attr->c, this_attr->address)) {
873 		case IIO_VAL_INT:
874 			fract_mult = 0;
875 			break;
876 		case IIO_VAL_INT_PLUS_MICRO:
877 			fract_mult = 100000;
878 			break;
879 		case IIO_VAL_INT_PLUS_NANO:
880 			fract_mult = 100000000;
881 			break;
882 		default:
883 			return -EINVAL;
884 		}
885 
886 	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
887 	if (ret)
888 		return ret;
889 
890 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
891 					 integer, fract, this_attr->address);
892 	if (ret)
893 		return ret;
894 
895 	return len;
896 }
897 
898 static
899 int __iio_device_attr_init(struct device_attribute *dev_attr,
900 			   const char *postfix,
901 			   struct iio_chan_spec const *chan,
902 			   ssize_t (*readfunc)(struct device *dev,
903 					       struct device_attribute *attr,
904 					       char *buf),
905 			   ssize_t (*writefunc)(struct device *dev,
906 						struct device_attribute *attr,
907 						const char *buf,
908 						size_t len),
909 			   enum iio_shared_by shared_by)
910 {
911 	int ret = 0;
912 	char *name = NULL;
913 	char *full_postfix;
914 	sysfs_attr_init(&dev_attr->attr);
915 
916 	/* Build up postfix of <extend_name>_<modifier>_postfix */
917 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
918 		if (chan->extend_name)
919 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
920 						 iio_modifier_names[chan
921 								    ->channel2],
922 						 chan->extend_name,
923 						 postfix);
924 		else
925 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
926 						 iio_modifier_names[chan
927 								    ->channel2],
928 						 postfix);
929 	} else {
930 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
931 			full_postfix = kstrdup(postfix, GFP_KERNEL);
932 		else
933 			full_postfix = kasprintf(GFP_KERNEL,
934 						 "%s_%s",
935 						 chan->extend_name,
936 						 postfix);
937 	}
938 	if (full_postfix == NULL)
939 		return -ENOMEM;
940 
941 	if (chan->differential) { /* Differential can not have modifier */
942 		switch (shared_by) {
943 		case IIO_SHARED_BY_ALL:
944 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
945 			break;
946 		case IIO_SHARED_BY_DIR:
947 			name = kasprintf(GFP_KERNEL, "%s_%s",
948 						iio_direction[chan->output],
949 						full_postfix);
950 			break;
951 		case IIO_SHARED_BY_TYPE:
952 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
953 					    iio_direction[chan->output],
954 					    iio_chan_type_name_spec[chan->type],
955 					    iio_chan_type_name_spec[chan->type],
956 					    full_postfix);
957 			break;
958 		case IIO_SEPARATE:
959 			if (!chan->indexed) {
960 				WARN(1, "Differential channels must be indexed\n");
961 				ret = -EINVAL;
962 				goto error_free_full_postfix;
963 			}
964 			name = kasprintf(GFP_KERNEL,
965 					    "%s_%s%d-%s%d_%s",
966 					    iio_direction[chan->output],
967 					    iio_chan_type_name_spec[chan->type],
968 					    chan->channel,
969 					    iio_chan_type_name_spec[chan->type],
970 					    chan->channel2,
971 					    full_postfix);
972 			break;
973 		}
974 	} else { /* Single ended */
975 		switch (shared_by) {
976 		case IIO_SHARED_BY_ALL:
977 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
978 			break;
979 		case IIO_SHARED_BY_DIR:
980 			name = kasprintf(GFP_KERNEL, "%s_%s",
981 						iio_direction[chan->output],
982 						full_postfix);
983 			break;
984 		case IIO_SHARED_BY_TYPE:
985 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
986 					    iio_direction[chan->output],
987 					    iio_chan_type_name_spec[chan->type],
988 					    full_postfix);
989 			break;
990 
991 		case IIO_SEPARATE:
992 			if (chan->indexed)
993 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
994 						    iio_direction[chan->output],
995 						    iio_chan_type_name_spec[chan->type],
996 						    chan->channel,
997 						    full_postfix);
998 			else
999 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1000 						    iio_direction[chan->output],
1001 						    iio_chan_type_name_spec[chan->type],
1002 						    full_postfix);
1003 			break;
1004 		}
1005 	}
1006 	if (name == NULL) {
1007 		ret = -ENOMEM;
1008 		goto error_free_full_postfix;
1009 	}
1010 	dev_attr->attr.name = name;
1011 
1012 	if (readfunc) {
1013 		dev_attr->attr.mode |= S_IRUGO;
1014 		dev_attr->show = readfunc;
1015 	}
1016 
1017 	if (writefunc) {
1018 		dev_attr->attr.mode |= S_IWUSR;
1019 		dev_attr->store = writefunc;
1020 	}
1021 
1022 error_free_full_postfix:
1023 	kfree(full_postfix);
1024 
1025 	return ret;
1026 }
1027 
1028 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1029 {
1030 	kfree(dev_attr->attr.name);
1031 }
1032 
1033 int __iio_add_chan_devattr(const char *postfix,
1034 			   struct iio_chan_spec const *chan,
1035 			   ssize_t (*readfunc)(struct device *dev,
1036 					       struct device_attribute *attr,
1037 					       char *buf),
1038 			   ssize_t (*writefunc)(struct device *dev,
1039 						struct device_attribute *attr,
1040 						const char *buf,
1041 						size_t len),
1042 			   u64 mask,
1043 			   enum iio_shared_by shared_by,
1044 			   struct device *dev,
1045 			   struct list_head *attr_list)
1046 {
1047 	int ret;
1048 	struct iio_dev_attr *iio_attr, *t;
1049 
1050 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1051 	if (iio_attr == NULL)
1052 		return -ENOMEM;
1053 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1054 				     postfix, chan,
1055 				     readfunc, writefunc, shared_by);
1056 	if (ret)
1057 		goto error_iio_dev_attr_free;
1058 	iio_attr->c = chan;
1059 	iio_attr->address = mask;
1060 	list_for_each_entry(t, attr_list, l)
1061 		if (strcmp(t->dev_attr.attr.name,
1062 			   iio_attr->dev_attr.attr.name) == 0) {
1063 			if (shared_by == IIO_SEPARATE)
1064 				dev_err(dev, "tried to double register : %s\n",
1065 					t->dev_attr.attr.name);
1066 			ret = -EBUSY;
1067 			goto error_device_attr_deinit;
1068 		}
1069 	list_add(&iio_attr->l, attr_list);
1070 
1071 	return 0;
1072 
1073 error_device_attr_deinit:
1074 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1075 error_iio_dev_attr_free:
1076 	kfree(iio_attr);
1077 	return ret;
1078 }
1079 
1080 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1081 					 struct iio_chan_spec const *chan,
1082 					 enum iio_shared_by shared_by,
1083 					 const long *infomask)
1084 {
1085 	int i, ret, attrcount = 0;
1086 
1087 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1088 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1089 			return -EINVAL;
1090 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1091 					     chan,
1092 					     &iio_read_channel_info,
1093 					     &iio_write_channel_info,
1094 					     i,
1095 					     shared_by,
1096 					     &indio_dev->dev,
1097 					     &indio_dev->channel_attr_list);
1098 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1099 			continue;
1100 		else if (ret < 0)
1101 			return ret;
1102 		attrcount++;
1103 	}
1104 
1105 	return attrcount;
1106 }
1107 
1108 static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
1109 					       struct iio_chan_spec const *chan,
1110 					       enum iio_shared_by shared_by,
1111 					       const long *infomask)
1112 {
1113 	int i, ret, attrcount = 0;
1114 	char *avail_postfix;
1115 
1116 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1117 		avail_postfix = kasprintf(GFP_KERNEL,
1118 					  "%s_available",
1119 					  iio_chan_info_postfix[i]);
1120 		if (!avail_postfix)
1121 			return -ENOMEM;
1122 
1123 		ret = __iio_add_chan_devattr(avail_postfix,
1124 					     chan,
1125 					     &iio_read_channel_info_avail,
1126 					     NULL,
1127 					     i,
1128 					     shared_by,
1129 					     &indio_dev->dev,
1130 					     &indio_dev->channel_attr_list);
1131 		kfree(avail_postfix);
1132 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1133 			continue;
1134 		else if (ret < 0)
1135 			return ret;
1136 		attrcount++;
1137 	}
1138 
1139 	return attrcount;
1140 }
1141 
1142 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1143 					struct iio_chan_spec const *chan)
1144 {
1145 	int ret, attrcount = 0;
1146 	const struct iio_chan_spec_ext_info *ext_info;
1147 
1148 	if (chan->channel < 0)
1149 		return 0;
1150 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1151 					    IIO_SEPARATE,
1152 					    &chan->info_mask_separate);
1153 	if (ret < 0)
1154 		return ret;
1155 	attrcount += ret;
1156 
1157 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1158 						  IIO_SEPARATE,
1159 						  &chan->
1160 						  info_mask_separate_available);
1161 	if (ret < 0)
1162 		return ret;
1163 	attrcount += ret;
1164 
1165 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1166 					    IIO_SHARED_BY_TYPE,
1167 					    &chan->info_mask_shared_by_type);
1168 	if (ret < 0)
1169 		return ret;
1170 	attrcount += ret;
1171 
1172 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1173 						  IIO_SHARED_BY_TYPE,
1174 						  &chan->
1175 						  info_mask_shared_by_type_available);
1176 	if (ret < 0)
1177 		return ret;
1178 	attrcount += ret;
1179 
1180 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1181 					    IIO_SHARED_BY_DIR,
1182 					    &chan->info_mask_shared_by_dir);
1183 	if (ret < 0)
1184 		return ret;
1185 	attrcount += ret;
1186 
1187 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1188 						  IIO_SHARED_BY_DIR,
1189 						  &chan->info_mask_shared_by_dir_available);
1190 	if (ret < 0)
1191 		return ret;
1192 	attrcount += ret;
1193 
1194 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1195 					    IIO_SHARED_BY_ALL,
1196 					    &chan->info_mask_shared_by_all);
1197 	if (ret < 0)
1198 		return ret;
1199 	attrcount += ret;
1200 
1201 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1202 						  IIO_SHARED_BY_ALL,
1203 						  &chan->info_mask_shared_by_all_available);
1204 	if (ret < 0)
1205 		return ret;
1206 	attrcount += ret;
1207 
1208 	if (chan->ext_info) {
1209 		unsigned int i = 0;
1210 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1211 			ret = __iio_add_chan_devattr(ext_info->name,
1212 					chan,
1213 					ext_info->read ?
1214 					    &iio_read_channel_ext_info : NULL,
1215 					ext_info->write ?
1216 					    &iio_write_channel_ext_info : NULL,
1217 					i,
1218 					ext_info->shared,
1219 					&indio_dev->dev,
1220 					&indio_dev->channel_attr_list);
1221 			i++;
1222 			if (ret == -EBUSY && ext_info->shared)
1223 				continue;
1224 
1225 			if (ret)
1226 				return ret;
1227 
1228 			attrcount++;
1229 		}
1230 	}
1231 
1232 	return attrcount;
1233 }
1234 
1235 /**
1236  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1237  * @attr_list: List of IIO device attributes
1238  *
1239  * This function frees the memory allocated for each of the IIO device
1240  * attributes in the list.
1241  */
1242 void iio_free_chan_devattr_list(struct list_head *attr_list)
1243 {
1244 	struct iio_dev_attr *p, *n;
1245 
1246 	list_for_each_entry_safe(p, n, attr_list, l) {
1247 		kfree(p->dev_attr.attr.name);
1248 		list_del(&p->l);
1249 		kfree(p);
1250 	}
1251 }
1252 
1253 static ssize_t iio_show_dev_name(struct device *dev,
1254 				 struct device_attribute *attr,
1255 				 char *buf)
1256 {
1257 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1258 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1259 }
1260 
1261 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1262 
1263 static ssize_t iio_show_timestamp_clock(struct device *dev,
1264 					struct device_attribute *attr,
1265 					char *buf)
1266 {
1267 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1268 	const clockid_t clk = iio_device_get_clock(indio_dev);
1269 	const char *name;
1270 	ssize_t sz;
1271 
1272 	switch (clk) {
1273 	case CLOCK_REALTIME:
1274 		name = "realtime\n";
1275 		sz = sizeof("realtime\n");
1276 		break;
1277 	case CLOCK_MONOTONIC:
1278 		name = "monotonic\n";
1279 		sz = sizeof("monotonic\n");
1280 		break;
1281 	case CLOCK_MONOTONIC_RAW:
1282 		name = "monotonic_raw\n";
1283 		sz = sizeof("monotonic_raw\n");
1284 		break;
1285 	case CLOCK_REALTIME_COARSE:
1286 		name = "realtime_coarse\n";
1287 		sz = sizeof("realtime_coarse\n");
1288 		break;
1289 	case CLOCK_MONOTONIC_COARSE:
1290 		name = "monotonic_coarse\n";
1291 		sz = sizeof("monotonic_coarse\n");
1292 		break;
1293 	case CLOCK_BOOTTIME:
1294 		name = "boottime\n";
1295 		sz = sizeof("boottime\n");
1296 		break;
1297 	case CLOCK_TAI:
1298 		name = "tai\n";
1299 		sz = sizeof("tai\n");
1300 		break;
1301 	default:
1302 		BUG();
1303 	}
1304 
1305 	memcpy(buf, name, sz);
1306 	return sz;
1307 }
1308 
1309 static ssize_t iio_store_timestamp_clock(struct device *dev,
1310 					 struct device_attribute *attr,
1311 					 const char *buf, size_t len)
1312 {
1313 	clockid_t clk;
1314 	int ret;
1315 
1316 	if (sysfs_streq(buf, "realtime"))
1317 		clk = CLOCK_REALTIME;
1318 	else if (sysfs_streq(buf, "monotonic"))
1319 		clk = CLOCK_MONOTONIC;
1320 	else if (sysfs_streq(buf, "monotonic_raw"))
1321 		clk = CLOCK_MONOTONIC_RAW;
1322 	else if (sysfs_streq(buf, "realtime_coarse"))
1323 		clk = CLOCK_REALTIME_COARSE;
1324 	else if (sysfs_streq(buf, "monotonic_coarse"))
1325 		clk = CLOCK_MONOTONIC_COARSE;
1326 	else if (sysfs_streq(buf, "boottime"))
1327 		clk = CLOCK_BOOTTIME;
1328 	else if (sysfs_streq(buf, "tai"))
1329 		clk = CLOCK_TAI;
1330 	else
1331 		return -EINVAL;
1332 
1333 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1334 	if (ret)
1335 		return ret;
1336 
1337 	return len;
1338 }
1339 
1340 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1341 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1342 
1343 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1344 {
1345 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1346 	struct iio_dev_attr *p;
1347 	struct attribute **attr, *clk = NULL;
1348 
1349 	/* First count elements in any existing group */
1350 	if (indio_dev->info->attrs) {
1351 		attr = indio_dev->info->attrs->attrs;
1352 		while (*attr++ != NULL)
1353 			attrcount_orig++;
1354 	}
1355 	attrcount = attrcount_orig;
1356 	/*
1357 	 * New channel registration method - relies on the fact a group does
1358 	 * not need to be initialized if its name is NULL.
1359 	 */
1360 	if (indio_dev->channels)
1361 		for (i = 0; i < indio_dev->num_channels; i++) {
1362 			const struct iio_chan_spec *chan =
1363 				&indio_dev->channels[i];
1364 
1365 			if (chan->type == IIO_TIMESTAMP)
1366 				clk = &dev_attr_current_timestamp_clock.attr;
1367 
1368 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1369 			if (ret < 0)
1370 				goto error_clear_attrs;
1371 			attrcount += ret;
1372 		}
1373 
1374 	if (indio_dev->event_interface)
1375 		clk = &dev_attr_current_timestamp_clock.attr;
1376 
1377 	if (indio_dev->name)
1378 		attrcount++;
1379 	if (clk)
1380 		attrcount++;
1381 
1382 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1383 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1384 						   GFP_KERNEL);
1385 	if (indio_dev->chan_attr_group.attrs == NULL) {
1386 		ret = -ENOMEM;
1387 		goto error_clear_attrs;
1388 	}
1389 	/* Copy across original attributes */
1390 	if (indio_dev->info->attrs)
1391 		memcpy(indio_dev->chan_attr_group.attrs,
1392 		       indio_dev->info->attrs->attrs,
1393 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1394 		       *attrcount_orig);
1395 	attrn = attrcount_orig;
1396 	/* Add all elements from the list. */
1397 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1398 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1399 	if (indio_dev->name)
1400 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1401 	if (clk)
1402 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1403 
1404 	indio_dev->groups[indio_dev->groupcounter++] =
1405 		&indio_dev->chan_attr_group;
1406 
1407 	return 0;
1408 
1409 error_clear_attrs:
1410 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1411 
1412 	return ret;
1413 }
1414 
1415 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1416 {
1417 
1418 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1419 	kfree(indio_dev->chan_attr_group.attrs);
1420 	indio_dev->chan_attr_group.attrs = NULL;
1421 }
1422 
1423 static void iio_dev_release(struct device *device)
1424 {
1425 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1426 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1427 		iio_device_unregister_trigger_consumer(indio_dev);
1428 	iio_device_unregister_eventset(indio_dev);
1429 	iio_device_unregister_sysfs(indio_dev);
1430 
1431 	iio_buffer_put(indio_dev->buffer);
1432 
1433 	ida_simple_remove(&iio_ida, indio_dev->id);
1434 	kfree(indio_dev);
1435 }
1436 
1437 struct device_type iio_device_type = {
1438 	.name = "iio_device",
1439 	.release = iio_dev_release,
1440 };
1441 
1442 /**
1443  * iio_device_alloc() - allocate an iio_dev from a driver
1444  * @sizeof_priv:	Space to allocate for private structure.
1445  **/
1446 struct iio_dev *iio_device_alloc(int sizeof_priv)
1447 {
1448 	struct iio_dev *dev;
1449 	size_t alloc_size;
1450 
1451 	alloc_size = sizeof(struct iio_dev);
1452 	if (sizeof_priv) {
1453 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1454 		alloc_size += sizeof_priv;
1455 	}
1456 	/* ensure 32-byte alignment of whole construct ? */
1457 	alloc_size += IIO_ALIGN - 1;
1458 
1459 	dev = kzalloc(alloc_size, GFP_KERNEL);
1460 
1461 	if (dev) {
1462 		dev->dev.groups = dev->groups;
1463 		dev->dev.type = &iio_device_type;
1464 		dev->dev.bus = &iio_bus_type;
1465 		device_initialize(&dev->dev);
1466 		dev_set_drvdata(&dev->dev, (void *)dev);
1467 		mutex_init(&dev->mlock);
1468 		mutex_init(&dev->info_exist_lock);
1469 		INIT_LIST_HEAD(&dev->channel_attr_list);
1470 
1471 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1472 		if (dev->id < 0) {
1473 			/* cannot use a dev_err as the name isn't available */
1474 			pr_err("failed to get device id\n");
1475 			kfree(dev);
1476 			return NULL;
1477 		}
1478 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1479 		INIT_LIST_HEAD(&dev->buffer_list);
1480 	}
1481 
1482 	return dev;
1483 }
1484 EXPORT_SYMBOL(iio_device_alloc);
1485 
1486 /**
1487  * iio_device_free() - free an iio_dev from a driver
1488  * @dev:		the iio_dev associated with the device
1489  **/
1490 void iio_device_free(struct iio_dev *dev)
1491 {
1492 	if (dev)
1493 		put_device(&dev->dev);
1494 }
1495 EXPORT_SYMBOL(iio_device_free);
1496 
1497 static void devm_iio_device_release(struct device *dev, void *res)
1498 {
1499 	iio_device_free(*(struct iio_dev **)res);
1500 }
1501 
1502 int devm_iio_device_match(struct device *dev, void *res, void *data)
1503 {
1504 	struct iio_dev **r = res;
1505 	if (!r || !*r) {
1506 		WARN_ON(!r || !*r);
1507 		return 0;
1508 	}
1509 	return *r == data;
1510 }
1511 EXPORT_SYMBOL_GPL(devm_iio_device_match);
1512 
1513 /**
1514  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1515  * @dev:		Device to allocate iio_dev for
1516  * @sizeof_priv:	Space to allocate for private structure.
1517  *
1518  * Managed iio_device_alloc. iio_dev allocated with this function is
1519  * automatically freed on driver detach.
1520  *
1521  * If an iio_dev allocated with this function needs to be freed separately,
1522  * devm_iio_device_free() must be used.
1523  *
1524  * RETURNS:
1525  * Pointer to allocated iio_dev on success, NULL on failure.
1526  */
1527 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1528 {
1529 	struct iio_dev **ptr, *iio_dev;
1530 
1531 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1532 			   GFP_KERNEL);
1533 	if (!ptr)
1534 		return NULL;
1535 
1536 	iio_dev = iio_device_alloc(sizeof_priv);
1537 	if (iio_dev) {
1538 		*ptr = iio_dev;
1539 		devres_add(dev, ptr);
1540 	} else {
1541 		devres_free(ptr);
1542 	}
1543 
1544 	return iio_dev;
1545 }
1546 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1547 
1548 /**
1549  * devm_iio_device_free - Resource-managed iio_device_free()
1550  * @dev:		Device this iio_dev belongs to
1551  * @iio_dev:		the iio_dev associated with the device
1552  *
1553  * Free iio_dev allocated with devm_iio_device_alloc().
1554  */
1555 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1556 {
1557 	int rc;
1558 
1559 	rc = devres_release(dev, devm_iio_device_release,
1560 			    devm_iio_device_match, iio_dev);
1561 	WARN_ON(rc);
1562 }
1563 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1564 
1565 /**
1566  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1567  * @inode:	Inode structure for identifying the device in the file system
1568  * @filp:	File structure for iio device used to keep and later access
1569  *		private data
1570  *
1571  * Return: 0 on success or -EBUSY if the device is already opened
1572  **/
1573 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1574 {
1575 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1576 						struct iio_dev, chrdev);
1577 
1578 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1579 		return -EBUSY;
1580 
1581 	iio_device_get(indio_dev);
1582 
1583 	filp->private_data = indio_dev;
1584 
1585 	return 0;
1586 }
1587 
1588 /**
1589  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1590  * @inode:	Inode structure pointer for the char device
1591  * @filp:	File structure pointer for the char device
1592  *
1593  * Return: 0 for successful release
1594  */
1595 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1596 {
1597 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1598 						struct iio_dev, chrdev);
1599 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1600 	iio_device_put(indio_dev);
1601 
1602 	return 0;
1603 }
1604 
1605 /* Somewhat of a cross file organization violation - ioctls here are actually
1606  * event related */
1607 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1608 {
1609 	struct iio_dev *indio_dev = filp->private_data;
1610 	int __user *ip = (int __user *)arg;
1611 	int fd;
1612 
1613 	if (!indio_dev->info)
1614 		return -ENODEV;
1615 
1616 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1617 		fd = iio_event_getfd(indio_dev);
1618 		if (fd < 0)
1619 			return fd;
1620 		if (copy_to_user(ip, &fd, sizeof(fd)))
1621 			return -EFAULT;
1622 		return 0;
1623 	}
1624 	return -EINVAL;
1625 }
1626 
1627 static const struct file_operations iio_buffer_fileops = {
1628 	.read = iio_buffer_read_first_n_outer_addr,
1629 	.release = iio_chrdev_release,
1630 	.open = iio_chrdev_open,
1631 	.poll = iio_buffer_poll_addr,
1632 	.owner = THIS_MODULE,
1633 	.llseek = noop_llseek,
1634 	.unlocked_ioctl = iio_ioctl,
1635 	.compat_ioctl = iio_ioctl,
1636 };
1637 
1638 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1639 {
1640 	int i, j;
1641 	const struct iio_chan_spec *channels = indio_dev->channels;
1642 
1643 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1644 		return 0;
1645 
1646 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1647 		if (channels[i].scan_index < 0)
1648 			continue;
1649 		for (j = i + 1; j < indio_dev->num_channels; j++)
1650 			if (channels[i].scan_index == channels[j].scan_index) {
1651 				dev_err(&indio_dev->dev,
1652 					"Duplicate scan index %d\n",
1653 					channels[i].scan_index);
1654 				return -EINVAL;
1655 			}
1656 	}
1657 
1658 	return 0;
1659 }
1660 
1661 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1662 
1663 /**
1664  * iio_device_register() - register a device with the IIO subsystem
1665  * @indio_dev:		Device structure filled by the device driver
1666  **/
1667 int iio_device_register(struct iio_dev *indio_dev)
1668 {
1669 	int ret;
1670 
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 	/* configure elements for the chrdev */
1680 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1681 
1682 	ret = iio_device_register_debugfs(indio_dev);
1683 	if (ret) {
1684 		dev_err(indio_dev->dev.parent,
1685 			"Failed to register debugfs interfaces\n");
1686 		return ret;
1687 	}
1688 
1689 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1690 	if (ret) {
1691 		dev_err(indio_dev->dev.parent,
1692 			"Failed to create buffer sysfs interfaces\n");
1693 		goto error_unreg_debugfs;
1694 	}
1695 
1696 	ret = iio_device_register_sysfs(indio_dev);
1697 	if (ret) {
1698 		dev_err(indio_dev->dev.parent,
1699 			"Failed to register sysfs interfaces\n");
1700 		goto error_buffer_free_sysfs;
1701 	}
1702 	ret = iio_device_register_eventset(indio_dev);
1703 	if (ret) {
1704 		dev_err(indio_dev->dev.parent,
1705 			"Failed to register event set\n");
1706 		goto error_free_sysfs;
1707 	}
1708 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1709 		iio_device_register_trigger_consumer(indio_dev);
1710 
1711 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1712 		indio_dev->setup_ops == NULL)
1713 		indio_dev->setup_ops = &noop_ring_setup_ops;
1714 
1715 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1716 	indio_dev->chrdev.owner = indio_dev->info->driver_module;
1717 
1718 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
1719 	if (ret < 0)
1720 		goto error_unreg_eventset;
1721 
1722 	return 0;
1723 
1724 error_unreg_eventset:
1725 	iio_device_unregister_eventset(indio_dev);
1726 error_free_sysfs:
1727 	iio_device_unregister_sysfs(indio_dev);
1728 error_buffer_free_sysfs:
1729 	iio_buffer_free_sysfs_and_mask(indio_dev);
1730 error_unreg_debugfs:
1731 	iio_device_unregister_debugfs(indio_dev);
1732 	return ret;
1733 }
1734 EXPORT_SYMBOL(iio_device_register);
1735 
1736 /**
1737  * iio_device_unregister() - unregister a device from the IIO subsystem
1738  * @indio_dev:		Device structure representing the device.
1739  **/
1740 void iio_device_unregister(struct iio_dev *indio_dev)
1741 {
1742 	mutex_lock(&indio_dev->info_exist_lock);
1743 
1744 	cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
1745 
1746 	iio_device_unregister_debugfs(indio_dev);
1747 
1748 	iio_disable_all_buffers(indio_dev);
1749 
1750 	indio_dev->info = NULL;
1751 
1752 	iio_device_wakeup_eventset(indio_dev);
1753 	iio_buffer_wakeup_poll(indio_dev);
1754 
1755 	mutex_unlock(&indio_dev->info_exist_lock);
1756 
1757 	iio_buffer_free_sysfs_and_mask(indio_dev);
1758 }
1759 EXPORT_SYMBOL(iio_device_unregister);
1760 
1761 static void devm_iio_device_unreg(struct device *dev, void *res)
1762 {
1763 	iio_device_unregister(*(struct iio_dev **)res);
1764 }
1765 
1766 /**
1767  * devm_iio_device_register - Resource-managed iio_device_register()
1768  * @dev:	Device to allocate iio_dev for
1769  * @indio_dev:	Device structure filled by the device driver
1770  *
1771  * Managed iio_device_register.  The IIO device registered with this
1772  * function is automatically unregistered on driver detach. This function
1773  * calls iio_device_register() internally. Refer to that function for more
1774  * information.
1775  *
1776  * If an iio_dev registered with this function needs to be unregistered
1777  * separately, devm_iio_device_unregister() must be used.
1778  *
1779  * RETURNS:
1780  * 0 on success, negative error number on failure.
1781  */
1782 int devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev)
1783 {
1784 	struct iio_dev **ptr;
1785 	int ret;
1786 
1787 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1788 	if (!ptr)
1789 		return -ENOMEM;
1790 
1791 	*ptr = indio_dev;
1792 	ret = iio_device_register(indio_dev);
1793 	if (!ret)
1794 		devres_add(dev, ptr);
1795 	else
1796 		devres_free(ptr);
1797 
1798 	return ret;
1799 }
1800 EXPORT_SYMBOL_GPL(devm_iio_device_register);
1801 
1802 /**
1803  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1804  * @dev:	Device this iio_dev belongs to
1805  * @indio_dev:	the iio_dev associated with the device
1806  *
1807  * Unregister iio_dev registered with devm_iio_device_register().
1808  */
1809 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1810 {
1811 	int rc;
1812 
1813 	rc = devres_release(dev, devm_iio_device_unreg,
1814 			    devm_iio_device_match, indio_dev);
1815 	WARN_ON(rc);
1816 }
1817 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1818 
1819 /**
1820  * iio_device_claim_direct_mode - Keep device in direct mode
1821  * @indio_dev:	the iio_dev associated with the device
1822  *
1823  * If the device is in direct mode it is guaranteed to stay
1824  * that way until iio_device_release_direct_mode() is called.
1825  *
1826  * Use with iio_device_release_direct_mode()
1827  *
1828  * Returns: 0 on success, -EBUSY on failure
1829  */
1830 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1831 {
1832 	mutex_lock(&indio_dev->mlock);
1833 
1834 	if (iio_buffer_enabled(indio_dev)) {
1835 		mutex_unlock(&indio_dev->mlock);
1836 		return -EBUSY;
1837 	}
1838 	return 0;
1839 }
1840 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1841 
1842 /**
1843  * iio_device_release_direct_mode - releases claim on direct mode
1844  * @indio_dev:	the iio_dev associated with the device
1845  *
1846  * Release the claim. Device is no longer guaranteed to stay
1847  * in direct mode.
1848  *
1849  * Use with iio_device_claim_direct_mode()
1850  */
1851 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1852 {
1853 	mutex_unlock(&indio_dev->mlock);
1854 }
1855 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1856 
1857 subsys_initcall(iio_init);
1858 module_exit(iio_exit);
1859 
1860 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1861 MODULE_DESCRIPTION("Industrial I/O core");
1862 MODULE_LICENSE("GPL");
1863