1 // SPDX-License-Identifier: GPL-2.0-only
2 /* The industrial I/O core
3  *
4  * Copyright (c) 2008 Jonathan Cameron
5  *
6  * Based on elements of hwmon and input subsystems.
7  */
8 
9 #define pr_fmt(fmt) "iio-core: " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/idr.h>
14 #include <linux/kdev_t.h>
15 #include <linux/err.h>
16 #include <linux/device.h>
17 #include <linux/fs.h>
18 #include <linux/poll.h>
19 #include <linux/property.h>
20 #include <linux/sched.h>
21 #include <linux/wait.h>
22 #include <linux/cdev.h>
23 #include <linux/slab.h>
24 #include <linux/anon_inodes.h>
25 #include <linux/debugfs.h>
26 #include <linux/mutex.h>
27 #include <linux/iio/iio.h>
28 #include "iio_core.h"
29 #include "iio_core_trigger.h"
30 #include <linux/iio/sysfs.h>
31 #include <linux/iio/events.h>
32 #include <linux/iio/buffer.h>
33 #include <linux/iio/buffer_impl.h>
34 
35 /* IDA to assign each registered device a unique id */
36 static DEFINE_IDA(iio_ida);
37 
38 static dev_t iio_devt;
39 
40 #define IIO_DEV_MAX 256
41 struct bus_type iio_bus_type = {
42 	.name = "iio",
43 };
44 EXPORT_SYMBOL(iio_bus_type);
45 
46 static struct dentry *iio_debugfs_dentry;
47 
48 static const char * const iio_direction[] = {
49 	[0] = "in",
50 	[1] = "out",
51 };
52 
53 static const char * const iio_chan_type_name_spec[] = {
54 	[IIO_VOLTAGE] = "voltage",
55 	[IIO_CURRENT] = "current",
56 	[IIO_POWER] = "power",
57 	[IIO_ACCEL] = "accel",
58 	[IIO_ANGL_VEL] = "anglvel",
59 	[IIO_MAGN] = "magn",
60 	[IIO_LIGHT] = "illuminance",
61 	[IIO_INTENSITY] = "intensity",
62 	[IIO_PROXIMITY] = "proximity",
63 	[IIO_TEMP] = "temp",
64 	[IIO_INCLI] = "incli",
65 	[IIO_ROT] = "rot",
66 	[IIO_ANGL] = "angl",
67 	[IIO_TIMESTAMP] = "timestamp",
68 	[IIO_CAPACITANCE] = "capacitance",
69 	[IIO_ALTVOLTAGE] = "altvoltage",
70 	[IIO_CCT] = "cct",
71 	[IIO_PRESSURE] = "pressure",
72 	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
73 	[IIO_ACTIVITY] = "activity",
74 	[IIO_STEPS] = "steps",
75 	[IIO_ENERGY] = "energy",
76 	[IIO_DISTANCE] = "distance",
77 	[IIO_VELOCITY] = "velocity",
78 	[IIO_CONCENTRATION] = "concentration",
79 	[IIO_RESISTANCE] = "resistance",
80 	[IIO_PH] = "ph",
81 	[IIO_UVINDEX] = "uvindex",
82 	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
83 	[IIO_COUNT] = "count",
84 	[IIO_INDEX] = "index",
85 	[IIO_GRAVITY]  = "gravity",
86 	[IIO_POSITIONRELATIVE]  = "positionrelative",
87 	[IIO_PHASE] = "phase",
88 	[IIO_MASSCONCENTRATION] = "massconcentration",
89 };
90 
91 static const char * const iio_modifier_names[] = {
92 	[IIO_MOD_X] = "x",
93 	[IIO_MOD_Y] = "y",
94 	[IIO_MOD_Z] = "z",
95 	[IIO_MOD_X_AND_Y] = "x&y",
96 	[IIO_MOD_X_AND_Z] = "x&z",
97 	[IIO_MOD_Y_AND_Z] = "y&z",
98 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
99 	[IIO_MOD_X_OR_Y] = "x|y",
100 	[IIO_MOD_X_OR_Z] = "x|z",
101 	[IIO_MOD_Y_OR_Z] = "y|z",
102 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
103 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
104 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
105 	[IIO_MOD_LIGHT_BOTH] = "both",
106 	[IIO_MOD_LIGHT_IR] = "ir",
107 	[IIO_MOD_LIGHT_CLEAR] = "clear",
108 	[IIO_MOD_LIGHT_RED] = "red",
109 	[IIO_MOD_LIGHT_GREEN] = "green",
110 	[IIO_MOD_LIGHT_BLUE] = "blue",
111 	[IIO_MOD_LIGHT_UV] = "uv",
112 	[IIO_MOD_LIGHT_DUV] = "duv",
113 	[IIO_MOD_QUATERNION] = "quaternion",
114 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
115 	[IIO_MOD_TEMP_OBJECT] = "object",
116 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
117 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
118 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
119 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
120 	[IIO_MOD_RUNNING] = "running",
121 	[IIO_MOD_JOGGING] = "jogging",
122 	[IIO_MOD_WALKING] = "walking",
123 	[IIO_MOD_STILL] = "still",
124 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
125 	[IIO_MOD_I] = "i",
126 	[IIO_MOD_Q] = "q",
127 	[IIO_MOD_CO2] = "co2",
128 	[IIO_MOD_VOC] = "voc",
129 	[IIO_MOD_PM1] = "pm1",
130 	[IIO_MOD_PM2P5] = "pm2p5",
131 	[IIO_MOD_PM4] = "pm4",
132 	[IIO_MOD_PM10] = "pm10",
133 	[IIO_MOD_ETHANOL] = "ethanol",
134 	[IIO_MOD_H2] = "h2",
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 	[IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
167 };
168 
169 /**
170  * iio_find_channel_from_si() - get channel from its scan index
171  * @indio_dev:		device
172  * @si:			scan index to match
173  */
174 const struct iio_chan_spec
175 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
176 {
177 	int i;
178 
179 	for (i = 0; i < indio_dev->num_channels; i++)
180 		if (indio_dev->channels[i].scan_index == si)
181 			return &indio_dev->channels[i];
182 	return NULL;
183 }
184 
185 /* This turns up an awful lot */
186 ssize_t iio_read_const_attr(struct device *dev,
187 			    struct device_attribute *attr,
188 			    char *buf)
189 {
190 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
191 }
192 EXPORT_SYMBOL(iio_read_const_attr);
193 
194 /**
195  * iio_device_set_clock() - Set current timestamping clock for the device
196  * @indio_dev: IIO device structure containing the device
197  * @clock_id: timestamping clock posix identifier to set.
198  */
199 int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
200 {
201 	int ret;
202 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
203 
204 	ret = mutex_lock_interruptible(&indio_dev->mlock);
205 	if (ret)
206 		return ret;
207 	if ((ev_int && iio_event_enabled(ev_int)) ||
208 	    iio_buffer_enabled(indio_dev)) {
209 		mutex_unlock(&indio_dev->mlock);
210 		return -EBUSY;
211 	}
212 	indio_dev->clock_id = clock_id;
213 	mutex_unlock(&indio_dev->mlock);
214 
215 	return 0;
216 }
217 EXPORT_SYMBOL(iio_device_set_clock);
218 
219 /**
220  * iio_get_time_ns() - utility function to get a time stamp for events etc
221  * @indio_dev: device
222  */
223 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
224 {
225 	struct timespec64 tp;
226 
227 	switch (iio_device_get_clock(indio_dev)) {
228 	case CLOCK_REALTIME:
229 		return ktime_get_real_ns();
230 	case CLOCK_MONOTONIC:
231 		return ktime_get_ns();
232 	case CLOCK_MONOTONIC_RAW:
233 		return ktime_get_raw_ns();
234 	case CLOCK_REALTIME_COARSE:
235 		return ktime_to_ns(ktime_get_coarse_real());
236 	case CLOCK_MONOTONIC_COARSE:
237 		ktime_get_coarse_ts64(&tp);
238 		return timespec64_to_ns(&tp);
239 	case CLOCK_BOOTTIME:
240 		return ktime_get_boottime_ns();
241 	case CLOCK_TAI:
242 		return ktime_get_clocktai_ns();
243 	default:
244 		BUG();
245 	}
246 }
247 EXPORT_SYMBOL(iio_get_time_ns);
248 
249 /**
250  * iio_get_time_res() - utility function to get time stamp clock resolution in
251  *                      nano seconds.
252  * @indio_dev: device
253  */
254 unsigned int iio_get_time_res(const struct iio_dev *indio_dev)
255 {
256 	switch (iio_device_get_clock(indio_dev)) {
257 	case CLOCK_REALTIME:
258 	case CLOCK_MONOTONIC:
259 	case CLOCK_MONOTONIC_RAW:
260 	case CLOCK_BOOTTIME:
261 	case CLOCK_TAI:
262 		return hrtimer_resolution;
263 	case CLOCK_REALTIME_COARSE:
264 	case CLOCK_MONOTONIC_COARSE:
265 		return LOW_RES_NSEC;
266 	default:
267 		BUG();
268 	}
269 }
270 EXPORT_SYMBOL(iio_get_time_res);
271 
272 static int __init iio_init(void)
273 {
274 	int ret;
275 
276 	/* Register sysfs bus */
277 	ret  = bus_register(&iio_bus_type);
278 	if (ret < 0) {
279 		pr_err("could not register bus type\n");
280 		goto error_nothing;
281 	}
282 
283 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
284 	if (ret < 0) {
285 		pr_err("failed to allocate char dev region\n");
286 		goto error_unregister_bus_type;
287 	}
288 
289 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
290 
291 	return 0;
292 
293 error_unregister_bus_type:
294 	bus_unregister(&iio_bus_type);
295 error_nothing:
296 	return ret;
297 }
298 
299 static void __exit iio_exit(void)
300 {
301 	if (iio_devt)
302 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
303 	bus_unregister(&iio_bus_type);
304 	debugfs_remove(iio_debugfs_dentry);
305 }
306 
307 #if defined(CONFIG_DEBUG_FS)
308 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
309 			      size_t count, loff_t *ppos)
310 {
311 	struct iio_dev *indio_dev = file->private_data;
312 	unsigned val = 0;
313 	int ret;
314 
315 	if (*ppos > 0)
316 		return simple_read_from_buffer(userbuf, count, ppos,
317 					       indio_dev->read_buf,
318 					       indio_dev->read_buf_len);
319 
320 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
321 						  indio_dev->cached_reg_addr,
322 						  0, &val);
323 	if (ret) {
324 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
325 		return ret;
326 	}
327 
328 	indio_dev->read_buf_len = snprintf(indio_dev->read_buf,
329 					   sizeof(indio_dev->read_buf),
330 					   "0x%X\n", val);
331 
332 	return simple_read_from_buffer(userbuf, count, ppos,
333 				       indio_dev->read_buf,
334 				       indio_dev->read_buf_len);
335 }
336 
337 static ssize_t iio_debugfs_write_reg(struct file *file,
338 		     const char __user *userbuf, size_t count, loff_t *ppos)
339 {
340 	struct iio_dev *indio_dev = file->private_data;
341 	unsigned reg, val;
342 	char buf[80];
343 	int ret;
344 
345 	count = min_t(size_t, count, (sizeof(buf)-1));
346 	if (copy_from_user(buf, userbuf, count))
347 		return -EFAULT;
348 
349 	buf[count] = 0;
350 
351 	ret = sscanf(buf, "%i %i", &reg, &val);
352 
353 	switch (ret) {
354 	case 1:
355 		indio_dev->cached_reg_addr = reg;
356 		break;
357 	case 2:
358 		indio_dev->cached_reg_addr = reg;
359 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
360 							  val, NULL);
361 		if (ret) {
362 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
363 				__func__);
364 			return ret;
365 		}
366 		break;
367 	default:
368 		return -EINVAL;
369 	}
370 
371 	return count;
372 }
373 
374 static const struct file_operations iio_debugfs_reg_fops = {
375 	.open = simple_open,
376 	.read = iio_debugfs_read_reg,
377 	.write = iio_debugfs_write_reg,
378 };
379 
380 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
381 {
382 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
383 }
384 
385 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
386 {
387 	if (indio_dev->info->debugfs_reg_access == NULL)
388 		return;
389 
390 	if (!iio_debugfs_dentry)
391 		return;
392 
393 	indio_dev->debugfs_dentry =
394 		debugfs_create_dir(dev_name(&indio_dev->dev),
395 				   iio_debugfs_dentry);
396 
397 	debugfs_create_file("direct_reg_access", 0644,
398 			    indio_dev->debugfs_dentry, indio_dev,
399 			    &iio_debugfs_reg_fops);
400 }
401 #else
402 static void iio_device_register_debugfs(struct iio_dev *indio_dev)
403 {
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  * iio_read_mount_matrix() - retrieve iio device mounting matrix from
534  *                           device "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 int iio_read_mount_matrix(struct device *dev, const char *propname,
545 			  struct iio_mount_matrix *matrix)
546 {
547 	size_t len = ARRAY_SIZE(iio_mount_idmatrix.rotation);
548 	int err;
549 
550 	err = device_property_read_string_array(dev, propname,
551 						matrix->rotation, len);
552 	if (err == len)
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 	/* Matrix was not declared at all: fallback to identity. */
564 	return iio_setup_mount_idmatrix(dev, matrix);
565 }
566 EXPORT_SYMBOL(iio_read_mount_matrix);
567 
568 static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
569 				  int size, const int *vals)
570 {
571 	unsigned long long tmp;
572 	int tmp0, tmp1;
573 	bool scale_db = false;
574 
575 	switch (type) {
576 	case IIO_VAL_INT:
577 		return scnprintf(buf, len, "%d", vals[0]);
578 	case IIO_VAL_INT_PLUS_MICRO_DB:
579 		scale_db = true;
580 		/* fall through */
581 	case IIO_VAL_INT_PLUS_MICRO:
582 		if (vals[1] < 0)
583 			return scnprintf(buf, len, "-%d.%06u%s", abs(vals[0]),
584 					-vals[1], scale_db ? " dB" : "");
585 		else
586 			return scnprintf(buf, len, "%d.%06u%s", vals[0], vals[1],
587 					scale_db ? " dB" : "");
588 	case IIO_VAL_INT_PLUS_NANO:
589 		if (vals[1] < 0)
590 			return scnprintf(buf, len, "-%d.%09u", abs(vals[0]),
591 					-vals[1]);
592 		else
593 			return scnprintf(buf, len, "%d.%09u", vals[0], vals[1]);
594 	case IIO_VAL_FRACTIONAL:
595 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
596 		tmp1 = vals[1];
597 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
598 		return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
599 	case IIO_VAL_FRACTIONAL_LOG2:
600 		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
601 		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
602 		return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
603 	case IIO_VAL_INT_MULTIPLE:
604 	{
605 		int i;
606 		int l = 0;
607 
608 		for (i = 0; i < size; ++i) {
609 			l += scnprintf(&buf[l], len - l, "%d ", vals[i]);
610 			if (l >= len)
611 				break;
612 		}
613 		return l;
614 	}
615 	case IIO_VAL_CHAR:
616 		return scnprintf(buf, len, "%c", (char)vals[0]);
617 	default:
618 		return 0;
619 	}
620 }
621 
622 /**
623  * iio_format_value() - Formats a IIO value into its string representation
624  * @buf:	The buffer to which the formatted value gets written
625  *		which is assumed to be big enough (i.e. PAGE_SIZE).
626  * @type:	One of the IIO_VAL_* constants. This decides how the val
627  *		and val2 parameters are formatted.
628  * @size:	Number of IIO value entries contained in vals
629  * @vals:	Pointer to the values, exact meaning depends on the
630  *		type parameter.
631  *
632  * Return: 0 by default, a negative number on failure or the
633  *	   total number of characters written for a type that belongs
634  *	   to the IIO_VAL_* constant.
635  */
636 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
637 {
638 	ssize_t len;
639 
640 	len = __iio_format_value(buf, PAGE_SIZE, type, size, vals);
641 	if (len >= PAGE_SIZE - 1)
642 		return -EFBIG;
643 
644 	return len + sprintf(buf + len, "\n");
645 }
646 EXPORT_SYMBOL_GPL(iio_format_value);
647 
648 static ssize_t iio_read_channel_info(struct device *dev,
649 				     struct device_attribute *attr,
650 				     char *buf)
651 {
652 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
653 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
654 	int vals[INDIO_MAX_RAW_ELEMENTS];
655 	int ret;
656 	int val_len = 2;
657 
658 	if (indio_dev->info->read_raw_multi)
659 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
660 							INDIO_MAX_RAW_ELEMENTS,
661 							vals, &val_len,
662 							this_attr->address);
663 	else
664 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
665 				    &vals[0], &vals[1], this_attr->address);
666 
667 	if (ret < 0)
668 		return ret;
669 
670 	return iio_format_value(buf, ret, val_len, vals);
671 }
672 
673 static ssize_t iio_format_avail_list(char *buf, const int *vals,
674 				     int type, int length)
675 {
676 	int i;
677 	ssize_t len = 0;
678 
679 	switch (type) {
680 	case IIO_VAL_INT:
681 		for (i = 0; i < length; i++) {
682 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
683 						  type, 1, &vals[i]);
684 			if (len >= PAGE_SIZE)
685 				return -EFBIG;
686 			if (i < length - 1)
687 				len += scnprintf(buf + len, PAGE_SIZE - len,
688 						" ");
689 			else
690 				len += scnprintf(buf + len, PAGE_SIZE - len,
691 						"\n");
692 			if (len >= PAGE_SIZE)
693 				return -EFBIG;
694 		}
695 		break;
696 	default:
697 		for (i = 0; i < length / 2; i++) {
698 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
699 						  type, 2, &vals[i * 2]);
700 			if (len >= PAGE_SIZE)
701 				return -EFBIG;
702 			if (i < length / 2 - 1)
703 				len += scnprintf(buf + len, PAGE_SIZE - len,
704 						" ");
705 			else
706 				len += scnprintf(buf + len, PAGE_SIZE - len,
707 						"\n");
708 			if (len >= PAGE_SIZE)
709 				return -EFBIG;
710 		}
711 	}
712 
713 	return len;
714 }
715 
716 static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
717 {
718 	int i;
719 	ssize_t len;
720 
721 	len = snprintf(buf, PAGE_SIZE, "[");
722 	switch (type) {
723 	case IIO_VAL_INT:
724 		for (i = 0; i < 3; i++) {
725 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
726 						  type, 1, &vals[i]);
727 			if (len >= PAGE_SIZE)
728 				return -EFBIG;
729 			if (i < 2)
730 				len += scnprintf(buf + len, PAGE_SIZE - len,
731 						" ");
732 			else
733 				len += scnprintf(buf + len, PAGE_SIZE - len,
734 						"]\n");
735 			if (len >= PAGE_SIZE)
736 				return -EFBIG;
737 		}
738 		break;
739 	default:
740 		for (i = 0; i < 3; i++) {
741 			len += __iio_format_value(buf + len, PAGE_SIZE - len,
742 						  type, 2, &vals[i * 2]);
743 			if (len >= PAGE_SIZE)
744 				return -EFBIG;
745 			if (i < 2)
746 				len += scnprintf(buf + len, PAGE_SIZE - len,
747 						" ");
748 			else
749 				len += scnprintf(buf + len, PAGE_SIZE - len,
750 						"]\n");
751 			if (len >= PAGE_SIZE)
752 				return -EFBIG;
753 		}
754 	}
755 
756 	return len;
757 }
758 
759 static ssize_t iio_read_channel_info_avail(struct device *dev,
760 					   struct device_attribute *attr,
761 					   char *buf)
762 {
763 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
764 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
765 	const int *vals;
766 	int ret;
767 	int length;
768 	int type;
769 
770 	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
771 					  &vals, &type, &length,
772 					  this_attr->address);
773 
774 	if (ret < 0)
775 		return ret;
776 	switch (ret) {
777 	case IIO_AVAIL_LIST:
778 		return iio_format_avail_list(buf, vals, type, length);
779 	case IIO_AVAIL_RANGE:
780 		return iio_format_avail_range(buf, vals, type);
781 	default:
782 		return -EINVAL;
783 	}
784 }
785 
786 /**
787  * __iio_str_to_fixpoint() - Parse a fixed-point number from a string
788  * @str: The string to parse
789  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
790  * @integer: The integer part of the number
791  * @fract: The fractional part of the number
792  * @scale_db: True if this should parse as dB
793  *
794  * Returns 0 on success, or a negative error code if the string could not be
795  * parsed.
796  */
797 static int __iio_str_to_fixpoint(const char *str, int fract_mult,
798 				 int *integer, int *fract, bool scale_db)
799 {
800 	int i = 0, f = 0;
801 	bool integer_part = true, negative = false;
802 
803 	if (fract_mult == 0) {
804 		*fract = 0;
805 
806 		return kstrtoint(str, 0, integer);
807 	}
808 
809 	if (str[0] == '-') {
810 		negative = true;
811 		str++;
812 	} else if (str[0] == '+') {
813 		str++;
814 	}
815 
816 	while (*str) {
817 		if ('0' <= *str && *str <= '9') {
818 			if (integer_part) {
819 				i = i * 10 + *str - '0';
820 			} else {
821 				f += fract_mult * (*str - '0');
822 				fract_mult /= 10;
823 			}
824 		} else if (*str == '\n') {
825 			if (*(str + 1) == '\0')
826 				break;
827 			else
828 				return -EINVAL;
829 		} else if (!strncmp(str, " dB", sizeof(" dB") - 1) && scale_db) {
830 			/* Ignore the dB suffix */
831 			str += sizeof(" dB") - 1;
832 			continue;
833 		} else if (!strncmp(str, "dB", sizeof("dB") - 1) && scale_db) {
834 			/* Ignore the dB suffix */
835 			str += sizeof("dB") - 1;
836 			continue;
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 
858 /**
859  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
860  * @str: The string to parse
861  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
862  * @integer: The integer part of the number
863  * @fract: The fractional part of the number
864  *
865  * Returns 0 on success, or a negative error code if the string could not be
866  * parsed.
867  */
868 int iio_str_to_fixpoint(const char *str, int fract_mult,
869 			int *integer, int *fract)
870 {
871 	return __iio_str_to_fixpoint(str, fract_mult, integer, fract, false);
872 }
873 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
874 
875 static ssize_t iio_write_channel_info(struct device *dev,
876 				      struct device_attribute *attr,
877 				      const char *buf,
878 				      size_t len)
879 {
880 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
881 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
882 	int ret, fract_mult = 100000;
883 	int integer, fract = 0;
884 	bool is_char = false;
885 	bool scale_db = false;
886 
887 	/* Assumes decimal - precision based on number of digits */
888 	if (!indio_dev->info->write_raw)
889 		return -EINVAL;
890 
891 	if (indio_dev->info->write_raw_get_fmt)
892 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
893 			this_attr->c, this_attr->address)) {
894 		case IIO_VAL_INT:
895 			fract_mult = 0;
896 			break;
897 		case IIO_VAL_INT_PLUS_MICRO_DB:
898 			scale_db = true;
899 			/* fall through */
900 		case IIO_VAL_INT_PLUS_MICRO:
901 			fract_mult = 100000;
902 			break;
903 		case IIO_VAL_INT_PLUS_NANO:
904 			fract_mult = 100000000;
905 			break;
906 		case IIO_VAL_CHAR:
907 			is_char = true;
908 			break;
909 		default:
910 			return -EINVAL;
911 		}
912 
913 	if (is_char) {
914 		char ch;
915 
916 		if (sscanf(buf, "%c", &ch) != 1)
917 			return -EINVAL;
918 		integer = ch;
919 	} else {
920 		ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
921 					    scale_db);
922 		if (ret)
923 			return ret;
924 	}
925 
926 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
927 					 integer, fract, this_attr->address);
928 	if (ret)
929 		return ret;
930 
931 	return len;
932 }
933 
934 static
935 int __iio_device_attr_init(struct device_attribute *dev_attr,
936 			   const char *postfix,
937 			   struct iio_chan_spec const *chan,
938 			   ssize_t (*readfunc)(struct device *dev,
939 					       struct device_attribute *attr,
940 					       char *buf),
941 			   ssize_t (*writefunc)(struct device *dev,
942 						struct device_attribute *attr,
943 						const char *buf,
944 						size_t len),
945 			   enum iio_shared_by shared_by)
946 {
947 	int ret = 0;
948 	char *name = NULL;
949 	char *full_postfix;
950 	sysfs_attr_init(&dev_attr->attr);
951 
952 	/* Build up postfix of <extend_name>_<modifier>_postfix */
953 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
954 		if (chan->extend_name)
955 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
956 						 iio_modifier_names[chan
957 								    ->channel2],
958 						 chan->extend_name,
959 						 postfix);
960 		else
961 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
962 						 iio_modifier_names[chan
963 								    ->channel2],
964 						 postfix);
965 	} else {
966 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
967 			full_postfix = kstrdup(postfix, GFP_KERNEL);
968 		else
969 			full_postfix = kasprintf(GFP_KERNEL,
970 						 "%s_%s",
971 						 chan->extend_name,
972 						 postfix);
973 	}
974 	if (full_postfix == NULL)
975 		return -ENOMEM;
976 
977 	if (chan->differential) { /* Differential can not have modifier */
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_%s",
989 					    iio_direction[chan->output],
990 					    iio_chan_type_name_spec[chan->type],
991 					    iio_chan_type_name_spec[chan->type],
992 					    full_postfix);
993 			break;
994 		case IIO_SEPARATE:
995 			if (!chan->indexed) {
996 				WARN(1, "Differential channels must be indexed\n");
997 				ret = -EINVAL;
998 				goto error_free_full_postfix;
999 			}
1000 			name = kasprintf(GFP_KERNEL,
1001 					    "%s_%s%d-%s%d_%s",
1002 					    iio_direction[chan->output],
1003 					    iio_chan_type_name_spec[chan->type],
1004 					    chan->channel,
1005 					    iio_chan_type_name_spec[chan->type],
1006 					    chan->channel2,
1007 					    full_postfix);
1008 			break;
1009 		}
1010 	} else { /* Single ended */
1011 		switch (shared_by) {
1012 		case IIO_SHARED_BY_ALL:
1013 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
1014 			break;
1015 		case IIO_SHARED_BY_DIR:
1016 			name = kasprintf(GFP_KERNEL, "%s_%s",
1017 						iio_direction[chan->output],
1018 						full_postfix);
1019 			break;
1020 		case IIO_SHARED_BY_TYPE:
1021 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1022 					    iio_direction[chan->output],
1023 					    iio_chan_type_name_spec[chan->type],
1024 					    full_postfix);
1025 			break;
1026 
1027 		case IIO_SEPARATE:
1028 			if (chan->indexed)
1029 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
1030 						    iio_direction[chan->output],
1031 						    iio_chan_type_name_spec[chan->type],
1032 						    chan->channel,
1033 						    full_postfix);
1034 			else
1035 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
1036 						    iio_direction[chan->output],
1037 						    iio_chan_type_name_spec[chan->type],
1038 						    full_postfix);
1039 			break;
1040 		}
1041 	}
1042 	if (name == NULL) {
1043 		ret = -ENOMEM;
1044 		goto error_free_full_postfix;
1045 	}
1046 	dev_attr->attr.name = name;
1047 
1048 	if (readfunc) {
1049 		dev_attr->attr.mode |= S_IRUGO;
1050 		dev_attr->show = readfunc;
1051 	}
1052 
1053 	if (writefunc) {
1054 		dev_attr->attr.mode |= S_IWUSR;
1055 		dev_attr->store = writefunc;
1056 	}
1057 
1058 error_free_full_postfix:
1059 	kfree(full_postfix);
1060 
1061 	return ret;
1062 }
1063 
1064 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
1065 {
1066 	kfree(dev_attr->attr.name);
1067 }
1068 
1069 int __iio_add_chan_devattr(const char *postfix,
1070 			   struct iio_chan_spec const *chan,
1071 			   ssize_t (*readfunc)(struct device *dev,
1072 					       struct device_attribute *attr,
1073 					       char *buf),
1074 			   ssize_t (*writefunc)(struct device *dev,
1075 						struct device_attribute *attr,
1076 						const char *buf,
1077 						size_t len),
1078 			   u64 mask,
1079 			   enum iio_shared_by shared_by,
1080 			   struct device *dev,
1081 			   struct list_head *attr_list)
1082 {
1083 	int ret;
1084 	struct iio_dev_attr *iio_attr, *t;
1085 
1086 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1087 	if (iio_attr == NULL)
1088 		return -ENOMEM;
1089 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
1090 				     postfix, chan,
1091 				     readfunc, writefunc, shared_by);
1092 	if (ret)
1093 		goto error_iio_dev_attr_free;
1094 	iio_attr->c = chan;
1095 	iio_attr->address = mask;
1096 	list_for_each_entry(t, attr_list, l)
1097 		if (strcmp(t->dev_attr.attr.name,
1098 			   iio_attr->dev_attr.attr.name) == 0) {
1099 			if (shared_by == IIO_SEPARATE)
1100 				dev_err(dev, "tried to double register : %s\n",
1101 					t->dev_attr.attr.name);
1102 			ret = -EBUSY;
1103 			goto error_device_attr_deinit;
1104 		}
1105 	list_add(&iio_attr->l, attr_list);
1106 
1107 	return 0;
1108 
1109 error_device_attr_deinit:
1110 	__iio_device_attr_deinit(&iio_attr->dev_attr);
1111 error_iio_dev_attr_free:
1112 	kfree(iio_attr);
1113 	return ret;
1114 }
1115 
1116 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
1117 					 struct iio_chan_spec const *chan,
1118 					 enum iio_shared_by shared_by,
1119 					 const long *infomask)
1120 {
1121 	int i, ret, attrcount = 0;
1122 
1123 	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
1124 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1125 			return -EINVAL;
1126 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
1127 					     chan,
1128 					     &iio_read_channel_info,
1129 					     &iio_write_channel_info,
1130 					     i,
1131 					     shared_by,
1132 					     &indio_dev->dev,
1133 					     &indio_dev->channel_attr_list);
1134 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1135 			continue;
1136 		else if (ret < 0)
1137 			return ret;
1138 		attrcount++;
1139 	}
1140 
1141 	return attrcount;
1142 }
1143 
1144 static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
1145 					       struct iio_chan_spec const *chan,
1146 					       enum iio_shared_by shared_by,
1147 					       const long *infomask)
1148 {
1149 	int i, ret, attrcount = 0;
1150 	char *avail_postfix;
1151 
1152 	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
1153 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
1154 			return -EINVAL;
1155 		avail_postfix = kasprintf(GFP_KERNEL,
1156 					  "%s_available",
1157 					  iio_chan_info_postfix[i]);
1158 		if (!avail_postfix)
1159 			return -ENOMEM;
1160 
1161 		ret = __iio_add_chan_devattr(avail_postfix,
1162 					     chan,
1163 					     &iio_read_channel_info_avail,
1164 					     NULL,
1165 					     i,
1166 					     shared_by,
1167 					     &indio_dev->dev,
1168 					     &indio_dev->channel_attr_list);
1169 		kfree(avail_postfix);
1170 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
1171 			continue;
1172 		else if (ret < 0)
1173 			return ret;
1174 		attrcount++;
1175 	}
1176 
1177 	return attrcount;
1178 }
1179 
1180 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
1181 					struct iio_chan_spec const *chan)
1182 {
1183 	int ret, attrcount = 0;
1184 	const struct iio_chan_spec_ext_info *ext_info;
1185 
1186 	if (chan->channel < 0)
1187 		return 0;
1188 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1189 					    IIO_SEPARATE,
1190 					    &chan->info_mask_separate);
1191 	if (ret < 0)
1192 		return ret;
1193 	attrcount += ret;
1194 
1195 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1196 						  IIO_SEPARATE,
1197 						  &chan->
1198 						  info_mask_separate_available);
1199 	if (ret < 0)
1200 		return ret;
1201 	attrcount += ret;
1202 
1203 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1204 					    IIO_SHARED_BY_TYPE,
1205 					    &chan->info_mask_shared_by_type);
1206 	if (ret < 0)
1207 		return ret;
1208 	attrcount += ret;
1209 
1210 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1211 						  IIO_SHARED_BY_TYPE,
1212 						  &chan->
1213 						  info_mask_shared_by_type_available);
1214 	if (ret < 0)
1215 		return ret;
1216 	attrcount += ret;
1217 
1218 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1219 					    IIO_SHARED_BY_DIR,
1220 					    &chan->info_mask_shared_by_dir);
1221 	if (ret < 0)
1222 		return ret;
1223 	attrcount += ret;
1224 
1225 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1226 						  IIO_SHARED_BY_DIR,
1227 						  &chan->info_mask_shared_by_dir_available);
1228 	if (ret < 0)
1229 		return ret;
1230 	attrcount += ret;
1231 
1232 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1233 					    IIO_SHARED_BY_ALL,
1234 					    &chan->info_mask_shared_by_all);
1235 	if (ret < 0)
1236 		return ret;
1237 	attrcount += ret;
1238 
1239 	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
1240 						  IIO_SHARED_BY_ALL,
1241 						  &chan->info_mask_shared_by_all_available);
1242 	if (ret < 0)
1243 		return ret;
1244 	attrcount += ret;
1245 
1246 	if (chan->ext_info) {
1247 		unsigned int i = 0;
1248 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1249 			ret = __iio_add_chan_devattr(ext_info->name,
1250 					chan,
1251 					ext_info->read ?
1252 					    &iio_read_channel_ext_info : NULL,
1253 					ext_info->write ?
1254 					    &iio_write_channel_ext_info : NULL,
1255 					i,
1256 					ext_info->shared,
1257 					&indio_dev->dev,
1258 					&indio_dev->channel_attr_list);
1259 			i++;
1260 			if (ret == -EBUSY && ext_info->shared)
1261 				continue;
1262 
1263 			if (ret)
1264 				return ret;
1265 
1266 			attrcount++;
1267 		}
1268 	}
1269 
1270 	return attrcount;
1271 }
1272 
1273 /**
1274  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1275  * @attr_list: List of IIO device attributes
1276  *
1277  * This function frees the memory allocated for each of the IIO device
1278  * attributes in the list.
1279  */
1280 void iio_free_chan_devattr_list(struct list_head *attr_list)
1281 {
1282 	struct iio_dev_attr *p, *n;
1283 
1284 	list_for_each_entry_safe(p, n, attr_list, l) {
1285 		kfree(p->dev_attr.attr.name);
1286 		list_del(&p->l);
1287 		kfree(p);
1288 	}
1289 }
1290 
1291 static ssize_t iio_show_dev_name(struct device *dev,
1292 				 struct device_attribute *attr,
1293 				 char *buf)
1294 {
1295 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1296 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1297 }
1298 
1299 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1300 
1301 static ssize_t iio_show_dev_label(struct device *dev,
1302 				 struct device_attribute *attr,
1303 				 char *buf)
1304 {
1305 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1306 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->label);
1307 }
1308 
1309 static DEVICE_ATTR(label, S_IRUGO, iio_show_dev_label, NULL);
1310 
1311 static ssize_t iio_show_timestamp_clock(struct device *dev,
1312 					struct device_attribute *attr,
1313 					char *buf)
1314 {
1315 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1316 	const clockid_t clk = iio_device_get_clock(indio_dev);
1317 	const char *name;
1318 	ssize_t sz;
1319 
1320 	switch (clk) {
1321 	case CLOCK_REALTIME:
1322 		name = "realtime\n";
1323 		sz = sizeof("realtime\n");
1324 		break;
1325 	case CLOCK_MONOTONIC:
1326 		name = "monotonic\n";
1327 		sz = sizeof("monotonic\n");
1328 		break;
1329 	case CLOCK_MONOTONIC_RAW:
1330 		name = "monotonic_raw\n";
1331 		sz = sizeof("monotonic_raw\n");
1332 		break;
1333 	case CLOCK_REALTIME_COARSE:
1334 		name = "realtime_coarse\n";
1335 		sz = sizeof("realtime_coarse\n");
1336 		break;
1337 	case CLOCK_MONOTONIC_COARSE:
1338 		name = "monotonic_coarse\n";
1339 		sz = sizeof("monotonic_coarse\n");
1340 		break;
1341 	case CLOCK_BOOTTIME:
1342 		name = "boottime\n";
1343 		sz = sizeof("boottime\n");
1344 		break;
1345 	case CLOCK_TAI:
1346 		name = "tai\n";
1347 		sz = sizeof("tai\n");
1348 		break;
1349 	default:
1350 		BUG();
1351 	}
1352 
1353 	memcpy(buf, name, sz);
1354 	return sz;
1355 }
1356 
1357 static ssize_t iio_store_timestamp_clock(struct device *dev,
1358 					 struct device_attribute *attr,
1359 					 const char *buf, size_t len)
1360 {
1361 	clockid_t clk;
1362 	int ret;
1363 
1364 	if (sysfs_streq(buf, "realtime"))
1365 		clk = CLOCK_REALTIME;
1366 	else if (sysfs_streq(buf, "monotonic"))
1367 		clk = CLOCK_MONOTONIC;
1368 	else if (sysfs_streq(buf, "monotonic_raw"))
1369 		clk = CLOCK_MONOTONIC_RAW;
1370 	else if (sysfs_streq(buf, "realtime_coarse"))
1371 		clk = CLOCK_REALTIME_COARSE;
1372 	else if (sysfs_streq(buf, "monotonic_coarse"))
1373 		clk = CLOCK_MONOTONIC_COARSE;
1374 	else if (sysfs_streq(buf, "boottime"))
1375 		clk = CLOCK_BOOTTIME;
1376 	else if (sysfs_streq(buf, "tai"))
1377 		clk = CLOCK_TAI;
1378 	else
1379 		return -EINVAL;
1380 
1381 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1382 	if (ret)
1383 		return ret;
1384 
1385 	return len;
1386 }
1387 
1388 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1389 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1390 
1391 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1392 {
1393 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1394 	struct iio_dev_attr *p;
1395 	struct attribute **attr, *clk = NULL;
1396 
1397 	/* First count elements in any existing group */
1398 	if (indio_dev->info->attrs) {
1399 		attr = indio_dev->info->attrs->attrs;
1400 		while (*attr++ != NULL)
1401 			attrcount_orig++;
1402 	}
1403 	attrcount = attrcount_orig;
1404 	/*
1405 	 * New channel registration method - relies on the fact a group does
1406 	 * not need to be initialized if its name is NULL.
1407 	 */
1408 	if (indio_dev->channels)
1409 		for (i = 0; i < indio_dev->num_channels; i++) {
1410 			const struct iio_chan_spec *chan =
1411 				&indio_dev->channels[i];
1412 
1413 			if (chan->type == IIO_TIMESTAMP)
1414 				clk = &dev_attr_current_timestamp_clock.attr;
1415 
1416 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1417 			if (ret < 0)
1418 				goto error_clear_attrs;
1419 			attrcount += ret;
1420 		}
1421 
1422 	if (indio_dev->event_interface)
1423 		clk = &dev_attr_current_timestamp_clock.attr;
1424 
1425 	if (indio_dev->name)
1426 		attrcount++;
1427 	if (indio_dev->label)
1428 		attrcount++;
1429 	if (clk)
1430 		attrcount++;
1431 
1432 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1433 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1434 						   GFP_KERNEL);
1435 	if (indio_dev->chan_attr_group.attrs == NULL) {
1436 		ret = -ENOMEM;
1437 		goto error_clear_attrs;
1438 	}
1439 	/* Copy across original attributes */
1440 	if (indio_dev->info->attrs)
1441 		memcpy(indio_dev->chan_attr_group.attrs,
1442 		       indio_dev->info->attrs->attrs,
1443 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1444 		       *attrcount_orig);
1445 	attrn = attrcount_orig;
1446 	/* Add all elements from the list. */
1447 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1448 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1449 	if (indio_dev->name)
1450 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1451 	if (indio_dev->label)
1452 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_label.attr;
1453 	if (clk)
1454 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1455 
1456 	indio_dev->groups[indio_dev->groupcounter++] =
1457 		&indio_dev->chan_attr_group;
1458 
1459 	return 0;
1460 
1461 error_clear_attrs:
1462 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1463 
1464 	return ret;
1465 }
1466 
1467 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1468 {
1469 
1470 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1471 	kfree(indio_dev->chan_attr_group.attrs);
1472 	indio_dev->chan_attr_group.attrs = NULL;
1473 }
1474 
1475 static void iio_dev_release(struct device *device)
1476 {
1477 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1478 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1479 		iio_device_unregister_trigger_consumer(indio_dev);
1480 	iio_device_unregister_eventset(indio_dev);
1481 	iio_device_unregister_sysfs(indio_dev);
1482 
1483 	iio_buffer_put(indio_dev->buffer);
1484 
1485 	ida_simple_remove(&iio_ida, indio_dev->id);
1486 	kfree(indio_dev);
1487 }
1488 
1489 struct device_type iio_device_type = {
1490 	.name = "iio_device",
1491 	.release = iio_dev_release,
1492 };
1493 
1494 /**
1495  * iio_device_alloc() - allocate an iio_dev from a driver
1496  * @sizeof_priv:	Space to allocate for private structure.
1497  **/
1498 struct iio_dev *iio_device_alloc(int sizeof_priv)
1499 {
1500 	struct iio_dev *dev;
1501 	size_t alloc_size;
1502 
1503 	alloc_size = sizeof(struct iio_dev);
1504 	if (sizeof_priv) {
1505 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1506 		alloc_size += sizeof_priv;
1507 	}
1508 	/* ensure 32-byte alignment of whole construct ? */
1509 	alloc_size += IIO_ALIGN - 1;
1510 
1511 	dev = kzalloc(alloc_size, GFP_KERNEL);
1512 	if (!dev)
1513 		return NULL;
1514 
1515 	dev->dev.groups = dev->groups;
1516 	dev->dev.type = &iio_device_type;
1517 	dev->dev.bus = &iio_bus_type;
1518 	device_initialize(&dev->dev);
1519 	dev_set_drvdata(&dev->dev, (void *)dev);
1520 	mutex_init(&dev->mlock);
1521 	mutex_init(&dev->info_exist_lock);
1522 	INIT_LIST_HEAD(&dev->channel_attr_list);
1523 
1524 	dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1525 	if (dev->id < 0) {
1526 		/* cannot use a dev_err as the name isn't available */
1527 		pr_err("failed to get device id\n");
1528 		kfree(dev);
1529 		return NULL;
1530 	}
1531 	dev_set_name(&dev->dev, "iio:device%d", dev->id);
1532 	INIT_LIST_HEAD(&dev->buffer_list);
1533 
1534 	return dev;
1535 }
1536 EXPORT_SYMBOL(iio_device_alloc);
1537 
1538 /**
1539  * iio_device_free() - free an iio_dev from a driver
1540  * @dev:		the iio_dev associated with the device
1541  **/
1542 void iio_device_free(struct iio_dev *dev)
1543 {
1544 	if (dev)
1545 		put_device(&dev->dev);
1546 }
1547 EXPORT_SYMBOL(iio_device_free);
1548 
1549 static void devm_iio_device_release(struct device *dev, void *res)
1550 {
1551 	iio_device_free(*(struct iio_dev **)res);
1552 }
1553 
1554 /**
1555  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1556  * @dev:		Device to allocate iio_dev for
1557  * @sizeof_priv:	Space to allocate for private structure.
1558  *
1559  * Managed iio_device_alloc. iio_dev allocated with this function is
1560  * automatically freed on driver detach.
1561  *
1562  * RETURNS:
1563  * Pointer to allocated iio_dev on success, NULL on failure.
1564  */
1565 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1566 {
1567 	struct iio_dev **ptr, *iio_dev;
1568 
1569 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1570 			   GFP_KERNEL);
1571 	if (!ptr)
1572 		return NULL;
1573 
1574 	iio_dev = iio_device_alloc(sizeof_priv);
1575 	if (iio_dev) {
1576 		*ptr = iio_dev;
1577 		devres_add(dev, ptr);
1578 	} else {
1579 		devres_free(ptr);
1580 	}
1581 
1582 	return iio_dev;
1583 }
1584 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1585 
1586 /**
1587  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1588  * @inode:	Inode structure for identifying the device in the file system
1589  * @filp:	File structure for iio device used to keep and later access
1590  *		private data
1591  *
1592  * Return: 0 on success or -EBUSY if the device is already opened
1593  **/
1594 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1595 {
1596 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1597 						struct iio_dev, chrdev);
1598 
1599 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1600 		return -EBUSY;
1601 
1602 	iio_device_get(indio_dev);
1603 
1604 	filp->private_data = indio_dev;
1605 
1606 	return 0;
1607 }
1608 
1609 /**
1610  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1611  * @inode:	Inode structure pointer for the char device
1612  * @filp:	File structure pointer for the char device
1613  *
1614  * Return: 0 for successful release
1615  */
1616 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1617 {
1618 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1619 						struct iio_dev, chrdev);
1620 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1621 	iio_device_put(indio_dev);
1622 
1623 	return 0;
1624 }
1625 
1626 /* Somewhat of a cross file organization violation - ioctls here are actually
1627  * event related */
1628 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1629 {
1630 	struct iio_dev *indio_dev = filp->private_data;
1631 	int __user *ip = (int __user *)arg;
1632 	int fd;
1633 
1634 	if (!indio_dev->info)
1635 		return -ENODEV;
1636 
1637 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1638 		fd = iio_event_getfd(indio_dev);
1639 		if (fd < 0)
1640 			return fd;
1641 		if (copy_to_user(ip, &fd, sizeof(fd)))
1642 			return -EFAULT;
1643 		return 0;
1644 	}
1645 	return -EINVAL;
1646 }
1647 
1648 static const struct file_operations iio_buffer_fileops = {
1649 	.read = iio_buffer_read_outer_addr,
1650 	.release = iio_chrdev_release,
1651 	.open = iio_chrdev_open,
1652 	.poll = iio_buffer_poll_addr,
1653 	.owner = THIS_MODULE,
1654 	.llseek = noop_llseek,
1655 	.unlocked_ioctl = iio_ioctl,
1656 	.compat_ioctl = compat_ptr_ioctl,
1657 };
1658 
1659 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1660 {
1661 	int i, j;
1662 	const struct iio_chan_spec *channels = indio_dev->channels;
1663 
1664 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1665 		return 0;
1666 
1667 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1668 		if (channels[i].scan_index < 0)
1669 			continue;
1670 		for (j = i + 1; j < indio_dev->num_channels; j++)
1671 			if (channels[i].scan_index == channels[j].scan_index) {
1672 				dev_err(&indio_dev->dev,
1673 					"Duplicate scan index %d\n",
1674 					channels[i].scan_index);
1675 				return -EINVAL;
1676 			}
1677 	}
1678 
1679 	return 0;
1680 }
1681 
1682 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1683 
1684 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
1685 {
1686 	int ret;
1687 
1688 	if (!indio_dev->info)
1689 		return -EINVAL;
1690 
1691 	indio_dev->driver_module = this_mod;
1692 	/* If the calling driver did not initialize of_node, do it here */
1693 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1694 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1695 
1696 	indio_dev->label = of_get_property(indio_dev->dev.of_node, "label",
1697 					   NULL);
1698 
1699 	ret = iio_check_unique_scan_index(indio_dev);
1700 	if (ret < 0)
1701 		return ret;
1702 
1703 	/* configure elements for the chrdev */
1704 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1705 
1706 	iio_device_register_debugfs(indio_dev);
1707 
1708 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1709 	if (ret) {
1710 		dev_err(indio_dev->dev.parent,
1711 			"Failed to create buffer sysfs interfaces\n");
1712 		goto error_unreg_debugfs;
1713 	}
1714 
1715 	ret = iio_device_register_sysfs(indio_dev);
1716 	if (ret) {
1717 		dev_err(indio_dev->dev.parent,
1718 			"Failed to register sysfs interfaces\n");
1719 		goto error_buffer_free_sysfs;
1720 	}
1721 	ret = iio_device_register_eventset(indio_dev);
1722 	if (ret) {
1723 		dev_err(indio_dev->dev.parent,
1724 			"Failed to register event set\n");
1725 		goto error_free_sysfs;
1726 	}
1727 	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
1728 		iio_device_register_trigger_consumer(indio_dev);
1729 
1730 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1731 		indio_dev->setup_ops == NULL)
1732 		indio_dev->setup_ops = &noop_ring_setup_ops;
1733 
1734 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1735 
1736 	indio_dev->chrdev.owner = this_mod;
1737 
1738 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
1739 	if (ret < 0)
1740 		goto error_unreg_eventset;
1741 
1742 	return 0;
1743 
1744 error_unreg_eventset:
1745 	iio_device_unregister_eventset(indio_dev);
1746 error_free_sysfs:
1747 	iio_device_unregister_sysfs(indio_dev);
1748 error_buffer_free_sysfs:
1749 	iio_buffer_free_sysfs_and_mask(indio_dev);
1750 error_unreg_debugfs:
1751 	iio_device_unregister_debugfs(indio_dev);
1752 	return ret;
1753 }
1754 EXPORT_SYMBOL(__iio_device_register);
1755 
1756 /**
1757  * iio_device_unregister() - unregister a device from the IIO subsystem
1758  * @indio_dev:		Device structure representing the device.
1759  **/
1760 void iio_device_unregister(struct iio_dev *indio_dev)
1761 {
1762 	cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
1763 
1764 	mutex_lock(&indio_dev->info_exist_lock);
1765 
1766 	iio_device_unregister_debugfs(indio_dev);
1767 
1768 	iio_disable_all_buffers(indio_dev);
1769 
1770 	indio_dev->info = NULL;
1771 
1772 	iio_device_wakeup_eventset(indio_dev);
1773 	iio_buffer_wakeup_poll(indio_dev);
1774 
1775 	mutex_unlock(&indio_dev->info_exist_lock);
1776 
1777 	iio_buffer_free_sysfs_and_mask(indio_dev);
1778 }
1779 EXPORT_SYMBOL(iio_device_unregister);
1780 
1781 static void devm_iio_device_unreg(struct device *dev, void *res)
1782 {
1783 	iio_device_unregister(*(struct iio_dev **)res);
1784 }
1785 
1786 int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
1787 			       struct module *this_mod)
1788 {
1789 	struct iio_dev **ptr;
1790 	int ret;
1791 
1792 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1793 	if (!ptr)
1794 		return -ENOMEM;
1795 
1796 	*ptr = indio_dev;
1797 	ret = __iio_device_register(indio_dev, this_mod);
1798 	if (!ret)
1799 		devres_add(dev, ptr);
1800 	else
1801 		devres_free(ptr);
1802 
1803 	return ret;
1804 }
1805 EXPORT_SYMBOL_GPL(__devm_iio_device_register);
1806 
1807 /**
1808  * iio_device_claim_direct_mode - Keep device in direct mode
1809  * @indio_dev:	the iio_dev associated with the device
1810  *
1811  * If the device is in direct mode it is guaranteed to stay
1812  * that way until iio_device_release_direct_mode() is called.
1813  *
1814  * Use with iio_device_release_direct_mode()
1815  *
1816  * Returns: 0 on success, -EBUSY on failure
1817  */
1818 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1819 {
1820 	mutex_lock(&indio_dev->mlock);
1821 
1822 	if (iio_buffer_enabled(indio_dev)) {
1823 		mutex_unlock(&indio_dev->mlock);
1824 		return -EBUSY;
1825 	}
1826 	return 0;
1827 }
1828 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1829 
1830 /**
1831  * iio_device_release_direct_mode - releases claim on direct mode
1832  * @indio_dev:	the iio_dev associated with the device
1833  *
1834  * Release the claim. Device is no longer guaranteed to stay
1835  * in direct mode.
1836  *
1837  * Use with iio_device_claim_direct_mode()
1838  */
1839 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1840 {
1841 	mutex_unlock(&indio_dev->mlock);
1842 }
1843 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1844 
1845 subsys_initcall(iio_init);
1846 module_exit(iio_exit);
1847 
1848 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1849 MODULE_DESCRIPTION("Industrial I/O core");
1850 MODULE_LICENSE("GPL");
1851