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 
36 /* IDA to assign each registered device a unique id */
37 static DEFINE_IDA(iio_ida);
38 
39 static dev_t iio_devt;
40 
41 #define IIO_DEV_MAX 256
42 struct bus_type iio_bus_type = {
43 	.name = "iio",
44 };
45 EXPORT_SYMBOL(iio_bus_type);
46 
47 static struct dentry *iio_debugfs_dentry;
48 
49 static const char * const iio_direction[] = {
50 	[0] = "in",
51 	[1] = "out",
52 };
53 
54 static const char * const iio_chan_type_name_spec[] = {
55 	[IIO_VOLTAGE] = "voltage",
56 	[IIO_CURRENT] = "current",
57 	[IIO_POWER] = "power",
58 	[IIO_ACCEL] = "accel",
59 	[IIO_ANGL_VEL] = "anglvel",
60 	[IIO_MAGN] = "magn",
61 	[IIO_LIGHT] = "illuminance",
62 	[IIO_INTENSITY] = "intensity",
63 	[IIO_PROXIMITY] = "proximity",
64 	[IIO_TEMP] = "temp",
65 	[IIO_INCLI] = "incli",
66 	[IIO_ROT] = "rot",
67 	[IIO_ANGL] = "angl",
68 	[IIO_TIMESTAMP] = "timestamp",
69 	[IIO_CAPACITANCE] = "capacitance",
70 	[IIO_ALTVOLTAGE] = "altvoltage",
71 	[IIO_CCT] = "cct",
72 	[IIO_PRESSURE] = "pressure",
73 	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
74 	[IIO_ACTIVITY] = "activity",
75 	[IIO_STEPS] = "steps",
76 	[IIO_ENERGY] = "energy",
77 	[IIO_DISTANCE] = "distance",
78 	[IIO_VELOCITY] = "velocity",
79 	[IIO_CONCENTRATION] = "concentration",
80 	[IIO_RESISTANCE] = "resistance",
81 	[IIO_PH] = "ph",
82 	[IIO_UVINDEX] = "uvindex",
83 	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
84 };
85 
86 static const char * const iio_modifier_names[] = {
87 	[IIO_MOD_X] = "x",
88 	[IIO_MOD_Y] = "y",
89 	[IIO_MOD_Z] = "z",
90 	[IIO_MOD_X_AND_Y] = "x&y",
91 	[IIO_MOD_X_AND_Z] = "x&z",
92 	[IIO_MOD_Y_AND_Z] = "y&z",
93 	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
94 	[IIO_MOD_X_OR_Y] = "x|y",
95 	[IIO_MOD_X_OR_Z] = "x|z",
96 	[IIO_MOD_Y_OR_Z] = "y|z",
97 	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
98 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
99 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
100 	[IIO_MOD_LIGHT_BOTH] = "both",
101 	[IIO_MOD_LIGHT_IR] = "ir",
102 	[IIO_MOD_LIGHT_CLEAR] = "clear",
103 	[IIO_MOD_LIGHT_RED] = "red",
104 	[IIO_MOD_LIGHT_GREEN] = "green",
105 	[IIO_MOD_LIGHT_BLUE] = "blue",
106 	[IIO_MOD_LIGHT_UV] = "uv",
107 	[IIO_MOD_QUATERNION] = "quaternion",
108 	[IIO_MOD_TEMP_AMBIENT] = "ambient",
109 	[IIO_MOD_TEMP_OBJECT] = "object",
110 	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
111 	[IIO_MOD_NORTH_TRUE] = "from_north_true",
112 	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
113 	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
114 	[IIO_MOD_RUNNING] = "running",
115 	[IIO_MOD_JOGGING] = "jogging",
116 	[IIO_MOD_WALKING] = "walking",
117 	[IIO_MOD_STILL] = "still",
118 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
119 	[IIO_MOD_I] = "i",
120 	[IIO_MOD_Q] = "q",
121 	[IIO_MOD_CO2] = "co2",
122 	[IIO_MOD_VOC] = "voc",
123 };
124 
125 /* relies on pairs of these shared then separate */
126 static const char * const iio_chan_info_postfix[] = {
127 	[IIO_CHAN_INFO_RAW] = "raw",
128 	[IIO_CHAN_INFO_PROCESSED] = "input",
129 	[IIO_CHAN_INFO_SCALE] = "scale",
130 	[IIO_CHAN_INFO_OFFSET] = "offset",
131 	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
132 	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
133 	[IIO_CHAN_INFO_PEAK] = "peak_raw",
134 	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
135 	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
136 	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
137 	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
138 	= "filter_low_pass_3db_frequency",
139 	[IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY]
140 	= "filter_high_pass_3db_frequency",
141 	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
142 	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
143 	[IIO_CHAN_INFO_PHASE] = "phase",
144 	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
145 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
146 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
147 	[IIO_CHAN_INFO_ENABLE] = "en",
148 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
149 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
150 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
151 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
152 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
153 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
154 };
155 
156 /**
157  * iio_find_channel_from_si() - get channel from its scan index
158  * @indio_dev:		device
159  * @si:			scan index to match
160  */
161 const struct iio_chan_spec
162 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
163 {
164 	int i;
165 
166 	for (i = 0; i < indio_dev->num_channels; i++)
167 		if (indio_dev->channels[i].scan_index == si)
168 			return &indio_dev->channels[i];
169 	return NULL;
170 }
171 
172 /* This turns up an awful lot */
173 ssize_t iio_read_const_attr(struct device *dev,
174 			    struct device_attribute *attr,
175 			    char *buf)
176 {
177 	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
178 }
179 EXPORT_SYMBOL(iio_read_const_attr);
180 
181 static int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
182 {
183 	int ret;
184 	const struct iio_event_interface *ev_int = indio_dev->event_interface;
185 
186 	ret = mutex_lock_interruptible(&indio_dev->mlock);
187 	if (ret)
188 		return ret;
189 	if ((ev_int && iio_event_enabled(ev_int)) ||
190 	    iio_buffer_enabled(indio_dev)) {
191 		mutex_unlock(&indio_dev->mlock);
192 		return -EBUSY;
193 	}
194 	indio_dev->clock_id = clock_id;
195 	mutex_unlock(&indio_dev->mlock);
196 
197 	return 0;
198 }
199 
200 /**
201  * iio_get_time_ns() - utility function to get a time stamp for events etc
202  * @indio_dev: device
203  */
204 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
205 {
206 	struct timespec tp;
207 
208 	switch (iio_device_get_clock(indio_dev)) {
209 	case CLOCK_REALTIME:
210 		ktime_get_real_ts(&tp);
211 		break;
212 	case CLOCK_MONOTONIC:
213 		ktime_get_ts(&tp);
214 		break;
215 	case CLOCK_MONOTONIC_RAW:
216 		getrawmonotonic(&tp);
217 		break;
218 	case CLOCK_REALTIME_COARSE:
219 		tp = current_kernel_time();
220 		break;
221 	case CLOCK_MONOTONIC_COARSE:
222 		tp = get_monotonic_coarse();
223 		break;
224 	case CLOCK_BOOTTIME:
225 		get_monotonic_boottime(&tp);
226 		break;
227 	case CLOCK_TAI:
228 		timekeeping_clocktai(&tp);
229 		break;
230 	default:
231 		BUG();
232 	}
233 
234 	return timespec_to_ns(&tp);
235 }
236 EXPORT_SYMBOL(iio_get_time_ns);
237 
238 /**
239  * iio_get_time_res() - utility function to get time stamp clock resolution in
240  *                      nano seconds.
241  * @indio_dev: device
242  */
243 unsigned int iio_get_time_res(const struct iio_dev *indio_dev)
244 {
245 	switch (iio_device_get_clock(indio_dev)) {
246 	case CLOCK_REALTIME:
247 	case CLOCK_MONOTONIC:
248 	case CLOCK_MONOTONIC_RAW:
249 	case CLOCK_BOOTTIME:
250 	case CLOCK_TAI:
251 		return hrtimer_resolution;
252 	case CLOCK_REALTIME_COARSE:
253 	case CLOCK_MONOTONIC_COARSE:
254 		return LOW_RES_NSEC;
255 	default:
256 		BUG();
257 	}
258 }
259 EXPORT_SYMBOL(iio_get_time_res);
260 
261 static int __init iio_init(void)
262 {
263 	int ret;
264 
265 	/* Register sysfs bus */
266 	ret  = bus_register(&iio_bus_type);
267 	if (ret < 0) {
268 		pr_err("could not register bus type\n");
269 		goto error_nothing;
270 	}
271 
272 	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
273 	if (ret < 0) {
274 		pr_err("failed to allocate char dev region\n");
275 		goto error_unregister_bus_type;
276 	}
277 
278 	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
279 
280 	return 0;
281 
282 error_unregister_bus_type:
283 	bus_unregister(&iio_bus_type);
284 error_nothing:
285 	return ret;
286 }
287 
288 static void __exit iio_exit(void)
289 {
290 	if (iio_devt)
291 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
292 	bus_unregister(&iio_bus_type);
293 	debugfs_remove(iio_debugfs_dentry);
294 }
295 
296 #if defined(CONFIG_DEBUG_FS)
297 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
298 			      size_t count, loff_t *ppos)
299 {
300 	struct iio_dev *indio_dev = file->private_data;
301 	char buf[20];
302 	unsigned val = 0;
303 	ssize_t len;
304 	int ret;
305 
306 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
307 						  indio_dev->cached_reg_addr,
308 						  0, &val);
309 	if (ret)
310 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
311 
312 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
313 
314 	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
315 }
316 
317 static ssize_t iio_debugfs_write_reg(struct file *file,
318 		     const char __user *userbuf, size_t count, loff_t *ppos)
319 {
320 	struct iio_dev *indio_dev = file->private_data;
321 	unsigned reg, val;
322 	char buf[80];
323 	int ret;
324 
325 	count = min_t(size_t, count, (sizeof(buf)-1));
326 	if (copy_from_user(buf, userbuf, count))
327 		return -EFAULT;
328 
329 	buf[count] = 0;
330 
331 	ret = sscanf(buf, "%i %i", &reg, &val);
332 
333 	switch (ret) {
334 	case 1:
335 		indio_dev->cached_reg_addr = reg;
336 		break;
337 	case 2:
338 		indio_dev->cached_reg_addr = reg;
339 		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
340 							  val, NULL);
341 		if (ret) {
342 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
343 				__func__);
344 			return ret;
345 		}
346 		break;
347 	default:
348 		return -EINVAL;
349 	}
350 
351 	return count;
352 }
353 
354 static const struct file_operations iio_debugfs_reg_fops = {
355 	.open = simple_open,
356 	.read = iio_debugfs_read_reg,
357 	.write = iio_debugfs_write_reg,
358 };
359 
360 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
361 {
362 	debugfs_remove_recursive(indio_dev->debugfs_dentry);
363 }
364 
365 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
366 {
367 	struct dentry *d;
368 
369 	if (indio_dev->info->debugfs_reg_access == NULL)
370 		return 0;
371 
372 	if (!iio_debugfs_dentry)
373 		return 0;
374 
375 	indio_dev->debugfs_dentry =
376 		debugfs_create_dir(dev_name(&indio_dev->dev),
377 				   iio_debugfs_dentry);
378 	if (indio_dev->debugfs_dentry == NULL) {
379 		dev_warn(indio_dev->dev.parent,
380 			 "Failed to create debugfs directory\n");
381 		return -EFAULT;
382 	}
383 
384 	d = debugfs_create_file("direct_reg_access", 0644,
385 				indio_dev->debugfs_dentry,
386 				indio_dev, &iio_debugfs_reg_fops);
387 	if (!d) {
388 		iio_device_unregister_debugfs(indio_dev);
389 		return -ENOMEM;
390 	}
391 
392 	return 0;
393 }
394 #else
395 static int iio_device_register_debugfs(struct iio_dev *indio_dev)
396 {
397 	return 0;
398 }
399 
400 static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
401 {
402 }
403 #endif /* CONFIG_DEBUG_FS */
404 
405 static ssize_t iio_read_channel_ext_info(struct device *dev,
406 				     struct device_attribute *attr,
407 				     char *buf)
408 {
409 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
410 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
411 	const struct iio_chan_spec_ext_info *ext_info;
412 
413 	ext_info = &this_attr->c->ext_info[this_attr->address];
414 
415 	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
416 }
417 
418 static ssize_t iio_write_channel_ext_info(struct device *dev,
419 				     struct device_attribute *attr,
420 				     const char *buf,
421 					 size_t len)
422 {
423 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
424 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
425 	const struct iio_chan_spec_ext_info *ext_info;
426 
427 	ext_info = &this_attr->c->ext_info[this_attr->address];
428 
429 	return ext_info->write(indio_dev, ext_info->private,
430 			       this_attr->c, buf, len);
431 }
432 
433 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
434 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
435 {
436 	const struct iio_enum *e = (const struct iio_enum *)priv;
437 	unsigned int i;
438 	size_t len = 0;
439 
440 	if (!e->num_items)
441 		return 0;
442 
443 	for (i = 0; i < e->num_items; ++i)
444 		len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
445 
446 	/* replace last space with a newline */
447 	buf[len - 1] = '\n';
448 
449 	return len;
450 }
451 EXPORT_SYMBOL_GPL(iio_enum_available_read);
452 
453 ssize_t iio_enum_read(struct iio_dev *indio_dev,
454 	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
455 {
456 	const struct iio_enum *e = (const struct iio_enum *)priv;
457 	int i;
458 
459 	if (!e->get)
460 		return -EINVAL;
461 
462 	i = e->get(indio_dev, chan);
463 	if (i < 0)
464 		return i;
465 	else if (i >= e->num_items)
466 		return -EINVAL;
467 
468 	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
469 }
470 EXPORT_SYMBOL_GPL(iio_enum_read);
471 
472 ssize_t iio_enum_write(struct iio_dev *indio_dev,
473 	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
474 	size_t len)
475 {
476 	const struct iio_enum *e = (const struct iio_enum *)priv;
477 	unsigned int i;
478 	int ret;
479 
480 	if (!e->set)
481 		return -EINVAL;
482 
483 	for (i = 0; i < e->num_items; i++) {
484 		if (sysfs_streq(buf, e->items[i]))
485 			break;
486 	}
487 
488 	if (i == e->num_items)
489 		return -EINVAL;
490 
491 	ret = e->set(indio_dev, chan, i);
492 	return ret ? ret : len;
493 }
494 EXPORT_SYMBOL_GPL(iio_enum_write);
495 
496 static const struct iio_mount_matrix iio_mount_idmatrix = {
497 	.rotation = {
498 		"1", "0", "0",
499 		"0", "1", "0",
500 		"0", "0", "1"
501 	}
502 };
503 
504 static int iio_setup_mount_idmatrix(const struct device *dev,
505 				    struct iio_mount_matrix *matrix)
506 {
507 	*matrix = iio_mount_idmatrix;
508 	dev_info(dev, "mounting matrix not found: using identity...\n");
509 	return 0;
510 }
511 
512 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
513 			      const struct iio_chan_spec *chan, char *buf)
514 {
515 	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
516 					      priv)(indio_dev, chan);
517 
518 	if (IS_ERR(mtx))
519 		return PTR_ERR(mtx);
520 
521 	if (!mtx)
522 		mtx = &iio_mount_idmatrix;
523 
524 	return snprintf(buf, PAGE_SIZE, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
525 			mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
526 			mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
527 			mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
528 }
529 EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
530 
531 /**
532  * of_iio_read_mount_matrix() - retrieve iio device mounting matrix from
533  *                              device-tree "mount-matrix" property
534  * @dev:	device the mounting matrix property is assigned to
535  * @propname:	device specific mounting matrix property name
536  * @matrix:	where to store retrieved matrix
537  *
538  * If device is assigned no mounting matrix property, a default 3x3 identity
539  * matrix will be filled in.
540  *
541  * Return: 0 if success, or a negative error code on failure.
542  */
543 #ifdef CONFIG_OF
544 int of_iio_read_mount_matrix(const struct device *dev,
545 			     const char *propname,
546 			     struct iio_mount_matrix *matrix)
547 {
548 	if (dev->of_node) {
549 		int err = of_property_read_string_array(dev->of_node,
550 				propname, matrix->rotation,
551 				ARRAY_SIZE(iio_mount_idmatrix.rotation));
552 
553 		if (err == ARRAY_SIZE(iio_mount_idmatrix.rotation))
554 			return 0;
555 
556 		if (err >= 0)
557 			/* Invalid number of matrix entries. */
558 			return -EINVAL;
559 
560 		if (err != -EINVAL)
561 			/* Invalid matrix declaration format. */
562 			return err;
563 	}
564 
565 	/* Matrix was not declared at all: fallback to identity. */
566 	return iio_setup_mount_idmatrix(dev, matrix);
567 }
568 #else
569 int of_iio_read_mount_matrix(const struct device *dev,
570 			     const char *propname,
571 			     struct iio_mount_matrix *matrix)
572 {
573 	return iio_setup_mount_idmatrix(dev, matrix);
574 }
575 #endif
576 EXPORT_SYMBOL(of_iio_read_mount_matrix);
577 
578 /**
579  * iio_format_value() - Formats a IIO value into its string representation
580  * @buf:	The buffer to which the formatted value gets written
581  * @type:	One of the IIO_VAL_... constants. This decides how the val
582  *		and val2 parameters are formatted.
583  * @size:	Number of IIO value entries contained in vals
584  * @vals:	Pointer to the values, exact meaning depends on the
585  *		type parameter.
586  *
587  * Return: 0 by default, a negative number on failure or the
588  *	   total number of characters written for a type that belongs
589  *	   to the IIO_VAL_... constant.
590  */
591 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
592 {
593 	unsigned long long tmp;
594 	bool scale_db = false;
595 
596 	switch (type) {
597 	case IIO_VAL_INT:
598 		return sprintf(buf, "%d\n", vals[0]);
599 	case IIO_VAL_INT_PLUS_MICRO_DB:
600 		scale_db = true;
601 	case IIO_VAL_INT_PLUS_MICRO:
602 		if (vals[1] < 0)
603 			return sprintf(buf, "-%d.%06u%s\n", abs(vals[0]),
604 				       -vals[1], scale_db ? " dB" : "");
605 		else
606 			return sprintf(buf, "%d.%06u%s\n", vals[0], vals[1],
607 				scale_db ? " dB" : "");
608 	case IIO_VAL_INT_PLUS_NANO:
609 		if (vals[1] < 0)
610 			return sprintf(buf, "-%d.%09u\n", abs(vals[0]),
611 				       -vals[1]);
612 		else
613 			return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
614 	case IIO_VAL_FRACTIONAL:
615 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
616 		vals[0] = (int)div_s64_rem(tmp, 1000000000, &vals[1]);
617 		return sprintf(buf, "%d.%09u\n", vals[0], abs(vals[1]));
618 	case IIO_VAL_FRACTIONAL_LOG2:
619 		tmp = (s64)vals[0] * 1000000000LL >> vals[1];
620 		vals[1] = do_div(tmp, 1000000000LL);
621 		vals[0] = tmp;
622 		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
623 	case IIO_VAL_INT_MULTIPLE:
624 	{
625 		int i;
626 		int len = 0;
627 
628 		for (i = 0; i < size; ++i)
629 			len += snprintf(&buf[len], PAGE_SIZE - len, "%d ",
630 								vals[i]);
631 		len += snprintf(&buf[len], PAGE_SIZE - len, "\n");
632 		return len;
633 	}
634 	default:
635 		return 0;
636 	}
637 }
638 EXPORT_SYMBOL_GPL(iio_format_value);
639 
640 static ssize_t iio_read_channel_info(struct device *dev,
641 				     struct device_attribute *attr,
642 				     char *buf)
643 {
644 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
645 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
646 	int vals[INDIO_MAX_RAW_ELEMENTS];
647 	int ret;
648 	int val_len = 2;
649 
650 	if (indio_dev->info->read_raw_multi)
651 		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
652 							INDIO_MAX_RAW_ELEMENTS,
653 							vals, &val_len,
654 							this_attr->address);
655 	else
656 		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
657 				    &vals[0], &vals[1], this_attr->address);
658 
659 	if (ret < 0)
660 		return ret;
661 
662 	return iio_format_value(buf, ret, val_len, vals);
663 }
664 
665 /**
666  * iio_str_to_fixpoint() - Parse a fixed-point number from a string
667  * @str: The string to parse
668  * @fract_mult: Multiplier for the first decimal place, should be a power of 10
669  * @integer: The integer part of the number
670  * @fract: The fractional part of the number
671  *
672  * Returns 0 on success, or a negative error code if the string could not be
673  * parsed.
674  */
675 int iio_str_to_fixpoint(const char *str, int fract_mult,
676 	int *integer, int *fract)
677 {
678 	int i = 0, f = 0;
679 	bool integer_part = true, negative = false;
680 
681 	if (fract_mult == 0) {
682 		*fract = 0;
683 
684 		return kstrtoint(str, 0, integer);
685 	}
686 
687 	if (str[0] == '-') {
688 		negative = true;
689 		str++;
690 	} else if (str[0] == '+') {
691 		str++;
692 	}
693 
694 	while (*str) {
695 		if ('0' <= *str && *str <= '9') {
696 			if (integer_part) {
697 				i = i * 10 + *str - '0';
698 			} else {
699 				f += fract_mult * (*str - '0');
700 				fract_mult /= 10;
701 			}
702 		} else if (*str == '\n') {
703 			if (*(str + 1) == '\0')
704 				break;
705 			else
706 				return -EINVAL;
707 		} else if (*str == '.' && integer_part) {
708 			integer_part = false;
709 		} else {
710 			return -EINVAL;
711 		}
712 		str++;
713 	}
714 
715 	if (negative) {
716 		if (i)
717 			i = -i;
718 		else
719 			f = -f;
720 	}
721 
722 	*integer = i;
723 	*fract = f;
724 
725 	return 0;
726 }
727 EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
728 
729 static ssize_t iio_write_channel_info(struct device *dev,
730 				      struct device_attribute *attr,
731 				      const char *buf,
732 				      size_t len)
733 {
734 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
735 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
736 	int ret, fract_mult = 100000;
737 	int integer, fract;
738 
739 	/* Assumes decimal - precision based on number of digits */
740 	if (!indio_dev->info->write_raw)
741 		return -EINVAL;
742 
743 	if (indio_dev->info->write_raw_get_fmt)
744 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
745 			this_attr->c, this_attr->address)) {
746 		case IIO_VAL_INT:
747 			fract_mult = 0;
748 			break;
749 		case IIO_VAL_INT_PLUS_MICRO:
750 			fract_mult = 100000;
751 			break;
752 		case IIO_VAL_INT_PLUS_NANO:
753 			fract_mult = 100000000;
754 			break;
755 		default:
756 			return -EINVAL;
757 		}
758 
759 	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
760 	if (ret)
761 		return ret;
762 
763 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
764 					 integer, fract, this_attr->address);
765 	if (ret)
766 		return ret;
767 
768 	return len;
769 }
770 
771 static
772 int __iio_device_attr_init(struct device_attribute *dev_attr,
773 			   const char *postfix,
774 			   struct iio_chan_spec const *chan,
775 			   ssize_t (*readfunc)(struct device *dev,
776 					       struct device_attribute *attr,
777 					       char *buf),
778 			   ssize_t (*writefunc)(struct device *dev,
779 						struct device_attribute *attr,
780 						const char *buf,
781 						size_t len),
782 			   enum iio_shared_by shared_by)
783 {
784 	int ret = 0;
785 	char *name = NULL;
786 	char *full_postfix;
787 	sysfs_attr_init(&dev_attr->attr);
788 
789 	/* Build up postfix of <extend_name>_<modifier>_postfix */
790 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
791 		if (chan->extend_name)
792 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
793 						 iio_modifier_names[chan
794 								    ->channel2],
795 						 chan->extend_name,
796 						 postfix);
797 		else
798 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
799 						 iio_modifier_names[chan
800 								    ->channel2],
801 						 postfix);
802 	} else {
803 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
804 			full_postfix = kstrdup(postfix, GFP_KERNEL);
805 		else
806 			full_postfix = kasprintf(GFP_KERNEL,
807 						 "%s_%s",
808 						 chan->extend_name,
809 						 postfix);
810 	}
811 	if (full_postfix == NULL)
812 		return -ENOMEM;
813 
814 	if (chan->differential) { /* Differential can not have modifier */
815 		switch (shared_by) {
816 		case IIO_SHARED_BY_ALL:
817 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
818 			break;
819 		case IIO_SHARED_BY_DIR:
820 			name = kasprintf(GFP_KERNEL, "%s_%s",
821 						iio_direction[chan->output],
822 						full_postfix);
823 			break;
824 		case IIO_SHARED_BY_TYPE:
825 			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
826 					    iio_direction[chan->output],
827 					    iio_chan_type_name_spec[chan->type],
828 					    iio_chan_type_name_spec[chan->type],
829 					    full_postfix);
830 			break;
831 		case IIO_SEPARATE:
832 			if (!chan->indexed) {
833 				WARN(1, "Differential channels must be indexed\n");
834 				ret = -EINVAL;
835 				goto error_free_full_postfix;
836 			}
837 			name = kasprintf(GFP_KERNEL,
838 					    "%s_%s%d-%s%d_%s",
839 					    iio_direction[chan->output],
840 					    iio_chan_type_name_spec[chan->type],
841 					    chan->channel,
842 					    iio_chan_type_name_spec[chan->type],
843 					    chan->channel2,
844 					    full_postfix);
845 			break;
846 		}
847 	} else { /* Single ended */
848 		switch (shared_by) {
849 		case IIO_SHARED_BY_ALL:
850 			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
851 			break;
852 		case IIO_SHARED_BY_DIR:
853 			name = kasprintf(GFP_KERNEL, "%s_%s",
854 						iio_direction[chan->output],
855 						full_postfix);
856 			break;
857 		case IIO_SHARED_BY_TYPE:
858 			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
859 					    iio_direction[chan->output],
860 					    iio_chan_type_name_spec[chan->type],
861 					    full_postfix);
862 			break;
863 
864 		case IIO_SEPARATE:
865 			if (chan->indexed)
866 				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
867 						    iio_direction[chan->output],
868 						    iio_chan_type_name_spec[chan->type],
869 						    chan->channel,
870 						    full_postfix);
871 			else
872 				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
873 						    iio_direction[chan->output],
874 						    iio_chan_type_name_spec[chan->type],
875 						    full_postfix);
876 			break;
877 		}
878 	}
879 	if (name == NULL) {
880 		ret = -ENOMEM;
881 		goto error_free_full_postfix;
882 	}
883 	dev_attr->attr.name = name;
884 
885 	if (readfunc) {
886 		dev_attr->attr.mode |= S_IRUGO;
887 		dev_attr->show = readfunc;
888 	}
889 
890 	if (writefunc) {
891 		dev_attr->attr.mode |= S_IWUSR;
892 		dev_attr->store = writefunc;
893 	}
894 
895 error_free_full_postfix:
896 	kfree(full_postfix);
897 
898 	return ret;
899 }
900 
901 static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
902 {
903 	kfree(dev_attr->attr.name);
904 }
905 
906 int __iio_add_chan_devattr(const char *postfix,
907 			   struct iio_chan_spec const *chan,
908 			   ssize_t (*readfunc)(struct device *dev,
909 					       struct device_attribute *attr,
910 					       char *buf),
911 			   ssize_t (*writefunc)(struct device *dev,
912 						struct device_attribute *attr,
913 						const char *buf,
914 						size_t len),
915 			   u64 mask,
916 			   enum iio_shared_by shared_by,
917 			   struct device *dev,
918 			   struct list_head *attr_list)
919 {
920 	int ret;
921 	struct iio_dev_attr *iio_attr, *t;
922 
923 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
924 	if (iio_attr == NULL)
925 		return -ENOMEM;
926 	ret = __iio_device_attr_init(&iio_attr->dev_attr,
927 				     postfix, chan,
928 				     readfunc, writefunc, shared_by);
929 	if (ret)
930 		goto error_iio_dev_attr_free;
931 	iio_attr->c = chan;
932 	iio_attr->address = mask;
933 	list_for_each_entry(t, attr_list, l)
934 		if (strcmp(t->dev_attr.attr.name,
935 			   iio_attr->dev_attr.attr.name) == 0) {
936 			if (shared_by == IIO_SEPARATE)
937 				dev_err(dev, "tried to double register : %s\n",
938 					t->dev_attr.attr.name);
939 			ret = -EBUSY;
940 			goto error_device_attr_deinit;
941 		}
942 	list_add(&iio_attr->l, attr_list);
943 
944 	return 0;
945 
946 error_device_attr_deinit:
947 	__iio_device_attr_deinit(&iio_attr->dev_attr);
948 error_iio_dev_attr_free:
949 	kfree(iio_attr);
950 	return ret;
951 }
952 
953 static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
954 					 struct iio_chan_spec const *chan,
955 					 enum iio_shared_by shared_by,
956 					 const long *infomask)
957 {
958 	int i, ret, attrcount = 0;
959 
960 	for_each_set_bit(i, infomask, sizeof(infomask)*8) {
961 		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
962 			return -EINVAL;
963 		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
964 					     chan,
965 					     &iio_read_channel_info,
966 					     &iio_write_channel_info,
967 					     i,
968 					     shared_by,
969 					     &indio_dev->dev,
970 					     &indio_dev->channel_attr_list);
971 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
972 			continue;
973 		else if (ret < 0)
974 			return ret;
975 		attrcount++;
976 	}
977 
978 	return attrcount;
979 }
980 
981 static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
982 					struct iio_chan_spec const *chan)
983 {
984 	int ret, attrcount = 0;
985 	const struct iio_chan_spec_ext_info *ext_info;
986 
987 	if (chan->channel < 0)
988 		return 0;
989 	ret = iio_device_add_info_mask_type(indio_dev, chan,
990 					    IIO_SEPARATE,
991 					    &chan->info_mask_separate);
992 	if (ret < 0)
993 		return ret;
994 	attrcount += ret;
995 
996 	ret = iio_device_add_info_mask_type(indio_dev, chan,
997 					    IIO_SHARED_BY_TYPE,
998 					    &chan->info_mask_shared_by_type);
999 	if (ret < 0)
1000 		return ret;
1001 	attrcount += ret;
1002 
1003 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1004 					    IIO_SHARED_BY_DIR,
1005 					    &chan->info_mask_shared_by_dir);
1006 	if (ret < 0)
1007 		return ret;
1008 	attrcount += ret;
1009 
1010 	ret = iio_device_add_info_mask_type(indio_dev, chan,
1011 					    IIO_SHARED_BY_ALL,
1012 					    &chan->info_mask_shared_by_all);
1013 	if (ret < 0)
1014 		return ret;
1015 	attrcount += ret;
1016 
1017 	if (chan->ext_info) {
1018 		unsigned int i = 0;
1019 		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
1020 			ret = __iio_add_chan_devattr(ext_info->name,
1021 					chan,
1022 					ext_info->read ?
1023 					    &iio_read_channel_ext_info : NULL,
1024 					ext_info->write ?
1025 					    &iio_write_channel_ext_info : NULL,
1026 					i,
1027 					ext_info->shared,
1028 					&indio_dev->dev,
1029 					&indio_dev->channel_attr_list);
1030 			i++;
1031 			if (ret == -EBUSY && ext_info->shared)
1032 				continue;
1033 
1034 			if (ret)
1035 				return ret;
1036 
1037 			attrcount++;
1038 		}
1039 	}
1040 
1041 	return attrcount;
1042 }
1043 
1044 /**
1045  * iio_free_chan_devattr_list() - Free a list of IIO device attributes
1046  * @attr_list: List of IIO device attributes
1047  *
1048  * This function frees the memory allocated for each of the IIO device
1049  * attributes in the list.
1050  */
1051 void iio_free_chan_devattr_list(struct list_head *attr_list)
1052 {
1053 	struct iio_dev_attr *p, *n;
1054 
1055 	list_for_each_entry_safe(p, n, attr_list, l) {
1056 		kfree(p->dev_attr.attr.name);
1057 		list_del(&p->l);
1058 		kfree(p);
1059 	}
1060 }
1061 
1062 static ssize_t iio_show_dev_name(struct device *dev,
1063 				 struct device_attribute *attr,
1064 				 char *buf)
1065 {
1066 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1067 	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
1068 }
1069 
1070 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
1071 
1072 static ssize_t iio_show_timestamp_clock(struct device *dev,
1073 					struct device_attribute *attr,
1074 					char *buf)
1075 {
1076 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1077 	const clockid_t clk = iio_device_get_clock(indio_dev);
1078 	const char *name;
1079 	ssize_t sz;
1080 
1081 	switch (clk) {
1082 	case CLOCK_REALTIME:
1083 		name = "realtime\n";
1084 		sz = sizeof("realtime\n");
1085 		break;
1086 	case CLOCK_MONOTONIC:
1087 		name = "monotonic\n";
1088 		sz = sizeof("monotonic\n");
1089 		break;
1090 	case CLOCK_MONOTONIC_RAW:
1091 		name = "monotonic_raw\n";
1092 		sz = sizeof("monotonic_raw\n");
1093 		break;
1094 	case CLOCK_REALTIME_COARSE:
1095 		name = "realtime_coarse\n";
1096 		sz = sizeof("realtime_coarse\n");
1097 		break;
1098 	case CLOCK_MONOTONIC_COARSE:
1099 		name = "monotonic_coarse\n";
1100 		sz = sizeof("monotonic_coarse\n");
1101 		break;
1102 	case CLOCK_BOOTTIME:
1103 		name = "boottime\n";
1104 		sz = sizeof("boottime\n");
1105 		break;
1106 	case CLOCK_TAI:
1107 		name = "tai\n";
1108 		sz = sizeof("tai\n");
1109 		break;
1110 	default:
1111 		BUG();
1112 	}
1113 
1114 	memcpy(buf, name, sz);
1115 	return sz;
1116 }
1117 
1118 static ssize_t iio_store_timestamp_clock(struct device *dev,
1119 					 struct device_attribute *attr,
1120 					 const char *buf, size_t len)
1121 {
1122 	clockid_t clk;
1123 	int ret;
1124 
1125 	if (sysfs_streq(buf, "realtime"))
1126 		clk = CLOCK_REALTIME;
1127 	else if (sysfs_streq(buf, "monotonic"))
1128 		clk = CLOCK_MONOTONIC;
1129 	else if (sysfs_streq(buf, "monotonic_raw"))
1130 		clk = CLOCK_MONOTONIC_RAW;
1131 	else if (sysfs_streq(buf, "realtime_coarse"))
1132 		clk = CLOCK_REALTIME_COARSE;
1133 	else if (sysfs_streq(buf, "monotonic_coarse"))
1134 		clk = CLOCK_MONOTONIC_COARSE;
1135 	else if (sysfs_streq(buf, "boottime"))
1136 		clk = CLOCK_BOOTTIME;
1137 	else if (sysfs_streq(buf, "tai"))
1138 		clk = CLOCK_TAI;
1139 	else
1140 		return -EINVAL;
1141 
1142 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
1143 	if (ret)
1144 		return ret;
1145 
1146 	return len;
1147 }
1148 
1149 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
1150 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
1151 
1152 static int iio_device_register_sysfs(struct iio_dev *indio_dev)
1153 {
1154 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
1155 	struct iio_dev_attr *p;
1156 	struct attribute **attr, *clk = NULL;
1157 
1158 	/* First count elements in any existing group */
1159 	if (indio_dev->info->attrs) {
1160 		attr = indio_dev->info->attrs->attrs;
1161 		while (*attr++ != NULL)
1162 			attrcount_orig++;
1163 	}
1164 	attrcount = attrcount_orig;
1165 	/*
1166 	 * New channel registration method - relies on the fact a group does
1167 	 * not need to be initialized if its name is NULL.
1168 	 */
1169 	if (indio_dev->channels)
1170 		for (i = 0; i < indio_dev->num_channels; i++) {
1171 			const struct iio_chan_spec *chan =
1172 				&indio_dev->channels[i];
1173 
1174 			if (chan->type == IIO_TIMESTAMP)
1175 				clk = &dev_attr_current_timestamp_clock.attr;
1176 
1177 			ret = iio_device_add_channel_sysfs(indio_dev, chan);
1178 			if (ret < 0)
1179 				goto error_clear_attrs;
1180 			attrcount += ret;
1181 		}
1182 
1183 	if (indio_dev->event_interface)
1184 		clk = &dev_attr_current_timestamp_clock.attr;
1185 
1186 	if (indio_dev->name)
1187 		attrcount++;
1188 	if (clk)
1189 		attrcount++;
1190 
1191 	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
1192 						   sizeof(indio_dev->chan_attr_group.attrs[0]),
1193 						   GFP_KERNEL);
1194 	if (indio_dev->chan_attr_group.attrs == NULL) {
1195 		ret = -ENOMEM;
1196 		goto error_clear_attrs;
1197 	}
1198 	/* Copy across original attributes */
1199 	if (indio_dev->info->attrs)
1200 		memcpy(indio_dev->chan_attr_group.attrs,
1201 		       indio_dev->info->attrs->attrs,
1202 		       sizeof(indio_dev->chan_attr_group.attrs[0])
1203 		       *attrcount_orig);
1204 	attrn = attrcount_orig;
1205 	/* Add all elements from the list. */
1206 	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
1207 		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
1208 	if (indio_dev->name)
1209 		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
1210 	if (clk)
1211 		indio_dev->chan_attr_group.attrs[attrn++] = clk;
1212 
1213 	indio_dev->groups[indio_dev->groupcounter++] =
1214 		&indio_dev->chan_attr_group;
1215 
1216 	return 0;
1217 
1218 error_clear_attrs:
1219 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1220 
1221 	return ret;
1222 }
1223 
1224 static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
1225 {
1226 
1227 	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
1228 	kfree(indio_dev->chan_attr_group.attrs);
1229 	indio_dev->chan_attr_group.attrs = NULL;
1230 }
1231 
1232 static void iio_dev_release(struct device *device)
1233 {
1234 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
1235 	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
1236 		iio_device_unregister_trigger_consumer(indio_dev);
1237 	iio_device_unregister_eventset(indio_dev);
1238 	iio_device_unregister_sysfs(indio_dev);
1239 
1240 	iio_buffer_put(indio_dev->buffer);
1241 
1242 	ida_simple_remove(&iio_ida, indio_dev->id);
1243 	kfree(indio_dev);
1244 }
1245 
1246 struct device_type iio_device_type = {
1247 	.name = "iio_device",
1248 	.release = iio_dev_release,
1249 };
1250 
1251 /**
1252  * iio_device_alloc() - allocate an iio_dev from a driver
1253  * @sizeof_priv:	Space to allocate for private structure.
1254  **/
1255 struct iio_dev *iio_device_alloc(int sizeof_priv)
1256 {
1257 	struct iio_dev *dev;
1258 	size_t alloc_size;
1259 
1260 	alloc_size = sizeof(struct iio_dev);
1261 	if (sizeof_priv) {
1262 		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
1263 		alloc_size += sizeof_priv;
1264 	}
1265 	/* ensure 32-byte alignment of whole construct ? */
1266 	alloc_size += IIO_ALIGN - 1;
1267 
1268 	dev = kzalloc(alloc_size, GFP_KERNEL);
1269 
1270 	if (dev) {
1271 		dev->dev.groups = dev->groups;
1272 		dev->dev.type = &iio_device_type;
1273 		dev->dev.bus = &iio_bus_type;
1274 		device_initialize(&dev->dev);
1275 		dev_set_drvdata(&dev->dev, (void *)dev);
1276 		mutex_init(&dev->mlock);
1277 		mutex_init(&dev->info_exist_lock);
1278 		INIT_LIST_HEAD(&dev->channel_attr_list);
1279 
1280 		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
1281 		if (dev->id < 0) {
1282 			/* cannot use a dev_err as the name isn't available */
1283 			pr_err("failed to get device id\n");
1284 			kfree(dev);
1285 			return NULL;
1286 		}
1287 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
1288 		INIT_LIST_HEAD(&dev->buffer_list);
1289 	}
1290 
1291 	return dev;
1292 }
1293 EXPORT_SYMBOL(iio_device_alloc);
1294 
1295 /**
1296  * iio_device_free() - free an iio_dev from a driver
1297  * @dev:		the iio_dev associated with the device
1298  **/
1299 void iio_device_free(struct iio_dev *dev)
1300 {
1301 	if (dev)
1302 		put_device(&dev->dev);
1303 }
1304 EXPORT_SYMBOL(iio_device_free);
1305 
1306 static void devm_iio_device_release(struct device *dev, void *res)
1307 {
1308 	iio_device_free(*(struct iio_dev **)res);
1309 }
1310 
1311 int devm_iio_device_match(struct device *dev, void *res, void *data)
1312 {
1313 	struct iio_dev **r = res;
1314 	if (!r || !*r) {
1315 		WARN_ON(!r || !*r);
1316 		return 0;
1317 	}
1318 	return *r == data;
1319 }
1320 EXPORT_SYMBOL_GPL(devm_iio_device_match);
1321 
1322 /**
1323  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
1324  * @dev:		Device to allocate iio_dev for
1325  * @sizeof_priv:	Space to allocate for private structure.
1326  *
1327  * Managed iio_device_alloc. iio_dev allocated with this function is
1328  * automatically freed on driver detach.
1329  *
1330  * If an iio_dev allocated with this function needs to be freed separately,
1331  * devm_iio_device_free() must be used.
1332  *
1333  * RETURNS:
1334  * Pointer to allocated iio_dev on success, NULL on failure.
1335  */
1336 struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
1337 {
1338 	struct iio_dev **ptr, *iio_dev;
1339 
1340 	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
1341 			   GFP_KERNEL);
1342 	if (!ptr)
1343 		return NULL;
1344 
1345 	iio_dev = iio_device_alloc(sizeof_priv);
1346 	if (iio_dev) {
1347 		*ptr = iio_dev;
1348 		devres_add(dev, ptr);
1349 	} else {
1350 		devres_free(ptr);
1351 	}
1352 
1353 	return iio_dev;
1354 }
1355 EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
1356 
1357 /**
1358  * devm_iio_device_free - Resource-managed iio_device_free()
1359  * @dev:		Device this iio_dev belongs to
1360  * @iio_dev:		the iio_dev associated with the device
1361  *
1362  * Free iio_dev allocated with devm_iio_device_alloc().
1363  */
1364 void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
1365 {
1366 	int rc;
1367 
1368 	rc = devres_release(dev, devm_iio_device_release,
1369 			    devm_iio_device_match, iio_dev);
1370 	WARN_ON(rc);
1371 }
1372 EXPORT_SYMBOL_GPL(devm_iio_device_free);
1373 
1374 /**
1375  * iio_chrdev_open() - chrdev file open for buffer access and ioctls
1376  * @inode:	Inode structure for identifying the device in the file system
1377  * @filp:	File structure for iio device used to keep and later access
1378  *		private data
1379  *
1380  * Return: 0 on success or -EBUSY if the device is already opened
1381  **/
1382 static int iio_chrdev_open(struct inode *inode, struct file *filp)
1383 {
1384 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1385 						struct iio_dev, chrdev);
1386 
1387 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
1388 		return -EBUSY;
1389 
1390 	iio_device_get(indio_dev);
1391 
1392 	filp->private_data = indio_dev;
1393 
1394 	return 0;
1395 }
1396 
1397 /**
1398  * iio_chrdev_release() - chrdev file close buffer access and ioctls
1399  * @inode:	Inode structure pointer for the char device
1400  * @filp:	File structure pointer for the char device
1401  *
1402  * Return: 0 for successful release
1403  */
1404 static int iio_chrdev_release(struct inode *inode, struct file *filp)
1405 {
1406 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
1407 						struct iio_dev, chrdev);
1408 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
1409 	iio_device_put(indio_dev);
1410 
1411 	return 0;
1412 }
1413 
1414 /* Somewhat of a cross file organization violation - ioctls here are actually
1415  * event related */
1416 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1417 {
1418 	struct iio_dev *indio_dev = filp->private_data;
1419 	int __user *ip = (int __user *)arg;
1420 	int fd;
1421 
1422 	if (!indio_dev->info)
1423 		return -ENODEV;
1424 
1425 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
1426 		fd = iio_event_getfd(indio_dev);
1427 		if (fd < 0)
1428 			return fd;
1429 		if (copy_to_user(ip, &fd, sizeof(fd)))
1430 			return -EFAULT;
1431 		return 0;
1432 	}
1433 	return -EINVAL;
1434 }
1435 
1436 static const struct file_operations iio_buffer_fileops = {
1437 	.read = iio_buffer_read_first_n_outer_addr,
1438 	.release = iio_chrdev_release,
1439 	.open = iio_chrdev_open,
1440 	.poll = iio_buffer_poll_addr,
1441 	.owner = THIS_MODULE,
1442 	.llseek = noop_llseek,
1443 	.unlocked_ioctl = iio_ioctl,
1444 	.compat_ioctl = iio_ioctl,
1445 };
1446 
1447 static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
1448 {
1449 	int i, j;
1450 	const struct iio_chan_spec *channels = indio_dev->channels;
1451 
1452 	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
1453 		return 0;
1454 
1455 	for (i = 0; i < indio_dev->num_channels - 1; i++) {
1456 		if (channels[i].scan_index < 0)
1457 			continue;
1458 		for (j = i + 1; j < indio_dev->num_channels; j++)
1459 			if (channels[i].scan_index == channels[j].scan_index) {
1460 				dev_err(&indio_dev->dev,
1461 					"Duplicate scan index %d\n",
1462 					channels[i].scan_index);
1463 				return -EINVAL;
1464 			}
1465 	}
1466 
1467 	return 0;
1468 }
1469 
1470 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
1471 
1472 /**
1473  * iio_device_register() - register a device with the IIO subsystem
1474  * @indio_dev:		Device structure filled by the device driver
1475  **/
1476 int iio_device_register(struct iio_dev *indio_dev)
1477 {
1478 	int ret;
1479 
1480 	/* If the calling driver did not initialize of_node, do it here */
1481 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
1482 		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
1483 
1484 	ret = iio_check_unique_scan_index(indio_dev);
1485 	if (ret < 0)
1486 		return ret;
1487 
1488 	/* configure elements for the chrdev */
1489 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
1490 
1491 	ret = iio_device_register_debugfs(indio_dev);
1492 	if (ret) {
1493 		dev_err(indio_dev->dev.parent,
1494 			"Failed to register debugfs interfaces\n");
1495 		return ret;
1496 	}
1497 
1498 	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
1499 	if (ret) {
1500 		dev_err(indio_dev->dev.parent,
1501 			"Failed to create buffer sysfs interfaces\n");
1502 		goto error_unreg_debugfs;
1503 	}
1504 
1505 	ret = iio_device_register_sysfs(indio_dev);
1506 	if (ret) {
1507 		dev_err(indio_dev->dev.parent,
1508 			"Failed to register sysfs interfaces\n");
1509 		goto error_buffer_free_sysfs;
1510 	}
1511 	ret = iio_device_register_eventset(indio_dev);
1512 	if (ret) {
1513 		dev_err(indio_dev->dev.parent,
1514 			"Failed to register event set\n");
1515 		goto error_free_sysfs;
1516 	}
1517 	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
1518 		iio_device_register_trigger_consumer(indio_dev);
1519 
1520 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
1521 		indio_dev->setup_ops == NULL)
1522 		indio_dev->setup_ops = &noop_ring_setup_ops;
1523 
1524 	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
1525 	indio_dev->chrdev.owner = indio_dev->info->driver_module;
1526 	indio_dev->chrdev.kobj.parent = &indio_dev->dev.kobj;
1527 	ret = cdev_add(&indio_dev->chrdev, indio_dev->dev.devt, 1);
1528 	if (ret < 0)
1529 		goto error_unreg_eventset;
1530 
1531 	ret = device_add(&indio_dev->dev);
1532 	if (ret < 0)
1533 		goto error_cdev_del;
1534 
1535 	return 0;
1536 error_cdev_del:
1537 	cdev_del(&indio_dev->chrdev);
1538 error_unreg_eventset:
1539 	iio_device_unregister_eventset(indio_dev);
1540 error_free_sysfs:
1541 	iio_device_unregister_sysfs(indio_dev);
1542 error_buffer_free_sysfs:
1543 	iio_buffer_free_sysfs_and_mask(indio_dev);
1544 error_unreg_debugfs:
1545 	iio_device_unregister_debugfs(indio_dev);
1546 	return ret;
1547 }
1548 EXPORT_SYMBOL(iio_device_register);
1549 
1550 /**
1551  * iio_device_unregister() - unregister a device from the IIO subsystem
1552  * @indio_dev:		Device structure representing the device.
1553  **/
1554 void iio_device_unregister(struct iio_dev *indio_dev)
1555 {
1556 	mutex_lock(&indio_dev->info_exist_lock);
1557 
1558 	device_del(&indio_dev->dev);
1559 
1560 	if (indio_dev->chrdev.dev)
1561 		cdev_del(&indio_dev->chrdev);
1562 	iio_device_unregister_debugfs(indio_dev);
1563 
1564 	iio_disable_all_buffers(indio_dev);
1565 
1566 	indio_dev->info = NULL;
1567 
1568 	iio_device_wakeup_eventset(indio_dev);
1569 	iio_buffer_wakeup_poll(indio_dev);
1570 
1571 	mutex_unlock(&indio_dev->info_exist_lock);
1572 
1573 	iio_buffer_free_sysfs_and_mask(indio_dev);
1574 }
1575 EXPORT_SYMBOL(iio_device_unregister);
1576 
1577 static void devm_iio_device_unreg(struct device *dev, void *res)
1578 {
1579 	iio_device_unregister(*(struct iio_dev **)res);
1580 }
1581 
1582 /**
1583  * devm_iio_device_register - Resource-managed iio_device_register()
1584  * @dev:	Device to allocate iio_dev for
1585  * @indio_dev:	Device structure filled by the device driver
1586  *
1587  * Managed iio_device_register.  The IIO device registered with this
1588  * function is automatically unregistered on driver detach. This function
1589  * calls iio_device_register() internally. Refer to that function for more
1590  * information.
1591  *
1592  * If an iio_dev registered with this function needs to be unregistered
1593  * separately, devm_iio_device_unregister() must be used.
1594  *
1595  * RETURNS:
1596  * 0 on success, negative error number on failure.
1597  */
1598 int devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev)
1599 {
1600 	struct iio_dev **ptr;
1601 	int ret;
1602 
1603 	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
1604 	if (!ptr)
1605 		return -ENOMEM;
1606 
1607 	*ptr = indio_dev;
1608 	ret = iio_device_register(indio_dev);
1609 	if (!ret)
1610 		devres_add(dev, ptr);
1611 	else
1612 		devres_free(ptr);
1613 
1614 	return ret;
1615 }
1616 EXPORT_SYMBOL_GPL(devm_iio_device_register);
1617 
1618 /**
1619  * devm_iio_device_unregister - Resource-managed iio_device_unregister()
1620  * @dev:	Device this iio_dev belongs to
1621  * @indio_dev:	the iio_dev associated with the device
1622  *
1623  * Unregister iio_dev registered with devm_iio_device_register().
1624  */
1625 void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
1626 {
1627 	int rc;
1628 
1629 	rc = devres_release(dev, devm_iio_device_unreg,
1630 			    devm_iio_device_match, indio_dev);
1631 	WARN_ON(rc);
1632 }
1633 EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
1634 
1635 /**
1636  * iio_device_claim_direct_mode - Keep device in direct mode
1637  * @indio_dev:	the iio_dev associated with the device
1638  *
1639  * If the device is in direct mode it is guaranteed to stay
1640  * that way until iio_device_release_direct_mode() is called.
1641  *
1642  * Use with iio_device_release_direct_mode()
1643  *
1644  * Returns: 0 on success, -EBUSY on failure
1645  */
1646 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
1647 {
1648 	mutex_lock(&indio_dev->mlock);
1649 
1650 	if (iio_buffer_enabled(indio_dev)) {
1651 		mutex_unlock(&indio_dev->mlock);
1652 		return -EBUSY;
1653 	}
1654 	return 0;
1655 }
1656 EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
1657 
1658 /**
1659  * iio_device_release_direct_mode - releases claim on direct mode
1660  * @indio_dev:	the iio_dev associated with the device
1661  *
1662  * Release the claim. Device is no longer guaranteed to stay
1663  * in direct mode.
1664  *
1665  * Use with iio_device_claim_direct_mode()
1666  */
1667 void iio_device_release_direct_mode(struct iio_dev *indio_dev)
1668 {
1669 	mutex_unlock(&indio_dev->mlock);
1670 }
1671 EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
1672 
1673 subsys_initcall(iio_init);
1674 module_exit(iio_exit);
1675 
1676 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
1677 MODULE_DESCRIPTION("Industrial I/O core");
1678 MODULE_LICENSE("GPL");
1679