1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Sensirion SHT3x-DIS humidity and temperature sensor driver.
3 * The SHT3x comes in many different versions, this driver is for the
4 * I2C version only.
5 *
6 * Copyright (C) 2016 Sensirion AG, Switzerland
7 * Author: David Frey <david.frey@sensirion.com>
8 * Author: Pascal Sachs <pascal.sachs@sensirion.com>
9 */
10
11#include <asm/page.h>
12#include <linux/crc8.h>
13#include <linux/debugfs.h>
14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/hwmon.h>
17#include <linux/hwmon-sysfs.h>
18#include <linux/i2c.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/slab.h>
23#include <linux/jiffies.h>
24
25/* commands (high repeatability mode) */
26static const unsigned char sht3x_cmd_measure_single_hpm[] = { 0x24, 0x00 };
27
28/* commands (medium repeatability mode) */
29static const unsigned char sht3x_cmd_measure_single_mpm[] = { 0x24, 0x0b };
30
31/* commands (low repeatability mode) */
32static const unsigned char sht3x_cmd_measure_single_lpm[] = { 0x24, 0x16 };
33
34/* commands for periodic mode */
35static const unsigned char sht3x_cmd_measure_periodic_mode[]   = { 0xe0, 0x00 };
36static const unsigned char sht3x_cmd_break[]                   = { 0x30, 0x93 };
37
38/* commands for heater control */
39static const unsigned char sht3x_cmd_heater_on[]               = { 0x30, 0x6d };
40static const unsigned char sht3x_cmd_heater_off[]              = { 0x30, 0x66 };
41
42/* other commands */
43static const unsigned char sht3x_cmd_read_status_reg[]         = { 0xf3, 0x2d };
44static const unsigned char sht3x_cmd_clear_status_reg[]        = { 0x30, 0x41 };
45static const unsigned char sht3x_cmd_read_serial_number[]      = { 0x37, 0x80 };
46
47static struct dentry *debugfs;
48
49/* delays for single-shot mode i2c commands, both in us */
50#define SHT3X_SINGLE_WAIT_TIME_HPM  15000
51#define SHT3X_SINGLE_WAIT_TIME_MPM   6000
52#define SHT3X_SINGLE_WAIT_TIME_LPM   4000
53
54#define SHT3X_WORD_LEN         2
55#define SHT3X_CMD_LENGTH       2
56#define SHT3X_CRC8_LEN         1
57#define SHT3X_RESPONSE_LENGTH  6
58#define SHT3X_CRC8_POLYNOMIAL  0x31
59#define SHT3X_CRC8_INIT        0xFF
60#define SHT3X_MIN_TEMPERATURE  -45000
61#define SHT3X_MAX_TEMPERATURE  130000
62#define SHT3X_MIN_HUMIDITY     0
63#define SHT3X_MAX_HUMIDITY     100000
64
65enum sht3x_chips {
66	sht3x,
67	sts3x,
68};
69
70enum sht3x_limits {
71	limit_max = 0,
72	limit_max_hyst,
73	limit_min,
74	limit_min_hyst,
75};
76
77enum sht3x_repeatability {
78	low_repeatability,
79	medium_repeatability,
80	high_repeatability,
81};
82
83DECLARE_CRC8_TABLE(sht3x_crc8_table);
84
85/* periodic measure commands (high repeatability mode) */
86static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
87	/* 0.5 measurements per second */
88	{0x20, 0x32},
89	/* 1 measurements per second */
90	{0x21, 0x30},
91	/* 2 measurements per second */
92	{0x22, 0x36},
93	/* 4 measurements per second */
94	{0x23, 0x34},
95	/* 10 measurements per second */
96	{0x27, 0x37},
97};
98
99/* periodic measure commands (medium repeatability) */
100static const char periodic_measure_commands_mpm[][SHT3X_CMD_LENGTH] = {
101	/* 0.5 measurements per second */
102	{0x20, 0x24},
103	/* 1 measurements per second */
104	{0x21, 0x26},
105	/* 2 measurements per second */
106	{0x22, 0x20},
107	/* 4 measurements per second */
108	{0x23, 0x22},
109	/* 10 measurements per second */
110	{0x27, 0x21},
111};
112
113/* periodic measure commands (low repeatability mode) */
114static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
115	/* 0.5 measurements per second */
116	{0x20, 0x2f},
117	/* 1 measurements per second */
118	{0x21, 0x2d},
119	/* 2 measurements per second */
120	{0x22, 0x2b},
121	/* 4 measurements per second */
122	{0x23, 0x29},
123	/* 10 measurements per second */
124	{0x27, 0x2a},
125};
126
127struct sht3x_limit_commands {
128	const char read_command[SHT3X_CMD_LENGTH];
129	const char write_command[SHT3X_CMD_LENGTH];
130};
131
132static const struct sht3x_limit_commands limit_commands[] = {
133	/* temp1_max, humidity1_max */
134	[limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
135	/* temp_1_max_hyst, humidity1_max_hyst */
136	[limit_max_hyst] = { {0xe1, 0x14}, {0x61, 0x16} },
137	/* temp1_min, humidity1_min */
138	[limit_min] = { {0xe1, 0x02}, {0x61, 0x00} },
139	/* temp_1_min_hyst, humidity1_min_hyst */
140	[limit_min_hyst] = { {0xe1, 0x09}, {0x61, 0x0B} },
141};
142
143#define SHT3X_NUM_LIMIT_CMD  ARRAY_SIZE(limit_commands)
144
145static const u16 mode_to_update_interval[] = {
146	   0,
147	2000,
148	1000,
149	 500,
150	 250,
151	 100,
152};
153
154static const struct hwmon_channel_info * const sht3x_channel_info[] = {
155	HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
156	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MIN |
157				HWMON_T_MIN_HYST | HWMON_T_MAX |
158				HWMON_T_MAX_HYST | HWMON_T_ALARM),
159	HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT | HWMON_H_MIN |
160				HWMON_H_MIN_HYST | HWMON_H_MAX |
161				HWMON_H_MAX_HYST | HWMON_H_ALARM),
162	NULL,
163};
164
165struct sht3x_data {
166	struct i2c_client *client;
167	enum sht3x_chips chip_id;
168	struct mutex i2c_lock; /* lock for sending i2c commands */
169	struct mutex data_lock; /* lock for updating driver data */
170	struct dentry *sensor_dir;
171
172	u8 mode;
173	const unsigned char *command;
174	u32 wait_time;			/* in us*/
175	unsigned long last_update;	/* last update in periodic mode*/
176	enum sht3x_repeatability repeatability;
177	u32 serial_number;
178
179	/*
180	 * cached values for temperature and humidity and limits
181	 * the limits arrays have the following order:
182	 * max, max_hyst, min, min_hyst
183	 */
184	int temperature;
185	int temperature_limits[SHT3X_NUM_LIMIT_CMD];
186	u32 humidity;
187	u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
188};
189
190static u8 get_mode_from_update_interval(u16 value)
191{
192	size_t index;
193	u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
194
195	if (value == 0)
196		return 0;
197
198	/* find next faster update interval */
199	for (index = 1; index < number_of_modes; index++) {
200		if (mode_to_update_interval[index] <= value)
201			return index;
202	}
203
204	return number_of_modes - 1;
205}
206
207static int sht3x_read_from_command(struct i2c_client *client,
208				   struct sht3x_data *data,
209				   const char *command,
210				   char *buf, int length, u32 wait_time)
211{
212	int ret;
213
214	mutex_lock(&data->i2c_lock);
215	ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
216
217	if (ret != SHT3X_CMD_LENGTH) {
218		ret = ret < 0 ? ret : -EIO;
219		goto out;
220	}
221
222	if (wait_time)
223		usleep_range(wait_time, wait_time + 1000);
224
225	ret = i2c_master_recv(client, buf, length);
226	if (ret != length) {
227		ret = ret < 0 ? ret : -EIO;
228		goto out;
229	}
230
231	ret = 0;
232out:
233	mutex_unlock(&data->i2c_lock);
234	return ret;
235}
236
237static int sht3x_extract_temperature(u16 raw)
238{
239	/*
240	 * From datasheet:
241	 * T = -45 + 175 * ST / 2^16
242	 * Adapted for integer fixed point (3 digit) arithmetic.
243	 */
244	return ((21875 * (int)raw) >> 13) - 45000;
245}
246
247static u32 sht3x_extract_humidity(u16 raw)
248{
249	/*
250	 * From datasheet:
251	 * RH = 100 * SRH / 2^16
252	 * Adapted for integer fixed point (3 digit) arithmetic.
253	 */
254	return (12500 * (u32)raw) >> 13;
255}
256
257static struct sht3x_data *sht3x_update_client(struct device *dev)
258{
259	struct sht3x_data *data = dev_get_drvdata(dev);
260	struct i2c_client *client = data->client;
261	u16 interval_ms = mode_to_update_interval[data->mode];
262	unsigned long interval_jiffies = msecs_to_jiffies(interval_ms);
263	unsigned char buf[SHT3X_RESPONSE_LENGTH];
264	u16 val;
265	int ret = 0;
266
267	mutex_lock(&data->data_lock);
268	/*
269	 * Only update cached readings once per update interval in periodic
270	 * mode. In single shot mode the sensor measures values on demand, so
271	 * every time the sysfs interface is called, a measurement is triggered.
272	 * In periodic mode however, the measurement process is handled
273	 * internally by the sensor and reading out sensor values only makes
274	 * sense if a new reading is available.
275	 */
276	if (time_after(jiffies, data->last_update + interval_jiffies)) {
277		ret = sht3x_read_from_command(client, data, data->command, buf,
278					      sizeof(buf), data->wait_time);
279		if (ret)
280			goto out;
281
282		val = be16_to_cpup((__be16 *)buf);
283		data->temperature = sht3x_extract_temperature(val);
284		val = be16_to_cpup((__be16 *)(buf + 3));
285		data->humidity = sht3x_extract_humidity(val);
286		data->last_update = jiffies;
287	}
288
289out:
290	mutex_unlock(&data->data_lock);
291	if (ret)
292		return ERR_PTR(ret);
293
294	return data;
295}
296
297static int temp1_input_read(struct device *dev)
298{
299	struct sht3x_data *data = sht3x_update_client(dev);
300
301	if (IS_ERR(data))
302		return PTR_ERR(data);
303
304	return data->temperature;
305}
306
307static int humidity1_input_read(struct device *dev)
308{
309	struct sht3x_data *data = sht3x_update_client(dev);
310
311	if (IS_ERR(data))
312		return PTR_ERR(data);
313
314	return data->humidity;
315}
316
317/*
318 * limits_update must only be called from probe or with data_lock held
319 */
320static int limits_update(struct sht3x_data *data)
321{
322	int ret;
323	u8 index;
324	int temperature;
325	u32 humidity;
326	u16 raw;
327	char buffer[SHT3X_RESPONSE_LENGTH];
328	const struct sht3x_limit_commands *commands;
329	struct i2c_client *client = data->client;
330
331	for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
332		commands = &limit_commands[index];
333		ret = sht3x_read_from_command(client, data,
334					      commands->read_command, buffer,
335					      SHT3X_RESPONSE_LENGTH, 0);
336
337		if (ret)
338			return ret;
339
340		raw = be16_to_cpup((__be16 *)buffer);
341		temperature = sht3x_extract_temperature((raw & 0x01ff) << 7);
342		humidity = sht3x_extract_humidity(raw & 0xfe00);
343		data->temperature_limits[index] = temperature;
344		data->humidity_limits[index] = humidity;
345	}
346
347	return ret;
348}
349
350static int temp1_limit_read(struct device *dev, int index)
351{
352	struct sht3x_data *data = dev_get_drvdata(dev);
353
354	return data->temperature_limits[index];
355}
356
357static int humidity1_limit_read(struct device *dev, int index)
358{
359	struct sht3x_data *data = dev_get_drvdata(dev);
360
361	return data->humidity_limits[index];
362}
363
364/*
365 * limit_write must only be called with data_lock held
366 */
367static size_t limit_write(struct device *dev,
368			  u8 index,
369			  int temperature,
370			  u32 humidity)
371{
372	char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
373	char *position = buffer;
374	int ret;
375	u16 raw;
376	struct sht3x_data *data = dev_get_drvdata(dev);
377	struct i2c_client *client = data->client;
378	const struct sht3x_limit_commands *commands;
379
380	commands = &limit_commands[index];
381
382	memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
383	position += SHT3X_CMD_LENGTH;
384	/*
385	 * ST = (T + 45) / 175 * 2^16
386	 * SRH = RH / 100 * 2^16
387	 * adapted for fixed point arithmetic and packed the same as
388	 * in limit_read()
389	 */
390	raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
391	raw |= ((humidity * 42950) >> 16) & 0xfe00;
392
393	*((__be16 *)position) = cpu_to_be16(raw);
394	position += SHT3X_WORD_LEN;
395	*position = crc8(sht3x_crc8_table,
396			 position - SHT3X_WORD_LEN,
397			 SHT3X_WORD_LEN,
398			 SHT3X_CRC8_INIT);
399
400	mutex_lock(&data->i2c_lock);
401	ret = i2c_master_send(client, buffer, sizeof(buffer));
402	mutex_unlock(&data->i2c_lock);
403
404	if (ret != sizeof(buffer))
405		return ret < 0 ? ret : -EIO;
406
407	data->temperature_limits[index] = temperature;
408	data->humidity_limits[index] = humidity;
409
410	return 0;
411}
412
413static int temp1_limit_write(struct device *dev, int index, int val)
414{
415	int temperature;
416	int ret;
417	struct sht3x_data *data = dev_get_drvdata(dev);
418
419	temperature = clamp_val(val, SHT3X_MIN_TEMPERATURE,
420				SHT3X_MAX_TEMPERATURE);
421	mutex_lock(&data->data_lock);
422	ret = limit_write(dev, index, temperature,
423			  data->humidity_limits[index]);
424	mutex_unlock(&data->data_lock);
425
426	return ret;
427}
428
429static int humidity1_limit_write(struct device *dev, int index, int val)
430{
431	u32 humidity;
432	int ret;
433	struct sht3x_data *data = dev_get_drvdata(dev);
434
435	humidity = clamp_val(val, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
436	mutex_lock(&data->data_lock);
437	ret = limit_write(dev, index, data->temperature_limits[index],
438			  humidity);
439	mutex_unlock(&data->data_lock);
440
441	return ret;
442}
443
444static void sht3x_select_command(struct sht3x_data *data)
445{
446	/*
447	 * For single-shot mode, only non blocking mode is support,
448	 * we have to wait ourselves for result.
449	 */
450	if (data->mode > 0) {
451		data->command = sht3x_cmd_measure_periodic_mode;
452		data->wait_time = 0;
453	} else {
454		if (data->repeatability == high_repeatability) {
455			data->command = sht3x_cmd_measure_single_hpm;
456			data->wait_time = SHT3X_SINGLE_WAIT_TIME_HPM;
457		} else if (data->repeatability ==  medium_repeatability) {
458			data->command = sht3x_cmd_measure_single_mpm;
459			data->wait_time = SHT3X_SINGLE_WAIT_TIME_MPM;
460		} else {
461			data->command = sht3x_cmd_measure_single_lpm;
462			data->wait_time = SHT3X_SINGLE_WAIT_TIME_LPM;
463		}
464	}
465}
466
467static int status_register_read(struct device *dev,
468				char *buffer, int length)
469{
470	int ret;
471	struct sht3x_data *data = dev_get_drvdata(dev);
472	struct i2c_client *client = data->client;
473
474	ret = sht3x_read_from_command(client, data, sht3x_cmd_read_status_reg,
475				      buffer, length, 0);
476
477	return ret;
478}
479
480static int temp1_alarm_read(struct device *dev)
481{
482	char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
483	int ret;
484
485	ret = status_register_read(dev, buffer,
486				   SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
487	if (ret)
488		return ret;
489
490	return !!(buffer[0] & 0x04);
491}
492
493static int humidity1_alarm_read(struct device *dev)
494{
495	char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
496	int ret;
497
498	ret = status_register_read(dev, buffer,
499				   SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
500	if (ret)
501		return ret;
502
503	return !!(buffer[0] & 0x08);
504}
505
506static ssize_t heater_enable_show(struct device *dev,
507				  struct device_attribute *attr,
508				  char *buf)
509{
510	char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
511	int ret;
512
513	ret = status_register_read(dev, buffer,
514				   SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
515	if (ret)
516		return ret;
517
518	return sysfs_emit(buf, "%d\n", !!(buffer[0] & 0x20));
519}
520
521static ssize_t heater_enable_store(struct device *dev,
522				   struct device_attribute *attr,
523				   const char *buf,
524				   size_t count)
525{
526	struct sht3x_data *data = dev_get_drvdata(dev);
527	struct i2c_client *client = data->client;
528	int ret;
529	bool status;
530
531	ret = kstrtobool(buf, &status);
532	if (ret)
533		return ret;
534
535	mutex_lock(&data->i2c_lock);
536
537	if (status)
538		ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
539				      SHT3X_CMD_LENGTH);
540	else
541		ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
542				      SHT3X_CMD_LENGTH);
543
544	mutex_unlock(&data->i2c_lock);
545
546	return ret;
547}
548
549static int update_interval_read(struct device *dev)
550{
551	struct sht3x_data *data = dev_get_drvdata(dev);
552
553	return mode_to_update_interval[data->mode];
554}
555
556static int update_interval_write(struct device *dev, int val)
557{
558	u8 mode;
559	int ret;
560	const char *command;
561	struct sht3x_data *data = dev_get_drvdata(dev);
562	struct i2c_client *client = data->client;
563
564	mode = get_mode_from_update_interval(val);
565
566	mutex_lock(&data->data_lock);
567	/* mode did not change */
568	if (mode == data->mode) {
569		mutex_unlock(&data->data_lock);
570		return 0;
571	}
572
573	mutex_lock(&data->i2c_lock);
574	/*
575	 * Abort periodic measure mode.
576	 * To do any changes to the configuration while in periodic mode, we
577	 * have to send a break command to the sensor, which then falls back
578	 * to single shot (mode = 0).
579	 */
580	if (data->mode > 0) {
581		ret = i2c_master_send(client, sht3x_cmd_break,
582				      SHT3X_CMD_LENGTH);
583		if (ret != SHT3X_CMD_LENGTH)
584			goto out;
585		data->mode = 0;
586	}
587
588	if (mode > 0) {
589		if (data->repeatability == high_repeatability)
590			command = periodic_measure_commands_hpm[mode - 1];
591		else if (data->repeatability == medium_repeatability)
592			command = periodic_measure_commands_mpm[mode - 1];
593		else
594			command = periodic_measure_commands_lpm[mode - 1];
595
596		/* select mode */
597		ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
598		if (ret != SHT3X_CMD_LENGTH)
599			goto out;
600	}
601
602	/* select mode and command */
603	data->mode = mode;
604	sht3x_select_command(data);
605
606out:
607	mutex_unlock(&data->i2c_lock);
608	mutex_unlock(&data->data_lock);
609	if (ret != SHT3X_CMD_LENGTH)
610		return ret < 0 ? ret : -EIO;
611
612	return 0;
613}
614
615static ssize_t repeatability_show(struct device *dev,
616				  struct device_attribute *attr,
617				  char *buf)
618{
619	struct sht3x_data *data = dev_get_drvdata(dev);
620
621	return sysfs_emit(buf, "%d\n", data->repeatability);
622}
623
624static ssize_t repeatability_store(struct device *dev,
625				   struct device_attribute *attr,
626				   const char *buf,
627				   size_t count)
628{
629	int ret;
630	u8 val;
631
632	struct sht3x_data *data = dev_get_drvdata(dev);
633
634	ret = kstrtou8(buf, 0, &val);
635	if (ret)
636		return ret;
637
638	if (val > 2)
639		return -EINVAL;
640
641	data->repeatability = val;
642
643	return count;
644}
645
646static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
647static SENSOR_DEVICE_ATTR_RW(repeatability, repeatability, 0);
648
649static struct attribute *sht3x_attrs[] = {
650	&sensor_dev_attr_heater_enable.dev_attr.attr,
651	&sensor_dev_attr_repeatability.dev_attr.attr,
652	NULL
653};
654
655ATTRIBUTE_GROUPS(sht3x);
656
657static umode_t sht3x_is_visible(const void *data, enum hwmon_sensor_types type,
658				u32 attr, int channel)
659{
660	const struct sht3x_data *chip_data = data;
661
662	switch (type) {
663	case hwmon_chip:
664		switch (attr) {
665		case hwmon_chip_update_interval:
666			return 0644;
667		default:
668			break;
669		}
670		break;
671	case hwmon_temp:
672		switch (attr) {
673		case hwmon_temp_input:
674		case hwmon_temp_alarm:
675			return 0444;
676		case hwmon_temp_max:
677		case hwmon_temp_max_hyst:
678		case hwmon_temp_min:
679		case hwmon_temp_min_hyst:
680			return 0644;
681		default:
682			break;
683		}
684		break;
685	case hwmon_humidity:
686		if (chip_data->chip_id == sts3x)
687			break;
688		switch (attr) {
689		case hwmon_humidity_input:
690		case hwmon_humidity_alarm:
691			return 0444;
692		case hwmon_humidity_max:
693		case hwmon_humidity_max_hyst:
694		case hwmon_humidity_min:
695		case hwmon_humidity_min_hyst:
696			return 0644;
697		default:
698			break;
699		}
700		break;
701	default:
702		break;
703	}
704
705	return 0;
706}
707
708static int sht3x_read(struct device *dev, enum hwmon_sensor_types type,
709		      u32 attr, int channel, long *val)
710{
711	enum sht3x_limits index;
712
713	switch (type) {
714	case hwmon_chip:
715		switch (attr) {
716		case hwmon_chip_update_interval:
717			*val = update_interval_read(dev);
718			break;
719		default:
720			return -EOPNOTSUPP;
721		}
722		break;
723	case hwmon_temp:
724		switch (attr) {
725		case hwmon_temp_input:
726			*val = temp1_input_read(dev);
727			break;
728		case hwmon_temp_alarm:
729			*val = temp1_alarm_read(dev);
730			break;
731		case hwmon_temp_max:
732			index = limit_max;
733			*val = temp1_limit_read(dev, index);
734			break;
735		case hwmon_temp_max_hyst:
736			index = limit_max_hyst;
737			*val = temp1_limit_read(dev, index);
738			break;
739		case hwmon_temp_min:
740			index = limit_min;
741			*val = temp1_limit_read(dev, index);
742			break;
743		case hwmon_temp_min_hyst:
744			index = limit_min_hyst;
745			*val = temp1_limit_read(dev, index);
746			break;
747		default:
748			return -EOPNOTSUPP;
749		}
750		break;
751	case hwmon_humidity:
752		switch (attr) {
753		case hwmon_humidity_input:
754			*val = humidity1_input_read(dev);
755			break;
756		case hwmon_humidity_alarm:
757			*val = humidity1_alarm_read(dev);
758			break;
759		case hwmon_humidity_max:
760			index = limit_max;
761			*val = humidity1_limit_read(dev, index);
762			break;
763		case hwmon_humidity_max_hyst:
764			index = limit_max_hyst;
765			*val = humidity1_limit_read(dev, index);
766			break;
767		case hwmon_humidity_min:
768			index = limit_min;
769			*val = humidity1_limit_read(dev, index);
770			break;
771		case hwmon_humidity_min_hyst:
772			index = limit_min_hyst;
773			*val = humidity1_limit_read(dev, index);
774			break;
775		default:
776			return -EOPNOTSUPP;
777		}
778		break;
779	default:
780		return -EOPNOTSUPP;
781	}
782
783	return 0;
784}
785
786static int sht3x_write(struct device *dev, enum hwmon_sensor_types type,
787		       u32 attr, int channel, long val)
788{
789	enum sht3x_limits index;
790
791	switch (type) {
792	case hwmon_chip:
793		switch (attr) {
794		case hwmon_chip_update_interval:
795			return update_interval_write(dev, val);
796		default:
797			return -EOPNOTSUPP;
798		}
799	case hwmon_temp:
800		switch (attr) {
801		case hwmon_temp_max:
802			index = limit_max;
803			break;
804		case hwmon_temp_max_hyst:
805			index = limit_max_hyst;
806			break;
807		case hwmon_temp_min:
808			index = limit_min;
809			break;
810		case hwmon_temp_min_hyst:
811			index = limit_min_hyst;
812			break;
813		default:
814			return -EOPNOTSUPP;
815		}
816		return temp1_limit_write(dev, index, val);
817	case hwmon_humidity:
818		switch (attr) {
819		case hwmon_humidity_max:
820			index = limit_max;
821			break;
822		case hwmon_humidity_max_hyst:
823			index = limit_max_hyst;
824			break;
825		case hwmon_humidity_min:
826			index = limit_min;
827			break;
828		case hwmon_humidity_min_hyst:
829			index = limit_min_hyst;
830			break;
831		default:
832			return -EOPNOTSUPP;
833		}
834		return humidity1_limit_write(dev, index, val);
835	default:
836		return -EOPNOTSUPP;
837	}
838}
839
840static void sht3x_debugfs_init(struct sht3x_data *data)
841{
842	char name[32];
843
844	snprintf(name, sizeof(name), "i2c%u-%02x",
845		 data->client->adapter->nr, data->client->addr);
846	data->sensor_dir = debugfs_create_dir(name, debugfs);
847	debugfs_create_u32("serial_number", 0444,
848			   data->sensor_dir, &data->serial_number);
849}
850
851static void sht3x_debugfs_remove(void *sensor_dir)
852{
853	debugfs_remove_recursive(sensor_dir);
854}
855
856static int sht3x_serial_number_read(struct sht3x_data *data)
857{
858	int ret;
859	char buffer[SHT3X_RESPONSE_LENGTH];
860	struct i2c_client *client = data->client;
861
862	ret = sht3x_read_from_command(client, data,
863				      sht3x_cmd_read_serial_number,
864				      buffer,
865				      SHT3X_RESPONSE_LENGTH, 0);
866	if (ret)
867		return ret;
868
869	data->serial_number = (buffer[0] << 24) | (buffer[1] << 16) |
870			      (buffer[3] << 8) | buffer[4];
871	return ret;
872}
873
874static const struct hwmon_ops sht3x_ops = {
875	.is_visible = sht3x_is_visible,
876	.read = sht3x_read,
877	.write = sht3x_write,
878};
879
880static const struct hwmon_chip_info sht3x_chip_info = {
881	.ops = &sht3x_ops,
882	.info = sht3x_channel_info,
883};
884
885/* device ID table */
886static const struct i2c_device_id sht3x_ids[] = {
887	{"sht3x", sht3x},
888	{"sts3x", sts3x},
889	{}
890};
891
892MODULE_DEVICE_TABLE(i2c, sht3x_ids);
893
894static int sht3x_probe(struct i2c_client *client)
895{
896	int ret;
897	struct sht3x_data *data;
898	struct device *hwmon_dev;
899	struct i2c_adapter *adap = client->adapter;
900	struct device *dev = &client->dev;
901
902	/*
903	 * we require full i2c support since the sht3x uses multi-byte read and
904	 * writes as well as multi-byte commands which are not supported by
905	 * the smbus protocol
906	 */
907	if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
908		return -ENODEV;
909
910	ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
911			      SHT3X_CMD_LENGTH);
912	if (ret != SHT3X_CMD_LENGTH)
913		return ret < 0 ? ret : -ENODEV;
914
915	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
916	if (!data)
917		return -ENOMEM;
918
919	data->repeatability = high_repeatability;
920	data->mode = 0;
921	data->last_update = jiffies - msecs_to_jiffies(3000);
922	data->client = client;
923	data->chip_id = i2c_match_id(sht3x_ids, client)->driver_data;
924	crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
925
926	sht3x_select_command(data);
927
928	mutex_init(&data->i2c_lock);
929	mutex_init(&data->data_lock);
930
931	/*
932	 * An attempt to read limits register too early
933	 * causes a NACK response from the chip.
934	 * Waiting for an empirical delay of 500 us solves the issue.
935	 */
936	usleep_range(500, 600);
937
938	ret = limits_update(data);
939	if (ret)
940		return ret;
941
942	ret = sht3x_serial_number_read(data);
943	if (ret) {
944		dev_dbg(dev, "unable to read serial number\n");
945	} else {
946		sht3x_debugfs_init(data);
947		ret = devm_add_action_or_reset(dev,
948					       sht3x_debugfs_remove,
949					       data->sensor_dir);
950		if (ret)
951			return ret;
952	}
953
954	hwmon_dev = devm_hwmon_device_register_with_info(dev,
955							 client->name,
956							 data,
957							 &sht3x_chip_info,
958							 sht3x_groups);
959
960	if (IS_ERR(hwmon_dev))
961		dev_dbg(dev, "unable to register hwmon device\n");
962
963	return PTR_ERR_OR_ZERO(hwmon_dev);
964}
965
966static struct i2c_driver sht3x_i2c_driver = {
967	.driver.name = "sht3x",
968	.probe       = sht3x_probe,
969	.id_table    = sht3x_ids,
970};
971
972static int __init sht3x_init(void)
973{
974	debugfs = debugfs_create_dir("sht3x", NULL);
975	return i2c_add_driver(&sht3x_i2c_driver);
976}
977module_init(sht3x_init);
978
979static void __exit sht3x_cleanup(void)
980{
981	debugfs_remove_recursive(debugfs);
982	i2c_del_driver(&sht3x_i2c_driver);
983}
984module_exit(sht3x_cleanup);
985
986MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
987MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
988MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
989MODULE_LICENSE("GPL");
990