1/* Sensirion SHT3x-DIS humidity and temperature sensor driver.
2 * The SHT3x comes in many different versions, this driver is for the
3 * I2C version only.
4 *
5 * Copyright (C) 2016 Sensirion AG, Switzerland
6 * Author: David Frey <david.frey@sensirion.com>
7 * Author: Pascal Sachs <pascal.sachs@sensirion.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 */
20
21#include <asm/page.h>
22#include <linux/crc8.h>
23#include <linux/delay.h>
24#include <linux/err.h>
25#include <linux/hwmon.h>
26#include <linux/hwmon-sysfs.h>
27#include <linux/i2c.h>
28#include <linux/init.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32#include <linux/jiffies.h>
33#include <linux/platform_data/sht3x.h>
34
35/* commands (high precision mode) */
36static const unsigned char sht3x_cmd_measure_blocking_hpm[] = { 0x2c, 0x06 };
37static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };
38
39/* commands (low power mode) */
40static const unsigned char sht3x_cmd_measure_blocking_lpm[] = { 0x2c, 0x10 };
41static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };
42
43/* commands for periodic mode */
44static const unsigned char sht3x_cmd_measure_periodic_mode[] = { 0xe0, 0x00 };
45static const unsigned char sht3x_cmd_break[] = { 0x30, 0x93 };
46
47/* commands for heater control */
48static const unsigned char sht3x_cmd_heater_on[] = { 0x30, 0x6d };
49static const unsigned char sht3x_cmd_heater_off[] = { 0x30, 0x66 };
50
51/* other commands */
52static const unsigned char sht3x_cmd_read_status_reg[] = { 0xf3, 0x2d };
53static const unsigned char sht3x_cmd_clear_status_reg[] = { 0x30, 0x41 };
54
55/* delays for non-blocking i2c commands, both in us */
56#define SHT3X_NONBLOCKING_WAIT_TIME_HPM 15000
57#define SHT3X_NONBLOCKING_WAIT_TIME_LPM 4000
58
59#define SHT3X_WORD_LEN 2
60#define SHT3X_CMD_LENGTH 2
61#define SHT3X_CRC8_LEN 1
62#define SHT3X_RESPONSE_LENGTH 6
63#define SHT3X_CRC8_POLYNOMIAL 0x31
64#define SHT3X_CRC8_INIT 0xFF
65#define SHT3X_MIN_TEMPERATURE -45000
66#define SHT3X_MAX_TEMPERATURE 130000
67#define SHT3X_MIN_HUMIDITY 0
68#define SHT3X_MAX_HUMIDITY 100000
69
70enum sht3x_chips {
71 sht3x,
72 sts3x,
73};
74
75enum sht3x_limits {
76 limit_max = 0,
77 limit_max_hyst,
78 limit_min,
79 limit_min_hyst,
80};
81
82DECLARE_CRC8_TABLE(sht3x_crc8_table);
83
84/* periodic measure commands (high precision mode) */
85static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
86 /* 0.5 measurements per second */
87 {0x20, 0x32},
88 /* 1 measurements per second */
89 {0x21, 0x30},
90 /* 2 measurements per second */
91 {0x22, 0x36},
92 /* 4 measurements per second */
93 {0x23, 0x34},
94 /* 10 measurements per second */
95 {0x27, 0x37},
96};
97
98/* periodic measure commands (low power mode) */
99static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
100 /* 0.5 measurements per second */
101 {0x20, 0x2f},
102 /* 1 measurements per second */
103 {0x21, 0x2d},
104 /* 2 measurements per second */
105 {0x22, 0x2b},
106 /* 4 measurements per second */
107 {0x23, 0x29},
108 /* 10 measurements per second */
109 {0x27, 0x2a},
110};
111
112struct sht3x_limit_commands {
113 const char read_command[SHT3X_CMD_LENGTH];
114 const char write_command[SHT3X_CMD_LENGTH];
115};
116
117static const struct sht3x_limit_commands limit_commands[] = {
118 /* temp1_max, humidity1_max */
119 [limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
120 /* temp_1_max_hyst, humidity1_max_hyst */
121 [limit_max_hyst] = { {0xe1, 0x14}, {0x61, 0x16} },
122 /* temp1_min, humidity1_min */
123 [limit_min] = { {0xe1, 0x02}, {0x61, 0x00} },
124 /* temp_1_min_hyst, humidity1_min_hyst */
125 [limit_min_hyst] = { {0xe1, 0x09}, {0x61, 0x0B} },
126};
127
128#define SHT3X_NUM_LIMIT_CMD ARRAY_SIZE(limit_commands)
129
130static const u16 mode_to_update_interval[] = {
131 0,
132 2000,
133 1000,
134 500,
135 250,
136 100,
137};
138
139struct sht3x_data {
140 struct i2c_client *client;
141 struct mutex i2c_lock; /* lock for sending i2c commands */
142 struct mutex data_lock; /* lock for updating driver data */
143
144 u8 mode;
145 const unsigned char *command;
146 u32 wait_time; /* in us*/
147 unsigned long last_update; /* last update in periodic mode*/
148
149 struct sht3x_platform_data setup;
150
151 /*
152 * cached values for temperature and humidity and limits
153 * the limits arrays have the following order:
154 * max, max_hyst, min, min_hyst
155 */
156 int temperature;
157 int temperature_limits[SHT3X_NUM_LIMIT_CMD];
158 u32 humidity;
159 u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
160};
161
162static u8 get_mode_from_update_interval(u16 value)
163{
164 size_t index;
165 u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
166
167 if (value == 0)
168 return 0;
169
170 /* find next faster update interval */
171 for (index = 1; index < number_of_modes; index++) {
172 if (mode_to_update_interval[index] <= value)
173 return index;
174 }
175
176 return number_of_modes - 1;
177}
178
179static int sht3x_read_from_command(struct i2c_client *client,
180 struct sht3x_data *data,
181 const char *command,
182 char *buf, int length, u32 wait_time)
183{
184 int ret;
185
186 mutex_lock(&data->i2c_lock);
187 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
188
189 if (ret != SHT3X_CMD_LENGTH) {
190 ret = ret < 0 ? ret : -EIO;
191 goto out;
192 }
193
194 if (wait_time)
195 usleep_range(wait_time, wait_time + 1000);
196
197 ret = i2c_master_recv(client, buf, length);
198 if (ret != length) {
199 ret = ret < 0 ? ret : -EIO;
200 goto out;
201 }
202
203 ret = 0;
204out:
205 mutex_unlock(&data->i2c_lock);
206 return ret;
207}
208
209static int sht3x_extract_temperature(u16 raw)
210{
211 /*
212 * From datasheet:
213 * T = -45 + 175 * ST / 2^16
214 * Adapted for integer fixed point (3 digit) arithmetic.
215 */
216 return ((21875 * (int)raw) >> 13) - 45000;
217}
218
219static u32 sht3x_extract_humidity(u16 raw)
220{
221 /*
222 * From datasheet:
223 * RH = 100 * SRH / 2^16
224 * Adapted for integer fixed point (3 digit) arithmetic.
225 */
226 return (12500 * (u32)raw) >> 13;
227}
228
229static struct sht3x_data *sht3x_update_client(struct device *dev)
230{
231 struct sht3x_data *data = dev_get_drvdata(dev);
232 struct i2c_client *client = data->client;
233 u16 interval_ms = mode_to_update_interval[data->mode];
234 unsigned long interval_jiffies = msecs_to_jiffies(interval_ms);
235 unsigned char buf[SHT3X_RESPONSE_LENGTH];
236 u16 val;
237 int ret = 0;
238
239 mutex_lock(&data->data_lock);
240 /*
241 * Only update cached readings once per update interval in periodic
242 * mode. In single shot mode the sensor measures values on demand, so
243 * every time the sysfs interface is called, a measurement is triggered.
244 * In periodic mode however, the measurement process is handled
245 * internally by the sensor and reading out sensor values only makes
246 * sense if a new reading is available.
247 */
248 if (time_after(jiffies, data->last_update + interval_jiffies)) {
249 ret = sht3x_read_from_command(client, data, data->command, buf,
250 sizeof(buf), data->wait_time);
251 if (ret)
252 goto out;
253
254 val = be16_to_cpup((__be16 *)buf);
255 data->temperature = sht3x_extract_temperature(val);
256 val = be16_to_cpup((__be16 *)(buf + 3));
257 data->humidity = sht3x_extract_humidity(val);
258 data->last_update = jiffies;
259 }
260
261out:
262 mutex_unlock(&data->data_lock);
263 if (ret)
264 return ERR_PTR(ret);
265
266 return data;
267}
268
269/* sysfs attributes */
270static ssize_t temp1_input_show(struct device *dev,
271 struct device_attribute *attr, char *buf)
272{
273 struct sht3x_data *data = sht3x_update_client(dev);
274
275 if (IS_ERR(data))
276 return PTR_ERR(data);
277
278 return sprintf(buf, "%d\n", data->temperature);
279}
280
281static ssize_t humidity1_input_show(struct device *dev,
282 struct device_attribute *attr, char *buf)
283{
284 struct sht3x_data *data = sht3x_update_client(dev);
285
286 if (IS_ERR(data))
287 return PTR_ERR(data);
288
289 return sprintf(buf, "%u\n", data->humidity);
290}
291
292/*
293 * limits_update must only be called from probe or with data_lock held
294 */
295static int limits_update(struct sht3x_data *data)
296{
297 int ret;
298 u8 index;
299 int temperature;
300 u32 humidity;
301 u16 raw;
302 char buffer[SHT3X_RESPONSE_LENGTH];
303 const struct sht3x_limit_commands *commands;
304 struct i2c_client *client = data->client;
305
306 for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
307 commands = &limit_commands[index];
308 ret = sht3x_read_from_command(client, data,
309 commands->read_command, buffer,
310 SHT3X_RESPONSE_LENGTH, 0);
311
312 if (ret)
313 return ret;
314
315 raw = be16_to_cpup((__be16 *)buffer);
316 temperature = sht3x_extract_temperature((raw & 0x01ff) << 7);
317 humidity = sht3x_extract_humidity(raw & 0xfe00);
318 data->temperature_limits[index] = temperature;
319 data->humidity_limits[index] = humidity;
320 }
321
322 return ret;
323}
324
325static ssize_t temp1_limit_show(struct device *dev,
326 struct device_attribute *attr,
327 char *buf)
328{
329 struct sht3x_data *data = dev_get_drvdata(dev);
330 u8 index = to_sensor_dev_attr(attr)->index;
331 int temperature_limit = data->temperature_limits[index];
332
333 return scnprintf(buf, PAGE_SIZE, "%d\n", temperature_limit);
334}
335
336static ssize_t humidity1_limit_show(struct device *dev,
337 struct device_attribute *attr,
338 char *buf)
339{
340 struct sht3x_data *data = dev_get_drvdata(dev);
341 u8 index = to_sensor_dev_attr(attr)->index;
342 u32 humidity_limit = data->humidity_limits[index];
343
344 return scnprintf(buf, PAGE_SIZE, "%u\n", humidity_limit);
345}
346
347/*
348 * limit_store must only be called with data_lock held
349 */
350static size_t limit_store(struct device *dev,
351 size_t count,
352 u8 index,
353 int temperature,
354 u32 humidity)
355{
356 char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
357 char *position = buffer;
358 int ret;
359 u16 raw;
360 struct sht3x_data *data = dev_get_drvdata(dev);
361 struct i2c_client *client = data->client;
362 const struct sht3x_limit_commands *commands;
363
364 commands = &limit_commands[index];
365
366 memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
367 position += SHT3X_CMD_LENGTH;
368 /*
369 * ST = (T + 45) / 175 * 2^16
370 * SRH = RH / 100 * 2^16
371 * adapted for fixed point arithmetic and packed the same as
372 * in limit_show()
373 */
374 raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
375 raw |= ((humidity * 42950) >> 16) & 0xfe00;
376
377 *((__be16 *)position) = cpu_to_be16(raw);
378 position += SHT3X_WORD_LEN;
379 *position = crc8(sht3x_crc8_table,
380 position - SHT3X_WORD_LEN,
381 SHT3X_WORD_LEN,
382 SHT3X_CRC8_INIT);
383
384 mutex_lock(&data->i2c_lock);
385 ret = i2c_master_send(client, buffer, sizeof(buffer));
386 mutex_unlock(&data->i2c_lock);
387
388 if (ret != sizeof(buffer))
389 return ret < 0 ? ret : -EIO;
390
391 data->temperature_limits[index] = temperature;
392 data->humidity_limits[index] = humidity;
393 return count;
394}
395
396static ssize_t temp1_limit_store(struct device *dev,
397 struct device_attribute *attr,
398 const char *buf,
399 size_t count)
400{
401 int temperature;
402 int ret;
403 struct sht3x_data *data = dev_get_drvdata(dev);
404 u8 index = to_sensor_dev_attr(attr)->index;
405
406 ret = kstrtoint(buf, 0, &temperature);
407 if (ret)
408 return ret;
409
410 temperature = clamp_val(temperature, SHT3X_MIN_TEMPERATURE,
411 SHT3X_MAX_TEMPERATURE);
412 mutex_lock(&data->data_lock);
413 ret = limit_store(dev, count, index, temperature,
414 data->humidity_limits[index]);
415 mutex_unlock(&data->data_lock);
416
417 return ret;
418}
419
420static ssize_t humidity1_limit_store(struct device *dev,
421 struct device_attribute *attr,
422 const char *buf,
423 size_t count)
424{
425 u32 humidity;
426 int ret;
427 struct sht3x_data *data = dev_get_drvdata(dev);
428 u8 index = to_sensor_dev_attr(attr)->index;
429
430 ret = kstrtou32(buf, 0, &humidity);
431 if (ret)
432 return ret;
433
434 humidity = clamp_val(humidity, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
435 mutex_lock(&data->data_lock);
436 ret = limit_store(dev, count, index, data->temperature_limits[index],
437 humidity);
438 mutex_unlock(&data->data_lock);
439
440 return ret;
441}
442
443static void sht3x_select_command(struct sht3x_data *data)
444{
445 /*
446 * In blocking mode (clock stretching mode) the I2C bus
447 * is blocked for other traffic, thus the call to i2c_master_recv()
448 * will wait until the data is ready. For non blocking mode, we
449 * have to wait ourselves.
450 */
451 if (data->mode > 0) {
452 data->command = sht3x_cmd_measure_periodic_mode;
453 data->wait_time = 0;
454 } else if (data->setup.blocking_io) {
455 data->command = data->setup.high_precision ?
456 sht3x_cmd_measure_blocking_hpm :
457 sht3x_cmd_measure_blocking_lpm;
458 data->wait_time = 0;
459 } else {
460 if (data->setup.high_precision) {
461 data->command = sht3x_cmd_measure_nonblocking_hpm;
462 data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM;
463 } else {
464 data->command = sht3x_cmd_measure_nonblocking_lpm;
465 data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_LPM;
466 }
467 }
468}
469
470static int status_register_read(struct device *dev,
471 struct device_attribute *attr,
472 char *buffer, int length)
473{
474 int ret;
475 struct sht3x_data *data = dev_get_drvdata(dev);
476 struct i2c_client *client = data->client;
477
478 ret = sht3x_read_from_command(client, data, sht3x_cmd_read_status_reg,
479 buffer, length, 0);
480
481 return ret;
482}
483
484static ssize_t temp1_alarm_show(struct device *dev,
485 struct device_attribute *attr,
486 char *buf)
487{
488 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
489 int ret;
490
491 ret = status_register_read(dev, attr, buffer,
492 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
493 if (ret)
494 return ret;
495
496 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x04));
497}
498
499static ssize_t humidity1_alarm_show(struct device *dev,
500 struct device_attribute *attr,
501 char *buf)
502{
503 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
504 int ret;
505
506 ret = status_register_read(dev, attr, buffer,
507 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
508 if (ret)
509 return ret;
510
511 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x08));
512}
513
514static ssize_t heater_enable_show(struct device *dev,
515 struct device_attribute *attr,
516 char *buf)
517{
518 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
519 int ret;
520
521 ret = status_register_read(dev, attr, buffer,
522 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
523 if (ret)
524 return ret;
525
526 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x20));
527}
528
529static ssize_t heater_enable_store(struct device *dev,
530 struct device_attribute *attr,
531 const char *buf,
532 size_t count)
533{
534 struct sht3x_data *data = dev_get_drvdata(dev);
535 struct i2c_client *client = data->client;
536 int ret;
537 bool status;
538
539 ret = kstrtobool(buf, &status);
540 if (ret)
541 return ret;
542
543 mutex_lock(&data->i2c_lock);
544
545 if (status)
546 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
547 SHT3X_CMD_LENGTH);
548 else
549 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
550 SHT3X_CMD_LENGTH);
551
552 mutex_unlock(&data->i2c_lock);
553
554 return ret;
555}
556
557static ssize_t update_interval_show(struct device *dev,
558 struct device_attribute *attr,
559 char *buf)
560{
561 struct sht3x_data *data = dev_get_drvdata(dev);
562
563 return scnprintf(buf, PAGE_SIZE, "%u\n",
564 mode_to_update_interval[data->mode]);
565}
566
567static ssize_t update_interval_store(struct device *dev,
568 struct device_attribute *attr,
569 const char *buf,
570 size_t count)
571{
572 u16 update_interval;
573 u8 mode;
574 int ret;
575 const char *command;
576 struct sht3x_data *data = dev_get_drvdata(dev);
577 struct i2c_client *client = data->client;
578
579 ret = kstrtou16(buf, 0, &update_interval);
580 if (ret)
581 return ret;
582
583 mode = get_mode_from_update_interval(update_interval);
584
585 mutex_lock(&data->data_lock);
586 /* mode did not change */
587 if (mode == data->mode) {
588 mutex_unlock(&data->data_lock);
589 return count;
590 }
591
592 mutex_lock(&data->i2c_lock);
593 /*
594 * Abort periodic measure mode.
595 * To do any changes to the configuration while in periodic mode, we
596 * have to send a break command to the sensor, which then falls back
597 * to single shot (mode = 0).
598 */
599 if (data->mode > 0) {
600 ret = i2c_master_send(client, sht3x_cmd_break,
601 SHT3X_CMD_LENGTH);
602 if (ret != SHT3X_CMD_LENGTH)
603 goto out;
604 data->mode = 0;
605 }
606
607 if (mode > 0) {
608 if (data->setup.high_precision)
609 command = periodic_measure_commands_hpm[mode - 1];
610 else
611 command = periodic_measure_commands_lpm[mode - 1];
612
613 /* select mode */
614 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
615 if (ret != SHT3X_CMD_LENGTH)
616 goto out;
617 }
618
619 /* select mode and command */
620 data->mode = mode;
621 sht3x_select_command(data);
622
623out:
624 mutex_unlock(&data->i2c_lock);
625 mutex_unlock(&data->data_lock);
626 if (ret != SHT3X_CMD_LENGTH)
627 return ret < 0 ? ret : -EIO;
628
629 return count;
630}
631
632static SENSOR_DEVICE_ATTR_RO(temp1_input, temp1_input, 0);
633static SENSOR_DEVICE_ATTR_RO(humidity1_input, humidity1_input, 0);
634static SENSOR_DEVICE_ATTR_RW(temp1_max, temp1_limit, limit_max);
635static SENSOR_DEVICE_ATTR_RW(humidity1_max, humidity1_limit, limit_max);
636static SENSOR_DEVICE_ATTR_RW(temp1_max_hyst, temp1_limit, limit_max_hyst);
637static SENSOR_DEVICE_ATTR_RW(humidity1_max_hyst, humidity1_limit,
638 limit_max_hyst);
639static SENSOR_DEVICE_ATTR_RW(temp1_min, temp1_limit, limit_min);
640static SENSOR_DEVICE_ATTR_RW(humidity1_min, humidity1_limit, limit_min);
641static SENSOR_DEVICE_ATTR_RW(temp1_min_hyst, temp1_limit, limit_min_hyst);
642static SENSOR_DEVICE_ATTR_RW(humidity1_min_hyst, humidity1_limit,
643 limit_min_hyst);
644static SENSOR_DEVICE_ATTR_RO(temp1_alarm, temp1_alarm, 0);
645static SENSOR_DEVICE_ATTR_RO(humidity1_alarm, humidity1_alarm, 0);
646static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
647static SENSOR_DEVICE_ATTR_RW(update_interval, update_interval, 0);
648
649static struct attribute *sht3x_attrs[] = {
650 &sensor_dev_attr_temp1_input.dev_attr.attr,
651 &sensor_dev_attr_humidity1_input.dev_attr.attr,
652 &sensor_dev_attr_temp1_max.dev_attr.attr,
653 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
654 &sensor_dev_attr_humidity1_max.dev_attr.attr,
655 &sensor_dev_attr_humidity1_max_hyst.dev_attr.attr,
656 &sensor_dev_attr_temp1_min.dev_attr.attr,
657 &sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
658 &sensor_dev_attr_humidity1_min.dev_attr.attr,
659 &sensor_dev_attr_humidity1_min_hyst.dev_attr.attr,
660 &sensor_dev_attr_temp1_alarm.dev_attr.attr,
661 &sensor_dev_attr_humidity1_alarm.dev_attr.attr,
662 &sensor_dev_attr_heater_enable.dev_attr.attr,
663 &sensor_dev_attr_update_interval.dev_attr.attr,
664 NULL
665};
666
667static struct attribute *sts3x_attrs[] = {
668 &sensor_dev_attr_temp1_input.dev_attr.attr,
669 NULL
670};
671
672ATTRIBUTE_GROUPS(sht3x);
673ATTRIBUTE_GROUPS(sts3x);
674
675static int sht3x_probe(struct i2c_client *client,
676 const struct i2c_device_id *id)
677{
678 int ret;
679 struct sht3x_data *data;
680 struct device *hwmon_dev;
681 struct i2c_adapter *adap = client->adapter;
682 struct device *dev = &client->dev;
683 const struct attribute_group **attribute_groups;
684
685 /*
686 * we require full i2c support since the sht3x uses multi-byte read and
687 * writes as well as multi-byte commands which are not supported by
688 * the smbus protocol
689 */
690 if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
691 return -ENODEV;
692
693 ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
694 SHT3X_CMD_LENGTH);
695 if (ret != SHT3X_CMD_LENGTH)
696 return ret < 0 ? ret : -ENODEV;
697
698 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
699 if (!data)
700 return -ENOMEM;
701
702 data->setup.blocking_io = false;
703 data->setup.high_precision = true;
704 data->mode = 0;
705 data->last_update = jiffies - msecs_to_jiffies(3000);
706 data->client = client;
707 crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
708
709 if (client->dev.platform_data)
710 data->setup = *(struct sht3x_platform_data *)dev->platform_data;
711
712 sht3x_select_command(data);
713
714 mutex_init(&data->i2c_lock);
715 mutex_init(&data->data_lock);
716
717 /*
718 * An attempt to read limits register too early
719 * causes a NACK response from the chip.
720 * Waiting for an empirical delay of 500 us solves the issue.
721 */
722 usleep_range(500, 600);
723
724 ret = limits_update(data);
725 if (ret)
726 return ret;
727
728 if (id->driver_data == sts3x)
729 attribute_groups = sts3x_groups;
730 else
731 attribute_groups = sht3x_groups;
732
733 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
734 client->name,
735 data,
736 attribute_groups);
737
738 if (IS_ERR(hwmon_dev))
739 dev_dbg(dev, "unable to register hwmon device\n");
740
741 return PTR_ERR_OR_ZERO(hwmon_dev);
742}
743
744/* device ID table */
745static const struct i2c_device_id sht3x_ids[] = {
746 {"sht3x", sht3x},
747 {"sts3x", sts3x},
748 {}
749};
750
751MODULE_DEVICE_TABLE(i2c, sht3x_ids);
752
753static struct i2c_driver sht3x_i2c_driver = {
754 .driver.name = "sht3x",
755 .probe = sht3x_probe,
756 .id_table = sht3x_ids,
757};
758
759module_i2c_driver(sht3x_i2c_driver);
760
761MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
762MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
763MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
764MODULE_LICENSE("GPL");
765