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/delay.h>
14#include <linux/err.h>
15#include <linux/hwmon.h>
16#include <linux/hwmon-sysfs.h>
17#include <linux/i2c.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22#include <linux/jiffies.h>
23
24/* commands (high repeatability mode) */
25static const unsigned char sht3x_cmd_measure_single_hpm[] = { 0x24, 0x00 };
26
27/* commands (medium repeatability mode) */
28static const unsigned char sht3x_cmd_measure_single_mpm[] = { 0x24, 0x0b };
29
30/* commands (low repeatability mode) */
31static const unsigned char sht3x_cmd_measure_single_lpm[] = { 0x24, 0x16 };
32
33/* commands for periodic mode */
34static const unsigned char sht3x_cmd_measure_periodic_mode[] = { 0xe0, 0x00 };
35static const unsigned char sht3x_cmd_break[] = { 0x30, 0x93 };
36
37/* commands for heater control */
38static const unsigned char sht3x_cmd_heater_on[] = { 0x30, 0x6d };
39static const unsigned char sht3x_cmd_heater_off[] = { 0x30, 0x66 };
40
41/* other commands */
42static const unsigned char sht3x_cmd_read_status_reg[] = { 0xf3, 0x2d };
43static const unsigned char sht3x_cmd_clear_status_reg[] = { 0x30, 0x41 };
44
45/* delays for single-shot mode i2c commands, both in us */
46#define SHT3X_SINGLE_WAIT_TIME_HPM 15000
47#define SHT3X_SINGLE_WAIT_TIME_MPM 6000
48#define SHT3X_SINGLE_WAIT_TIME_LPM 4000
49
50#define SHT3X_WORD_LEN 2
51#define SHT3X_CMD_LENGTH 2
52#define SHT3X_CRC8_LEN 1
53#define SHT3X_RESPONSE_LENGTH 6
54#define SHT3X_CRC8_POLYNOMIAL 0x31
55#define SHT3X_CRC8_INIT 0xFF
56#define SHT3X_MIN_TEMPERATURE -45000
57#define SHT3X_MAX_TEMPERATURE 130000
58#define SHT3X_MIN_HUMIDITY 0
59#define SHT3X_MAX_HUMIDITY 100000
60
61enum sht3x_chips {
62 sht3x,
63 sts3x,
64};
65
66enum sht3x_limits {
67 limit_max = 0,
68 limit_max_hyst,
69 limit_min,
70 limit_min_hyst,
71};
72
73enum sht3x_repeatability {
74 low_repeatability,
75 medium_repeatability,
76 high_repeatability,
77};
78
79DECLARE_CRC8_TABLE(sht3x_crc8_table);
80
81/* periodic measure commands (high repeatability mode) */
82static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
83 /* 0.5 measurements per second */
84 {0x20, 0x32},
85 /* 1 measurements per second */
86 {0x21, 0x30},
87 /* 2 measurements per second */
88 {0x22, 0x36},
89 /* 4 measurements per second */
90 {0x23, 0x34},
91 /* 10 measurements per second */
92 {0x27, 0x37},
93};
94
95/* periodic measure commands (medium repeatability) */
96static const char periodic_measure_commands_mpm[][SHT3X_CMD_LENGTH] = {
97 /* 0.5 measurements per second */
98 {0x20, 0x24},
99 /* 1 measurements per second */
100 {0x21, 0x26},
101 /* 2 measurements per second */
102 {0x22, 0x20},
103 /* 4 measurements per second */
104 {0x23, 0x22},
105 /* 10 measurements per second */
106 {0x27, 0x21},
107};
108
109/* periodic measure commands (low repeatability mode) */
110static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
111 /* 0.5 measurements per second */
112 {0x20, 0x2f},
113 /* 1 measurements per second */
114 {0x21, 0x2d},
115 /* 2 measurements per second */
116 {0x22, 0x2b},
117 /* 4 measurements per second */
118 {0x23, 0x29},
119 /* 10 measurements per second */
120 {0x27, 0x2a},
121};
122
123struct sht3x_limit_commands {
124 const char read_command[SHT3X_CMD_LENGTH];
125 const char write_command[SHT3X_CMD_LENGTH];
126};
127
128static const struct sht3x_limit_commands limit_commands[] = {
129 /* temp1_max, humidity1_max */
130 [limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
131 /* temp_1_max_hyst, humidity1_max_hyst */
132 [limit_max_hyst] = { .read_command: {0xe1, 0x14}, .write_command: {0x61, 0x16} },
133 /* temp1_min, humidity1_min */
134 [limit_min] = { .read_command: {0xe1, 0x02}, .write_command: {0x61, 0x00} },
135 /* temp_1_min_hyst, humidity1_min_hyst */
136 [limit_min_hyst] = { .read_command: {0xe1, 0x09}, .write_command: {0x61, 0x0B} },
137};
138
139#define SHT3X_NUM_LIMIT_CMD ARRAY_SIZE(limit_commands)
140
141static const u16 mode_to_update_interval[] = {
142 0,
143 2000,
144 1000,
145 500,
146 250,
147 100,
148};
149
150static const struct hwmon_channel_info * const sht3x_channel_info[] = {
151 HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
152 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MIN |
153 HWMON_T_MIN_HYST | HWMON_T_MAX |
154 HWMON_T_MAX_HYST | HWMON_T_ALARM),
155 HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT | HWMON_H_MIN |
156 HWMON_H_MIN_HYST | HWMON_H_MAX |
157 HWMON_H_MAX_HYST | HWMON_H_ALARM),
158 NULL,
159};
160
161struct sht3x_data {
162 struct i2c_client *client;
163 enum sht3x_chips chip_id;
164 struct mutex i2c_lock; /* lock for sending i2c commands */
165 struct mutex data_lock; /* lock for updating driver data */
166
167 u8 mode;
168 const unsigned char *command;
169 u32 wait_time; /* in us*/
170 unsigned long last_update; /* last update in periodic mode*/
171 enum sht3x_repeatability repeatability;
172
173 /*
174 * cached values for temperature and humidity and limits
175 * the limits arrays have the following order:
176 * max, max_hyst, min, min_hyst
177 */
178 int temperature;
179 int temperature_limits[SHT3X_NUM_LIMIT_CMD];
180 u32 humidity;
181 u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
182};
183
184static u8 get_mode_from_update_interval(u16 value)
185{
186 size_t index;
187 u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
188
189 if (value == 0)
190 return 0;
191
192 /* find next faster update interval */
193 for (index = 1; index < number_of_modes; index++) {
194 if (mode_to_update_interval[index] <= value)
195 return index;
196 }
197
198 return number_of_modes - 1;
199}
200
201static int sht3x_read_from_command(struct i2c_client *client,
202 struct sht3x_data *data,
203 const char *command,
204 char *buf, int length, u32 wait_time)
205{
206 int ret;
207
208 mutex_lock(&data->i2c_lock);
209 ret = i2c_master_send(client, buf: command, SHT3X_CMD_LENGTH);
210
211 if (ret != SHT3X_CMD_LENGTH) {
212 ret = ret < 0 ? ret : -EIO;
213 goto out;
214 }
215
216 if (wait_time)
217 usleep_range(min: wait_time, max: wait_time + 1000);
218
219 ret = i2c_master_recv(client, buf, count: length);
220 if (ret != length) {
221 ret = ret < 0 ? ret : -EIO;
222 goto out;
223 }
224
225 ret = 0;
226out:
227 mutex_unlock(lock: &data->i2c_lock);
228 return ret;
229}
230
231static int sht3x_extract_temperature(u16 raw)
232{
233 /*
234 * From datasheet:
235 * T = -45 + 175 * ST / 2^16
236 * Adapted for integer fixed point (3 digit) arithmetic.
237 */
238 return ((21875 * (int)raw) >> 13) - 45000;
239}
240
241static u32 sht3x_extract_humidity(u16 raw)
242{
243 /*
244 * From datasheet:
245 * RH = 100 * SRH / 2^16
246 * Adapted for integer fixed point (3 digit) arithmetic.
247 */
248 return (12500 * (u32)raw) >> 13;
249}
250
251static struct sht3x_data *sht3x_update_client(struct device *dev)
252{
253 struct sht3x_data *data = dev_get_drvdata(dev);
254 struct i2c_client *client = data->client;
255 u16 interval_ms = mode_to_update_interval[data->mode];
256 unsigned long interval_jiffies = msecs_to_jiffies(m: interval_ms);
257 unsigned char buf[SHT3X_RESPONSE_LENGTH];
258 u16 val;
259 int ret = 0;
260
261 mutex_lock(&data->data_lock);
262 /*
263 * Only update cached readings once per update interval in periodic
264 * mode. In single shot mode the sensor measures values on demand, so
265 * every time the sysfs interface is called, a measurement is triggered.
266 * In periodic mode however, the measurement process is handled
267 * internally by the sensor and reading out sensor values only makes
268 * sense if a new reading is available.
269 */
270 if (time_after(jiffies, data->last_update + interval_jiffies)) {
271 ret = sht3x_read_from_command(client, data, command: data->command, buf,
272 length: sizeof(buf), wait_time: data->wait_time);
273 if (ret)
274 goto out;
275
276 val = be16_to_cpup(p: (__be16 *)buf);
277 data->temperature = sht3x_extract_temperature(raw: val);
278 val = be16_to_cpup(p: (__be16 *)(buf + 3));
279 data->humidity = sht3x_extract_humidity(raw: val);
280 data->last_update = jiffies;
281 }
282
283out:
284 mutex_unlock(lock: &data->data_lock);
285 if (ret)
286 return ERR_PTR(error: ret);
287
288 return data;
289}
290
291static int temp1_input_read(struct device *dev)
292{
293 struct sht3x_data *data = sht3x_update_client(dev);
294
295 if (IS_ERR(ptr: data))
296 return PTR_ERR(ptr: data);
297
298 return data->temperature;
299}
300
301static int humidity1_input_read(struct device *dev)
302{
303 struct sht3x_data *data = sht3x_update_client(dev);
304
305 if (IS_ERR(ptr: data))
306 return PTR_ERR(ptr: data);
307
308 return data->humidity;
309}
310
311/*
312 * limits_update must only be called from probe or with data_lock held
313 */
314static int limits_update(struct sht3x_data *data)
315{
316 int ret;
317 u8 index;
318 int temperature;
319 u32 humidity;
320 u16 raw;
321 char buffer[SHT3X_RESPONSE_LENGTH];
322 const struct sht3x_limit_commands *commands;
323 struct i2c_client *client = data->client;
324
325 for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
326 commands = &limit_commands[index];
327 ret = sht3x_read_from_command(client, data,
328 command: commands->read_command, buf: buffer,
329 SHT3X_RESPONSE_LENGTH, wait_time: 0);
330
331 if (ret)
332 return ret;
333
334 raw = be16_to_cpup(p: (__be16 *)buffer);
335 temperature = sht3x_extract_temperature(raw: (raw & 0x01ff) << 7);
336 humidity = sht3x_extract_humidity(raw: raw & 0xfe00);
337 data->temperature_limits[index] = temperature;
338 data->humidity_limits[index] = humidity;
339 }
340
341 return ret;
342}
343
344static int temp1_limit_read(struct device *dev, int index)
345{
346 struct sht3x_data *data = dev_get_drvdata(dev);
347
348 return data->temperature_limits[index];
349}
350
351static int humidity1_limit_read(struct device *dev, int index)
352{
353 struct sht3x_data *data = dev_get_drvdata(dev);
354
355 return data->humidity_limits[index];
356}
357
358/*
359 * limit_write must only be called with data_lock held
360 */
361static size_t limit_write(struct device *dev,
362 u8 index,
363 int temperature,
364 u32 humidity)
365{
366 char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
367 char *position = buffer;
368 int ret;
369 u16 raw;
370 struct sht3x_data *data = dev_get_drvdata(dev);
371 struct i2c_client *client = data->client;
372 const struct sht3x_limit_commands *commands;
373
374 commands = &limit_commands[index];
375
376 memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
377 position += SHT3X_CMD_LENGTH;
378 /*
379 * ST = (T + 45) / 175 * 2^16
380 * SRH = RH / 100 * 2^16
381 * adapted for fixed point arithmetic and packed the same as
382 * in limit_read()
383 */
384 raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
385 raw |= ((humidity * 42950) >> 16) & 0xfe00;
386
387 *((__be16 *)position) = cpu_to_be16(raw);
388 position += SHT3X_WORD_LEN;
389 *position = crc8(table: sht3x_crc8_table,
390 pdata: position - SHT3X_WORD_LEN,
391 SHT3X_WORD_LEN,
392 SHT3X_CRC8_INIT);
393
394 mutex_lock(&data->i2c_lock);
395 ret = i2c_master_send(client, buf: buffer, count: sizeof(buffer));
396 mutex_unlock(lock: &data->i2c_lock);
397
398 if (ret != sizeof(buffer))
399 return ret < 0 ? ret : -EIO;
400
401 data->temperature_limits[index] = temperature;
402 data->humidity_limits[index] = humidity;
403
404 return 0;
405}
406
407static int temp1_limit_write(struct device *dev, int index, int val)
408{
409 int temperature;
410 int ret;
411 struct sht3x_data *data = dev_get_drvdata(dev);
412
413 temperature = clamp_val(val, SHT3X_MIN_TEMPERATURE,
414 SHT3X_MAX_TEMPERATURE);
415 mutex_lock(&data->data_lock);
416 ret = limit_write(dev, index, temperature,
417 humidity: data->humidity_limits[index]);
418 mutex_unlock(lock: &data->data_lock);
419
420 return ret;
421}
422
423static int humidity1_limit_write(struct device *dev, int index, int val)
424{
425 u32 humidity;
426 int ret;
427 struct sht3x_data *data = dev_get_drvdata(dev);
428
429 humidity = clamp_val(val, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
430 mutex_lock(&data->data_lock);
431 ret = limit_write(dev, index, temperature: data->temperature_limits[index],
432 humidity);
433 mutex_unlock(lock: &data->data_lock);
434
435 return ret;
436}
437
438static void sht3x_select_command(struct sht3x_data *data)
439{
440 /*
441 * For single-shot mode, only non blocking mode is support,
442 * we have to wait ourselves for result.
443 */
444 if (data->mode > 0) {
445 data->command = sht3x_cmd_measure_periodic_mode;
446 data->wait_time = 0;
447 } else {
448 if (data->repeatability == high_repeatability) {
449 data->command = sht3x_cmd_measure_single_hpm;
450 data->wait_time = SHT3X_SINGLE_WAIT_TIME_HPM;
451 } else if (data->repeatability == medium_repeatability) {
452 data->command = sht3x_cmd_measure_single_mpm;
453 data->wait_time = SHT3X_SINGLE_WAIT_TIME_MPM;
454 } else {
455 data->command = sht3x_cmd_measure_single_lpm;
456 data->wait_time = SHT3X_SINGLE_WAIT_TIME_LPM;
457 }
458 }
459}
460
461static int status_register_read(struct device *dev,
462 char *buffer, int length)
463{
464 int ret;
465 struct sht3x_data *data = dev_get_drvdata(dev);
466 struct i2c_client *client = data->client;
467
468 ret = sht3x_read_from_command(client, data, command: sht3x_cmd_read_status_reg,
469 buf: buffer, length, wait_time: 0);
470
471 return ret;
472}
473
474static int temp1_alarm_read(struct device *dev)
475{
476 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
477 int ret;
478
479 ret = status_register_read(dev, buffer,
480 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
481 if (ret)
482 return ret;
483
484 return !!(buffer[0] & 0x04);
485}
486
487static int humidity1_alarm_read(struct device *dev)
488{
489 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
490 int ret;
491
492 ret = status_register_read(dev, buffer,
493 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
494 if (ret)
495 return ret;
496
497 return !!(buffer[0] & 0x08);
498}
499
500static ssize_t heater_enable_show(struct device *dev,
501 struct device_attribute *attr,
502 char *buf)
503{
504 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
505 int ret;
506
507 ret = status_register_read(dev, buffer,
508 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
509 if (ret)
510 return ret;
511
512 return sysfs_emit(buf, fmt: "%d\n", !!(buffer[0] & 0x20));
513}
514
515static ssize_t heater_enable_store(struct device *dev,
516 struct device_attribute *attr,
517 const char *buf,
518 size_t count)
519{
520 struct sht3x_data *data = dev_get_drvdata(dev);
521 struct i2c_client *client = data->client;
522 int ret;
523 bool status;
524
525 ret = kstrtobool(s: buf, res: &status);
526 if (ret)
527 return ret;
528
529 mutex_lock(&data->i2c_lock);
530
531 if (status)
532 ret = i2c_master_send(client, buf: (char *)&sht3x_cmd_heater_on,
533 SHT3X_CMD_LENGTH);
534 else
535 ret = i2c_master_send(client, buf: (char *)&sht3x_cmd_heater_off,
536 SHT3X_CMD_LENGTH);
537
538 mutex_unlock(lock: &data->i2c_lock);
539
540 return ret;
541}
542
543static int update_interval_read(struct device *dev)
544{
545 struct sht3x_data *data = dev_get_drvdata(dev);
546
547 return mode_to_update_interval[data->mode];
548}
549
550static int update_interval_write(struct device *dev, int val)
551{
552 u8 mode;
553 int ret;
554 const char *command;
555 struct sht3x_data *data = dev_get_drvdata(dev);
556 struct i2c_client *client = data->client;
557
558 mode = get_mode_from_update_interval(value: val);
559
560 mutex_lock(&data->data_lock);
561 /* mode did not change */
562 if (mode == data->mode) {
563 mutex_unlock(lock: &data->data_lock);
564 return 0;
565 }
566
567 mutex_lock(&data->i2c_lock);
568 /*
569 * Abort periodic measure mode.
570 * To do any changes to the configuration while in periodic mode, we
571 * have to send a break command to the sensor, which then falls back
572 * to single shot (mode = 0).
573 */
574 if (data->mode > 0) {
575 ret = i2c_master_send(client, buf: sht3x_cmd_break,
576 SHT3X_CMD_LENGTH);
577 if (ret != SHT3X_CMD_LENGTH)
578 goto out;
579 data->mode = 0;
580 }
581
582 if (mode > 0) {
583 if (data->repeatability == high_repeatability)
584 command = periodic_measure_commands_hpm[mode - 1];
585 else if (data->repeatability == medium_repeatability)
586 command = periodic_measure_commands_mpm[mode - 1];
587 else
588 command = periodic_measure_commands_lpm[mode - 1];
589
590 /* select mode */
591 ret = i2c_master_send(client, buf: command, SHT3X_CMD_LENGTH);
592 if (ret != SHT3X_CMD_LENGTH)
593 goto out;
594 }
595
596 /* select mode and command */
597 data->mode = mode;
598 sht3x_select_command(data);
599
600out:
601 mutex_unlock(lock: &data->i2c_lock);
602 mutex_unlock(lock: &data->data_lock);
603 if (ret != SHT3X_CMD_LENGTH)
604 return ret < 0 ? ret : -EIO;
605
606 return 0;
607}
608
609static ssize_t repeatability_show(struct device *dev,
610 struct device_attribute *attr,
611 char *buf)
612{
613 struct sht3x_data *data = dev_get_drvdata(dev);
614
615 return sysfs_emit(buf, fmt: "%d\n", data->repeatability);
616}
617
618static ssize_t repeatability_store(struct device *dev,
619 struct device_attribute *attr,
620 const char *buf,
621 size_t count)
622{
623 int ret;
624 u8 val;
625
626 struct sht3x_data *data = dev_get_drvdata(dev);
627
628 ret = kstrtou8(s: buf, base: 0, res: &val);
629 if (ret)
630 return ret;
631
632 if (val > 2)
633 return -EINVAL;
634
635 data->repeatability = val;
636
637 return count;
638}
639
640static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
641static SENSOR_DEVICE_ATTR_RW(repeatability, repeatability, 0);
642
643static struct attribute *sht3x_attrs[] = {
644 &sensor_dev_attr_heater_enable.dev_attr.attr,
645 &sensor_dev_attr_repeatability.dev_attr.attr,
646 NULL
647};
648
649ATTRIBUTE_GROUPS(sht3x);
650
651static umode_t sht3x_is_visible(const void *data, enum hwmon_sensor_types type,
652 u32 attr, int channel)
653{
654 const struct sht3x_data *chip_data = data;
655
656 switch (type) {
657 case hwmon_chip:
658 switch (attr) {
659 case hwmon_chip_update_interval:
660 return 0644;
661 default:
662 break;
663 }
664 break;
665 case hwmon_temp:
666 switch (attr) {
667 case hwmon_temp_input:
668 case hwmon_temp_alarm:
669 return 0444;
670 case hwmon_temp_max:
671 case hwmon_temp_max_hyst:
672 case hwmon_temp_min:
673 case hwmon_temp_min_hyst:
674 return 0644;
675 default:
676 break;
677 }
678 break;
679 case hwmon_humidity:
680 if (chip_data->chip_id == sts3x)
681 break;
682 switch (attr) {
683 case hwmon_humidity_input:
684 case hwmon_humidity_alarm:
685 return 0444;
686 case hwmon_humidity_max:
687 case hwmon_humidity_max_hyst:
688 case hwmon_humidity_min:
689 case hwmon_humidity_min_hyst:
690 return 0644;
691 default:
692 break;
693 }
694 break;
695 default:
696 break;
697 }
698
699 return 0;
700}
701
702static int sht3x_read(struct device *dev, enum hwmon_sensor_types type,
703 u32 attr, int channel, long *val)
704{
705 enum sht3x_limits index;
706
707 switch (type) {
708 case hwmon_chip:
709 switch (attr) {
710 case hwmon_chip_update_interval:
711 *val = update_interval_read(dev);
712 break;
713 default:
714 return -EOPNOTSUPP;
715 }
716 break;
717 case hwmon_temp:
718 switch (attr) {
719 case hwmon_temp_input:
720 *val = temp1_input_read(dev);
721 break;
722 case hwmon_temp_alarm:
723 *val = temp1_alarm_read(dev);
724 break;
725 case hwmon_temp_max:
726 index = limit_max;
727 *val = temp1_limit_read(dev, index);
728 break;
729 case hwmon_temp_max_hyst:
730 index = limit_max_hyst;
731 *val = temp1_limit_read(dev, index);
732 break;
733 case hwmon_temp_min:
734 index = limit_min;
735 *val = temp1_limit_read(dev, index);
736 break;
737 case hwmon_temp_min_hyst:
738 index = limit_min_hyst;
739 *val = temp1_limit_read(dev, index);
740 break;
741 default:
742 return -EOPNOTSUPP;
743 }
744 break;
745 case hwmon_humidity:
746 switch (attr) {
747 case hwmon_humidity_input:
748 *val = humidity1_input_read(dev);
749 break;
750 case hwmon_humidity_alarm:
751 *val = humidity1_alarm_read(dev);
752 break;
753 case hwmon_humidity_max:
754 index = limit_max;
755 *val = humidity1_limit_read(dev, index);
756 break;
757 case hwmon_humidity_max_hyst:
758 index = limit_max_hyst;
759 *val = humidity1_limit_read(dev, index);
760 break;
761 case hwmon_humidity_min:
762 index = limit_min;
763 *val = humidity1_limit_read(dev, index);
764 break;
765 case hwmon_humidity_min_hyst:
766 index = limit_min_hyst;
767 *val = humidity1_limit_read(dev, index);
768 break;
769 default:
770 return -EOPNOTSUPP;
771 }
772 break;
773 default:
774 return -EOPNOTSUPP;
775 }
776
777 return 0;
778}
779
780static int sht3x_write(struct device *dev, enum hwmon_sensor_types type,
781 u32 attr, int channel, long val)
782{
783 enum sht3x_limits index;
784
785 switch (type) {
786 case hwmon_chip:
787 switch (attr) {
788 case hwmon_chip_update_interval:
789 return update_interval_write(dev, val);
790 default:
791 return -EOPNOTSUPP;
792 }
793 case hwmon_temp:
794 switch (attr) {
795 case hwmon_temp_max:
796 index = limit_max;
797 break;
798 case hwmon_temp_max_hyst:
799 index = limit_max_hyst;
800 break;
801 case hwmon_temp_min:
802 index = limit_min;
803 break;
804 case hwmon_temp_min_hyst:
805 index = limit_min_hyst;
806 break;
807 default:
808 return -EOPNOTSUPP;
809 }
810 return temp1_limit_write(dev, index, val);
811 case hwmon_humidity:
812 switch (attr) {
813 case hwmon_humidity_max:
814 index = limit_max;
815 break;
816 case hwmon_humidity_max_hyst:
817 index = limit_max_hyst;
818 break;
819 case hwmon_humidity_min:
820 index = limit_min;
821 break;
822 case hwmon_humidity_min_hyst:
823 index = limit_min_hyst;
824 break;
825 default:
826 return -EOPNOTSUPP;
827 }
828 return humidity1_limit_write(dev, index, val);
829 default:
830 return -EOPNOTSUPP;
831 }
832}
833
834static const struct hwmon_ops sht3x_ops = {
835 .is_visible = sht3x_is_visible,
836 .read = sht3x_read,
837 .write = sht3x_write,
838};
839
840static const struct hwmon_chip_info sht3x_chip_info = {
841 .ops = &sht3x_ops,
842 .info = sht3x_channel_info,
843};
844
845/* device ID table */
846static const struct i2c_device_id sht3x_ids[] = {
847 {"sht3x", sht3x},
848 {"sts3x", sts3x},
849 {}
850};
851
852MODULE_DEVICE_TABLE(i2c, sht3x_ids);
853
854static int sht3x_probe(struct i2c_client *client)
855{
856 int ret;
857 struct sht3x_data *data;
858 struct device *hwmon_dev;
859 struct i2c_adapter *adap = client->adapter;
860 struct device *dev = &client->dev;
861
862 /*
863 * we require full i2c support since the sht3x uses multi-byte read and
864 * writes as well as multi-byte commands which are not supported by
865 * the smbus protocol
866 */
867 if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
868 return -ENODEV;
869
870 ret = i2c_master_send(client, buf: sht3x_cmd_clear_status_reg,
871 SHT3X_CMD_LENGTH);
872 if (ret != SHT3X_CMD_LENGTH)
873 return ret < 0 ? ret : -ENODEV;
874
875 data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL);
876 if (!data)
877 return -ENOMEM;
878
879 data->repeatability = high_repeatability;
880 data->mode = 0;
881 data->last_update = jiffies - msecs_to_jiffies(m: 3000);
882 data->client = client;
883 data->chip_id = i2c_match_id(id: sht3x_ids, client)->driver_data;
884 crc8_populate_msb(table: sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
885
886 sht3x_select_command(data);
887
888 mutex_init(&data->i2c_lock);
889 mutex_init(&data->data_lock);
890
891 /*
892 * An attempt to read limits register too early
893 * causes a NACK response from the chip.
894 * Waiting for an empirical delay of 500 us solves the issue.
895 */
896 usleep_range(min: 500, max: 600);
897
898 ret = limits_update(data);
899 if (ret)
900 return ret;
901
902 hwmon_dev = devm_hwmon_device_register_with_info(dev,
903 name: client->name,
904 drvdata: data,
905 info: &sht3x_chip_info,
906 extra_groups: sht3x_groups);
907
908 if (IS_ERR(ptr: hwmon_dev))
909 dev_dbg(dev, "unable to register hwmon device\n");
910
911 return PTR_ERR_OR_ZERO(ptr: hwmon_dev);
912}
913
914static struct i2c_driver sht3x_i2c_driver = {
915 .driver.name = "sht3x",
916 .probe = sht3x_probe,
917 .id_table = sht3x_ids,
918};
919
920module_i2c_driver(sht3x_i2c_driver);
921
922MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
923MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
924MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
925MODULE_LICENSE("GPL");
926

source code of linux/drivers/hwmon/sht3x.c