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] = { .read_command: {0xe1, 0x14}, .write_command: {0x61, 0x16} },
137 /* temp1_min, humidity1_min */
138 [limit_min] = { .read_command: {0xe1, 0x02}, .write_command: {0x61, 0x00} },
139 /* temp_1_min_hyst, humidity1_min_hyst */
140 [limit_min_hyst] = { .read_command: {0xe1, 0x09}, .write_command: {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, buf: 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(min: wait_time, max: wait_time + 1000);
224
225 ret = i2c_master_recv(client, buf, count: length);
226 if (ret != length) {
227 ret = ret < 0 ? ret : -EIO;
228 goto out;
229 }
230
231 ret = 0;
232out:
233 mutex_unlock(lock: &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(m: 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, command: data->command, buf,
278 length: sizeof(buf), wait_time: data->wait_time);
279 if (ret)
280 goto out;
281
282 val = be16_to_cpup(p: (__be16 *)buf);
283 data->temperature = sht3x_extract_temperature(raw: val);
284 val = be16_to_cpup(p: (__be16 *)(buf + 3));
285 data->humidity = sht3x_extract_humidity(raw: val);
286 data->last_update = jiffies;
287 }
288
289out:
290 mutex_unlock(lock: &data->data_lock);
291 if (ret)
292 return ERR_PTR(error: 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(ptr: data))
302 return PTR_ERR(ptr: 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(ptr: data))
312 return PTR_ERR(ptr: 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 command: commands->read_command, buf: buffer,
335 SHT3X_RESPONSE_LENGTH, wait_time: 0);
336
337 if (ret)
338 return ret;
339
340 raw = be16_to_cpup(p: (__be16 *)buffer);
341 temperature = sht3x_extract_temperature(raw: (raw & 0x01ff) << 7);
342 humidity = sht3x_extract_humidity(raw: 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(table: sht3x_crc8_table,
396 pdata: 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, buf: buffer, count: sizeof(buffer));
402 mutex_unlock(lock: &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 humidity: data->humidity_limits[index]);
424 mutex_unlock(lock: &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, temperature: data->temperature_limits[index],
438 humidity);
439 mutex_unlock(lock: &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, command: sht3x_cmd_read_status_reg,
475 buf: buffer, length, wait_time: 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, fmt: "%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(s: buf, res: &status);
532 if (ret)
533 return ret;
534
535 mutex_lock(&data->i2c_lock);
536
537 if (status)
538 ret = i2c_master_send(client, buf: (char *)&sht3x_cmd_heater_on,
539 SHT3X_CMD_LENGTH);
540 else
541 ret = i2c_master_send(client, buf: (char *)&sht3x_cmd_heater_off,
542 SHT3X_CMD_LENGTH);
543
544 mutex_unlock(lock: &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(value: val);
565
566 mutex_lock(&data->data_lock);
567 /* mode did not change */
568 if (mode == data->mode) {
569 mutex_unlock(lock: &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, buf: 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, buf: 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(lock: &data->i2c_lock);
608 mutex_unlock(lock: &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, fmt: "%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(s: buf, base: 0, res: &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(buf: name, size: sizeof(name), fmt: "i2c%u-%02x",
845 data->client->adapter->nr, data->client->addr);
846 data->sensor_dir = debugfs_create_dir(name, parent: debugfs);
847 debugfs_create_u32(name: "serial_number", mode: 0444,
848 parent: data->sensor_dir, value: &data->serial_number);
849}
850
851static void sht3x_debugfs_remove(void *sensor_dir)
852{
853 debugfs_remove_recursive(dentry: 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 command: sht3x_cmd_read_serial_number,
864 buf: buffer,
865 SHT3X_RESPONSE_LENGTH, wait_time: 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, buf: 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, size: 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(m: 3000);
922 data->client = client;
923 data->chip_id = i2c_match_id(id: sht3x_ids, client)->driver_data;
924 crc8_populate_msb(table: 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(min: 500, max: 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 name: client->name,
956 drvdata: data,
957 info: &sht3x_chip_info,
958 extra_groups: sht3x_groups);
959
960 if (IS_ERR(ptr: hwmon_dev))
961 dev_dbg(dev, "unable to register hwmon device\n");
962
963 return PTR_ERR_OR_ZERO(ptr: 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(name: "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(dentry: debugfs);
982 i2c_del_driver(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

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