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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / hwmon / sht3x.c
blob7364764baaeb731e9526f92ce2f78ce4fb20a226
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 #include <linux/platform_data/sht3x.h>
24
25 /* commands (high precision mode) */
26 static const unsigned char sht3x_cmd_measure_blocking_hpm[] = { 0x2c, 0x06 };
27 static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };
28
29 /* commands (low power mode) */
30 static const unsigned char sht3x_cmd_measure_blocking_lpm[] = { 0x2c, 0x10 };
31 static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };
32
33 /* commands for periodic mode */
34 static const unsigned char sht3x_cmd_measure_periodic_mode[] = { 0xe0, 0x00 };
35 static const unsigned char sht3x_cmd_break[] = { 0x30, 0x93 };
36
37 /* commands for heater control */
38 static const unsigned char sht3x_cmd_heater_on[] = { 0x30, 0x6d };
39 static const unsigned char sht3x_cmd_heater_off[] = { 0x30, 0x66 };
40
41 /* other commands */
42 static const unsigned char sht3x_cmd_read_status_reg[] = { 0xf3, 0x2d };
43 static const unsigned char sht3x_cmd_clear_status_reg[] = { 0x30, 0x41 };
44
45 /* delays for non-blocking i2c commands, both in us */
46 #define SHT3X_NONBLOCKING_WAIT_TIME_HPM 15000
47 #define SHT3X_NONBLOCKING_WAIT_TIME_LPM 4000
48
49 #define SHT3X_WORD_LEN 2
50 #define SHT3X_CMD_LENGTH 2
51 #define SHT3X_CRC8_LEN 1
52 #define SHT3X_RESPONSE_LENGTH 6
53 #define SHT3X_CRC8_POLYNOMIAL 0x31
54 #define SHT3X_CRC8_INIT 0xFF
55 #define SHT3X_MIN_TEMPERATURE -45000
56 #define SHT3X_MAX_TEMPERATURE 130000
57 #define SHT3X_MIN_HUMIDITY 0
58 #define SHT3X_MAX_HUMIDITY 100000
59
60 enum sht3x_chips {
61 sht3x,
62 sts3x,
63 };
64
65 enum sht3x_limits {
66 limit_max = 0,
67 limit_max_hyst,
68 limit_min,
69 limit_min_hyst,
70 };
71
72 DECLARE_CRC8_TABLE(sht3x_crc8_table);
73
74 /* periodic measure commands (high precision mode) */
75 static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
76 /* 0.5 measurements per second */
77 {0x20, 0x32},
78 /* 1 measurements per second */
79 {0x21, 0x30},
80 /* 2 measurements per second */
81 {0x22, 0x36},
82 /* 4 measurements per second */
83 {0x23, 0x34},
84 /* 10 measurements per second */
85 {0x27, 0x37},
86 };
87
88 /* periodic measure commands (low power mode) */
89 static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
90 /* 0.5 measurements per second */
91 {0x20, 0x2f},
92 /* 1 measurements per second */
93 {0x21, 0x2d},
94 /* 2 measurements per second */
95 {0x22, 0x2b},
96 /* 4 measurements per second */
97 {0x23, 0x29},
98 /* 10 measurements per second */
99 {0x27, 0x2a},
100 };
101
102 struct sht3x_limit_commands {
103 const char read_command[SHT3X_CMD_LENGTH];
104 const char write_command[SHT3X_CMD_LENGTH];
105 };
106
107 static const struct sht3x_limit_commands limit_commands[] = {
108 /* temp1_max, humidity1_max */
109 [limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
110 /* temp_1_max_hyst, humidity1_max_hyst */
111 [limit_max_hyst] = { {0xe1, 0x14}, {0x61, 0x16} },
112 /* temp1_min, humidity1_min */
113 [limit_min] = { {0xe1, 0x02}, {0x61, 0x00} },
114 /* temp_1_min_hyst, humidity1_min_hyst */
115 [limit_min_hyst] = { {0xe1, 0x09}, {0x61, 0x0B} },
116 };
117
118 #define SHT3X_NUM_LIMIT_CMD ARRAY_SIZE(limit_commands)
119
120 static const u16 mode_to_update_interval[] = {
121 0,
122 2000,
123 1000,
124 500,
125 250,
126 100,
127 };
128
129 struct sht3x_data {
130 struct i2c_client *client;
131 struct mutex i2c_lock; /* lock for sending i2c commands */
132 struct mutex data_lock; /* lock for updating driver data */
133
134 u8 mode;
135 const unsigned char *command;
136 u32 wait_time; /* in us*/
137 unsigned long last_update; /* last update in periodic mode*/
138
139 struct sht3x_platform_data setup;
140
141 /*
142 * cached values for temperature and humidity and limits
143 * the limits arrays have the following order:
144 * max, max_hyst, min, min_hyst
145 */
146 int temperature;
147 int temperature_limits[SHT3X_NUM_LIMIT_CMD];
148 u32 humidity;
149 u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
150 };
151
152 static u8 get_mode_from_update_interval(u16 value)
153 {
154 size_t index;
155 u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
156
157 if (value == 0)
158 return 0;
159
160 /* find next faster update interval */
161 for (index = 1; index < number_of_modes; index++) {
162 if (mode_to_update_interval[index] <= value)
163 return index;
164 }
165
166 return number_of_modes - 1;
167 }
168
169 static int sht3x_read_from_command(struct i2c_client *client,
170 struct sht3x_data *data,
171 const char *command,
172 char *buf, int length, u32 wait_time)
173 {
174 int ret;
175
176 mutex_lock(&data->i2c_lock);
177 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
178
179 if (ret != SHT3X_CMD_LENGTH) {
180 ret = ret < 0 ? ret : -EIO;
181 goto out;
182 }
183
184 if (wait_time)
185 usleep_range(wait_time, wait_time + 1000);
186
187 ret = i2c_master_recv(client, buf, length);
188 if (ret != length) {
189 ret = ret < 0 ? ret : -EIO;
190 goto out;
191 }
192
193 ret = 0;
194 out:
195 mutex_unlock(&data->i2c_lock);
196 return ret;
197 }
198
199 static int sht3x_extract_temperature(u16 raw)
200 {
201 /*
202 * From datasheet:
203 * T = -45 + 175 * ST / 2^16
204 * Adapted for integer fixed point (3 digit) arithmetic.
205 */
206 return ((21875 * (int)raw) >> 13) - 45000;
207 }
208
209 static u32 sht3x_extract_humidity(u16 raw)
210 {
211 /*
212 * From datasheet:
213 * RH = 100 * SRH / 2^16
214 * Adapted for integer fixed point (3 digit) arithmetic.
215 */
216 return (12500 * (u32)raw) >> 13;
217 }
218
219 static struct sht3x_data *sht3x_update_client(struct device *dev)
220 {
221 struct sht3x_data *data = dev_get_drvdata(dev);
222 struct i2c_client *client = data->client;
223 u16 interval_ms = mode_to_update_interval[data->mode];
224 unsigned long interval_jiffies = msecs_to_jiffies(interval_ms);
225 unsigned char buf[SHT3X_RESPONSE_LENGTH];
226 u16 val;
227 int ret = 0;
228
229 mutex_lock(&data->data_lock);
230 /*
231 * Only update cached readings once per update interval in periodic
232 * mode. In single shot mode the sensor measures values on demand, so
233 * every time the sysfs interface is called, a measurement is triggered.
234 * In periodic mode however, the measurement process is handled
235 * internally by the sensor and reading out sensor values only makes
236 * sense if a new reading is available.
237 */
238 if (time_after(jiffies, data->last_update + interval_jiffies)) {
239 ret = sht3x_read_from_command(client, data, data->command, buf,
240 sizeof(buf), data->wait_time);
241 if (ret)
242 goto out;
243
244 val = be16_to_cpup((__be16 *)buf);
245 data->temperature = sht3x_extract_temperature(val);
246 val = be16_to_cpup((__be16 *)(buf + 3));
247 data->humidity = sht3x_extract_humidity(val);
248 data->last_update = jiffies;
249 }
250
251 out:
252 mutex_unlock(&data->data_lock);
253 if (ret)
254 return ERR_PTR(ret);
255
256 return data;
257 }
258
259 /* sysfs attributes */
260 static ssize_t temp1_input_show(struct device *dev,
261 struct device_attribute *attr, char *buf)
262 {
263 struct sht3x_data *data = sht3x_update_client(dev);
264
265 if (IS_ERR(data))
266 return PTR_ERR(data);
267
268 return sprintf(buf, "%d\n", data->temperature);
269 }
270
271 static ssize_t humidity1_input_show(struct device *dev,
272 struct device_attribute *attr, char *buf)
273 {
274 struct sht3x_data *data = sht3x_update_client(dev);
275
276 if (IS_ERR(data))
277 return PTR_ERR(data);
278
279 return sprintf(buf, "%u\n", data->humidity);
280 }
281
282 /*
283 * limits_update must only be called from probe or with data_lock held
284 */
285 static int limits_update(struct sht3x_data *data)
286 {
287 int ret;
288 u8 index;
289 int temperature;
290 u32 humidity;
291 u16 raw;
292 char buffer[SHT3X_RESPONSE_LENGTH];
293 const struct sht3x_limit_commands *commands;
294 struct i2c_client *client = data->client;
295
296 for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
297 commands = &limit_commands[index];
298 ret = sht3x_read_from_command(client, data,
299 commands->read_command, buffer,
300 SHT3X_RESPONSE_LENGTH, 0);
301
302 if (ret)
303 return ret;
304
305 raw = be16_to_cpup((__be16 *)buffer);
306 temperature = sht3x_extract_temperature((raw & 0x01ff) << 7);
307 humidity = sht3x_extract_humidity(raw & 0xfe00);
308 data->temperature_limits[index] = temperature;
309 data->humidity_limits[index] = humidity;
310 }
311
312 return ret;
313 }
314
315 static ssize_t temp1_limit_show(struct device *dev,
316 struct device_attribute *attr,
317 char *buf)
318 {
319 struct sht3x_data *data = dev_get_drvdata(dev);
320 u8 index = to_sensor_dev_attr(attr)->index;
321 int temperature_limit = data->temperature_limits[index];
322
323 return scnprintf(buf, PAGE_SIZE, "%d\n", temperature_limit);
324 }
325
326 static ssize_t humidity1_limit_show(struct device *dev,
327 struct device_attribute *attr,
328 char *buf)
329 {
330 struct sht3x_data *data = dev_get_drvdata(dev);
331 u8 index = to_sensor_dev_attr(attr)->index;
332 u32 humidity_limit = data->humidity_limits[index];
333
334 return scnprintf(buf, PAGE_SIZE, "%u\n", humidity_limit);
335 }
336
337 /*
338 * limit_store must only be called with data_lock held
339 */
340 static size_t limit_store(struct device *dev,
341 size_t count,
342 u8 index,
343 int temperature,
344 u32 humidity)
345 {
346 char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
347 char *position = buffer;
348 int ret;
349 u16 raw;
350 struct sht3x_data *data = dev_get_drvdata(dev);
351 struct i2c_client *client = data->client;
352 const struct sht3x_limit_commands *commands;
353
354 commands = &limit_commands[index];
355
356 memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
357 position += SHT3X_CMD_LENGTH;
358 /*
359 * ST = (T + 45) / 175 * 2^16
360 * SRH = RH / 100 * 2^16
361 * adapted for fixed point arithmetic and packed the same as
362 * in limit_show()
363 */
364 raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
365 raw |= ((humidity * 42950) >> 16) & 0xfe00;
366
367 *((__be16 *)position) = cpu_to_be16(raw);
368 position += SHT3X_WORD_LEN;
369 *position = crc8(sht3x_crc8_table,
370 position - SHT3X_WORD_LEN,
371 SHT3X_WORD_LEN,
372 SHT3X_CRC8_INIT);
373
374 mutex_lock(&data->i2c_lock);
375 ret = i2c_master_send(client, buffer, sizeof(buffer));
376 mutex_unlock(&data->i2c_lock);
377
378 if (ret != sizeof(buffer))
379 return ret < 0 ? ret : -EIO;
380
381 data->temperature_limits[index] = temperature;
382 data->humidity_limits[index] = humidity;
383 return count;
384 }
385
386 static ssize_t temp1_limit_store(struct device *dev,
387 struct device_attribute *attr,
388 const char *buf,
389 size_t count)
390 {
391 int temperature;
392 int ret;
393 struct sht3x_data *data = dev_get_drvdata(dev);
394 u8 index = to_sensor_dev_attr(attr)->index;
395
396 ret = kstrtoint(buf, 0, &temperature);
397 if (ret)
398 return ret;
399
400 temperature = clamp_val(temperature, SHT3X_MIN_TEMPERATURE,
401 SHT3X_MAX_TEMPERATURE);
402 mutex_lock(&data->data_lock);
403 ret = limit_store(dev, count, index, temperature,
404 data->humidity_limits[index]);
405 mutex_unlock(&data->data_lock);
406
407 return ret;
408 }
409
410 static ssize_t humidity1_limit_store(struct device *dev,
411 struct device_attribute *attr,
412 const char *buf,
413 size_t count)
414 {
415 u32 humidity;
416 int ret;
417 struct sht3x_data *data = dev_get_drvdata(dev);
418 u8 index = to_sensor_dev_attr(attr)->index;
419
420 ret = kstrtou32(buf, 0, &humidity);
421 if (ret)
422 return ret;
423
424 humidity = clamp_val(humidity, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
425 mutex_lock(&data->data_lock);
426 ret = limit_store(dev, count, index, data->temperature_limits[index],
427 humidity);
428 mutex_unlock(&data->data_lock);
429
430 return ret;
431 }
432
433 static void sht3x_select_command(struct sht3x_data *data)
434 {
435 /*
436 * In blocking mode (clock stretching mode) the I2C bus
437 * is blocked for other traffic, thus the call to i2c_master_recv()
438 * will wait until the data is ready. For non blocking mode, we
439 * have to wait ourselves.
440 */
441 if (data->mode > 0) {
442 data->command = sht3x_cmd_measure_periodic_mode;
443 data->wait_time = 0;
444 } else if (data->setup.blocking_io) {
445 data->command = data->setup.high_precision ?
446 sht3x_cmd_measure_blocking_hpm :
447 sht3x_cmd_measure_blocking_lpm;
448 data->wait_time = 0;
449 } else {
450 if (data->setup.high_precision) {
451 data->command = sht3x_cmd_measure_nonblocking_hpm;
452 data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM;
453 } else {
454 data->command = sht3x_cmd_measure_nonblocking_lpm;
455 data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_LPM;
456 }
457 }
458 }
459
460 static int status_register_read(struct device *dev,
461 struct device_attribute *attr,
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, sht3x_cmd_read_status_reg,
469 buffer, length, 0);
470
471 return ret;
472 }
473
474 static ssize_t temp1_alarm_show(struct device *dev,
475 struct device_attribute *attr,
476 char *buf)
477 {
478 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
479 int ret;
480
481 ret = status_register_read(dev, attr, buffer,
482 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
483 if (ret)
484 return ret;
485
486 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x04));
487 }
488
489 static ssize_t humidity1_alarm_show(struct device *dev,
490 struct device_attribute *attr,
491 char *buf)
492 {
493 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
494 int ret;
495
496 ret = status_register_read(dev, attr, buffer,
497 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
498 if (ret)
499 return ret;
500
501 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x08));
502 }
503
504 static ssize_t heater_enable_show(struct device *dev,
505 struct device_attribute *attr,
506 char *buf)
507 {
508 char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
509 int ret;
510
511 ret = status_register_read(dev, attr, buffer,
512 SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
513 if (ret)
514 return ret;
515
516 return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x20));
517 }
518
519 static ssize_t heater_enable_store(struct device *dev,
520 struct device_attribute *attr,
521 const char *buf,
522 size_t count)
523 {
524 struct sht3x_data *data = dev_get_drvdata(dev);
525 struct i2c_client *client = data->client;
526 int ret;
527 bool status;
528
529 ret = kstrtobool(buf, &status);
530 if (ret)
531 return ret;
532
533 mutex_lock(&data->i2c_lock);
534
535 if (status)
536 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
537 SHT3X_CMD_LENGTH);
538 else
539 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
540 SHT3X_CMD_LENGTH);
541
542 mutex_unlock(&data->i2c_lock);
543
544 return ret;
545 }
546
547 static ssize_t update_interval_show(struct device *dev,
548 struct device_attribute *attr,
549 char *buf)
550 {
551 struct sht3x_data *data = dev_get_drvdata(dev);
552
553 return scnprintf(buf, PAGE_SIZE, "%u\n",
554 mode_to_update_interval[data->mode]);
555 }
556
557 static ssize_t update_interval_store(struct device *dev,
558 struct device_attribute *attr,
559 const char *buf,
560 size_t count)
561 {
562 u16 update_interval;
563 u8 mode;
564 int ret;
565 const char *command;
566 struct sht3x_data *data = dev_get_drvdata(dev);
567 struct i2c_client *client = data->client;
568
569 ret = kstrtou16(buf, 0, &update_interval);
570 if (ret)
571 return ret;
572
573 mode = get_mode_from_update_interval(update_interval);
574
575 mutex_lock(&data->data_lock);
576 /* mode did not change */
577 if (mode == data->mode) {
578 mutex_unlock(&data->data_lock);
579 return count;
580 }
581
582 mutex_lock(&data->i2c_lock);
583 /*
584 * Abort periodic measure mode.
585 * To do any changes to the configuration while in periodic mode, we
586 * have to send a break command to the sensor, which then falls back
587 * to single shot (mode = 0).
588 */
589 if (data->mode > 0) {
590 ret = i2c_master_send(client, sht3x_cmd_break,
591 SHT3X_CMD_LENGTH);
592 if (ret != SHT3X_CMD_LENGTH)
593 goto out;
594 data->mode = 0;
595 }
596
597 if (mode > 0) {
598 if (data->setup.high_precision)
599 command = periodic_measure_commands_hpm[mode - 1];
600 else
601 command = periodic_measure_commands_lpm[mode - 1];
602
603 /* select mode */
604 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
605 if (ret != SHT3X_CMD_LENGTH)
606 goto out;
607 }
608
609 /* select mode and command */
610 data->mode = mode;
611 sht3x_select_command(data);
612
613 out:
614 mutex_unlock(&data->i2c_lock);
615 mutex_unlock(&data->data_lock);
616 if (ret != SHT3X_CMD_LENGTH)
617 return ret < 0 ? ret : -EIO;
618
619 return count;
620 }
621
622 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp1_input, 0);
623 static SENSOR_DEVICE_ATTR_RO(humidity1_input, humidity1_input, 0);
624 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp1_limit, limit_max);
625 static SENSOR_DEVICE_ATTR_RW(humidity1_max, humidity1_limit, limit_max);
626 static SENSOR_DEVICE_ATTR_RW(temp1_max_hyst, temp1_limit, limit_max_hyst);
627 static SENSOR_DEVICE_ATTR_RW(humidity1_max_hyst, humidity1_limit,
628 limit_max_hyst);
629 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp1_limit, limit_min);
630 static SENSOR_DEVICE_ATTR_RW(humidity1_min, humidity1_limit, limit_min);
631 static SENSOR_DEVICE_ATTR_RW(temp1_min_hyst, temp1_limit, limit_min_hyst);
632 static SENSOR_DEVICE_ATTR_RW(humidity1_min_hyst, humidity1_limit,
633 limit_min_hyst);
634 static SENSOR_DEVICE_ATTR_RO(temp1_alarm, temp1_alarm, 0);
635 static SENSOR_DEVICE_ATTR_RO(humidity1_alarm, humidity1_alarm, 0);
636 static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
637 static SENSOR_DEVICE_ATTR_RW(update_interval, update_interval, 0);
638
639 static struct attribute *sht3x_attrs[] = {
640 &sensor_dev_attr_temp1_input.dev_attr.attr,
641 &sensor_dev_attr_humidity1_input.dev_attr.attr,
642 &sensor_dev_attr_temp1_max.dev_attr.attr,
643 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
644 &sensor_dev_attr_humidity1_max.dev_attr.attr,
645 &sensor_dev_attr_humidity1_max_hyst.dev_attr.attr,
646 &sensor_dev_attr_temp1_min.dev_attr.attr,
647 &sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
648 &sensor_dev_attr_humidity1_min.dev_attr.attr,
649 &sensor_dev_attr_humidity1_min_hyst.dev_attr.attr,
650 &sensor_dev_attr_temp1_alarm.dev_attr.attr,
651 &sensor_dev_attr_humidity1_alarm.dev_attr.attr,
652 &sensor_dev_attr_heater_enable.dev_attr.attr,
653 &sensor_dev_attr_update_interval.dev_attr.attr,
654 NULL
655 };
656
657 static struct attribute *sts3x_attrs[] = {
658 &sensor_dev_attr_temp1_input.dev_attr.attr,
659 NULL
660 };
661
662 ATTRIBUTE_GROUPS(sht3x);
663 ATTRIBUTE_GROUPS(sts3x);
664
665 static int sht3x_probe(struct i2c_client *client,
666 const struct i2c_device_id *id)
667 {
668 int ret;
669 struct sht3x_data *data;
670 struct device *hwmon_dev;
671 struct i2c_adapter *adap = client->adapter;
672 struct device *dev = &client->dev;
673 const struct attribute_group **attribute_groups;
674
675 /*
676 * we require full i2c support since the sht3x uses multi-byte read and
677 * writes as well as multi-byte commands which are not supported by
678 * the smbus protocol
679 */
680 if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
681 return -ENODEV;
682
683 ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
684 SHT3X_CMD_LENGTH);
685 if (ret != SHT3X_CMD_LENGTH)
686 return ret < 0 ? ret : -ENODEV;
687
688 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
689 if (!data)
690 return -ENOMEM;
691
692 data->setup.blocking_io = false;
693 data->setup.high_precision = true;
694 data->mode = 0;
695 data->last_update = jiffies - msecs_to_jiffies(3000);
696 data->client = client;
697 crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
698
699 if (client->dev.platform_data)
700 data->setup = *(struct sht3x_platform_data *)dev->platform_data;
701
702 sht3x_select_command(data);
703
704 mutex_init(&data->i2c_lock);
705 mutex_init(&data->data_lock);
706
707 /*
708 * An attempt to read limits register too early
709 * causes a NACK response from the chip.
710 * Waiting for an empirical delay of 500 us solves the issue.
711 */
712 usleep_range(500, 600);
713
714 ret = limits_update(data);
715 if (ret)
716 return ret;
717
718 if (id->driver_data == sts3x)
719 attribute_groups = sts3x_groups;
720 else
721 attribute_groups = sht3x_groups;
722
723 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
724 client->name,
725 data,
726 attribute_groups);
727
728 if (IS_ERR(hwmon_dev))
729 dev_dbg(dev, "unable to register hwmon device\n");
730
731 return PTR_ERR_OR_ZERO(hwmon_dev);
732 }
733
734 /* device ID table */
735 static const struct i2c_device_id sht3x_ids[] = {
736 {"sht3x", sht3x},
737 {"sts3x", sts3x},
738 {}
739 };
740
741 MODULE_DEVICE_TABLE(i2c, sht3x_ids);
742
743 static struct i2c_driver sht3x_i2c_driver = {
744 .driver.name = "sht3x",
745 .probe = sht3x_probe,
746 .id_table = sht3x_ids,
747 };
748
749 module_i2c_driver(sht3x_i2c_driver);
750
751 MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
752 MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
753 MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
754 MODULE_LICENSE("GPL");
Linux with added FPC-III support