cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

sht3x.c (20263B)


      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) */
     26static const unsigned char sht3x_cmd_measure_blocking_hpm[]    = { 0x2c, 0x06 };
     27static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };
     28
     29/* commands (low power mode) */
     30static const unsigned char sht3x_cmd_measure_blocking_lpm[]    = { 0x2c, 0x10 };
     31static const unsigned char sht3x_cmd_measure_nonblocking_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 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
     60enum sht3x_chips {
     61	sht3x,
     62	sts3x,
     63};
     64
     65enum sht3x_limits {
     66	limit_max = 0,
     67	limit_max_hyst,
     68	limit_min,
     69	limit_min_hyst,
     70};
     71
     72DECLARE_CRC8_TABLE(sht3x_crc8_table);
     73
     74/* periodic measure commands (high precision mode) */
     75static 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) */
     89static 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
    102struct sht3x_limit_commands {
    103	const char read_command[SHT3X_CMD_LENGTH];
    104	const char write_command[SHT3X_CMD_LENGTH];
    105};
    106
    107static 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
    120static const u16 mode_to_update_interval[] = {
    121	   0,
    122	2000,
    123	1000,
    124	 500,
    125	 250,
    126	 100,
    127};
    128
    129struct 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
    152static 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
    169static 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;
    194out:
    195	mutex_unlock(&data->i2c_lock);
    196	return ret;
    197}
    198
    199static 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
    209static 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
    219static 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
    251out:
    252	mutex_unlock(&data->data_lock);
    253	if (ret)
    254		return ERR_PTR(ret);
    255
    256	return data;
    257}
    258
    259/* sysfs attributes */
    260static 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
    271static 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 */
    285static 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
    315static 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
    326static 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 */
    340static 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
    386static 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
    410static 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
    433static 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
    460static 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
    474static 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
    489static 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
    504static 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
    519static 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
    547static 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
    557static 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
    613out:
    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
    622static SENSOR_DEVICE_ATTR_RO(temp1_input, temp1_input, 0);
    623static SENSOR_DEVICE_ATTR_RO(humidity1_input, humidity1_input, 0);
    624static SENSOR_DEVICE_ATTR_RW(temp1_max, temp1_limit, limit_max);
    625static SENSOR_DEVICE_ATTR_RW(humidity1_max, humidity1_limit, limit_max);
    626static SENSOR_DEVICE_ATTR_RW(temp1_max_hyst, temp1_limit, limit_max_hyst);
    627static SENSOR_DEVICE_ATTR_RW(humidity1_max_hyst, humidity1_limit,
    628			     limit_max_hyst);
    629static SENSOR_DEVICE_ATTR_RW(temp1_min, temp1_limit, limit_min);
    630static SENSOR_DEVICE_ATTR_RW(humidity1_min, humidity1_limit, limit_min);
    631static SENSOR_DEVICE_ATTR_RW(temp1_min_hyst, temp1_limit, limit_min_hyst);
    632static SENSOR_DEVICE_ATTR_RW(humidity1_min_hyst, humidity1_limit,
    633			     limit_min_hyst);
    634static SENSOR_DEVICE_ATTR_RO(temp1_alarm, temp1_alarm, 0);
    635static SENSOR_DEVICE_ATTR_RO(humidity1_alarm, humidity1_alarm, 0);
    636static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
    637static SENSOR_DEVICE_ATTR_RW(update_interval, update_interval, 0);
    638
    639static 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
    657static struct attribute *sts3x_attrs[] = {
    658	&sensor_dev_attr_temp1_input.dev_attr.attr,
    659	NULL
    660};
    661
    662ATTRIBUTE_GROUPS(sht3x);
    663ATTRIBUTE_GROUPS(sts3x);
    664
    665static const struct i2c_device_id sht3x_ids[];
    666
    667static int sht3x_probe(struct i2c_client *client)
    668{
    669	int ret;
    670	struct sht3x_data *data;
    671	struct device *hwmon_dev;
    672	struct i2c_adapter *adap = client->adapter;
    673	struct device *dev = &client->dev;
    674	const struct attribute_group **attribute_groups;
    675
    676	/*
    677	 * we require full i2c support since the sht3x uses multi-byte read and
    678	 * writes as well as multi-byte commands which are not supported by
    679	 * the smbus protocol
    680	 */
    681	if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
    682		return -ENODEV;
    683
    684	ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
    685			      SHT3X_CMD_LENGTH);
    686	if (ret != SHT3X_CMD_LENGTH)
    687		return ret < 0 ? ret : -ENODEV;
    688
    689	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
    690	if (!data)
    691		return -ENOMEM;
    692
    693	data->setup.blocking_io = false;
    694	data->setup.high_precision = true;
    695	data->mode = 0;
    696	data->last_update = jiffies - msecs_to_jiffies(3000);
    697	data->client = client;
    698	crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
    699
    700	if (client->dev.platform_data)
    701		data->setup = *(struct sht3x_platform_data *)dev->platform_data;
    702
    703	sht3x_select_command(data);
    704
    705	mutex_init(&data->i2c_lock);
    706	mutex_init(&data->data_lock);
    707
    708	/*
    709	 * An attempt to read limits register too early
    710	 * causes a NACK response from the chip.
    711	 * Waiting for an empirical delay of 500 us solves the issue.
    712	 */
    713	usleep_range(500, 600);
    714
    715	ret = limits_update(data);
    716	if (ret)
    717		return ret;
    718
    719	if (i2c_match_id(sht3x_ids, client)->driver_data == sts3x)
    720		attribute_groups = sts3x_groups;
    721	else
    722		attribute_groups = sht3x_groups;
    723
    724	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
    725							   client->name,
    726							   data,
    727							   attribute_groups);
    728
    729	if (IS_ERR(hwmon_dev))
    730		dev_dbg(dev, "unable to register hwmon device\n");
    731
    732	return PTR_ERR_OR_ZERO(hwmon_dev);
    733}
    734
    735/* device ID table */
    736static const struct i2c_device_id sht3x_ids[] = {
    737	{"sht3x", sht3x},
    738	{"sts3x", sts3x},
    739	{}
    740};
    741
    742MODULE_DEVICE_TABLE(i2c, sht3x_ids);
    743
    744static struct i2c_driver sht3x_i2c_driver = {
    745	.driver.name = "sht3x",
    746	.probe_new   = sht3x_probe,
    747	.id_table    = sht3x_ids,
    748};
    749
    750module_i2c_driver(sht3x_i2c_driver);
    751
    752MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
    753MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
    754MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
    755MODULE_LICENSE("GPL");