Add base support for HTU31 temperature and humidity sensor. Besides temperature and humidity values, the driver also exports a 24-bit serial number to sysfs. Signed-off-by: Andrei Lalaev <andrey.lalaev@xxxxxxxxx> --- Documentation/hwmon/htu31.rst | 38 ++++ Documentation/hwmon/index.rst | 1 + drivers/hwmon/Kconfig | 11 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/htu31.c | 335 ++++++++++++++++++++++++++++++++++ 5 files changed, 386 insertions(+) create mode 100644 Documentation/hwmon/htu31.rst create mode 100644 drivers/hwmon/htu31.c diff --git a/Documentation/hwmon/htu31.rst b/Documentation/hwmon/htu31.rst new file mode 100644 index 000000000000..a7a960e215ec --- /dev/null +++ b/Documentation/hwmon/htu31.rst @@ -0,0 +1,38 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +Kernel driver HTU31 +==================== + +Supported chips: + + * Measurement Specialties HTU31 + + Prefix: 'htu31' + + Addresses scanned: - + + Datasheet: Publicly available from https://www.te.com/en/product-CAT-HSC0007.html + +Author: + + - Andrei Lalaev <andrey.lalaev@xxxxxxxxx> + +Description +----------- + +HTU31 is a humidity and temperature sensor. + +Supported temperature range is from -40 to 125 degrees Celsius. + +Communication with the device is performed via I2C protocol. Sensor's default address +is 0x40. + +sysfs-Interface +--------------- + +=================== ================= +temp1_input: temperature input +humidity1_input: humidity input +serial_number: serial number +heater_enable: heater control +=================== ================= diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst index 874f8fd26325..86f6f5e46b59 100644 --- a/Documentation/hwmon/index.rst +++ b/Documentation/hwmon/index.rst @@ -85,6 +85,7 @@ Hardware Monitoring Kernel Drivers hih6130 hp-wmi-sensors hs3001 + htu31 ibmaem ibm-cffps ibmpowernv diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 4cbaba15d86e..e123e06ba352 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -789,6 +789,17 @@ config SENSORS_HS3001 This driver can also be built as a module. If so, the module will be called hs3001. +config SENSORS_HTU31 + tristate "Measurement Specialties HTU31 humidity and temperature sensor" + depends on I2C + select CRC8 + help + If you say yes here you get support for the HTU31 humidity + and temperature sensors. + + This driver can also be built as a module. If so, the module + will be called htu31. + config SENSORS_IBMAEM tristate "IBM Active Energy Manager temperature/power sensors and control" select IPMI_SI diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index b7ef0f0562d3..02465d959d14 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -199,6 +199,7 @@ obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o obj-$(CONFIG_SENSORS_SFCTEMP) += sfctemp.o obj-$(CONFIG_SENSORS_SG2042_MCU) += sg2042-mcu.o obj-$(CONFIG_SENSORS_SL28CPLD) += sl28cpld-hwmon.o +obj-$(CONFIG_SENSORS_HTU31) += htu31.o obj-$(CONFIG_SENSORS_SHT15) += sht15.o obj-$(CONFIG_SENSORS_SHT21) += sht21.o obj-$(CONFIG_SENSORS_SHT3x) += sht3x.o diff --git a/drivers/hwmon/htu31.c b/drivers/hwmon/htu31.c new file mode 100644 index 000000000000..09f979a8db92 --- /dev/null +++ b/drivers/hwmon/htu31.c @@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * The driver for Measurement Specialties HTU31 Temperature and Humidity sensor. + * + * Copyright (C) 2025 + * Author: Andrei Lalaev <andrey.lalaev@xxxxxxxxx> + */ + +#include <linux/array_size.h> +#include <linux/cleanup.h> +#include <linux/crc8.h> +#include <linux/delay.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/module.h> + +#define HTU31_READ_TEMP_HUM_CMD 0x00 +#define HTU31_READ_SERIAL_CMD 0x0a +#define HTU31_CONVERSION_CMD 0x5e +#define HTU31_HEATER_OFF_CMD 0x02 +#define HTU31_HEATER_ON_CMD 0x04 + +#define HTU31_TEMP_HUM_LEN 6 + +/* Conversion time for the highest resolution */ +#define HTU31_HUMIDITY_CONV_TIME 10000 /* us */ +#define HTU31_TEMPERATURE_CONV_TIME 15000 /* us */ + +#define HTU31_SERIAL_NUMBER_LEN 3 +#define HTU31_SERIAL_NUMBER_CRC_LEN 1 +#define HTU31_SERIAL_NUMBER_CRC_OFFSET 3 + +#define HTU31_CRC8_INIT_VAL 0 +#define HTU31_CRC8_POLYNOMIAL 0x31 +DECLARE_CRC8_TABLE(htu31_crc8_table); + +struct htu31_data { + struct i2c_client *client; + struct mutex i2c_lock; + long wait_time; + long temperature; + long humidity; + u8 serial_number[HTU31_SERIAL_NUMBER_LEN]; + bool heater_enable; +}; + +static long htu31_temp_to_millicelsius(long val) +{ + return -40000 + DIV_ROUND_CLOSEST(165000 * val, 65535); +} + +static long htu31_relative_humidity(long val) +{ + return DIV_ROUND_CLOSEST(100000 * val, 65535); +} + +static int htu31_data_fetch_command(struct htu31_data *data) +{ + struct i2c_client *client = data->client; + u8 conversion_on = HTU31_CONVERSION_CMD; + u8 read_data_cmd = HTU31_READ_TEMP_HUM_CMD; + u8 t_h_buf[HTU31_TEMP_HUM_LEN] = {}; + struct i2c_msg msgs[] = { + { + .addr = client->addr, + .flags = 0, + .len = 1, + .buf = &read_data_cmd, + }, + { + .addr = client->addr, + .flags = I2C_M_RD, + .len = sizeof(t_h_buf), + .buf = t_h_buf, + }, + }; + int ret; + u8 crc; + + guard(mutex)(&data->i2c_lock); + + ret = i2c_master_send(client, &conversion_on, 1); + if (ret != 1) { + ret = ret < 0 ? ret : -EIO; + dev_err(&client->dev, + "Conversion command is failed. Error code: %d\n", ret); + return ret; + } + + fsleep(data->wait_time); + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret != ARRAY_SIZE(msgs)) { + ret = ret < 0 ? ret : -EIO; + dev_err(&client->dev, + "T&H command is failed. Error code: %d\n", ret); + return ret; + } + + crc = crc8(htu31_crc8_table, &t_h_buf[0], 2, HTU31_CRC8_INIT_VAL); + if (crc != t_h_buf[2]) { + dev_err(&client->dev, "Temperature CRC mismatch\n"); + return -EIO; + } + + crc = crc8(htu31_crc8_table, &t_h_buf[3], 2, HTU31_CRC8_INIT_VAL); + if (crc != t_h_buf[5]) { + dev_err(&client->dev, "Humidity CRC mismatch\n"); + return -EIO; + } + + data->temperature = htu31_temp_to_millicelsius(be16_to_cpup((__be16 *) &t_h_buf[0])); + data->humidity = htu31_relative_humidity(be16_to_cpup((__be16 *) &t_h_buf[3])); + + return 0; +} + +static umode_t htu31_is_visible(const void *data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + switch (type) { + case hwmon_temp: + case hwmon_humidity: + return 0444; + default: + return 0; + } +} + +static int htu31_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct htu31_data *data = dev_get_drvdata(dev); + int ret; + + ret = htu31_data_fetch_command(data); + + if (ret < 0) + return ret; + + switch (type) { + case hwmon_temp: + if (attr != hwmon_temp_input) + return -EINVAL; + + *val = data->temperature; + break; + case hwmon_humidity: + if (attr != hwmon_humidity_input) + return -EINVAL; + + *val = data->humidity; + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int serial_number_populate(struct htu31_data *data) +{ + struct i2c_client *client = data->client; + u8 read_sn_cmd = HTU31_READ_SERIAL_CMD; + u8 sn_buf[HTU31_SERIAL_NUMBER_LEN + HTU31_SERIAL_NUMBER_CRC_LEN]; + struct i2c_msg msgs[] = { + { + .addr = client->addr, + .flags = 0, + .len = 1, + .buf = &read_sn_cmd, + }, + { + .addr = client->addr, + .flags = I2C_M_RD, + .len = sizeof(sn_buf), + .buf = sn_buf, + }, + }; + int ret; + u8 crc; + + guard(mutex)(&data->i2c_lock); + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) + return -EIO; + + crc = crc8(htu31_crc8_table, sn_buf, HTU31_SERIAL_NUMBER_LEN, HTU31_CRC8_INIT_VAL); + if (crc != sn_buf[HTU31_SERIAL_NUMBER_CRC_OFFSET]) { + dev_err(&client->dev, "Serial number CRC mismatch\n"); + return -EIO; + } + + memcpy(data->serial_number, sn_buf, HTU31_SERIAL_NUMBER_LEN); + + return 0; +} + +static ssize_t heater_enable_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct htu31_data *data = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", data->heater_enable); +} + +static ssize_t heater_enable_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + struct htu31_data *data = dev_get_drvdata(dev); + u8 heater_cmd; + bool status; + int ret; + + ret = kstrtobool(buf, &status); + if (ret) + return ret; + + heater_cmd = status ? HTU31_HEATER_ON_CMD : HTU31_HEATER_OFF_CMD; + + guard(mutex)(&data->i2c_lock); + + ret = i2c_master_send(data->client, &heater_cmd, 1); + if (ret < 0) + return -EIO; + + data->heater_enable = status; + + return count; +} + +static DEVICE_ATTR_RW(heater_enable); + +static ssize_t serial_number_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct htu31_data *data = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%X%X%X\n", data->serial_number[0], + data->serial_number[1], + data->serial_number[2]); +} + +static DEVICE_ATTR_RO(serial_number); + +static struct attribute *htu31_attrs[] = { + &dev_attr_heater_enable.attr, + &dev_attr_serial_number.attr, + NULL, +}; + +ATTRIBUTE_GROUPS(htu31); + +static const struct hwmon_channel_info * const htu31_info[] = { + HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT), + HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT), + NULL, +}; + +static const struct hwmon_ops htu31_hwmon_ops = { + .is_visible = htu31_is_visible, + .read = htu31_read, +}; + +static const struct hwmon_chip_info htu31_chip_info = { + .info = htu31_info, + .ops = &htu31_hwmon_ops, +}; + +static int htu31_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct device *hwmon_dev; + struct htu31_data *data; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + data->wait_time = HTU31_TEMPERATURE_CONV_TIME + HTU31_HUMIDITY_CONV_TIME; + + mutex_init(&data->i2c_lock); + + crc8_populate_msb(htu31_crc8_table, HTU31_CRC8_POLYNOMIAL); + + if (serial_number_populate(data)) { + dev_err(dev, "Failed to read serial number\n"); + return -EIO; + } + + hwmon_dev = devm_hwmon_device_register_with_info(dev, + client->name, + data, + &htu31_chip_info, + htu31_groups); + + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id htu31_id[] = { + { "htu31" }, + { }, +}; +MODULE_DEVICE_TABLE(i2c, htu31_id); + +#if IS_ENABLED(CONFIG_OF) +static const struct of_device_id htu31_of_match[] = { + { .compatible = "meas,htu31" }, + { }, +}; +MODULE_DEVICE_TABLE(of, htu31_of_match); +#endif + +static struct i2c_driver htu31_driver = { + .driver = { + .name = "htu31", + .of_match_table = of_match_ptr(htu31_of_match), + }, + .probe = htu31_probe, + .id_table = htu31_id, +}; +module_i2c_driver(htu31_driver); + +MODULE_AUTHOR("Andrei Lalaev <andrey.lalaev@xxxxxxxxx>"); +MODULE_DESCRIPTION("HTU31 Temperature and Humidity sensor driver"); +MODULE_VERSION("1.0"); +MODULE_LICENSE("GPL"); -- 2.48.1
