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1Kernel driver sht3x2===================3 4Supported chips:5 6 * Sensirion SHT3x-DIS7 8 Prefix: 'sht3x'9 10 Addresses scanned: none11 12 Datasheets:13 - https://sensirion.com/media/documents/213E6A3B/63A5A569/Datasheet_SHT3x_DIS.pdf14 - https://sensirion.com/media/documents/051DF50B/639C8101/Sensirion_Humidity_and_Temperature_Sensors_Datasheet_SHT33.pdf15 16 * Sensirion STS3x-DIS17 18 Prefix: 'sts3x'19 20 Addresses scanned: none21 22 Datasheets:23 - https://sensirion.com/media/documents/1DA31AFD/61641F76/Sensirion_Temperature_Sensors_STS3x_Datasheet.pdf24 - https://sensirion.com/media/documents/292A335C/65537BAF/Sensirion_Datasheet_STS32_STS33.pdf25 26Author:27 28 - David Frey <david.frey@sensirion.com>29 - Pascal Sachs <pascal.sachs@sensirion.com>30 31Description32-----------33 34This driver implements support for the Sensirion SHT3x-DIS and STS3x-DIS35series of humidity and temperature sensors. Temperature is measured in degrees36celsius, relative humidity is expressed as a percentage. In the sysfs interface,37all values are scaled by 1000, i.e. the value for 31.5 degrees celsius is 31500.38 39The device communicates with the I2C protocol. Sensors can have the I2C40addresses 0x44 or 0x45 (0x4a or 0x4b for sts3x), depending on the wiring. See41Documentation/i2c/instantiating-devices.rst for methods to instantiate the42device.43 44Even if sht3x sensor supports clock-stretch (blocking mode) and non-stretch45(non-blocking mode) in single-shot mode, this driver only supports the latter.46 47The sht3x sensor supports a single shot mode as well as 5 periodic measure48modes, which can be controlled with the update_interval sysfs interface.49The allowed update_interval in milliseconds are as follows:50 51 ===== ======= ====================52 0 single shot mode53 2000 0.5 Hz periodic measurement54 1000 1 Hz periodic measurement55 500 2 Hz periodic measurement56 250 4 Hz periodic measurement57 100 10 Hz periodic measurement58 ===== ======= ====================59 60In the periodic measure mode, the sensor automatically triggers a measurement61with the configured update interval on the chip. When a temperature or humidity62reading exceeds the configured limits, the alert attribute is set to 1 and63the alert pin on the sensor is set to high.64When the temperature and humidity readings move back between the hysteresis65values, the alert bit is set to 0 and the alert pin on the sensor is set to66low.67 68The serial number exposed to debugfs allows for unique identification of the69sensors. For sts32, sts33 and sht33, the manufacturer provides calibration70certificates through an API.71 72sysfs-Interface73---------------74 75=================== ============================================================76temp1_input: temperature input77humidity1_input: humidity input78temp1_max: temperature max value79temp1_max_hyst: temperature hysteresis value for max limit80humidity1_max: humidity max value81humidity1_max_hyst: humidity hysteresis value for max limit82temp1_min: temperature min value83temp1_min_hyst: temperature hysteresis value for min limit84humidity1_min: humidity min value85humidity1_min_hyst: humidity hysteresis value for min limit86temp1_alarm: alarm flag is set to 1 if the temperature is outside the87 configured limits. Alarm only works in periodic measure mode88humidity1_alarm: alarm flag is set to 1 if the humidity is outside the89 configured limits. Alarm only works in periodic measure mode90heater_enable: heater enable, heating element removes excess humidity from91 sensor:92 93 - 0: turned off94 - 1: turned on95update_interval: update interval, 0 for single shot, interval in msec96 for periodic measurement. If the interval is not supported97 by the sensor, the next faster interval is chosen98repeatability: write or read repeatability, higher repeatability means99 longer measurement duration, lower noise level and100 larger energy consumption:101 102 - 0: low repeatability103 - 1: medium repeatability104 - 2: high repeatability105=================== ============================================================106 107debugfs-Interface108-----------------109 110=================== ============================================================111serial_number: unique serial number of the sensor in decimal112=================== ============================================================113