1Kernel driver htu21 2=================== 3 4Supported chips: 5 * Measurement Specialties HTU21D 6 Prefix: 'htu21' 7 Addresses scanned: none 8 Datasheet: Publicly available at the Measurement Specialties website 9 http://www.meas-spec.com/downloads/HTU21D.pdf 10 11 12Author: 13 William Markezana <william.markezana@meas-spec.com> 14 15Description 16----------- 17 18The HTU21D is a humidity and temperature sensor in a DFN package of 19only 3 x 3 mm footprint and 0.9 mm height. 20 21The devices communicate with the I2C protocol. All sensors are set to the 22same I2C address 0x40, so an entry with I2C_BOARD_INFO("htu21", 0x40) can 23be used in the board setup code. 24 25This driver does not auto-detect devices. You will have to instantiate the 26devices explicitly. Please see Documentation/i2c/instantiating-devices 27for details. 28 29sysfs-Interface 30--------------- 31 32temp1_input - temperature input 33humidity1_input - humidity input 34 35Notes 36----- 37 38The driver uses the default resolution settings of 12 bit for humidity and 14 39bit for temperature, which results in typical measurement times of 11 ms for 40humidity and 44 ms for temperature. To keep self heating below 0.1 degree 41Celsius, the device should not be active for more than 10% of the time. For 42this reason, the driver performs no more than two measurements per second and 43reports cached information if polled more frequently. 44 45Different resolutions, the on-chip heater, using the CRC checksum and reading 46the serial number are not supported yet. 47