1Kernel driver sht15 2=================== 3 4Authors: 5 6 * Wouter Horre 7 * Jonathan Cameron 8 * Vivien Didelot <vivien.didelot@savoirfairelinux.com> 9 * Jerome Oufella <jerome.oufella@savoirfairelinux.com> 10 11Supported chips: 12 13 * Sensirion SHT10 14 15 Prefix: 'sht10' 16 17 * Sensirion SHT11 18 19 Prefix: 'sht11' 20 21 * Sensirion SHT15 22 23 Prefix: 'sht15' 24 25 * Sensirion SHT71 26 27 Prefix: 'sht71' 28 29 * Sensirion SHT75 30 31 Prefix: 'sht75' 32 33Datasheet: Publicly available at the Sensirion website 34 35 http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf 36 37Description 38----------- 39 40The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature 41sensors. 42 43The devices communicate using two GPIO lines. 44 45Supported resolutions for the measurements are 14 bits for temperature and 12 46bits for humidity, or 12 bits for temperature and 8 bits for humidity. 47 48The humidity calibration coefficients are programmed into an OTP memory on the 49chip. These coefficients are used to internally calibrate the signals from the 50sensors. Disabling the reload of those coefficients allows saving 10ms for each 51measurement and decrease power consumption, while losing on precision. 52 53Some options may be set via sysfs attributes. 54 55Notes: 56 * The regulator supply name is set to "vcc". 57 * If a CRC validation fails, a soft reset command is sent, which resets 58 status register to its hardware default value, but the driver will try to 59 restore the previous device configuration. 60 61Platform data 62------------- 63 64* checksum: 65 set it to true to enable CRC validation of the readings (default to false). 66* no_otp_reload: 67 flag to indicate not to reload from OTP (default to false). 68* low_resolution: 69 flag to indicate the temp/humidity resolution to use (default to false). 70 71Sysfs interface 72--------------- 73 74================== ========================================================== 75temp1_input temperature input 76humidity1_input humidity input 77heater_enable write 1 in this attribute to enable the on-chip heater, 78 0 to disable it. Be careful not to enable the heater 79 for too long. 80temp1_fault if 1, this means that the voltage is low (below 2.47V) and 81 measurement may be invalid. 82humidity1_fault same as temp1_fault. 83================== ========================================================== 84