| Kernel driver sht15 | |
| =================== | |
| Authors: | |
| * Wouter Horre | |
| * Jonathan Cameron | |
| * Vivien Didelot <vivien.didelot@savoirfairelinux.com> | |
| * Jerome Oufella <jerome.oufella@savoirfairelinux.com> | |
| Supported chips: | |
| * Sensirion SHT10 | |
| Prefix: 'sht10' | |
| * Sensirion SHT11 | |
| Prefix: 'sht11' | |
| * Sensirion SHT15 | |
| Prefix: 'sht15' | |
| * Sensirion SHT71 | |
| Prefix: 'sht71' | |
| * Sensirion SHT75 | |
| Prefix: 'sht75' | |
| Datasheet: Publicly available at the Sensirion website | |
| http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf | |
| Description | |
| ----------- | |
| The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature | |
| sensors. | |
| The devices communicate using two GPIO lines. | |
| Supported resolutions for the measurements are 14 bits for temperature and 12 | |
| bits for humidity, or 12 bits for temperature and 8 bits for humidity. | |
| The humidity calibration coefficients are programmed into an OTP memory on the | |
| chip. These coefficients are used to internally calibrate the signals from the | |
| sensors. Disabling the reload of those coefficients allows saving 10ms for each | |
| measurement and decrease power consumption, while losing on precision. | |
| Some options may be set directly in the sht15_platform_data structure | |
| or via sysfs attributes. | |
| Notes: | |
| * The regulator supply name is set to "vcc". | |
| * If a CRC validation fails, a soft reset command is sent, which resets | |
| status register to its hardware default value, but the driver will try to | |
| restore the previous device configuration. | |
| Platform data | |
| ------------- | |
| * checksum: | |
| set it to true to enable CRC validation of the readings (default to false). | |
| * no_otp_reload: | |
| flag to indicate not to reload from OTP (default to false). | |
| * low_resolution: | |
| flag to indicate the temp/humidity resolution to use (default to false). | |
| Sysfs interface | |
| --------------- | |
| * temp1_input: temperature input | |
| * humidity1_input: humidity input | |
| * heater_enable: write 1 in this attribute to enable the on-chip heater, | |
| 0 to disable it. Be careful not to enable the heater | |
| for too long. | |
| * temp1_fault: if 1, this means that the voltage is low (below 2.47V) and | |
| measurement may be invalid. | |
| * humidity1_fault: same as temp1_fault. |