| 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. |
