From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- Documentation/hwmon/sht21.rst | 68 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 Documentation/hwmon/sht21.rst (limited to 'Documentation/hwmon/sht21.rst') diff --git a/Documentation/hwmon/sht21.rst b/Documentation/hwmon/sht21.rst new file mode 100644 index 000000000..1bccc8e8a --- /dev/null +++ b/Documentation/hwmon/sht21.rst @@ -0,0 +1,68 @@ +Kernel driver sht21 +=================== + +Supported chips: + + * Sensirion SHT21 + + Prefix: 'sht21' + + Addresses scanned: none + + Datasheet: Publicly available at the Sensirion website + + https://www.sensirion.com/file/datasheet_sht21 + + + + * Sensirion SHT25 + + Prefix: 'sht25' + + Addresses scanned: none + + Datasheet: Publicly available at the Sensirion website + + https://www.sensirion.com/file/datasheet_sht25 + + + +Author: + + Urs Fleisch + +Description +----------- + +The SHT21 and SHT25 are humidity and temperature sensors in a DFN package of +only 3 x 3 mm footprint and 1.1 mm height. The difference between the two +devices is the higher level of precision of the SHT25 (1.8% relative humidity, +0.2 degree Celsius) compared with the SHT21 (2.0% relative humidity, +0.3 degree Celsius). + +The devices communicate with the I2C protocol. All sensors are set to the same +I2C address 0x40, so an entry with I2C_BOARD_INFO("sht21", 0x40) can be used +in the board setup code. + +sysfs-Interface +--------------- + +temp1_input + - temperature input + +humidity1_input + - humidity input +eic + - Electronic Identification Code + +Notes +----- + +The driver uses the default resolution settings of 12 bit for humidity and 14 +bit for temperature, which results in typical measurement times of 22 ms for +humidity and 66 ms for temperature. To keep self heating below 0.1 degree +Celsius, the device should not be active for more than 10% of the time, +e.g. maximum two measurements per second at the given resolution. + +Different resolutions, the on-chip heater, and using the CRC checksum +are not supported yet. -- cgit v1.2.3