Documentation/hwmon/sht21.rst

Source file repositories/reference/linux-study-clean/Documentation/hwmon/sht21.rst

File Facts

System: Linux kernel
Corpus path: Documentation/hwmon/sht21.rst
Extension: .rst
Size: 1982 bytes
Lines: 73
Domain: Support Tooling And Documentation
Bucket: Documentation
Inferred role: Support Tooling And Documentation: documentation
Status: atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

No C-style include directives detected by the generator.

Detected Declarations

No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

Kernel driver sht21
===================

Supported chips:

  * Sensirion SHT20

    Prefix: 'sht20'

    Addresses scanned: none

    Datasheet: Publicly available at the Sensirion website

    https://www.sensirion.com/file/datasheet_sht20

  * 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 <urs.fleisch@sensirion.com>

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.

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.