Documentation/w1/slaves/w1_ds2423.rst

Source file repositories/reference/linux-study-clean/Documentation/w1/slaves/w1_ds2423.rst

File Facts

System: Linux kernel
Corpus path: Documentation/w1/slaves/w1_ds2423.rst
Extension: .rst
Size: 2425 bytes
Lines: 55
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 w1_ds2423
=======================

Supported chips:

  * Maxim DS2423 based counter devices.

supported family codes:

        ===============	====
	W1_THERM_DS2423	0x1D
        ===============	====

Author: Mika Laitio <lamikr@pilppa.org>

Description
-----------

Support is provided through the sysfs w1_slave file. Each opening and
read sequence of w1_slave file initiates the read of counters and ram
available in DS2423 pages 12 - 15.

Result of each page is provided as an ASCII output where each counter
value and associated ram buffer is outpputed to own line.

Each lines will contain the values of 42 bytes read from the counter and
memory page along the crc=YES or NO for indicating whether the read operation
was successful and CRC matched.
If the operation was successful, there is also in the end of each line
a counter value expressed as an integer after c=

Meaning of 42 bytes represented is following:

 - 1 byte from ram page
 - 4 bytes for the counter value
 - 4 zero bytes
 - 2 bytes for crc16 which was calculated from the data read since the previous crc bytes
 - 31 remaining bytes from the ram page
 - crc=YES/NO indicating whether read was ok and crc matched
 - c=<int> current counter value

example from the successful read::

  00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  00 02 00 00 00 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  00 29 c6 5d 18 00 00 00 00 04 37 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=408798761
  00 05 00 00 00 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=YES c=5

example from the read with crc errors::

  00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  00 02 00 00 22 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
  00 e1 61 5d 19 00 00 00 00 df 0b 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
  00 05 00 00 20 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=NO

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.