Staging
v0.8.1
swh:1:snp:a902887e4be9191b7c6c4406aa06b31c1ce2c7cc
Raw File
Tip revision: 521cb40b0c44418a4fd36dc633f575813d59a43d authored by Linus Torvalds on 15 March 2011, 01:20:32 UTC
Linux 2.6.38
Tip revision: 521cb40
w1_ds2423
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 successfull and CRC matched.
If the operation was successfull, 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 successfull 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
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