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w1: Add support for DS28EA00 sequence to w1-therm

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This patch provides support for the DS28EA00 digital thermometer.

The DS28EA00 provides an additional two pins for implementing a sequence
detection algorithm.  This feature allows you to determine the physical
location of the chip in the 1-wire bus without needing pre-existing
knowledge of the bus ordering.  Support is provided through the sysfs
w1_seq file.  The file will contain a single line with an integer value
representing the device index in the bus starting at 0.

Signed-off-by: Matt Campbell <mattrcampbell@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Matt Campbell
2015-04-28 07:44:17 -04:00
committed by Greg Kroah-Hartman
parent f7134eea05
commit d9411e57dc
3 changed files with 117 additions and 2 deletions
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11
Documentation/w1/slaves/w1_therm
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@@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Description
-----------
w1_therm provides basic temperature conversion for ds18*20 devices.
w1_therm provides basic temperature conversion for ds18*20 devices, and the
ds28ea00 device.
supported family codes:
W1_THERM_DS18S20 0x10
W1_THERM_DS1822 0x22
W1_THERM_DS18B20 0x28
W1_THERM_DS1825 0x3B
W1_THERM_DS28EA00 0x42
Support is provided through the sysfs w1_slave file. Each open and
read sequence will initiate a temperature conversion then provide two
@@ -48,3 +50,10 @@ resistor). The DS18b20 temperature sensor specification lists a
maximum current draw of 1.5mA and that a 5k pullup resistor is not
sufficient. The strong pullup is designed to provide the additional
current required.
The DS28EA00 provides an additional two pins for implementing a sequence
detection algorithm. This feature allows you to determine the physical
location of the chip in the 1-wire bus without needing pre-existing
knowledge of the bus ordering. Support is provided through the sysfs
w1_seq file. The file will contain a single line with an integer value
representing the device index in the bus starting at 0.