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r: 261741
b: refs/heads/master
c: f22aaaa
h: refs/heads/master
i:
  261739: 37c4861
v: v3
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Donggeun Kim authored and Guenter Roeck committed Jul 28, 2011
1 parent 3a1a488 commit 4f8328b
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: dabaa0d2b4085a2037d80a40b86ba215f00b601e
refs/heads/master: f22aaaa70d8c24e5dc7d23a219c4beace8354b65
93 changes: 93 additions & 0 deletions trunk/Documentation/hwmon/ntc_thermistor
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Kernel driver ntc_thermistor
=================

Supported thermistors:
* Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473, NCP15WL333
Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473', 'ncp15wl333'
Datasheet: Publicly available at Murata

Other NTC thermistors can be supported simply by adding compensation
tables; e.g., NCP15WL333 support is added by the table ncpXXwl333.

Authors:
MyungJoo Ham <myungjoo.ham@samsung.com>

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

The NTC thermistor is a simple thermistor that requires users to provide the
resistance and lookup the corresponding compensation table to get the
temperature input.

The NTC driver provides lookup tables with a linear approximation function
and four circuit models with an option not to use any of the four models.

The four circuit models provided are:

$: resister, [TH]: the thermistor

1. connect = NTC_CONNECTED_POSITIVE, pullup_ohm > 0

[pullup_uV]
| |
[TH] $ (pullup_ohm)
| |
+----+-----------------------[read_uV]
|
$ (pulldown_ohm)
|
--- (ground)

2. connect = NTC_CONNECTED_POSITIVE, pullup_ohm = 0 (not-connected)

[pullup_uV]
|
[TH]
|
+----------------------------[read_uV]
|
$ (pulldown_ohm)
|
--- (ground)

3. connect = NTC_CONNECTED_GROUND, pulldown_ohm > 0

[pullup_uV]
|
$ (pullup_ohm)
|
+----+-----------------------[read_uV]
| |
[TH] $ (pulldown_ohm)
| |
-------- (ground)

4. connect = NTC_CONNECTED_GROUND, pulldown_ohm = 0 (not-connected)

[pullup_uV]
|
$ (pullup_ohm)
|
+----------------------------[read_uV]
|
[TH]
|
--- (ground)

When one of the four circuit models is used, read_uV, pullup_uV, pullup_ohm,
pulldown_ohm, and connect should be provided. When none of the four models
are suitable or the user can get the resistance directly, the user should
provide read_ohm and _not_ provide the others.

Sysfs Interface
---------------
name the mandatory global attribute, the thermistor name.

temp1_type always 4 (thermistor)
RO

temp1_input measure the temperature and provide the measured value.
(reading this file initiates the reading procedure.)
RO

Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists.
14 changes: 14 additions & 0 deletions trunk/drivers/hwmon/Kconfig
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Expand Up @@ -777,6 +777,20 @@ config SENSORS_MAX6650
This driver can also be built as a module. If so, the module
will be called max6650.

config SENSORS_NTC_THERMISTOR
tristate "NTC thermistor support"
depends on EXPERIMENTAL
help
This driver supports NTC thermistors sensor reading and its
interpretation. The driver can also monitor the temperature and
send notifications about the temperature.

Currently, this driver supports
NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473, and NCP15WL333.

This driver can also be built as a module. If so, the module
will be called ntc-thermistor.

config SENSORS_PC87360
tristate "National Semiconductor PC87360 family"
select HWMON_VID
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1 change: 1 addition & 0 deletions trunk/drivers/hwmon/Makefile
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Expand Up @@ -92,6 +92,7 @@ obj-$(CONFIG_SENSORS_MAX6639) += max6639.o
obj-$(CONFIG_SENSORS_MAX6642) += max6642.o
obj-$(CONFIG_SENSORS_MAX6650) += max6650.o
obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
obj-$(CONFIG_SENSORS_NTC_THERMISTOR) += ntc_thermistor.o
obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
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