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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-30 08:57:57 -1000 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-30 08:57:57 -1000 |
commit | 464c9098bbc17b4596aa12191a7e646a28e7587a (patch) | |
tree | 1d97f02c1f071f358f0d0b5fd8e04db3b9a7a9af /Documentation/hwmon/ntc_thermistor | |
parent | 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d (diff) | |
parent | f90be42fb383f39aa814b8e14de138da8973e5c1 (diff) |
Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging: (24 commits)
hwmon: (lm90) Refactor reading of config2 register
hwmon: (lm90) Make SA56004 detection more robust
hwmon: (lm90) Simplify handling of extended local temp register
hwmon: (pmbus) Add client driver for LM25066, LM5064, and LM5066
hwmon: (max34440) Add support for peak attributes
hwmon: (max8688) Add support for peak attributes
hwmon: (max16064) Add support for peak attributes
hwmon: (adm1275) Add support for peak attributes
hwmon: (pmbus) Add support for peak attributes
hwmon: Add new attributes to sysfs ABI
hwmon: (pmbus) Strengthen check for status register existence
hwmon: (pmbus) Add support for virtual pages
hwmon: (pmbus) Support reading and writing of word registers in device specific code
hwmon: (pmbus) Increase attribute name size
hwmon: (pmbus) Add ADP4000, NCP4200 and NCP4208 to list of supported devices
hwmon: (pmbus) Add support for VID output voltage mode
hwmon: (pmbus) Move PMBus drivers to drivers/hwmon/pmbus
hwmon: (coretemp) Add core/pkg threshold support to Coretemp
hwmon: (lm95241) Add support for LM95231
hwmon: LM95245 driver
...
Diffstat (limited to 'Documentation/hwmon/ntc_thermistor')
-rw-r--r-- | Documentation/hwmon/ntc_thermistor | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/Documentation/hwmon/ntc_thermistor b/Documentation/hwmon/ntc_thermistor new file mode 100644 index 000000000000..3bfda94096fd --- /dev/null +++ b/Documentation/hwmon/ntc_thermistor @@ -0,0 +1,93 @@ +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. |