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Diffstat (limited to 'Documentation/hwmon/ntc_thermistor')
| -rw-r--r-- | Documentation/hwmon/ntc_thermistor | 123 |
1 files changed, 67 insertions, 56 deletions
diff --git a/Documentation/hwmon/ntc_thermistor b/Documentation/hwmon/ntc_thermistor index 8b9ff23edc32..d0e7f91726b9 100644 --- a/Documentation/hwmon/ntc_thermistor +++ b/Documentation/hwmon/ntc_thermistor @@ -1,22 +1,29 @@ Kernel driver ntc_thermistor -================= +============================ Supported thermistors from Murata: + * Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473, NCP15WL333, NCP03WF104, NCP15XH103 + Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473', 'ncp15wl333', 'ncp03wf104', 'ncp15xh103' + Datasheet: Publicly available at Murata Supported thermistors from EPCOS: + * EPCOS NTC Thermistors B57330V2103 + Prefixes: b57330v2103 + Datasheet: Publicly available at EPCOS 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 @@ -29,57 +36,60 @@ 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. +Using the following convention:: + + $ resistor + [TH] the thermistor + 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) +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 @@ -88,13 +98,14 @@ provide read_ohm and _not_ provide the others. Sysfs Interface --------------- -name the mandatory global attribute, the thermistor name. -temp1_type always 4 (thermistor) - RO +=============== == ============================================================= +name the mandatory global attribute, the thermistor name. +=============== == ============================================================= +temp1_type RO always 4 (thermistor) -temp1_input measure the temperature and provide the measured value. - (reading this file initiates the reading procedure.) - RO +temp1_input RO measure the temperature and provide the measured value. + (reading this file initiates the reading procedure.) +=============== == ============================================================= Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists. |