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1Kernel driver ntc_thermistor2============================3 4Supported thermistors from Murata:5 6* Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473,7 NCP15WL333, NCP03WF104, NCP15XH1038 9 Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473',10 'ncp15wl333', 'ncp03wf104', 'ncp15xh103'11 12 Datasheet: Publicly available at Murata13 14Supported thermistors from EPCOS:15 16* EPCOS NTC Thermistors B57330V210317 18 Prefixes: b57330v210319 20 Datasheet: Publicly available at EPCOS21 22Other NTC thermistors can be supported simply by adding compensation23tables; e.g., NCP15WL333 support is added by the table ncpXXwl333.24 25Authors:26 27 MyungJoo Ham <myungjoo.ham@samsung.com>28 29Description30-----------31 32The NTC (Negative Temperature Coefficient) thermistor is a simple thermistor33that requires users to provide the resistance and lookup the corresponding34compensation table to get the temperature input.35 36The NTC driver provides lookup tables with a linear approximation function37and four circuit models with an option not to use any of the four models.38 39Using the following convention::40 41 $ resistor42 [TH] the thermistor43 44The four circuit models provided are:45 461. connect = NTC_CONNECTED_POSITIVE, pullup_ohm > 0::47 48 [pullup_uV]49 | |50 [TH] $ (pullup_ohm)51 | |52 +----+-----------------------[read_uV]53 |54 $ (pulldown_ohm)55 |56 -+- (ground)57 582. connect = NTC_CONNECTED_POSITIVE, pullup_ohm = 0 (not-connected)::59 60 [pullup_uV]61 |62 [TH]63 |64 +----------------------------[read_uV]65 |66 $ (pulldown_ohm)67 |68 -+- (ground)69 703. connect = NTC_CONNECTED_GROUND, pulldown_ohm > 0::71 72 [pullup_uV]73 |74 $ (pullup_ohm)75 |76 +----+-----------------------[read_uV]77 | |78 [TH] $ (pulldown_ohm)79 | |80 -+----+- (ground)81 824. connect = NTC_CONNECTED_GROUND, pulldown_ohm = 0 (not-connected)::83 84 [pullup_uV]85 |86 $ (pullup_ohm)87 |88 +----------------------------[read_uV]89 |90 [TH]91 |92 -+- (ground)93 94When one of the four circuit models is used, read_uV, pullup_uV, pullup_ohm,95pulldown_ohm, and connect should be provided. When none of the four models96are suitable or the user can get the resistance directly, the user should97provide read_ohm and _not_ provide the others.98 99Sysfs Interface100---------------101 102=============== == =============================================================103name the mandatory global attribute, the thermistor name.104=============== == =============================================================105temp1_type RO always 4 (thermistor)106 107temp1_input RO measure the temperature and provide the measured value.108 (reading this file initiates the reading procedure.)109=============== == =============================================================110 111Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists.112