Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Kernel driver ntc_thermistor 2 ================= 3 4 Supported thermistors from Murata: 5 * Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473, 6 NCP15WL333, NCP03WF104, NCP15XH103 7 Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473', 8 'ncp15wl333', 'ncp03wf104', 'ncp15xh103' 9 Datasheet: Publicly available at Murata 10 11 Supported thermistors from EPCOS: 12 * EPCOS NTC Thermistors B57330V2103 13 Prefixes: b57330v2103 14 Datasheet: Publicly available at EPCOS 15 16 Other NTC thermistors can be supported simply by adding compensation 17 tables; e.g., NCP15WL333 support is added by the table ncpXXwl333. 18 19 Authors: 20 MyungJoo Ham <myungjoo.ham@samsung.com> 21 22 Description 23 ----------- 24 25 The NTC (Negative Temperature Coefficient) thermistor is a simple thermistor 26 that requires users to provide the resistance and lookup the corresponding 27 compensation table to get the temperature input. 28 29 The NTC driver provides lookup tables with a linear approximation function 30 and four circuit models with an option not to use any of the four models. 31 32 The four circuit models provided are: 33 34 $: resister, [TH]: the thermistor 35 36 1. connect = NTC_CONNECTED_POSITIVE, pullup_ohm > 0 37 38 [pullup_uV] 39 | | 40 [TH] $ (pullup_ohm) 41 | | 42 +----+-----------------------[read_uV] 43 | 44 $ (pulldown_ohm) 45 | 46 --- (ground) 47 48 2. connect = NTC_CONNECTED_POSITIVE, pullup_ohm = 0 (not-connected) 49 50 [pullup_uV] 51 | 52 [TH] 53 | 54 +----------------------------[read_uV] 55 | 56 $ (pulldown_ohm) 57 | 58 --- (ground) 59 60 3. connect = NTC_CONNECTED_GROUND, pulldown_ohm > 0 61 62 [pullup_uV] 63 | 64 $ (pullup_ohm) 65 | 66 +----+-----------------------[read_uV] 67 | | 68 [TH] $ (pulldown_ohm) 69 | | 70 -------- (ground) 71 72 4. connect = NTC_CONNECTED_GROUND, pulldown_ohm = 0 (not-connected) 73 74 [pullup_uV] 75 | 76 $ (pullup_ohm) 77 | 78 +----------------------------[read_uV] 79 | 80 [TH] 81 | 82 --- (ground) 83 84 When one of the four circuit models is used, read_uV, pullup_uV, pullup_ohm, 85 pulldown_ohm, and connect should be provided. When none of the four models 86 are suitable or the user can get the resistance directly, the user should 87 provide read_ohm and _not_ provide the others. 88 89 Sysfs Interface 90 --------------- 91 name the mandatory global attribute, the thermistor name. 92 93 temp1_type always 4 (thermistor) 94 RO 95 96 temp1_input measure the temperature and provide the measured value. 97 (reading this file initiates the reading procedure.) 98 RO 99 100 Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists.