^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) Kernel driver ntc_thermistor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) ============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) Supported thermistors from Murata:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) NCP15WL333, NCP03WF104, NCP15XH103
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473',
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 'ncp15wl333', 'ncp03wf104', 'ncp15xh103'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) Datasheet: Publicly available at Murata
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) Supported thermistors from EPCOS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * EPCOS NTC Thermistors B57330V2103
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) Prefixes: b57330v2103
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) Datasheet: Publicly available at EPCOS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) Other NTC thermistors can be supported simply by adding compensation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) tables; e.g., NCP15WL333 support is added by the table ncpXXwl333.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) MyungJoo Ham <myungjoo.ham@samsung.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) -----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) The NTC (Negative Temperature Coefficient) thermistor is a simple thermistor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) that requires users to provide the resistance and lookup the corresponding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) compensation table to get the temperature input.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) The NTC driver provides lookup tables with a linear approximation function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) and four circuit models with an option not to use any of the four models.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) Using the following convention::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) $ resistor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) [TH] the thermistor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) The four circuit models provided are:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 1. connect = NTC_CONNECTED_POSITIVE, pullup_ohm > 0::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) [pullup_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) [TH] $ (pullup_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) +----+-----------------------[read_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) $ (pulldown_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) -+- (ground)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 2. connect = NTC_CONNECTED_POSITIVE, pullup_ohm = 0 (not-connected)::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) [pullup_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) [TH]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) +----------------------------[read_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) $ (pulldown_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) -+- (ground)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 3. connect = NTC_CONNECTED_GROUND, pulldown_ohm > 0::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) [pullup_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) $ (pullup_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) +----+-----------------------[read_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) [TH] $ (pulldown_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) -+----+- (ground)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 4. connect = NTC_CONNECTED_GROUND, pulldown_ohm = 0 (not-connected)::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) [pullup_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) $ (pullup_ohm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) +----------------------------[read_uV]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) [TH]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) -+- (ground)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) When one of the four circuit models is used, read_uV, pullup_uV, pullup_ohm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) pulldown_ohm, and connect should be provided. When none of the four models
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) are suitable or the user can get the resistance directly, the user should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) provide read_ohm and _not_ provide the others.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) Sysfs Interface
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) ---------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) =============== == =============================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) name the mandatory global attribute, the thermistor name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) =============== == =============================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) temp1_type RO always 4 (thermistor)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) temp1_input RO measure the temperature and provide the measured value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) (reading this file initiates the reading procedure.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) =============== == =============================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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