1Kernel driver ntc_thermistor
  2=================
  3
  4Supported 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
 11Supported thermistors from EPCOS:
 12* EPCOS NTC Thermistors B57330V2103
 13  Prefixes: b57330v2103
 14  Datasheet: Publicly available at EPCOS
 15
 16Other NTC thermistors can be supported simply by adding compensation
 17tables; e.g., NCP15WL333 support is added by the table ncpXXwl333.
 18
 19Authors:
 20	MyungJoo Ham <myungjoo.ham@samsung.com>
 21
 22Description
 23-----------
 24
 25The NTC (Negative Temperature Coefficient) thermistor is a simple thermistor
 26that requires users to provide the resistance and lookup the corresponding
 27compensation table to get the temperature input.
 28
 29The NTC driver provides lookup tables with a linear approximation function
 30and four circuit models with an option not to use any of the four models.
 31
 32The 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
 84When one of the four circuit models is used, read_uV, pullup_uV, pullup_ohm,
 85pulldown_ohm, and connect should be provided. When none of the four models
 86are suitable or the user can get the resistance directly, the user should
 87provide read_ohm and _not_ provide the others.
 88
 89Sysfs Interface
 90---------------
 91name		the mandatory global attribute, the thermistor name.
 92
 93temp1_type	always 4 (thermistor)
 94		RO
 95
 96temp1_input	measure the temperature and provide the measured value.
 97		(reading this file initiates the reading procedure.)
 98		RO
 99
100Note that each NTC thermistor has only _one_ thermistor; thus, only temp1 exists.