1Kernel driver ntc_thermistor
  2============================
  3
  4Supported thermistors from Murata:
  5
  6* Murata NTC Thermistors NCP15WB473, NCP18WB473, NCP21WB473, NCP03WB473,
  7  NCP15WL333, NCP03WF104, NCP15XH103
  8
  9  Prefixes: 'ncp15wb473', 'ncp18wb473', 'ncp21wb473', 'ncp03wb473',
 10  'ncp15wl333', 'ncp03wf104', 'ncp15xh103'
 11
 12  Datasheet: Publicly available at Murata
 13
 14Supported thermistors from EPCOS:
 15
 16* EPCOS NTC Thermistors B57330V2103
 17
 18  Prefixes: b57330v2103
 19
 20  Datasheet: Publicly available at EPCOS
 21
 22Other NTC thermistors can be supported simply by adding compensation
 23tables; e.g., NCP15WL333 support is added by the table ncpXXwl333.
 24
 25Authors:
 26
 27	MyungJoo Ham <myungjoo.ham@samsung.com>
 28
 29Description
 30-----------
 31
 32The NTC (Negative Temperature Coefficient) thermistor is a simple thermistor
 33that requires users to provide the resistance and lookup the corresponding
 34compensation table to get the temperature input.
 35
 36The NTC driver provides lookup tables with a linear approximation function
 37and four circuit models with an option not to use any of the four models.
 38
 39Using the following convention::
 40
 41   $	resistor
 42   [TH]	the thermistor
 43
 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 models
 96are suitable or the user can get the resistance directly, the user should
 97provide read_ohm and _not_ provide the others.
 98
 99Sysfs Interface
100---------------
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.