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