Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
[linux-block.git] / Documentation / hwmon / lm75.rst
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1Kernel driver lm75
2==================
3
4Supported chips:
5
6 * National Semiconductor LM75
7
8 Prefix: 'lm75'
9
10 Addresses scanned: I2C 0x48 - 0x4f
11
12 Datasheet: Publicly available at the National Semiconductor website
13
14 http://www.national.com/
15
16 * National Semiconductor LM75A
17
18 Prefix: 'lm75a'
19
20 Addresses scanned: I2C 0x48 - 0x4f
21
22 Datasheet: Publicly available at the National Semiconductor website
23
24 http://www.national.com/
25
26 * Dallas Semiconductor (now Maxim) DS75, DS1775, DS7505
27
28 Prefixes: 'ds75', 'ds1775', 'ds7505'
29
30 Addresses scanned: none
31
32 Datasheet: Publicly available at the Maxim website
33
34 http://www.maximintegrated.com/
35
36 * Maxim MAX6625, MAX6626, MAX31725, MAX31726
37
38 Prefixes: 'max6625', 'max6626', 'max31725', 'max31726'
39
40 Addresses scanned: none
41
42 Datasheet: Publicly available at the Maxim website
43
44 http://www.maxim-ic.com/
45
46 * Microchip (TelCom) TCN75
47
48 Prefix: 'tcn75'
49
50 Addresses scanned: none
51
52 Datasheet: Publicly available at the Microchip website
53
54 http://www.microchip.com/
55
56 * Microchip MCP9800, MCP9801, MCP9802, MCP9803
57
58 Prefix: 'mcp980x'
59
60 Addresses scanned: none
61
62 Datasheet: Publicly available at the Microchip website
63
64 http://www.microchip.com/
65
66 * Analog Devices ADT75
67
68 Prefix: 'adt75'
69
70 Addresses scanned: none
71
72 Datasheet: Publicly available at the Analog Devices website
73
74 http://www.analog.com/adt75
75
76 * ST Microelectronics STDS75
77
78 Prefix: 'stds75'
79
80 Addresses scanned: none
81
82 Datasheet: Publicly available at the ST website
83
84 http://www.st.com/internet/analog/product/121769.jsp
85
86 * ST Microelectronics STLM75
87
88 Prefix: 'stlm75'
89
90 Addresses scanned: none
91
92 Datasheet: Publicly available at the ST website
93
94 https://www.st.com/resource/en/datasheet/stlm75.pdf
95
96 * Texas Instruments TMP100, TMP101, TMP105, TMP112, TMP75, TMP75B, TMP75C, TMP175, TMP275
97
98 Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp112', 'tmp175', 'tmp75', 'tmp75b', 'tmp75c', 'tmp275'
99
100 Addresses scanned: none
101
102 Datasheet: Publicly available at the Texas Instruments website
103
104 http://www.ti.com/product/tmp100
105
106 http://www.ti.com/product/tmp101
107
108 http://www.ti.com/product/tmp105
109
110 http://www.ti.com/product/tmp112
111
112 http://www.ti.com/product/tmp75
113
114 http://www.ti.com/product/tmp75b
115
116 http://www.ti.com/product/tmp75c
117
118 http://www.ti.com/product/tmp175
119
120 http://www.ti.com/product/tmp275
121
122 * NXP LM75B, PCT2075
123
124 Prefix: 'lm75b', 'pct2075'
125
126 Addresses scanned: none
127
128 Datasheet: Publicly available at the NXP website
129
130 http://www.nxp.com/documents/data_sheet/LM75B.pdf
131
132 http://www.nxp.com/docs/en/data-sheet/PCT2075.pdf
133
134Author: Frodo Looijaard <frodol@dds.nl>
135
136Description
137-----------
138
139The LM75 implements one temperature sensor. Limits can be set through the
140Overtemperature Shutdown register and Hysteresis register. Each value can be
141set and read to half-degree accuracy.
142An alarm is issued (usually to a connected LM78) when the temperature
143gets higher then the Overtemperature Shutdown value; it stays on until
144the temperature falls below the Hysteresis value.
145All temperatures are in degrees Celsius, and are guaranteed within a
146range of -55 to +125 degrees.
147
148The driver caches the values for a period varying between 1 second for the
149slowest chips and 125 ms for the fastest chips; reading it more often
150will do no harm, but will return 'old' values.
151
152The original LM75 was typically used in combination with LM78-like chips
153on PC motherboards, to measure the temperature of the processor(s). Clones
154are now used in various embedded designs.
155
156The LM75 is essentially an industry standard; there may be other
157LM75 clones not listed here, with or without various enhancements,
158that are supported. The clones are not detected by the driver, unless
159they reproduce the exact register tricks of the original LM75, and must
160therefore be instantiated explicitly. Higher resolution up to 16-bit
161is supported by this driver, other specific enhancements are not.
162
163The LM77 is not supported, contrary to what we pretended for a long time.
164Both chips are simply not compatible, value encoding differs.