xref: /OK3568_Linux_fs/kernel/Documentation/hwmon/lm75.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunKernel driver lm75
2*4882a593Smuzhiyun==================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunSupported chips:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun  * National Semiconductor LM75
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun    Prefix: 'lm75'
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun    Addresses scanned: I2C 0x48 - 0x4f
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun    Datasheet: Publicly available at the National Semiconductor website
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun	       http://www.national.com/
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun  * National Semiconductor LM75A
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun    Prefix: 'lm75a'
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun    Addresses scanned: I2C 0x48 - 0x4f
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun    Datasheet: Publicly available at the National Semiconductor website
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun	       http://www.national.com/
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun  * Dallas Semiconductor (now Maxim) DS75, DS1775, DS7505
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun    Prefixes: 'ds75', 'ds1775', 'ds7505'
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun    Addresses scanned: none
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun    Datasheet: Publicly available at the Maxim website
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun	       https://www.maximintegrated.com/
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun  * Maxim MAX6625, MAX6626, MAX31725, MAX31726
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun    Prefixes: 'max6625', 'max6626', 'max31725', 'max31726'
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun    Addresses scanned: none
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun    Datasheet: Publicly available at the Maxim website
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun	       http://www.maxim-ic.com/
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun  * Microchip (TelCom) TCN75
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun    Prefix: 'tcn75'
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun    Addresses scanned: none
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun    Datasheet: Publicly available at the Microchip website
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun	       http://www.microchip.com/
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun  * Microchip MCP9800, MCP9801, MCP9802, MCP9803
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun    Prefix: 'mcp980x'
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun    Addresses scanned: none
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun    Datasheet: Publicly available at the Microchip website
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun	       http://www.microchip.com/
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun  * Analog Devices ADT75
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun    Prefix: 'adt75'
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun    Addresses scanned: none
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun    Datasheet: Publicly available at the Analog Devices website
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun	       https://www.analog.com/adt75
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun  * ST Microelectronics STDS75
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun    Prefix: 'stds75'
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun    Addresses scanned: none
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun    Datasheet: Publicly available at the ST website
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun	       http://www.st.com/internet/analog/product/121769.jsp
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun  * ST Microelectronics STLM75
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun    Prefix: 'stlm75'
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun    Addresses scanned: none
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun    Datasheet: Publicly available at the ST website
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun	       https://www.st.com/resource/en/datasheet/stlm75.pdf
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun  * Texas Instruments TMP100, TMP101, TMP105, TMP112, TMP75, TMP75B, TMP75C, TMP175, TMP275
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun    Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp112', 'tmp175', 'tmp75', 'tmp75b', 'tmp75c', 'tmp275'
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun    Addresses scanned: none
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun    Datasheet: Publicly available at the Texas Instruments website
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun	       https://www.ti.com/product/tmp100
105*4882a593Smuzhiyun
106*4882a593Smuzhiyun	       https://www.ti.com/product/tmp101
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun	       https://www.ti.com/product/tmp105
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun	       https://www.ti.com/product/tmp112
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun	       https://www.ti.com/product/tmp75
113*4882a593Smuzhiyun
114*4882a593Smuzhiyun	       https://www.ti.com/product/tmp75b
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun	       https://www.ti.com/product/tmp75c
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun	       https://www.ti.com/product/tmp175
119*4882a593Smuzhiyun
120*4882a593Smuzhiyun	       https://www.ti.com/product/tmp275
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun  * NXP LM75B, PCT2075
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun    Prefix: 'lm75b', 'pct2075'
125*4882a593Smuzhiyun
126*4882a593Smuzhiyun    Addresses scanned: none
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun    Datasheet: Publicly available at the NXP website
129*4882a593Smuzhiyun
130*4882a593Smuzhiyun	       https://www.nxp.com/documents/data_sheet/LM75B.pdf
131*4882a593Smuzhiyun
132*4882a593Smuzhiyun               https://www.nxp.com/docs/en/data-sheet/PCT2075.pdf
133*4882a593Smuzhiyun
134*4882a593SmuzhiyunAuthor: Frodo Looijaard <frodol@dds.nl>
135*4882a593Smuzhiyun
136*4882a593SmuzhiyunDescription
137*4882a593Smuzhiyun-----------
138*4882a593Smuzhiyun
139*4882a593SmuzhiyunThe LM75 implements one temperature sensor. Limits can be set through the
140*4882a593SmuzhiyunOvertemperature Shutdown register and Hysteresis register. Each value can be
141*4882a593Smuzhiyunset and read to half-degree accuracy.
142*4882a593SmuzhiyunAn alarm is issued (usually to a connected LM78) when the temperature
143*4882a593Smuzhiyungets higher then the Overtemperature Shutdown value; it stays on until
144*4882a593Smuzhiyunthe temperature falls below the Hysteresis value.
145*4882a593SmuzhiyunAll temperatures are in degrees Celsius, and are guaranteed within a
146*4882a593Smuzhiyunrange of -55 to +125 degrees.
147*4882a593Smuzhiyun
148*4882a593SmuzhiyunThe driver caches the values for a period varying between 1 second for the
149*4882a593Smuzhiyunslowest chips and 125 ms for the fastest chips; reading it more often
150*4882a593Smuzhiyunwill do no harm, but will return 'old' values.
151*4882a593Smuzhiyun
152*4882a593SmuzhiyunThe original LM75 was typically used in combination with LM78-like chips
153*4882a593Smuzhiyunon PC motherboards, to measure the temperature of the processor(s). Clones
154*4882a593Smuzhiyunare now used in various embedded designs.
155*4882a593Smuzhiyun
156*4882a593SmuzhiyunThe LM75 is essentially an industry standard; there may be other
157*4882a593SmuzhiyunLM75 clones not listed here, with or without various enhancements,
158*4882a593Smuzhiyunthat are supported. The clones are not detected by the driver, unless
159*4882a593Smuzhiyunthey reproduce the exact register tricks of the original LM75, and must
160*4882a593Smuzhiyuntherefore be instantiated explicitly. Higher resolution up to 16-bit
161*4882a593Smuzhiyunis supported by this driver, other specific enhancements are not.
162*4882a593Smuzhiyun
163*4882a593SmuzhiyunThe LM77 is not supported, contrary to what we pretended for a long time.
164*4882a593SmuzhiyunBoth chips are simply not compatible, value encoding differs.
165