1Kernel driver adm1021
2=====================
3
4Supported chips:
5  * Analog Devices ADM1021
6    Prefix: 'adm1021'
7    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
8    Datasheet: Publicly available at the Analog Devices website
9  * Analog Devices ADM1021A/ADM1023
10    Prefix: 'adm1023'
11    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
12    Datasheet: Publicly available at the Analog Devices website
13  * Genesys Logic GL523SM
14    Prefix: 'gl523sm'
15    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
16    Datasheet:
17  * Maxim MAX1617
18    Prefix: 'max1617'
19    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
20    Datasheet: Publicly available at the Maxim website
21  * Maxim MAX1617A
22    Prefix: 'max1617a'
23    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
24    Datasheet: Publicly available at the Maxim website
25  * National Semiconductor LM84
26    Prefix: 'lm84'
27    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
28    Datasheet: Publicly available at the National Semiconductor website
29  * Philips NE1617
30    Prefix: 'max1617' (probably detected as a max1617)
31    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
32    Datasheet: Publicly available at the Philips website
33  * Philips NE1617A
34    Prefix: 'max1617' (probably detected as a max1617)
35    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
36    Datasheet: Publicly available at the Philips website
37  * TI THMC10
38    Prefix: 'thmc10'
39    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
40    Datasheet: Publicly available at the TI website
41  * Onsemi MC1066
42    Prefix: 'mc1066'
43    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
44    Datasheet: Publicly available at the Onsemi website
45
46
47Authors:
48        Frodo Looijaard <frodol@dds.nl>,
49        Philip Edelbrock <phil@netroedge.com>
50
51Module Parameters
52-----------------
53
54* read_only: int
55  Don't set any values, read only mode
56
57
58Description
59-----------
60
61The chips supported by this driver are very similar. The Maxim MAX1617 is
62the oldest; it has the problem that it is not very well detectable. The
63MAX1617A solves that. The ADM1021 is a straight clone of the MAX1617A.
64Ditto for the THMC10. From here on, we will refer to all these chips as
65ADM1021-clones.
66
67The ADM1021 and MAX1617A reports a die code, which is a sort of revision
68code. This can help us pinpoint problems; it is not very useful
69otherwise.
70
71ADM1021-clones implement two temperature sensors. One of them is internal,
72and measures the temperature of the chip itself; the other is external and
73is realised in the form of a transistor-like device. A special alarm
74indicates whether the remote sensor is connected.
75
76Each sensor has its own low and high limits. When they are crossed, the
77corresponding alarm is set and remains on as long as the temperature stays
78out of range. Temperatures are measured in degrees Celsius. Measurements
79are possible between -65 and +127 degrees, with a resolution of one degree.
80
81If an alarm triggers, it will remain triggered until the hardware register
82is read at least once. This means that the cause for the alarm may already
83have disappeared!
84
85This driver only updates its values each 1.5 seconds; reading it more often
86will do no harm, but will return 'old' values. It is possible to make
87ADM1021-clones do faster measurements, but there is really no good reason
88for that.
89
90
91Netburst-based Xeon support
92---------------------------
93
94Some Xeon processors based on the Netburst (early Pentium 4, from 2001 to
952003) microarchitecture had real MAX1617, ADM1021, or compatible chips
96within them, with two temperature sensors. Other Xeon processors of this
97era (with 400 MHz FSB) had chips with only one temperature sensor.
98
99If you have such an old Xeon, and you get two valid temperatures when
100loading the adm1021 module, then things are good.
101
102If nothing happens when loading the adm1021 module, and you are certain
103that your specific Xeon processor model includes compatible sensors, you
104will have to explicitly instantiate the sensor chips from user-space. See
105method 4 in Documentation/i2c/instantiating-devices. Possible slave
106addresses are 0x18, 0x1a, 0x29, 0x2b, 0x4c, or 0x4e. It is likely that
107only temp2 will be correct and temp1 will have to be ignored.
108
109Previous generations of the Xeon processor (based on Pentium II/III)
110didn't have these sensors. Next generations of Xeon processors (533 MHz
111FSB and faster) lost them, until the Core-based generation which
112introduced integrated digital thermal sensors. These are supported by
113the coretemp driver.
114