hwmon: Request the I/O regions in platform drivers
[linux-2.6-block.git] / Documentation / hwmon / smsc47m1
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1Kernel driver smsc47m1
2======================
3
4Supported chips:
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5 * SMSC LPC47B27x, LPC47M112, LPC47M10x, LPC47M13x, LPC47M14x,
6 LPC47M15x and LPC47M192
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7 Addresses scanned: none, address read from Super I/O config space
8 Prefix: 'smsc47m1'
9 Datasheets:
10 http://www.smsc.com/main/datasheets/47b27x.pdf
11 http://www.smsc.com/main/datasheets/47m10x.pdf
6091780e 12 http://www.smsc.com/main/datasheets/47m112.pdf
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13 http://www.smsc.com/main/tools/discontinued/47m13x.pdf
14 http://www.smsc.com/main/datasheets/47m14x.pdf
15 http://www.smsc.com/main/tools/discontinued/47m15x.pdf
16 http://www.smsc.com/main/datasheets/47m192.pdf
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17 * SMSC LPC47M997
18 Addresses scanned: none, address read from Super I/O config space
19 Prefix: 'smsc47m1'
20 Datasheet: none
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21
22Authors:
23 Mark D. Studebaker <mdsxyz123@yahoo.com>,
24 With assistance from Bruce Allen <ballen@uwm.edu>, and his
25 fan.c program: http://www.lsc-group.phys.uwm.edu/%7Eballen/driver/
26 Gabriele Gorla <gorlik@yahoo.com>,
27 Jean Delvare <khali@linux-fr.org>
28
29Description
30-----------
31
32The Standard Microsystems Corporation (SMSC) 47M1xx Super I/O chips
33contain monitoring and PWM control circuitry for two fans.
34
35The 47M15x and 47M192 chips contain a full 'hardware monitoring block'
36in addition to the fan monitoring and control. The hardware monitoring
37block is not supported by the driver.
38
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39No documentation is available for the 47M997, but it has the same device
40ID as the 47M15x and 47M192 chips and seems to be compatible.
41
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42Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
43triggered if the rotation speed has dropped below a programmable limit. Fan
44readings can be divided by a programmable divider (1, 2, 4 or 8) to give
45the readings more range or accuracy. Not all RPM values can accurately be
46represented, so some rounding is done. With a divider of 2, the lowest
47representable value is around 2600 RPM.
48
49PWM values are from 0 to 255.
50
51If an alarm triggers, it will remain triggered until the hardware register
52is read at least once. This means that the cause for the alarm may
53already have disappeared! Note that in the current implementation, all
54hardware registers are read whenever any data is read (unless it is less
55than 1.5 seconds since the last update). This means that you can easily
56miss once-only alarms.
57
58
59**********************
60The lm_sensors project gratefully acknowledges the support of
61Intel in the development of this driver.