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author | Jeff Garzik <jgarzik@pretzel.yyz.us> | 2005-06-26 23:38:58 -0400 |
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committer | Jeff Garzik <jgarzik@pobox.com> | 2005-06-26 23:38:58 -0400 |
commit | 5696c1944a33b4434a9a1ebb6383b906afd43a10 (patch) | |
tree | 16fbe6ba431bcf949ee8645510b0c2fd39b5810f /Documentation/i2c/chips/gl518sm | |
parent | 66b04a80eea60cabf9d89fd34deb3234a740052f (diff) | |
parent | 020f46a39eb7b99a575b9f4d105fce2b142acdf1 (diff) |
Merge /spare/repo/linux-2.6/
Diffstat (limited to 'Documentation/i2c/chips/gl518sm')
-rw-r--r-- | Documentation/i2c/chips/gl518sm | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/i2c/chips/gl518sm b/Documentation/i2c/chips/gl518sm new file mode 100644 index 000000000000..ce0881883bca --- /dev/null +++ b/Documentation/i2c/chips/gl518sm | |||
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1 | Kernel driver gl518sm | ||
2 | ===================== | ||
3 | |||
4 | Supported chips: | ||
5 | * Genesys Logic GL518SM release 0x00 | ||
6 | Prefix: 'gl518sm' | ||
7 | Addresses scanned: I2C 0x2c and 0x2d | ||
8 | Datasheet: http://www.genesyslogic.com/pdf | ||
9 | * Genesys Logic GL518SM release 0x80 | ||
10 | Prefix: 'gl518sm' | ||
11 | Addresses scanned: I2C 0x2c and 0x2d | ||
12 | Datasheet: http://www.genesyslogic.com/pdf | ||
13 | |||
14 | Authors: | ||
15 | Frodo Looijaard <frodol@dds.nl>, | ||
16 | Kyösti Mälkki <kmalkki@cc.hut.fi> | ||
17 | Hong-Gunn Chew <hglinux@gunnet.org> | ||
18 | Jean Delvare <khali@linux-fr.org> | ||
19 | |||
20 | Description | ||
21 | ----------- | ||
22 | |||
23 | IMPORTANT: | ||
24 | |||
25 | For the revision 0x00 chip, the in0, in1, and in2 values (+5V, +3V, | ||
26 | and +12V) CANNOT be read. This is a limitation of the chip, not the driver. | ||
27 | |||
28 | This driver supports the Genesys Logic GL518SM chip. There are at least | ||
29 | two revision of this chip, which we call revision 0x00 and 0x80. Revision | ||
30 | 0x80 chips support the reading of all voltages and revision 0x00 only | ||
31 | for VIN3. | ||
32 | |||
33 | The GL518SM implements one temperature sensor, two fan rotation speed | ||
34 | sensors, and four voltage sensors. It can report alarms through the | ||
35 | computer speakers. | ||
36 | |||
37 | Temperatures are measured in degrees Celsius. An alarm goes off while the | ||
38 | temperature is above the over temperature limit, and has not yet dropped | ||
39 | below the hysteresis limit. The alarm always reflects the current | ||
40 | situation. Measurements are guaranteed between -10 degrees and +110 | ||
41 | degrees, with a accuracy of +/-3 degrees. | ||
42 | |||
43 | Rotation speeds are reported in RPM (rotations per minute). An alarm is | ||
44 | triggered if the rotation speed has dropped below a programmable limit. In | ||
45 | case when you have selected to turn fan1 off, no fan1 alarm is triggered. | ||
46 | |||
47 | Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to | ||
48 | give the readings more range or accuracy. Not all RPM values can | ||
49 | accurately be represented, so some rounding is done. With a divider | ||
50 | of 2, the lowest representable value is around 1900 RPM. | ||
51 | |||
52 | Voltage sensors (also known as VIN sensors) report their values in volts. | ||
53 | An alarm is triggered if the voltage has crossed a programmable minimum or | ||
54 | maximum limit. Note that minimum in this case always means 'closest to | ||
55 | zero'; this is important for negative voltage measurements. The VDD input | ||
56 | measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023 | ||
57 | volt. The other inputs measure voltages between 0.000 and 4.845 volt, with | ||
58 | a resolution of 0.019 volt. Note that revision 0x00 chips do not support | ||
59 | reading the current voltage of any input except for VIN3; limit setting and | ||
60 | alarms work fine, though. | ||
61 | |||
62 | When an alarm is triggered, you can be warned by a beeping signal through your | ||
63 | computer speaker. It is possible to enable all beeping globally, or only the | ||
64 | beeping for some alarms. | ||
65 | |||
66 | If an alarm triggers, it will remain triggered until the hardware register | ||
67 | is read at least once (except for temperature alarms). This means that the | ||
68 | cause for the alarm may already have disappeared! Note that in the current | ||
69 | implementation, all hardware registers are read whenever any data is read | ||
70 | (unless it is less than 1.5 seconds since the last update). This means that | ||
71 | you can easily miss once-only alarms. | ||
72 | |||
73 | The GL518SM only updates its values each 1.5 seconds; reading it more often | ||
74 | will do no harm, but will return 'old' values. | ||