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7f15b664 M |
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 | |
7f15b664 M |
8 | * Genesys Logic GL518SM release 0x80 |
9 | Prefix: 'gl518sm' | |
10 | Addresses scanned: I2C 0x2c and 0x2d | |
0ea6e611 | 11 | Datasheet: http://www.genesyslogic.com/ |
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12 | |
13 | Authors: | |
14 | Frodo Looijaard <frodol@dds.nl>, | |
be2a608b | 15 | Kyösti Mälkki <kmalkki@cc.hut.fi> |
7f15b664 M |
16 | Hong-Gunn Chew <hglinux@gunnet.org> |
17 | Jean Delvare <khali@linux-fr.org> | |
18 | ||
19 | Description | |
20 | ----------- | |
21 | ||
22 | IMPORTANT: | |
23 | ||
24 | For the revision 0x00 chip, the in0, in1, and in2 values (+5V, +3V, | |
25 | and +12V) CANNOT be read. This is a limitation of the chip, not the driver. | |
26 | ||
27 | This driver supports the Genesys Logic GL518SM chip. There are at least | |
28 | two revision of this chip, which we call revision 0x00 and 0x80. Revision | |
29 | 0x80 chips support the reading of all voltages and revision 0x00 only | |
30 | for VIN3. | |
31 | ||
32 | The GL518SM implements one temperature sensor, two fan rotation speed | |
33 | sensors, and four voltage sensors. It can report alarms through the | |
34 | computer speakers. | |
35 | ||
36 | Temperatures are measured in degrees Celsius. An alarm goes off while the | |
37 | temperature is above the over temperature limit, and has not yet dropped | |
38 | below the hysteresis limit. The alarm always reflects the current | |
39 | situation. Measurements are guaranteed between -10 degrees and +110 | |
40 | degrees, with a accuracy of +/-3 degrees. | |
41 | ||
42 | Rotation speeds are reported in RPM (rotations per minute). An alarm is | |
43 | triggered if the rotation speed has dropped below a programmable limit. In | |
44 | case when you have selected to turn fan1 off, no fan1 alarm is triggered. | |
45 | ||
46 | Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to | |
47 | give the readings more range or accuracy. Not all RPM values can | |
48 | accurately be represented, so some rounding is done. With a divider | |
49 | of 2, the lowest representable value is around 1900 RPM. | |
50 | ||
51 | Voltage sensors (also known as VIN sensors) report their values in volts. | |
52 | An alarm is triggered if the voltage has crossed a programmable minimum or | |
53 | maximum limit. Note that minimum in this case always means 'closest to | |
54 | zero'; this is important for negative voltage measurements. The VDD input | |
55 | measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023 | |
56 | volt. The other inputs measure voltages between 0.000 and 4.845 volt, with | |
57 | a resolution of 0.019 volt. Note that revision 0x00 chips do not support | |
58 | reading the current voltage of any input except for VIN3; limit setting and | |
59 | alarms work fine, though. | |
60 | ||
61 | When an alarm is triggered, you can be warned by a beeping signal through your | |
62 | computer speaker. It is possible to enable all beeping globally, or only the | |
63 | beeping for some alarms. | |
64 | ||
65 | If an alarm triggers, it will remain triggered until the hardware register | |
66 | is read at least once (except for temperature alarms). This means that the | |
67 | cause for the alarm may already have disappeared! Note that in the current | |
68 | implementation, all hardware registers are read whenever any data is read | |
69 | (unless it is less than 1.5 seconds since the last update). This means that | |
70 | you can easily miss once-only alarms. | |
71 | ||
72 | The GL518SM only updates its values each 1.5 seconds; reading it more often | |
73 | will do no harm, but will return 'old' values. |