| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 | * Genesys Logic GL518SM release 0x80 |
| 9 | Prefix: 'gl518sm' |
| 10 | Addresses scanned: I2C 0x2c and 0x2d |
| 11 | Datasheet: http://www.genesyslogic.com/ |
| 12 | |
| 13 | Authors: |
| 14 | Frodo Looijaard <frodol@dds.nl>, |
| 15 | Kyösti Mälkki <kmalkki@cc.hut.fi> |
| 16 | Hong-Gunn Chew <hglinux@gunnet.org> |
| 17 | Jean Delvare <jdelvare@suse.de> |
| 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. |