1Kernel driver gl518sm 2===================== 3 4Supported chips: 5 6 * Genesys Logic GL518SM release 0x00 7 8 Prefix: 'gl518sm' 9 10 Addresses scanned: I2C 0x2c and 0x2d 11 12 * Genesys Logic GL518SM release 0x80 13 14 Prefix: 'gl518sm' 15 16 Addresses scanned: I2C 0x2c and 0x2d 17 18 Datasheet: http://www.genesyslogic.com/ 19 20Authors: 21 - Frodo Looijaard <frodol@dds.nl>, 22 - Kyösti Mälkki <kmalkki@cc.hut.fi> 23 - Hong-Gunn Chew <hglinux@gunnet.org> 24 - Jean Delvare <jdelvare@suse.de> 25 26Description 27----------- 28 29.. important:: 30 31 For the revision 0x00 chip, the in0, in1, and in2 values (+5V, +3V, 32 and +12V) CANNOT be read. This is a limitation of the chip, not the driver. 33 34This driver supports the Genesys Logic GL518SM chip. There are at least 35two revision of this chip, which we call revision 0x00 and 0x80. Revision 360x80 chips support the reading of all voltages and revision 0x00 only 37for VIN3. 38 39The GL518SM implements one temperature sensor, two fan rotation speed 40sensors, and four voltage sensors. It can report alarms through the 41computer speakers. 42 43Temperatures are measured in degrees Celsius. An alarm goes off while the 44temperature is above the over temperature limit, and has not yet dropped 45below the hysteresis limit. The alarm always reflects the current 46situation. Measurements are guaranteed between -10 degrees and +110 47degrees, with a accuracy of +/-3 degrees. 48 49Rotation speeds are reported in RPM (rotations per minute). An alarm is 50triggered if the rotation speed has dropped below a programmable limit. In 51case when you have selected to turn fan1 off, no fan1 alarm is triggered. 52 53Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to 54give the readings more range or accuracy. Not all RPM values can 55accurately be represented, so some rounding is done. With a divider 56of 2, the lowest representable value is around 1900 RPM. 57 58Voltage sensors (also known as VIN sensors) report their values in volts. 59An alarm is triggered if the voltage has crossed a programmable minimum or 60maximum limit. Note that minimum in this case always means 'closest to 61zero'; this is important for negative voltage measurements. The VDD input 62measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023 63volt. The other inputs measure voltages between 0.000 and 4.845 volt, with 64a resolution of 0.019 volt. Note that revision 0x00 chips do not support 65reading the current voltage of any input except for VIN3; limit setting and 66alarms work fine, though. 67 68When an alarm is triggered, you can be warned by a beeping signal through your 69computer speaker. It is possible to enable all beeping globally, or only the 70beeping for some alarms. 71 72If an alarm triggers, it will remain triggered until the hardware register 73is read at least once (except for temperature alarms). This means that the 74cause for the alarm may already have disappeared! Note that in the current 75implementation, all hardware registers are read whenever any data is read 76(unless it is less than 1.5 seconds since the last update). This means that 77you can easily miss once-only alarms. 78 79The GL518SM only updates its values each 1.5 seconds; reading it more often 80will do no harm, but will return 'old' values. 81