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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 @@ -0,0 +1,74 @@ +Kernel driver gl518sm +===================== + +Supported chips: + * Genesys Logic GL518SM release 0x00 + Prefix: 'gl518sm' + Addresses scanned: I2C 0x2c and 0x2d + Datasheet: http://www.genesyslogic.com/pdf + * Genesys Logic GL518SM release 0x80 + Prefix: 'gl518sm' + Addresses scanned: I2C 0x2c and 0x2d + Datasheet: http://www.genesyslogic.com/pdf + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Kysti Mlkki <kmalkki@cc.hut.fi> + Hong-Gunn Chew <hglinux@gunnet.org> + Jean Delvare <khali@linux-fr.org> + +Description +----------- + +IMPORTANT: + +For the revision 0x00 chip, the in0, in1, and in2 values (+5V, +3V, +and +12V) CANNOT be read. This is a limitation of the chip, not the driver. + +This driver supports the Genesys Logic GL518SM chip. There are at least +two revision of this chip, which we call revision 0x00 and 0x80. Revision +0x80 chips support the reading of all voltages and revision 0x00 only +for VIN3. + +The GL518SM implements one temperature sensor, two fan rotation speed +sensors, and four voltage sensors. It can report alarms through the +computer speakers. + +Temperatures are measured in degrees Celsius. An alarm goes off while the +temperature is above the over temperature limit, and has not yet dropped +below the hysteresis limit. The alarm always reflects the current +situation. Measurements are guaranteed between -10 degrees and +110 +degrees, with a accuracy of +/-3 degrees. + +Rotation speeds are reported in RPM (rotations per minute). An alarm is +triggered if the rotation speed has dropped below a programmable limit. In +case when you have selected to turn fan1 off, no fan1 alarm is triggered. + +Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to +give the readings more range or accuracy. Not all RPM values can +accurately be represented, so some rounding is done. With a divider +of 2, the lowest representable value is around 1900 RPM. + +Voltage sensors (also known as VIN sensors) report their values in volts. +An alarm is triggered if the voltage has crossed a programmable minimum or +maximum limit. Note that minimum in this case always means 'closest to +zero'; this is important for negative voltage measurements. The VDD input +measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023 +volt. The other inputs measure voltages between 0.000 and 4.845 volt, with +a resolution of 0.019 volt. Note that revision 0x00 chips do not support +reading the current voltage of any input except for VIN3; limit setting and +alarms work fine, though. + +When an alarm is triggered, you can be warned by a beeping signal through your +computer speaker. It is possible to enable all beeping globally, or only the +beeping for some alarms. + +If an alarm triggers, it will remain triggered until the hardware register +is read at least once (except for temperature alarms). This means that the +cause for the alarm may already have disappeared! Note that in the current +implementation, all hardware registers are read whenever any data is read +(unless it is less than 1.5 seconds since the last update). This means that +you can easily miss once-only alarms. + +The GL518SM only updates its values each 1.5 seconds; reading it more often +will do no harm, but will return 'old' values. |