1Kernel driver gl518sm
   4Supported 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:
  14        Frodo Looijaard <>,
  15        Ky\xC3\xB6sti M\xC3\xA4lkki <>
  16        Hong-Gunn Chew <>
  17        Jean Delvare <>
  24For the revision 0x00 chip, the in0, in1, and in2  values (+5V, +3V,
  25and +12V) CANNOT be read. This is a limitation of the chip, not the driver.
  27This driver supports the Genesys Logic GL518SM chip. There are at least
  28two revision of this chip, which we call revision 0x00 and 0x80. Revision
  290x80 chips support the reading of all voltages and revision 0x00 only
  30for VIN3.
  32The GL518SM implements one temperature sensor, two fan rotation speed
  33sensors, and four voltage sensors. It can report alarms through the
  34computer speakers.
  36Temperatures are measured in degrees Celsius. An alarm goes off while the
  37temperature is above the over temperature limit, and has not yet dropped
  38below the hysteresis limit. The alarm always reflects the current
  39situation. Measurements are guaranteed between -10 degrees and +110
  40degrees, with a accuracy of +/-3 degrees.
  42Rotation speeds are reported in RPM (rotations per minute). An alarm is
  43triggered if the rotation speed has dropped below a programmable limit. In
  44case when you have selected to turn fan1 off, no fan1 alarm is triggered.
  46Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to
  47give the readings more range or accuracy.  Not all RPM values can
  48accurately be represented, so some rounding is done. With a divider
  49of 2, the lowest representable value is around 1900 RPM.
  51Voltage sensors (also known as VIN sensors) report their values in volts.
  52An alarm is triggered if the voltage has crossed a programmable minimum or
  53maximum limit. Note that minimum in this case always means 'closest to
  54zero'; this is important for negative voltage measurements. The VDD input
  55measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023
  56volt. The other inputs measure voltages between 0.000 and 4.845 volt, with
  57a resolution of 0.019 volt. Note that revision 0x00 chips do not support
  58reading the current voltage of any input except for VIN3; limit setting and
  59alarms work fine, though.
  61When an alarm is triggered, you can be warned by a beeping signal through your
  62computer speaker. It is possible to enable all beeping globally, or only the
  63beeping for some alarms.
  65If an alarm triggers, it will remain triggered until the hardware register
  66is read at least once (except for temperature alarms). This means that the
  67cause for the alarm may already have disappeared! Note that in the current
  68implementation, 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
  70you can easily miss once-only alarms.
  72The GL518SM only updates its values each 1.5 seconds; reading it more often
  73will do no harm, but will return 'old' values.