0001 Kernel driver gl518sm
0002 =====================
0003
0004 Supported chips:
0005
0006 * Genesys Logic GL518SM release 0x00
0007
0008 Prefix: 'gl518sm'
0009
0010 Addresses scanned: I2C 0x2c and 0x2d
0011
0012 * Genesys Logic GL518SM release 0x80
0013
0014 Prefix: 'gl518sm'
0015
0016 Addresses scanned: I2C 0x2c and 0x2d
0017
0018 Datasheet: http://www.genesyslogic.com/
0019
0020 Authors:
0021 - Frodo Looijaard <frodol@dds.nl>,
0022 - Kyösti Mälkki <kmalkki@cc.hut.fi>
0023 - Hong-Gunn Chew <hglinux@gunnet.org>
0024 - Jean Delvare <jdelvare@suse.de>
0025
0026 Description
0027 -----------
0028
0029 .. important::
0030
0031 For the revision 0x00 chip, the in0, in1, and in2 values (+5V, +3V,
0032 and +12V) CANNOT be read. This is a limitation of the chip, not the driver.
0033
0034 This driver supports the Genesys Logic GL518SM chip. There are at least
0035 two revision of this chip, which we call revision 0x00 and 0x80. Revision
0036 0x80 chips support the reading of all voltages and revision 0x00 only
0037 for VIN3.
0038
0039 The GL518SM implements one temperature sensor, two fan rotation speed
0040 sensors, and four voltage sensors. It can report alarms through the
0041 computer speakers.
0042
0043 Temperatures are measured in degrees Celsius. An alarm goes off while the
0044 temperature is above the over temperature limit, and has not yet dropped
0045 below the hysteresis limit. The alarm always reflects the current
0046 situation. Measurements are guaranteed between -10 degrees and +110
0047 degrees, with a accuracy of +/-3 degrees.
0048
0049 Rotation speeds are reported in RPM (rotations per minute). An alarm is
0050 triggered if the rotation speed has dropped below a programmable limit. In
0051 case when you have selected to turn fan1 off, no fan1 alarm is triggered.
0052
0053 Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to
0054 give the readings more range or accuracy. Not all RPM values can
0055 accurately be represented, so some rounding is done. With a divider
0056 of 2, the lowest representable value is around 1900 RPM.
0057
0058 Voltage sensors (also known as VIN sensors) report their values in volts.
0059 An alarm is triggered if the voltage has crossed a programmable minimum or
0060 maximum limit. Note that minimum in this case always means 'closest to
0061 zero'; this is important for negative voltage measurements. The VDD input
0062 measures voltages between 0.000 and 5.865 volt, with a resolution of 0.023
0063 volt. The other inputs measure voltages between 0.000 and 4.845 volt, with
0064 a resolution of 0.019 volt. Note that revision 0x00 chips do not support
0065 reading the current voltage of any input except for VIN3; limit setting and
0066 alarms work fine, though.
0067
0068 When an alarm is triggered, you can be warned by a beeping signal through your
0069 computer speaker. It is possible to enable all beeping globally, or only the
0070 beeping for some alarms.
0071
0072 If an alarm triggers, it will remain triggered until the hardware register
0073 is read at least once (except for temperature alarms). This means that the
0074 cause for the alarm may already have disappeared! Note that in the current
0075 implementation, all hardware registers are read whenever any data is read
0076 (unless it is less than 1.5 seconds since the last update). This means that
0077 you can easily miss once-only alarms.
0078
0079 The GL518SM only updates its values each 1.5 seconds; reading it more often
0080 will do no harm, but will return 'old' values.
