1Kernel driver sis5595
  2=====================
  3
  4Supported chips:
  5  * Silicon Integrated Systems Corp. SiS5595 Southbridge Hardware Monitor
  6    Prefix: 'sis5595'
  7    Addresses scanned: ISA in PCI-space encoded address
  8    Datasheet: Publicly available at the Silicon Integrated Systems Corp. site.
  9
 10Authors:
 11        Kyösti Mälkki <kmalkki@cc.hut.fi>,
 12        Mark D. Studebaker <mdsxyz123@yahoo.com>,
 13        Aurelien Jarno <aurelien@aurel32.net> 2.6 port
 14
 15   SiS southbridge has a LM78-like chip integrated on the same IC.
 16   This driver is a customized copy of lm78.c
 17
 18   Supports following revisions:
 19       Version         PCI ID          PCI Revision
 20       1               1039/0008       AF or less
 21       2               1039/0008       B0 or greater
 22
 23   Note: these chips contain a 0008 device which is incompatible with the
 24        5595. We recognize these by the presence of the listed
 25        "blacklist" PCI ID and refuse to load.
 26
 27   NOT SUPPORTED       PCI ID          BLACKLIST PCI ID
 28        540            0008            0540
 29        550            0008            0550
 30       5513            0008            5511
 31       5581            0008            5597
 32       5582            0008            5597
 33       5597            0008            5597
 34        630            0008            0630
 35        645            0008            0645
 36        730            0008            0730
 37        735            0008            0735
 38
 39
 40Module Parameters
 41-----------------
 42force_addr=0xaddr	Set the I/O base address. Useful for boards
 43			that don't set the address in the BIOS. Does not do a
 44			PCI force; the device must still be present in lspci.
 45			Don't use this unless the driver complains that the
 46			base address is not set.
 47			Example: 'modprobe sis5595 force_addr=0x290'
 48
 49
 50Description
 51-----------
 52
 53The SiS5595 southbridge has integrated hardware monitor functions. It also
 54has an I2C bus, but this driver only supports the hardware monitor. For the
 55I2C bus driver see i2c-sis5595.
 56
 57The SiS5595 implements zero or one temperature sensor, two fan speed
 58sensors, four or five voltage sensors, and alarms.
 59
 60On the first version of the chip, there are four voltage sensors and one
 61temperature sensor.
 62
 63On the second version of the chip, the temperature sensor (temp) and the
 64fifth voltage sensor (in4) share a pin which is configurable, but not
 65through the driver. Sorry. The driver senses the configuration of the pin,
 66which was hopefully set by the BIOS.
 67
 68Temperatures are measured in degrees Celsius. An alarm is triggered once
 69when the max is crossed; it is also triggered when it drops below the min
 70value. Measurements are guaranteed between -55 and +125 degrees, with a
 71resolution of 1 degree.
 72
 73Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
 74triggered if the rotation speed has dropped below a programmable limit. Fan
 75readings can be divided by a programmable divider (1, 2, 4 or 8) to give
 76the readings more range or accuracy. Not all RPM values can accurately be
 77represented, so some rounding is done. With a divider of 2, the lowest
 78representable value is around 2600 RPM.
 79
 80Voltage sensors (also known as IN sensors) report their values in volts. An
 81alarm is triggered if the voltage has crossed a programmable minimum or
 82maximum limit. Note that minimum in this case always means 'closest to
 83zero'; this is important for negative voltage measurements. All voltage
 84inputs can measure voltages between 0 and 4.08 volts, with a resolution of
 850.016 volt.
 86
 87In addition to the alarms described above, there is a BTI alarm, which gets
 88triggered when an external chip has crossed its limits. Usually, this is
 89connected to some LM75-like chip; if at least one crosses its limits, this
 90bit gets set.
 91
 92If an alarm triggers, it will remain triggered until the hardware register
 93is read at least once. This means that the cause for the alarm may already
 94have disappeared! Note that in the current implementation, all hardware
 95registers are read whenever any data is read (unless it is less than 1.5
 96seconds since the last update). This means that you can easily miss
 97once-only alarms.
 98
 99The SiS5595 only updates its values each 1.5 seconds; reading it more often
100will do no harm, but will return 'old' values.
101
102Problems
103--------
104Some chips refuse to be enabled. We don't know why.
105The driver will recognize this and print a message in dmesg.
106