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
107