1Kernel driver sis5595
2=====================
3
4Supported chips:
5
6  * Silicon Integrated Systems Corp. SiS5595 Southbridge Hardware Monitor
7
8    Prefix: 'sis5595'
9
10    Addresses scanned: ISA in PCI-space encoded address
11
12    Datasheet: Publicly available at the Silicon Integrated Systems Corp. site.
13
14
15
16Authors:
17
18      - Kyösti Mälkki <kmalkki@cc.hut.fi>,
19      - Mark D. Studebaker <mdsxyz123@yahoo.com>,
20      - Aurelien Jarno <aurelien@aurel32.net> 2.6 port
21
22   SiS southbridge has a LM78-like chip integrated on the same IC.
23   This driver is a customized copy of lm78.c
24
25   Supports following revisions:
26
27       =============== =============== ==============
28       Version         PCI ID          PCI Revision
29       =============== =============== ==============
30       1               1039/0008       AF or less
31       2               1039/0008       B0 or greater
32       =============== =============== ==============
33
34   Note: these chips contain a 0008 device which is incompatible with the
35	5595. We recognize these by the presence of the listed
36	"blacklist" PCI ID and refuse to load.
37
38   =================== =============== ================
39   NOT SUPPORTED       PCI ID          BLACKLIST PCI ID
40   =================== =============== ================
41	540            0008            0540
42	550            0008            0550
43       5513            0008            5511
44       5581            0008            5597
45       5582            0008            5597
46       5597            0008            5597
47	630            0008            0630
48	645            0008            0645
49	730            0008            0730
50	735            0008            0735
51   =================== =============== ================
52
53
54Module Parameters
55-----------------
56
57======================= =====================================================
58force_addr=0xaddr	Set the I/O base address. Useful for boards
59			that don't set the address in the BIOS. Does not do a
60			PCI force; the device must still be present in lspci.
61			Don't use this unless the driver complains that the
62			base address is not set.
63
64			Example: 'modprobe sis5595 force_addr=0x290'
65======================= =====================================================
66
67
68Description
69-----------
70
71The SiS5595 southbridge has integrated hardware monitor functions. It also
72has an I2C bus, but this driver only supports the hardware monitor. For the
73I2C bus driver see i2c-sis5595.
74
75The SiS5595 implements zero or one temperature sensor, two fan speed
76sensors, four or five voltage sensors, and alarms.
77
78On the first version of the chip, there are four voltage sensors and one
79temperature sensor.
80
81On the second version of the chip, the temperature sensor (temp) and the
82fifth voltage sensor (in4) share a pin which is configurable, but not
83through the driver. Sorry. The driver senses the configuration of the pin,
84which was hopefully set by the BIOS.
85
86Temperatures are measured in degrees Celsius. An alarm is triggered once
87when the max is crossed; it is also triggered when it drops below the min
88value. Measurements are guaranteed between -55 and +125 degrees, with a
89resolution of 1 degree.
90
91Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
92triggered if the rotation speed has dropped below a programmable limit. Fan
93readings can be divided by a programmable divider (1, 2, 4 or 8) to give
94the readings more range or accuracy. Not all RPM values can accurately be
95represented, so some rounding is done. With a divider of 2, the lowest
96representable value is around 2600 RPM.
97
98Voltage sensors (also known as IN sensors) report their values in volts. An
99alarm is triggered if the voltage has crossed a programmable minimum or
100maximum limit. Note that minimum in this case always means 'closest to
101zero'; this is important for negative voltage measurements. All voltage
102inputs can measure voltages between 0 and 4.08 volts, with a resolution of
1030.016 volt.
104
105In addition to the alarms described above, there is a BTI alarm, which gets
106triggered when an external chip has crossed its limits. Usually, this is
107connected to some LM75-like chip; if at least one crosses its limits, this
108bit gets set.
109
110If an alarm triggers, it will remain triggered until the hardware register
111is read at least once. This means that the cause for the alarm may already
112have disappeared! Note that in the current implementation, all hardware
113registers are read whenever any data is read (unless it is less than 1.5
114seconds since the last update). This means that you can easily miss
115once-only alarms.
116
117The SiS5595 only updates its values each 1.5 seconds; reading it more often
118will do no harm, but will return 'old' values.
119
120Problems
121--------
122Some chips refuse to be enabled. We don't know why.
123The driver will recognize this and print a message in dmesg.
124