tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1Kernel driver it87
2==================
3
4Supported chips:
5 * IT8705F
6 Prefix: 'it87'
7 Addresses scanned: from Super I/O config space (8 I/O ports)
8 Datasheet: Publicly available at the ITE website
9 http://www.ite.com.tw/
10 * IT8712F
11 Prefix: 'it8712'
12 Addresses scanned: I2C 0x2d
13 from Super I/O config space (8 I/O ports)
14 Datasheet: Publicly available at the ITE website
15 http://www.ite.com.tw/
16 * SiS950 [clone of IT8705F]
17 Prefix: 'it87'
18 Addresses scanned: from Super I/O config space (8 I/O ports)
19 Datasheet: No longer be available
20
21Author: Christophe Gauthron <chrisg@0-in.com>
22
23
24Module Parameters
25-----------------
26
27* update_vbat: int
28
29 0 if vbat should report power on value, 1 if vbat should be updated after
30 each read. Default is 0. On some boards the battery voltage is provided
31 by either the battery or the onboard power supply. Only the first reading
32 at power on will be the actual battery voltage (which the chip does
33 automatically). On other boards the battery voltage is always fed to
34 the chip so can be read at any time. Excessive reading may decrease
35 battery life but no information is given in the datasheet.
36
37* fix_pwm_polarity int
38
39 Force PWM polarity to active high (DANGEROUS). Some chips are
40 misconfigured by BIOS - PWM values would be inverted. This option tries
41 to fix this. Please contact your BIOS manufacturer and ask him for fix.
42
43Description
44-----------
45
46This driver implements support for the IT8705F, IT8712F and SiS950 chips.
47
48This driver also supports IT8712F, which adds SMBus access, and a VID
49input, used to report the Vcore voltage of the Pentium processor.
50The IT8712F additionally features VID inputs.
51
52These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
53joysticks and other miscellaneous stuff. For hardware monitoring, they
54include an 'environment controller' with 3 temperature sensors, 3 fan
55rotation speed sensors, 8 voltage sensors, and associated alarms.
56
57Temperatures are measured in degrees Celsius. An alarm is triggered once
58when the Overtemperature Shutdown limit is crossed.
59
60Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
61triggered if the rotation speed has dropped below a programmable limit. Fan
62readings can be divided by a programmable divider (1, 2, 4 or 8) to give the
63readings more range or accuracy. Not all RPM values can accurately be
64represented, so some rounding is done. With a divider of 2, the lowest
65representable value is around 2600 RPM.
66
67Voltage sensors (also known as IN sensors) report their values in volts. An
68alarm is triggered if the voltage has crossed a programmable minimum or
69maximum limit. Note that minimum in this case always means 'closest to
70zero'; this is important for negative voltage measurements. All voltage
71inputs can measure voltages between 0 and 4.08 volts, with a resolution of
720.016 volt. The battery voltage in8 does not have limit registers.
73
74The VID lines (IT8712F only) encode the core voltage value: the voltage
75level your processor should work with. This is hardcoded by the mainboard
76and/or processor itself. It is a value in volts.
77
78If an alarm triggers, it will remain triggered until the hardware register
79is read at least once. This means that the cause for the alarm may already
80have disappeared! Note that in the current implementation, all hardware
81registers are read whenever any data is read (unless it is less than 1.5
82seconds since the last update). This means that you can easily miss
83once-only alarms.
84
85The IT87xx only updates its values each 1.5 seconds; reading it more often
86will do no harm, but will return 'old' values.
87
88To change sensor N to a thermistor, 'echo 2 > tempN_type' where N is 1, 2,
89or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
90Give 0 for unused sensor. Any other value is invalid. To configure this at
91startup, consult lm_sensors's /etc/sensors.conf. (2 = thermistor;
923 = thermal diode)
93
94The fan speed control features are limited to manual PWM mode. Automatic
95"Smart Guardian" mode control handling is not implemented. However
96if you want to go for "manual mode" just write 1 to pwmN_enable.