Root/Documentation/hwmon/f71882fg

1Kernel driver f71882fg
2======================
3
4Supported chips:
5  * Fintek F71858FG
6    Prefix: 'f71858fg'
7    Addresses scanned: none, address read from Super I/O config space
8    Datasheet: Available from the Fintek website
9  * Fintek F71862FG and F71863FG
10    Prefix: 'f71862fg'
11    Addresses scanned: none, address read from Super I/O config space
12    Datasheet: Available from the Fintek website
13  * Fintek F71882FG and F71883FG
14    Prefix: 'f71882fg'
15    Addresses scanned: none, address read from Super I/O config space
16    Datasheet: Available from the Fintek website
17  * Fintek F71889FG
18    Prefix: 'f71889fg'
19    Addresses scanned: none, address read from Super I/O config space
20    Datasheet: Should become available on the Fintek website soon
21  * Fintek F8000
22    Prefix: 'f8000'
23    Addresses scanned: none, address read from Super I/O config space
24    Datasheet: Not public
25
26Author: Hans de Goede <hdegoede@redhat.com>
27
28
29Description
30-----------
31
32Fintek F718xxFG/F8000 Super I/O chips include complete hardware monitoring
33capabilities. They can monitor up to 9 voltages (3 for the F8000), 4 fans and
343 temperature sensors.
35
36These chips also have fan controlling features, using either DC or PWM, in
37three different modes (one manual, two automatic).
38
39The driver assumes that no more than one chip is present, which seems
40reasonable.
41
42
43Monitoring
44----------
45
46The Voltage, Fan and Temperature Monitoring uses the standard sysfs
47interface as documented in sysfs-interface, without any exceptions.
48
49
50Fan Control
51-----------
52
53Both PWM (pulse-width modulation) and DC fan speed control methods are
54supported. The right one to use depends on external circuitry on the
55motherboard, so the driver assumes that the BIOS set the method
56properly.
57
58Note that the lowest numbered temperature zone trip point corresponds to
59to the border between the highest and one but highest temperature zones, and
60vica versa. So the temperature zone trip points 1-4 (or 1-2) go from high temp
61to low temp! This is how things are implemented in the IC, and the driver
62mimicks this.
63
64There are 2 modes to specify the speed of the fan, PWM duty cycle (or DC
65voltage) mode, where 0-100% duty cycle (0-100% of 12V) is specified. And RPM
66mode where the actual RPM of the fan (as measured) is controlled and the speed
67gets specified as 0-100% of the fan#_full_speed file.
68
69Since both modes work in a 0-100% (mapped to 0-255) scale, there isn't a
70whole lot of a difference when modifying fan control settings. The only
71important difference is that in RPM mode the 0-100% controls the fan speed
72between 0-100% of fan#_full_speed. It is assumed that if the BIOS programs
73RPM mode, it will also set fan#_full_speed properly, if it does not then
74fan control will not work properly, unless you set a sane fan#_full_speed
75value yourself.
76
77Switching between these modes requires re-initializing a whole bunch of
78registers, so the mode which the BIOS has set is kept. The mode is
79printed when loading the driver.
80
81Three different fan control modes are supported; the mode number is written
82to the pwm#_enable file. Note that not all modes are supported on all
83chips, and some modes may only be available in RPM / PWM mode.
84Writing an unsupported mode will result in an invalid parameter error.
85
86* 1: Manual mode
87  You ask for a specific PWM duty cycle / DC voltage or a specific % of
88  fan#_full_speed by writing to the pwm# file. This mode is only
89  available on the F71858FG / F8000 if the fan channel is in RPM mode.
90
91* 2: Normal auto mode
92  You can define a number of temperature/fan speed trip points, which % the
93  fan should run at at this temp and which temp a fan should follow using the
94  standard sysfs interface. The number and type of trip points is chip
95  depended, see which files are available in sysfs.
96  Fan/PWM channel 3 of the F8000 is always in this mode!
97
98* 3: Thermostat mode (Only available on the F8000 when in duty cycle mode)
99  The fan speed is regulated to keep the temp the fan is mapped to between
100  temp#_auto_point2_temp and temp#_auto_point3_temp.
101
102Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
103fan2 and pwm3 to fan3.
104

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