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authorHans de Goede <hdegoede@redhat.com>2009-01-07 10:37:31 -0500
committerJean Delvare <khali@linux-fr.org>2009-01-07 10:37:31 -0500
commit3b02d332b6f15cc8f7b6a04757c86034669600e0 (patch)
tree1f451911fe0d7a5db461a7491b26439cae1e1aa0 /Documentation/hwmon
parent30453018655a3acd5f59e793da55a2f969ed9c32 (diff)
hwmon: (f71882fg) Add documentation
Add some documentation about the f71882fg driver, and update the Kconfig documentation to report the new supported models. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
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1Kernel driver f71882fg
2======================
3
4Supported chips:
5 * Fintek F71882FG and F71883FG
6 Prefix: 'f71882fg'
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 F8000
14 Prefix: 'f8000'
15 Addresses scanned: none, address read from Super I/O config space
16 Datasheet: Not public
17
18Author: Hans de Goede <hdegoede@redhat.com>
19
20
21Description
22-----------
23
24Fintek F718xxFG/F8000 Super I/O chips include complete hardware monitoring
25capabilities. They can monitor up to 9 voltages (3 for the F8000), 4 fans and
263 temperature sensors.
27
28These chips also have fan controlling features, using either DC or PWM, in
29three different modes (one manual, two automatic).
30
31The driver assumes that no more than one chip is present, which seems
32reasonable.
33
34
35Monitoring
36----------
37
38The Voltage, Fan and Temperature Monitoring uses the standard sysfs
39interface as documented in sysfs-interface, without any exceptions.
40
41
42Fan Control
43-----------
44
45Both PWM (pulse-width modulation) and DC fan speed control methods are
46supported. The right one to use depends on external circuitry on the
47motherboard, so the driver assumes that the BIOS set the method
48properly.
49
50There are 2 modes to specify the speed of the fan, PWM duty cycle (or DC
51voltage) mode, where 0-100% duty cycle (0-100% of 12V) is specified. And RPM
52mode where the actual RPM of the fan (as measured) is controlled and the speed
53gets specified as 0-100% of the fan#_full_speed file.
54
55Since both modes work in a 0-100% (mapped to 0-255) scale, there isn't a
56whole lot of a difference when modifying fan control settings. The only
57important difference is that in RPM mode the 0-100% controls the fan speed
58between 0-100% of fan#_full_speed. It is assumed that if the BIOS programs
59RPM mode, it will also set fan#_full_speed properly, if it does not then
60fan control will not work properly, unless you set a sane fan#_full_speed
61value yourself.
62
63Switching between these modes requires re-initializing a whole bunch of
64registers, so the mode which the BIOS has set is kept. The mode is
65printed when loading the driver.
66
67Three different fan control modes are supported; the mode number is written
68to the pwm#_enable file. Note that not all modes are supported on all
69chips, and some modes may only be available in RPM / PWM mode on the F8000.
70Writing an unsupported mode will result in an invalid parameter error.
71
72* 1: Manual mode
73 You ask for a specific PWM duty cycle / DC voltage or a specific % of
74 fan#_full_speed by writing to the pwm# file. This mode is only
75 available on the F8000 if the fan channel is in RPM mode.
76
77* 2: Normal auto mode
78 You can define a number of temperature/fan speed trip points, which % the
79 fan should run at at this temp and which temp a fan should follow using the
80 standard sysfs interface. The number and type of trip points is chip
81 depended, see which files are available in sysfs.
82 Fan/PWM channel 3 of the F8000 is always in this mode!
83
84* 3: Thermostat mode (Only available on the F8000 when in duty cycle mode)
85 The fan speed is regulated to keep the temp the fan is mapped to between
86 temp#_auto_point2_temp and temp#_auto_point3_temp.
87
88Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
89fan2 and pwm3 to fan3.