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+Kernel driver f71805f
+Supported chips:
+ * Fintek F71805F/FG
+ Prefix: 'f71805f'
+ Addresses scanned: none, address read from Super I/O config space
+ Datasheet: Available from the Fintek website
+ * Fintek F71806F/FG
+ Prefix: 'f71872f'
+ Addresses scanned: none, address read from Super I/O config space
+ Datasheet: Available from the Fintek website
+ * Fintek F71872F/FG
+ Prefix: 'f71872f'
+ Addresses scanned: none, address read from Super I/O config space
+ Datasheet: Available from the Fintek website
+Author: Jean Delvare <khali@linux-fr.org>
+Thanks to Denis Kieft from Barracuda Networks for the donation of a
+test system (custom Jetway K8M8MS motherboard, with CPU and RAM) and
+for providing initial documentation.
+Thanks to Kris Chen and Aaron Huang from Fintek for answering technical
+questions and providing additional documentation.
+Thanks to Chris Lin from Jetway for providing wiring schematics and
+answering technical questions.
+The Fintek F71805F/FG Super I/O chip includes complete hardware monitoring
+capabilities. It can monitor up to 9 voltages (counting its own power
+source), 3 fans and 3 temperature sensors.
+This chip also has fan controlling features, using either DC or PWM, in
+three different modes (one manual, two automatic).
+The Fintek F71872F/FG Super I/O chip is almost the same, with two
+additional internal voltages monitored (VSB and battery). It also features
+6 VID inputs. The VID inputs are not yet supported by this driver.
+The Fintek F71806F/FG Super-I/O chip is essentially the same as the
+F71872F/FG, and is undistinguishable therefrom.
+The driver assumes that no more than one chip is present, which seems
+Voltage Monitoring
+Voltages are sampled by an 8-bit ADC with a LSB of 8 mV. The supported
+range is thus from 0 to 2.040 V. Voltage values outside of this range
+need external resistors. An exception is in0, which is used to monitor
+the chip's own power source (+3.3V), and is divided internally by a
+factor 2. For the F71872F/FG, in9 (VSB) and in10 (battery) are also
+divided internally by a factor 2.
+The two LSB of the voltage limit registers are not used (always 0), so
+you can only set the limits in steps of 32 mV (before scaling).
+The wirings and resistor values suggested by Fintek are as follow:
+ pin expected
+ name use R1 R2 divider raw val.
+in0 VCC VCC3.3V int. int. 2.00 1.65 V
+in1 VIN1 VTT1.2V 10K - 1.00 1.20 V
+in2 VIN2 VRAM 100K 100K 2.00 ~1.25 V (1)
+in3 VIN3 VCHIPSET 47K 100K 1.47 2.24 V (2)
+in4 VIN4 VCC5V 200K 47K 5.25 0.95 V
+in5 VIN5 +12V 200K 20K 11.00 1.05 V
+in6 VIN6 VCC1.5V 10K - 1.00 1.50 V
+in7 VIN7 VCORE 10K - 1.00 ~1.40 V (1)
+in8 VIN8 VSB5V 200K 47K 1.00 0.95 V
+in10 VSB VSB3.3V int. int. 2.00 1.65 V (3)
+in9 VBAT VBATTERY int. int. 2.00 1.50 V (3)
+(1) Depends on your hardware setup.
+(2) Obviously not correct, swapping R1 and R2 would make more sense.
+(3) F71872F/FG only.
+These values can be used as hints at best, as motherboard manufacturers
+are free to use a completely different setup. As a matter of fact, the
+Jetway K8M8MS uses a significantly different setup. You will have to
+find out documentation about your own motherboard, and edit sensors.conf
+Each voltage measured has associated low and high limits, each of which
+triggers an alarm when crossed.
+Fan Monitoring
+Fan rotation speeds are reported as 12-bit values from a gated clock
+signal. Speeds down to 366 RPM can be measured. There is no theoretical
+high limit, but values over 6000 RPM seem to cause problem. The effective
+resolution is much lower than you would expect, the step between different
+register values being 10 rather than 1.
+The chip assumes 2 pulse-per-revolution fans.
+An alarm is triggered if the rotation speed drops below a programmable
+limit or is too low to be measured.
+Temperature Monitoring
+Temperatures are reported in degrees Celsius. Each temperature measured
+has a high limit, those crossing triggers an alarm. There is an associated
+hysteresis value, below which the temperature has to drop before the
+alarm is cleared.
+All temperature channels are external, there is no embedded temperature
+sensor. Each channel can be used for connecting either a thermal diode
+or a thermistor. The driver reports the currently selected mode, but
+doesn't allow changing it. In theory, the BIOS should have configured
+everything properly.
+Fan Control
+Both PWM (pulse-width modulation) and DC fan speed control methods are
+supported. The right one to use depends on external circuitry on the
+motherboard, so the driver assumes that the BIOS set the method
+properly. The driver will report the method, but won't let you change
+When the PWM method is used, you can select the operating frequency,
+from 187.5 kHz (default) to 31 Hz. The best frequency depends on the
+fan model. As a rule of thumb, lower frequencies seem to give better
+control, but may generate annoying high-pitch noise. So a frequency just
+above the audible range, such as 25 kHz, may be a good choice; if this
+doesn't give you good linear control, try reducing it. Fintek recommends
+not going below 1 kHz, as the fan tachometers get confused by lower
+frequencies as well.
+When the DC method is used, Fintek recommends not going below 5 V, which
+corresponds to a pwm value of 106 for the driver. The driver doesn't
+enforce this limit though.
+Three different fan control modes are supported; the mode number is written
+to the pwm<n>_enable file.
+* 1: Manual mode
+ You ask for a specific PWM duty cycle or DC voltage by writing to the
+ pwm<n> file.
+* 2: Temperature mode
+ You define 3 temperature/fan speed trip points using the
+ pwm<n>_auto_point<m>_temp and _fan files. These define a staircase
+ relationship between temperature and fan speed with two additional points
+ interpolated between the values that you define. When the temperature
+ is below auto_point1_temp the fan is switched off.
+* 3: Fan speed mode
+ You ask for a specific fan speed by writing to the fan<n>_target file.
+Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
+fan2 and pwm3 to fan3. Temperature mode also requires that temp1 corresponds
+to pwm1 and fan1, etc.