src/kernel/linux/v4.19/Documentation/hwmon/f71805f - T800 - Gitiles

 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 <jdelvare@suse.de>

 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.


 Description
 -----------

 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
 reasonable.


 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
 accordingly.

 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
 it.

 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.
	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 <jdelvare@suse.de>

	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.


	Description
	-----------

	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
	reasonable.


	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
	accordingly.

	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
	it.

	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.