Documentation/hwmon/vt1211 - kernel/msm-4.9 - Gitiles

 Kernel driver vt1211
 ====================

 Supported chips:
   * VIA VT1211
     Prefix: 'vt1211'
     Addresses scanned: none, address read from Super-I/O config space
     Datasheet: Provided by VIA upon request and under NDA

 Authors: Juerg Haefliger <juergh@gmail.com>

 This driver is based on the driver for kernel 2.4 by Mark D. Studebaker and
 its port to kernel 2.6 by Lars Ekman.

 Thanks to Joseph Chan and Fiona Gatt from VIA for providing documentation and
 technical support.


 Module Parameters
 -----------------

 * uch_config: int	Override the BIOS default universal channel (UCH)
 			configuration for channels 1-5.
 			Legal values are in the range of 0-31. Bit 0 maps to
 			UCH1, bit 1 maps to UCH2 and so on. Setting a bit to 1
 			enables the thermal input of that particular UCH and
 			setting a bit to 0 enables the voltage input.

 * int_mode: int		Override the BIOS default temperature interrupt mode.
 			The only possible value is 0 which forces interrupt
 			mode 0. In this mode, any pending interrupt is cleared
 			when the status register is read but is regenerated as
 			long as the temperature stays above the hysteresis
 			limit.

 Be aware that overriding BIOS defaults might cause some unwanted side effects!


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

 The VIA VT1211 Super-I/O chip includes complete hardware monitoring
 capabilities. It monitors 2 dedicated temperature sensor inputs (temp1 and
 temp2), 1 dedicated voltage (in5) and 2 fans. Additionally, the chip
 implements 5 universal input channels (UCH1-5) that can be individually
 programmed to either monitor a voltage or a temperature.

 This chip also provides manual and automatic control of fan speeds (according
 to the datasheet). The driver only supports automatic control since the manual
 mode doesn't seem to work as advertised in the datasheet. In fact I couldn't
 get manual mode to work at all! Be aware that automatic mode hasn't been
 tested very well (due to the fact that my EPIA M10000 doesn't have the fans
 connected to the PWM outputs of the VT1211 :-().

 The following table shows the relationship between the vt1211 inputs and the
 sysfs nodes.

 Sensor          Voltage Mode   Temp Mode   Default Use (from the datasheet)
 ------          ------------   ---------   --------------------------------
 Reading 1                      temp1       Intel thermal diode
 Reading 3                      temp2       Internal thermal diode
 UCH1/Reading2   in0            temp3       NTC type thermistor
 UCH2            in1            temp4       +2.5V
 UCH3            in2            temp5       VccP (processor core)
 UCH4            in3            temp6       +5V
 UCH5            in4            temp7       +12V
 +3.3V           in5                        Internal VCC (+3.3V)


 Voltage Monitoring
 ------------------

 Voltages are sampled by an 8-bit ADC with a LSB of ~10mV. The supported input
 range is thus from 0 to 2.60V. Voltage values outside of this range need
 external scaling resistors. This external scaling needs to be compensated for
 via compute lines in sensors.conf, like:

 compute inx @*(1+R1/R2), @/(1+R1/R2)

 The board level scaling resistors according to VIA's recommendation are as
 follows. And this is of course totally dependent on the actual board
 implementation :-) You will have to find documentation for your own
 motherboard and edit sensors.conf accordingly.

                                       Expected
 Voltage       R1     R2     Divider   Raw Value
 -----------------------------------------------
 +2.5V         2K     10K    1.2       2083 mV
 VccP          ---    ---    1.0       1400 mV (1)
 +5V           14K    10K    2.4       2083 mV
 +12V          47K    10K    5.7       2105 mV
 +3.3V (int)   2K     3.4K   1.588     3300 mV (2)
 +3.3V (ext)   6.8K   10K    1.68      1964 mV

 (1) Depending on the CPU (1.4V is for a VIA C3 Nehemiah).
 (2) R1 and R2 for 3.3V (int) are internal to the VT1211 chip and the driver
     performs the scaling and returns the properly scaled voltage value.

 Each measured voltage has an associated low and high limit which triggers an
 alarm when crossed.


 Temperature Monitoring
 ----------------------

 Temperatures are reported in millidegree Celsius. Each measured temperature
 has a high limit which triggers an alarm if crossed. There is an associated
 hysteresis value with each temperature below which the temperature has to drop
 before the alarm is cleared (this is only true for interrupt mode 0). The
 interrupt mode can be forced to 0 in case the BIOS doesn't do it
 automatically. See the 'Module Parameters' section for details.

 All temperature channels except temp2 are external. Temp2 is the VT1211
 internal thermal diode and the driver does all the scaling for temp2 and
 returns the temperature in millidegree Celsius. For the external channels
 temp1 and temp3-temp7, scaling depends on the board implementation and needs
 to be performed in userspace via sensors.conf.

 Temp1 is an Intel-type thermal diode which requires the following formula to
 convert between sysfs readings and real temperatures:

 compute temp1 (@-Offset)/Gain, (@*Gain)+Offset

 According to the VIA VT1211 BIOS porting guide, the following gain and offset
 values should be used:

 Diode Type      Offset   Gain
 ----------      ------   ----
 Intel CPU       88.638   0.9528
                 65.000   0.9686   *)
 VIA C3 Ezra     83.869   0.9528
 VIA C3 Ezra-T   73.869   0.9528

 *) This is the formula from the lm_sensors 2.10.0 sensors.conf file. I don't
 know where it comes from or how it was derived, it's just listed here for
 completeness.

 Temp3-temp7 support NTC thermistors. For these channels, the driver returns
 the voltages as seen at the individual pins of UCH1-UCH5. The voltage at the
 pin (Vpin) is formed by a voltage divider made of the thermistor (Rth) and a
 scaling resistor (Rs):

 Vpin = 2200 * Rth / (Rs + Rth)   (2200 is the ADC max limit of 2200 mV)

 The equation for the thermistor is as follows (google it if you want to know
 more about it):

 Rth = Ro * exp(B * (1 / T - 1 / To))   (To is 298.15K (25C) and Ro is the
                                         nominal resistance at 25C)

 Mingling the above two equations and assuming Rs = Ro and B = 3435 yields the
 following formula for sensors.conf:

 compute tempx 1 / (1 / 298.15 - (` (2200 / @ - 1)) / 3435) - 273.15,
               2200 / (1 + (^ (3435 / 298.15 - 3435 / (273.15 + @))))


 Fan Speed Control
 -----------------

 The VT1211 provides 2 programmable PWM outputs to control the speeds of 2
 fans. Writing a 2 to any of the two pwm[1-2]_enable sysfs nodes will put the
 PWM controller in automatic mode. There is only a single controller that
 controls both PWM outputs but each PWM output can be individually enabled and
 disabled.

 Each PWM has 4 associated distinct output duty-cycles: full, high, low and
 off. Full and off are internally hard-wired to 255 (100%) and 0 (0%),
 respectively. High and low can be programmed via
 pwm[1-2]_auto_point[2-3]_pwm. Each PWM output can be associated with a
 different thermal input but - and here's the weird part - only one set of
 thermal thresholds exist that controls both PWMs output duty-cycles. The
 thermal thresholds are accessible via pwm[1-2]_auto_point[1-4]_temp. Note
 that even though there are 2 sets of 4 auto points each, they map to the same
 registers in the VT1211 and programming one set is sufficient (actually only
 the first set pwm1_auto_point[1-4]_temp is writable, the second set is
 read-only).

 PWM Auto Point             PWM Output Duty-Cycle
 ------------------------------------------------
 pwm[1-2]_auto_point4_pwm   full speed duty-cycle (hard-wired to 255)
 pwm[1-2]_auto_point3_pwm   high speed duty-cycle
 pwm[1-2]_auto_point2_pwm   low speed duty-cycle
 pwm[1-2]_auto_point1_pwm   off duty-cycle (hard-wired to 0)

 Temp Auto Point             Thermal Threshold
 ---------------------------------------------
 pwm[1-2]_auto_point4_temp   full speed temp
 pwm[1-2]_auto_point3_temp   high speed temp
 pwm[1-2]_auto_point2_temp   low speed temp
 pwm[1-2]_auto_point1_temp   off temp

 Long story short, the controller implements the following algorithm to set the
 PWM output duty-cycle based on the input temperature:

 Thermal Threshold             Output Duty-Cycle
                     (Rising Temp)           (Falling Temp)
 ----------------------------------------------------------
                     full speed duty-cycle   full speed duty-cycle
 full speed temp
                     high speed duty-cycle   full speed duty-cycle
 high speed temp
                     low speed duty-cycle    high speed duty-cycle
 low speed temp
                     off duty-cycle          low speed duty-cycle
 off temp
	Kernel driver vt1211
	====================

	Supported chips:
	* VIA VT1211
	Prefix: 'vt1211'
	Addresses scanned: none, address read from Super-I/O config space
	Datasheet: Provided by VIA upon request and under NDA

	Authors: Juerg Haefliger <juergh@gmail.com>

	This driver is based on the driver for kernel 2.4 by Mark D. Studebaker and
	its port to kernel 2.6 by Lars Ekman.

	Thanks to Joseph Chan and Fiona Gatt from VIA for providing documentation and
	technical support.


	Module Parameters
	-----------------

	* uch_config: int Override the BIOS default universal channel (UCH)
	configuration for channels 1-5.
	Legal values are in the range of 0-31. Bit 0 maps to
	UCH1, bit 1 maps to UCH2 and so on. Setting a bit to 1
	enables the thermal input of that particular UCH and
	setting a bit to 0 enables the voltage input.

	* int_mode: int Override the BIOS default temperature interrupt mode.
	The only possible value is 0 which forces interrupt
	mode 0. In this mode, any pending interrupt is cleared
	when the status register is read but is regenerated as
	long as the temperature stays above the hysteresis
	limit.

	Be aware that overriding BIOS defaults might cause some unwanted side effects!


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

	The VIA VT1211 Super-I/O chip includes complete hardware monitoring
	capabilities. It monitors 2 dedicated temperature sensor inputs (temp1 and
	temp2), 1 dedicated voltage (in5) and 2 fans. Additionally, the chip
	implements 5 universal input channels (UCH1-5) that can be individually
	programmed to either monitor a voltage or a temperature.

	This chip also provides manual and automatic control of fan speeds (according
	to the datasheet). The driver only supports automatic control since the manual
	mode doesn't seem to work as advertised in the datasheet. In fact I couldn't
	get manual mode to work at all! Be aware that automatic mode hasn't been
	tested very well (due to the fact that my EPIA M10000 doesn't have the fans
	connected to the PWM outputs of the VT1211 :-().

	The following table shows the relationship between the vt1211 inputs and the
	sysfs nodes.

	Sensor Voltage Mode Temp Mode Default Use (from the datasheet)
	------ ------------ --------- --------------------------------
	Reading 1 temp1 Intel thermal diode
	Reading 3 temp2 Internal thermal diode
	UCH1/Reading2 in0 temp3 NTC type thermistor
	UCH2 in1 temp4 +2.5V
	UCH3 in2 temp5 VccP (processor core)
	UCH4 in3 temp6 +5V
	UCH5 in4 temp7 +12V
	+3.3V in5 Internal VCC (+3.3V)


	Voltage Monitoring
	------------------

	Voltages are sampled by an 8-bit ADC with a LSB of ~10mV. The supported input
	range is thus from 0 to 2.60V. Voltage values outside of this range need
	external scaling resistors. This external scaling needs to be compensated for
	via compute lines in sensors.conf, like:

	compute inx @*(1+R1/R2), @/(1+R1/R2)

	The board level scaling resistors according to VIA's recommendation are as
	follows. And this is of course totally dependent on the actual board
	implementation :-) You will have to find documentation for your own
	motherboard and edit sensors.conf accordingly.

	Expected
	Voltage R1 R2 Divider Raw Value
	-----------------------------------------------
	+2.5V 2K 10K 1.2 2083 mV
	VccP --- --- 1.0 1400 mV (1)
	+5V 14K 10K 2.4 2083 mV
	+12V 47K 10K 5.7 2105 mV
	+3.3V (int) 2K 3.4K 1.588 3300 mV (2)
	+3.3V (ext) 6.8K 10K 1.68 1964 mV

	(1) Depending on the CPU (1.4V is for a VIA C3 Nehemiah).
	(2) R1 and R2 for 3.3V (int) are internal to the VT1211 chip and the driver
	performs the scaling and returns the properly scaled voltage value.

	Each measured voltage has an associated low and high limit which triggers an
	alarm when crossed.


	Temperature Monitoring
	----------------------

	Temperatures are reported in millidegree Celsius. Each measured temperature
	has a high limit which triggers an alarm if crossed. There is an associated
	hysteresis value with each temperature below which the temperature has to drop
	before the alarm is cleared (this is only true for interrupt mode 0). The
	interrupt mode can be forced to 0 in case the BIOS doesn't do it
	automatically. See the 'Module Parameters' section for details.

	All temperature channels except temp2 are external. Temp2 is the VT1211
	internal thermal diode and the driver does all the scaling for temp2 and
	returns the temperature in millidegree Celsius. For the external channels
	temp1 and temp3-temp7, scaling depends on the board implementation and needs
	to be performed in userspace via sensors.conf.

	Temp1 is an Intel-type thermal diode which requires the following formula to
	convert between sysfs readings and real temperatures:

	compute temp1 (@-Offset)/Gain, (@*Gain)+Offset

	According to the VIA VT1211 BIOS porting guide, the following gain and offset
	values should be used:

	Diode Type Offset Gain
	---------- ------ ----
	Intel CPU 88.638 0.9528
	65.000 0.9686 *)
	VIA C3 Ezra 83.869 0.9528
	VIA C3 Ezra-T 73.869 0.9528

	*) This is the formula from the lm_sensors 2.10.0 sensors.conf file. I don't
	know where it comes from or how it was derived, it's just listed here for
	completeness.

	Temp3-temp7 support NTC thermistors. For these channels, the driver returns
	the voltages as seen at the individual pins of UCH1-UCH5. The voltage at the
	pin (Vpin) is formed by a voltage divider made of the thermistor (Rth) and a
	scaling resistor (Rs):

	Vpin = 2200 * Rth / (Rs + Rth) (2200 is the ADC max limit of 2200 mV)

	The equation for the thermistor is as follows (google it if you want to know
	more about it):

	Rth = Ro * exp(B * (1 / T - 1 / To)) (To is 298.15K (25C) and Ro is the
	nominal resistance at 25C)

	Mingling the above two equations and assuming Rs = Ro and B = 3435 yields the
	following formula for sensors.conf:

	compute tempx 1 / (1 / 298.15 - (` (2200 / @ - 1)) / 3435) - 273.15,
	2200 / (1 + (^ (3435 / 298.15 - 3435 / (273.15 + @))))


	Fan Speed Control
	-----------------

	The VT1211 provides 2 programmable PWM outputs to control the speeds of 2
	fans. Writing a 2 to any of the two pwm[1-2]_enable sysfs nodes will put the
	PWM controller in automatic mode. There is only a single controller that
	controls both PWM outputs but each PWM output can be individually enabled and
	disabled.

	Each PWM has 4 associated distinct output duty-cycles: full, high, low and
	off. Full and off are internally hard-wired to 255 (100%) and 0 (0%),
	respectively. High and low can be programmed via
	pwm[1-2]_auto_point[2-3]_pwm. Each PWM output can be associated with a
	different thermal input but - and here's the weird part - only one set of
	thermal thresholds exist that controls both PWMs output duty-cycles. The
	thermal thresholds are accessible via pwm[1-2]_auto_point[1-4]_temp. Note
	that even though there are 2 sets of 4 auto points each, they map to the same
	registers in the VT1211 and programming one set is sufficient (actually only
	the first set pwm1_auto_point[1-4]_temp is writable, the second set is
	read-only).

	PWM Auto Point PWM Output Duty-Cycle
	------------------------------------------------
	pwm[1-2]_auto_point4_pwm full speed duty-cycle (hard-wired to 255)
	pwm[1-2]_auto_point3_pwm high speed duty-cycle
	pwm[1-2]_auto_point2_pwm low speed duty-cycle
	pwm[1-2]_auto_point1_pwm off duty-cycle (hard-wired to 0)

	Temp Auto Point Thermal Threshold
	---------------------------------------------
	pwm[1-2]_auto_point4_temp full speed temp
	pwm[1-2]_auto_point3_temp high speed temp
	pwm[1-2]_auto_point2_temp low speed temp
	pwm[1-2]_auto_point1_temp off temp

	Long story short, the controller implements the following algorithm to set the
	PWM output duty-cycle based on the input temperature:

	Thermal Threshold Output Duty-Cycle
	(Rising Temp) (Falling Temp)
	----------------------------------------------------------
	full speed duty-cycle full speed duty-cycle
	full speed temp
	high speed duty-cycle full speed duty-cycle
	high speed temp
	low speed duty-cycle high speed duty-cycle
	low speed temp
	off duty-cycle low speed duty-cycle
	off temp