[linux-2.6-block.git] / Documentation / hwmon / nct6775

Note
====

This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF
driver.

Kernel driver NCT6775
=====================

Supported chips:
  * Nuvoton NCT6102D/NCT6104D/NCT6106D
    Prefix: 'nct6106'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from the Nuvoton web site
  * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I
    Prefix: 'nct6775'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT5573D/NCT5577D/NCT6776D/NCT6776F
    Prefix: 'nct6776'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT5532D/NCT6779D
    Prefix: 'nct6779'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT6791D
    Prefix: 'nct6791'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT6792D
    Prefix: 'nct6792'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT6793D
    Prefix: 'nct6793'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT6795D
    Prefix: 'nct6795'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request
  * Nuvoton NCT6796D
    Prefix: 'nct6796'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: Available from Nuvoton upon request

Authors:
        Guenter Roeck <linux@roeck-us.net>

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

This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D
and compatible super I/O chips.

The chips support up to 25 temperature monitoring sources. Up to 6 of those are
direct temperature sensor inputs, the others are special sources such as PECI,
PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources
can be monitored and compared against minimum, maximum, and critical
temperatures. The driver reports up to 10 of the temperatures to the user.
There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
one VID, alarms with beep warnings (control unimplemented), and some automatic
fan regulation strategies (plus manual fan control mode).

The temperature sensor sources on all chips are configurable. The configured
source for each of the temperature sensors is provided in tempX_label.

Temperatures are measured in degrees Celsius and measurement resolution is
either 1 degC or 0.5 degC, depending on the temperature source and
configuration. An alarm is triggered when the temperature gets higher than
the high limit; it stays on until the temperature falls below the hysteresis
value. Alarms are only supported for temp1 to temp6, depending on the chip type.

Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
triggered if the rotation speed has dropped below a programmable limit. On
NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8,
16, 32, 64 or 128) to give the readings more range or accuracy; the other chips
do not have a fan speed divider. The driver sets the most suitable fan divisor
itself; specifically, it increases the divider value each time a fan speed
reading returns an invalid value, and it reduces it if the fan speed reading
is lower than optimal. Some fans might not be present because they share pins
with other functions.

Voltage sensors (also known as IN sensors) report their values in millivolts.
An alarm is triggered if the voltage has crossed a programmable minimum
or maximum limit.

The driver supports automatic fan control mode known as Thermal Cruise.
In this mode, the chip attempts to keep the measured temperature in a
predefined temperature range. If the temperature goes out of range, fan
is driven slower/faster to reach the predefined range again.

The mode works for fan1-fan5.

sysfs attributes
----------------

pwm[1-7] - this file stores PWM duty cycle or DC value (fan speed) in range:
	   0 (lowest speed) to 255 (full)

pwm[1-7]_enable - this file controls mode of fan/temperature control:
	* 0 Fan control disabled (fans set to maximum speed)
	* 1 Manual mode, write to pwm[0-5] any value 0-255
	* 2 "Thermal Cruise" mode
	* 3 "Fan Speed Cruise" mode
	* 4 "Smart Fan III" mode (NCT6775F only)
	* 5 "Smart Fan IV" mode

pwm[1-7]_mode - controls if output is PWM or DC level
        * 0 DC output
        * 1 PWM output

Common fan control attributes
-----------------------------

pwm[1-7]_temp_sel	Temperature source. Value is temperature sensor index.
			For example, select '1' for temp1_input.
pwm[1-7]_weight_temp_sel
			Secondary temperature source. Value is temperature
			sensor index. For example, select '1' for temp1_input.
			Set to 0 to disable secondary temperature control.

If secondary temperature functionality is enabled, it is controlled with the
following attributes.

pwm[1-7]_weight_duty_step
			Duty step size.
pwm[1-7]_weight_temp_step
			Temperature step size. With each step over
			temp_step_base, the value of weight_duty_step is added
			to the current pwm value.
pwm[1-7]_weight_temp_step_base
			Temperature at which secondary temperature control kicks
			in.
pwm[1-7]_weight_temp_step_tol
			Temperature step tolerance.

Thermal Cruise mode (2)
-----------------------

If the temperature is in the range defined by:

pwm[1-7]_target_temp	Target temperature, unit millidegree Celsius
			(range 0 - 127000)
pwm[1-7]_temp_tolerance
			Target temperature tolerance, unit millidegree Celsius

there are no changes to fan speed. Once the temperature leaves the interval, fan
speed increases (if temperature is higher that desired) or decreases (if
temperature is lower than desired), using the following limits and time
intervals.

pwm[1-7]_start		fan pwm start value (range 1 - 255), to start fan
			when the temperature is above defined range.
pwm[1-7]_floor		lowest fan pwm (range 0 - 255) if temperature is below
			the defined range. If set to 0, the fan is expected to
			stop if the temperature is below the defined range.
pwm[1-7]_step_up_time	milliseconds before fan speed is increased
pwm[1-7]_step_down_time	milliseconds before fan speed is decreased
pwm[1-7]_stop_time	how many milliseconds must elapse to switch
			corresponding fan off (when the temperature was below
			defined range).

Speed Cruise mode (3)
---------------------

This modes tries to keep the fan speed constant.

fan[1-7]_target		Target fan speed
fan[1-7]_tolerance
			Target speed tolerance


Untested; use at your own risk.

Smart Fan IV mode (5)
---------------------

This mode offers multiple slopes to control the fan speed. The slopes can be
controlled by setting the pwm and temperature attributes. When the temperature
rises, the chip will calculate the DC/PWM output based on the current slope.
There are up to seven data points depending on the chip type. Subsequent data
points should be set to higher temperatures and higher pwm values to achieve
higher fan speeds with increasing temperature. The last data point reflects
critical temperature mode, in which the fans should run at full speed.

pwm[1-7]_auto_point[1-7]_pwm
			pwm value to be set if temperature reaches matching
			temperature range.
pwm[1-7]_auto_point[1-7]_temp
			Temperature over which the matching pwm is enabled.
pwm[1-7]_temp_tolerance
			Temperature tolerance, unit millidegree Celsius
pwm[1-7]_crit_temp_tolerance
			Temperature tolerance for critical temperature,
			unit millidegree Celsius

pwm[1-7]_step_up_time	milliseconds before fan speed is increased
pwm[1-7]_step_down_time	milliseconds before fan speed is decreased

Usage Notes
-----------

On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
connected to anything and floats, or that it is connected to some non-standard
temperature measurement device. As a result, the temperature reported on CPUTIN
will not reflect a usable value. It often reports unreasonably high
temperatures, and in some cases the reported temperature declines if the actual
temperature increases (similar to the raw PECI temperature value - see PECI
specification for details). CPUTIN should therefore be be ignored on ASUS
boards. The CPU temperature on ASUS boards is reported from PECI 0.
Commit	Line	Data
9de2e2e8 GR	1	Note
	2	====
	3
	4	This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF
	5	driver.
	6
	7	Kernel driver NCT6775
	8	=====================
	9
	10	Supported chips:
b6e6dd8e GR	11	* Nuvoton NCT6102D/NCT6104D/NCT6106D
	12	Prefix: 'nct6106'
	13	Addresses scanned: ISA address retrieved from Super I/O registers
	14	Datasheet: Available from the Nuvoton web site
2c7fd30d	15	* Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I
9de2e2e8 GR	16	Prefix: 'nct6775'
	17	Addresses scanned: ISA address retrieved from Super I/O registers
	18	Datasheet: Available from Nuvoton upon request
b6e6dd8e	19	* Nuvoton NCT5573D/NCT5577D/NCT6776D/NCT6776F
9de2e2e8 GR	20	Prefix: 'nct6776'
	21	Addresses scanned: ISA address retrieved from Super I/O registers
	22	Datasheet: Available from Nuvoton upon request
2c7fd30d	23	* Nuvoton NCT5532D/NCT6779D
9de2e2e8 GR	24	Prefix: 'nct6779'
	25	Addresses scanned: ISA address retrieved from Super I/O registers
	26	Datasheet: Available from Nuvoton upon request
b6e6dd8e GR	27	* Nuvoton NCT6791D
	28	Prefix: 'nct6791'
	29	Addresses scanned: ISA address retrieved from Super I/O registers
	30	Datasheet: Available from Nuvoton upon request
8aefb93f GR	31	* Nuvoton NCT6792D
	32	Prefix: 'nct6792'
	33	Addresses scanned: ISA address retrieved from Super I/O registers
	34	Datasheet: Available from Nuvoton upon request
cd1faefa GR	35	* Nuvoton NCT6793D
	36	Prefix: 'nct6793'
	37	Addresses scanned: ISA address retrieved from Super I/O registers
	38	Datasheet: Available from Nuvoton upon request
81820059 GR	39	* Nuvoton NCT6795D
	40	Prefix: 'nct6795'
	41	Addresses scanned: ISA address retrieved from Super I/O registers
	42	Datasheet: Available from Nuvoton upon request
	43	* Nuvoton NCT6796D
	44	Prefix: 'nct6796'
	45	Addresses scanned: ISA address retrieved from Super I/O registers
	46	Datasheet: Available from Nuvoton upon request
9de2e2e8 GR	47
	48	Authors:
	49	Guenter Roeck <linux@roeck-us.net>
	50
	51	Description
	52	-----------
	53
	54	This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D
2c7fd30d	55	and compatible super I/O chips.
9de2e2e8 GR	56
	57	The chips support up to 25 temperature monitoring sources. Up to 6 of those are
	58	direct temperature sensor inputs, the others are special sources such as PECI,
	59	PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources
	60	can be monitored and compared against minimum, maximum, and critical
	61	temperatures. The driver reports up to 10 of the temperatures to the user.
	62	There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
	63	one VID, alarms with beep warnings (control unimplemented), and some automatic
	64	fan regulation strategies (plus manual fan control mode).
	65
	66	The temperature sensor sources on all chips are configurable. The configured
	67	source for each of the temperature sensors is provided in tempX_label.
	68
	69	Temperatures are measured in degrees Celsius and measurement resolution is
	70	either 1 degC or 0.5 degC, depending on the temperature source and
	71	configuration. An alarm is triggered when the temperature gets higher than
	72	the high limit; it stays on until the temperature falls below the hysteresis
	73	value. Alarms are only supported for temp1 to temp6, depending on the chip type.
	74
	75	Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
	76	triggered if the rotation speed has dropped below a programmable limit. On
	77	NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8,
	78	16, 32, 64 or 128) to give the readings more range or accuracy; the other chips
	79	do not have a fan speed divider. The driver sets the most suitable fan divisor
1c65dc36 GR	80	itself; specifically, it increases the divider value each time a fan speed
	81	reading returns an invalid value, and it reduces it if the fan speed reading
	82	is lower than optimal. Some fans might not be present because they share pins
9de2e2e8 GR	83	with other functions.
	84
	85	Voltage sensors (also known as IN sensors) report their values in millivolts.
	86	An alarm is triggered if the voltage has crossed a programmable minimum
	87	or maximum limit.
	88
	89	The driver supports automatic fan control mode known as Thermal Cruise.
	90	In this mode, the chip attempts to keep the measured temperature in a
	91	predefined temperature range. If the temperature goes out of range, fan
	92	is driven slower/faster to reach the predefined range again.
	93
	94	The mode works for fan1-fan5.
	95
77eb5b37 GR	96	sysfs attributes
	97	----------------
	98
81820059	99	pwm[1-7] - this file stores PWM duty cycle or DC value (fan speed) in range:
77eb5b37 GR	100	0 (lowest speed) to 255 (full)
77eb5b37 GR	101
81820059	102	pwm[1-7]_enable - this file controls mode of fan/temperature control:
77eb5b37 GR	103	* 0 Fan control disabled (fans set to maximum speed)
	104	* 1 Manual mode, write to pwm[0-5] any value 0-255
	105	* 2 "Thermal Cruise" mode
	106	* 3 "Fan Speed Cruise" mode
	107	* 4 "Smart Fan III" mode (NCT6775F only)
	108	* 5 "Smart Fan IV" mode
	109
81820059	110	pwm[1-7]_mode - controls if output is PWM or DC level
77eb5b37 GR	111	* 0 DC output
	112	* 1 PWM output
	113
cdcaeceb GR	114	Common fan control attributes
	115	-----------------------------
	116
81820059	117	pwm[1-7]_temp_sel Temperature source. Value is temperature sensor index.
cdcaeceb	118	For example, select '1' for temp1_input.
81820059	119	pwm[1-7]_weight_temp_sel
bbd8decd GR	120	Secondary temperature source. Value is temperature
	121	sensor index. For example, select '1' for temp1_input.
	122	Set to 0 to disable secondary temperature control.
	123
	124	If secondary temperature functionality is enabled, it is controlled with the
	125	following attributes.
	126
81820059	127	pwm[1-7]_weight_duty_step
bbd8decd	128	Duty step size.
81820059	129	pwm[1-7]_weight_temp_step
bbd8decd GR	130	Temperature step size. With each step over
	131	temp_step_base, the value of weight_duty_step is added
	132	to the current pwm value.
81820059	133	pwm[1-7]_weight_temp_step_base
bbd8decd GR	134	Temperature at which secondary temperature control kicks
bbd8decd GR	135	in.
81820059	136	pwm[1-7]_weight_temp_step_tol
bbd8decd	137	Temperature step tolerance.
cdcaeceb GR	138
	139	Thermal Cruise mode (2)
	140	-----------------------
	141
	142	If the temperature is in the range defined by:
	143
81820059	144	pwm[1-7]_target_temp Target temperature, unit millidegree Celsius
cdcaeceb	145	(range 0 - 127000)
81820059	146	pwm[1-7]_temp_tolerance
cdcaeceb GR	147	Target temperature tolerance, unit millidegree Celsius
	148
	149	there are no changes to fan speed. Once the temperature leaves the interval, fan
	150	speed increases (if temperature is higher that desired) or decreases (if
	151	temperature is lower than desired), using the following limits and time
	152	intervals.
	153
81820059	154	pwm[1-7]_start fan pwm start value (range 1 - 255), to start fan
cdcaeceb	155	when the temperature is above defined range.
81820059	156	pwm[1-7]_floor lowest fan pwm (range 0 - 255) if temperature is below
cdcaeceb GR	157	the defined range. If set to 0, the fan is expected to
cdcaeceb GR	158	stop if the temperature is below the defined range.
81820059 GR	159	pwm[1-7]_step_up_time milliseconds before fan speed is increased
	160	pwm[1-7]_step_down_time milliseconds before fan speed is decreased
	161	pwm[1-7]_stop_time how many milliseconds must elapse to switch
cdcaeceb GR	162	corresponding fan off (when the temperature was below
	163	defined range).
	164
	165	Speed Cruise mode (3)
	166	---------------------
	167
	168	This modes tries to keep the fan speed constant.
	169
81820059 GR	170	fan[1-7]_target Target fan speed
81820059 GR	171	fan[1-7]_tolerance
cdcaeceb GR	172	Target speed tolerance
	173
	174
	175	Untested; use at your own risk.
	176
	177	Smart Fan IV mode (5)
	178	---------------------
	179
	180	This mode offers multiple slopes to control the fan speed. The slopes can be
	181	controlled by setting the pwm and temperature attributes. When the temperature
	182	rises, the chip will calculate the DC/PWM output based on the current slope.
	183	There are up to seven data points depending on the chip type. Subsequent data
	184	points should be set to higher temperatures and higher pwm values to achieve
	185	higher fan speeds with increasing temperature. The last data point reflects
	186	critical temperature mode, in which the fans should run at full speed.
	187
81820059	188	pwm[1-7]_auto_point[1-7]_pwm
cdcaeceb GR	189	pwm value to be set if temperature reaches matching
cdcaeceb GR	190	temperature range.
81820059	191	pwm[1-7]_auto_point[1-7]_temp
cdcaeceb	192	Temperature over which the matching pwm is enabled.
81820059	193	pwm[1-7]_temp_tolerance
cdcaeceb	194	Temperature tolerance, unit millidegree Celsius
81820059	195	pwm[1-7]_crit_temp_tolerance
cdcaeceb GR	196	Temperature tolerance for critical temperature,
	197	unit millidegree Celsius
	198
81820059 GR	199	pwm[1-7]_step_up_time milliseconds before fan speed is increased
81820059 GR	200	pwm[1-7]_step_down_time milliseconds before fan speed is decreased
cdcaeceb	201
9de2e2e8 GR	202	Usage Notes
	203	-----------
	204
	205	On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
	206	connected to anything and floats, or that it is connected to some non-standard
	207	temperature measurement device. As a result, the temperature reported on CPUTIN
	208	will not reflect a usable value. It often reports unreasonably high
	209	temperatures, and in some cases the reported temperature declines if the actual
	210	temperature increases (similar to the raw PECI temperature value - see PECI
	211	specification for details). CPUTIN should therefore be be ignored on ASUS
	212	boards. The CPU temperature on ASUS boards is reported from PECI 0.