DBCOOL(4)						   BSD Kernel Interfaces Manual 						 DBCOOL(4)

NAME

     dbcool, adm1027, adm1030, adm1031, adt7463, adt7466, adt7467, adt7468, adt7473, adt7475, adt7476, adt7490, emc6d103s -- dbCool(tm) family of
     environmental monitors and fan controllers

SYNOPSIS

     dbcool* at ki2c?
     dbcool* at iic? addr 0x2e

DESCRIPTION

     The dbcool driver provides support for the Analog Devices dbCool and the SMSC EMC6D103S environmental monitor chips to be used with the
     envsys(4) API.

     These chips support up to fifteen sensors.  Not all of the following sensors are supported on all chips.

	   Sensor    Units    Typical Use
	   l_temp    uK       local chip temperature
	   r1_temp   uK       CPU temperature
	   r2_temp   uK       GPU temperature
	   Vccp      uV DC    CPU Vcore
	   Vcc	     uV DC    Chip's supply voltage
	   2.5V      uV DC    2.5V supply
	   5V	     uV DC    5V supply
	   12V	     uV DC    12V supply
	   Vtt	     uV DC    PECI ref. voltage (2.25V ref, ADT7490 only)
	   Imon      uV DC    Current monitor (2.25V ref, ADT7490 only)
	   AIN1      uV DC    Analog In (2.25V ref, ADT7466 only)
	   AIN2      uV DC    Analog In (2.25V ref, ADT7466 only)
	   fan1      RPM      Chassis Fan
	   fan2      RPM      Chassis Fan
	   fan3      RPM      Chassis Fan
	   fan4      RPM      Chassis Fan
	   VID	     (none)   CPU VID code (selected chips only)

     Each temperature and voltage sensor has programmable hardware high- and low-limits; fan sensors have only a low-limit.  These limits can be
     set using the envstat(8) utility.	Due to hardware limitations, the minimum permissible value for the fan speed low-limits is 83 RPM.

     Temperature sensors also have Tmin, Trange, Thyst, and Ttherm sysctl(8) variables; these values are used by the fan speed controllers.  Their
     values are in units of degC, since this is the unit which is programmed into the device registers.

     All members of the dbCool family support Pulse-Width Modulated (PWM) fan speed control based on temperature thresholds - the fan will spin up
     when its associated thermal sensor(s) exceeds its configured Tmin value.  The fan will go faster as the temperature rises, and will slow down
     as the temperature falls.	If the temperature exceeds the sensor's Ttherm value, the THERM signal will be asserted, and if enabled the fan
     will run at full speed.  The fan will be turned off when the sensor(s) that triggered it reports a temperature which is at least Thyst
     degrees below its Tmin threshold.

     Each fan controller is programmable using the following sysctl(8) variables.

	   hw.dbcool0.fan_ctl_0.behavior
	   hw.dbcool0.fan_ctl_0.min_duty
	   hw.dbcool0.fan_ctl_0.max_duty
	   hw.dbcool0.fan_ctl_0.cur_duty

     The behavior variable controls the selection of temperature sensors associated with the fan controller.  When the associated temperature sen-
     sor reaches its Tmin value, the fan controller starts the fan at its minimum duty cycle; when the associated temperature sensor reaches its
     Ttherm value and asserts the THERM signal (or if an external THERM signal is asserted), the fan controller sets the fan speed to a 100% duty
     cycle.  Between these two settings, each temperature sensor is used to calculate a duty cycle linearly based on the slope defined by the tem-
     perature sensor's range variable.	When the associated temperature falls at least Thyst degress below its Tmin value, the fan controller will
     turn off the fan.	(On the ADM1030, the value for Thyst is fixed at 5 degC.)

     Valid values for the behavior variable are:

	   local	   (not available on ADM1030)
	   remote1
	   remote2	   (not available on ADM1030)
	   local+remote2   (not available on ADM1030)
	   all-temps
	   full-speed	   (not available on ADM1030)
	   manual
	   disabled

     When the behavior variable is set to ``manual'', the cur-duty variable becomes user-writable and can be set to any value between 0 and 100
     inclusive to control the fan's duty cycle manually.  In all other behavior modes, the cur-duty variable is read-only and updates are ignored.

     The min-duty and max-duty variables define the range over which the fan controller will manage the fan's duty cycle.  On the ADM1030, these
     values are not separately controllable.  The max-duty is fixed at 100%, and the cur-duty variable is used to specify the minimum duty cycle
     when the fan controller is running in automatic mode.

     Note that the duty-cycle value does not directly correspond to the fan's speed.  That is, a 33% duty cycle does not mean that the fan runs at
     33% of its maximum speed; in actuality, a 33% duty cycle drives the fan at a speed close to 50% of its maximum.  Fan speed correlates approx-
     imately to the square root of the duty cycle.

EXAMPLES

     The envstat(8) utility can be used to determine the sensors supported:

		       Current	CritMax  WarnMax  WarnMin  CritMin Unit
	    l_temp:	44.250					   degC
	   r1_temp:	41.250					   degC
	   r2_temp:	   N/A
	      Vccp:	 0.002					   V
	       Vcc:	 3.351					   V
	      fan1:	   N/A
	      fan2:	   N/A
	      fan3:	   N/A
	      fan4:	   N/A

     Using this information, the following commands in /etc/envsys.conf will set appropriate limits for CPU temperature and chip supply voltage,
     and powerd will be notified if the limits are exceeded:

	   dbcool0 {
		   sensor1 {
			   warning-max	= 60C;
			   critical-max = 65C;
		   }
		   sensor4 {
			   critical-min = 3.1;
			   warning-min =  3.2;
			   critical-max = 3.5;
		   }
	   }

SEE ALSO

     envsys(4), iic(4), envstat(8), powerd(8), sysctl(8)

HISTORY

     The dbcool device appeared in NetBSD 5.0.

BUGS

     Although the sensor limit registers can be programmed, there is currently no use of the dbCool chips' ability to generate an SMBus interrupt
     when the limits are exceeded.  Limit checking and event generation are done in software, and are performed only when the sensor values are
     polled and refreshed.

     The ADT7466 chip, although officially a member of the dbCool family, is programmed quite differently.  The fan controllers on this chip are
     not currently implemented.

     The PECI (Processor Environment Control Interface) temperature sensors and the associated PWM behavior modes on the ADT7490 are not currently
     supported.

BSD
								  March 12, 2011							       BSD