hwmon: (lm85) Document the ADT7468 as supported

    Prefix: 'adt7463'

    Addresses scanned: I2C 0x2c, 0x2d, 0x2e

    Datasheet: http://www.onsemi.com/PowerSolutions/product.do?id=ADT7463

  * Analog Devices ADT7468

    Prefix: 'adt7468'

    Addresses scanned: I2C 0x2c, 0x2d, 0x2e

    Datasheet: http://www.onsemi.com/PowerSolutions/product.do?id=ADT7468

  * SMSC EMC6D100, SMSC EMC6D101

    Prefix: 'emc6d100'

    Addresses scanned: I2C 0x2c, 0x2d, 0x2e

-----------

This driver implements support for the National Semiconductor LM85 and

compatible chips including the Analog Devices ADM1027, ADT7463 and

compatible chips including the Analog Devices ADM1027, ADT7463, ADT7468 and

SMSC EMC6D10x chips family.

The LM85 uses the 2-wire interface compatible with the SMBUS 2.0

optional filter for smoothing temperatures. The ADM1027 has the same

config option but uses it to rate limit the changes to fan speed instead.

The ADM1027 and ADT7463 have a 10-bit ADC and can therefore measure

temperatures with 0.25 degC resolution. They also provide an offset to the

temperature readings that is automatically applied during measurement.

This offset can be used to zero out any errors due to traces and placement.

The documentation says that the offset is in 0.25 degC steps, but in

initial testing of the ADM1027 it was 1.00 degC steps. Analog Devices has

confirmed this "bug". The ADT7463 is reported to work as described in the

documentation. The current lm85 driver does not show the offset register.

The ADM1027, ADT7463 and ADT7468 have a 10-bit ADC and can therefore

measure temperatures with 0.25 degC resolution. They also provide an offset

to the temperature readings that is automatically applied during

measurement. This offset can be used to zero out any errors due to traces

and placement. The documentation says that the offset is in 0.25 degC

steps, but in initial testing of the ADM1027 it was 1.00 degC steps. Analog

Devices has confirmed this "bug". The ADT7463 is reported to work as

described in the documentation. The current lm85 driver does not show the

offset register.

See the vendor datasheets for more information. There is application note

from National (AN-1260) with some additional information about the LM85.

identifying the chip, the driver behaves no differently with regard to

these two chips. The LM85B is recommended for new designs.

The ADM1027 and ADT7463 chips have an optional SMBALERT output that can be

used to signal the chipset in case a limit is exceeded or the temperature

sensors fail. Individual sensor interrupts can be masked so they won't

trigger SMBALERT. The SMBALERT output if configured replaces one of the other

functions (PWM2 or IN0). This functionality is not implemented in current

driver.

The ADM1027, ADT7463 and ADT7468 chips have an optional SMBALERT output

that can be used to signal the chipset in case a limit is exceeded or the

temperature sensors fail. Individual sensor interrupts can be masked so

they won't trigger SMBALERT. The SMBALERT output if configured replaces one

of the other functions (PWM2 or IN0). This functionality is not implemented

in current driver.

The ADT7463 also has an optional THERM output/input which can be connected

to the processor PROC_HOT output. If available, the autofan control

dynamic Tmin feature can be enabled to keep the system temperature within

spec (just?!) with the least possible fan noise.

The ADT7463 and ADT7468 also have an optional THERM output/input which can

be connected to the processor PROC_HOT output. If available, the autofan

control dynamic Tmin feature can be enabled to keep the system temperature

within spec (just?!) with the least possible fan noise.

Configuration Notes

-------------------

measurements. These features are not currently supported by the lm85

driver.

In addition to the ADM1027 features, the ADT7463 also has Tmin control

and THERM asserted counts. Automatic Tmin control acts to adjust the

Tmin value to maintain the measured temperature sensor at a specified

temperature. There isn't much documentation on this feature in the

ADT7463 data sheet. This is not supported by current driver.

In addition to the ADM1027 features, the ADT7463 and ADT7468 also have

Tmin control and THERM asserted counts. Automatic Tmin control acts to

adjust the Tmin value to maintain the measured temperature sensor at a

specified temperature. There isn't much documentation on this feature in

the ADT7463 data sheet. This is not supported by current driver.

	select HWMON_VID

	help

	  If you say yes here you get support for National Semiconductor LM85

	  sensor chips and clones: ADT7463, EMC6D100, EMC6D102 and ADM1027.

	  sensor chips and clones: ADM1027, ADT7463, ADT7468, EMC6D100,

	  EMC6D101 and EMC6D102.

	  This driver can also be built as a module.  If so, the module

	  will be called lm85.