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xianfeng |
Kernel driver thmc50
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=====================
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Supported chips:
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* Analog Devices ADM1022
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Prefix: 'adm1022'
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Addresses scanned: I2C 0x2c - 0x2e
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Datasheet: http://www.analog.com/en/prod/0,2877,ADM1022,00.html
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* Texas Instruments THMC50
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Prefix: 'thmc50'
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Addresses scanned: I2C 0x2c - 0x2e
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Datasheet: http://focus.ti.com/docs/prod/folders/print/thmc50.html
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Author: Krzysztof Helt
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This driver was derived from the 2.4 kernel thmc50.c source file.
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Credits:
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thmc50.c (2.4 kernel):
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Frodo Looijaard
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Philip Edelbrock
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Module Parameters
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-----------------
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* adm1022_temp3: short array
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List of adapter,address pairs to force chips into ADM1022 mode with
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second remote temperature. This does not work for original THMC50 chips.
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Description
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-----------
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The THMC50 implements: an internal temperature sensor, support for an
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external diode-type temperature sensor (compatible w/ the diode sensor inside
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many processors), and a controllable fan/analog_out DAC. For the temperature
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sensors, limits can be set through the appropriate Overtemperature Shutdown
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register and Hysteresis register. Each value can be set and read to half-degree
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accuracy. An alarm is issued (usually to a connected LM78) when the
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temperature gets higher then the Overtemperature Shutdown value; it stays on
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until the temperature falls below the Hysteresis value. All temperatures are in
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degrees Celsius, and are guaranteed within a range of -55 to +125 degrees.
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The THMC50 only updates its values each 1.5 seconds; reading it more often
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will do no harm, but will return 'old' values.
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The THMC50 is usually used in combination with LM78-like chips, to measure
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the temperature of the processor(s).
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The ADM1022 works the same as THMC50 but it is faster (5 Hz instead of
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1 Hz for THMC50). It can be also put in a new mode to handle additional
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remote temperature sensor. The driver use the mode set by BIOS by default.
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In case the BIOS is broken and the mode is set incorrectly, you can force
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the mode with additional remote temperature with adm1022_temp3 parameter.
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A typical symptom of wrong setting is a fan forced to full speed.
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Driver Features
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---------------
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The driver provides up to three temperatures:
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temp1 -- internal
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temp2 -- remote
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temp3 -- 2nd remote only for ADM1022
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pwm1 -- fan speed (0 = stop, 255 = full)
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pwm1_mode -- always 0 (DC mode)
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The value of 0 for pwm1 also forces FAN_OFF signal from the chip,
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so it stops fans even if the value 0 into the ANALOG_OUT register does not.
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The driver was tested on Compaq AP550 with two ADM1022 chips (one works
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in the temp3 mode), five temperature readings and two fans.
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