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List:       freebsd-hackers
Subject:    Re: AMD System Management driver and Newbus
From:       Andrew Gallatin <gallatin () cs ! duke ! edu>
Date:       2000-12-29 19:26:39
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Nicolas Souchu writes:

 > > If I beat on lm.c from
 > > http://www.planet.sci.kobe-u.ac.jp/~takawata/smbus/examples/lm.c
 > > enough and use 0x90 as cmd.slave, I can get the CPU temp of 41 C.
 > > This is the same as firmware gives me, which is encouraging.
 > > 
 > > As you can probably tell, I don't know enough about smb to fight my
 > > way out of a wet paper bag.  Is there an SMB savy person out there
 > > who can take me by the hand and help me figure out where the fan
 > > speed and voltage is lurking and how to read it?
 > 
 > Maybe not over SMBus :( Some boards are designed such a way that
 > SMBus is only used for SDRAM detection not monitoring. The lm75/78
 > can also be controlled over both ISA... But this seems not to be the
 > case for you since you found many chip on the SMBus.
 > 
 > Grab the linux lm_sensor documentation and see if these I2C addresses
 > are listed and which chips they are potentially assigned to. At this
 > point, it is not SMBus dependent, but chip/vendor dependent.
 > 
 > The only problem you can have with smbus/iicbus is now timings, but
 > with alpm, these are handled by the controller.
 > 
 > By the way, there's a port (lmmon) that accesses the lm75/78 over ISA, if
 > you have such a monitoring chip...
 > 

I know what chips they are (From the UP1000 Tech. Ref. Manual):

  The UP1000 has one main SM bus and two sub-SM busses.  Acces to the
  sub-SM bus is controlled by a multiplexer (MUX) which sits on the main 
  SM bus. 
  
  The SM bus from the Alpha Slot B Module [processor module, akin to a
  Slot A Athlon] connects the first sub-SM bus; the DIMM EEPROMs are
  connected to the second sub-SM bus.
  
  SM bus addresses for all UP1000 devices are provided in Table 4-3.
  
  Table 4-3: SM Bus Address of Each Device:
  
  	Device					Address
  ----------------------------------	-------------------
  ADM 9240 (system mgmnt unit)		0101 100X
  
  ICS9179-06 (Zero delay clock buffer)	1011 001X
  
  PCF8574AT (LED Controller)		1010 001X
  
  PCF8574AT (I2C bus MUX Controller)	1010 010X
  
  PCF8582 (MB revision EEPROM)		1010 001X
  
  Revision EEPROM on Alpha Slot B	1010 000X
  Module
  LM79 (Thermal Detector on Alpha	0101 111X
  Slot B Module)
  Dimm0					1010 000X
  
  Dimm1					1010 001X
  
  Dimm2					1010 010X


This knowledge doesn't seem to help me much..  Is the I2C bus MUX
controller common?  Could that be why the "detect" program shows
device addresses which are different than those given in the table?

What software would you suggest for dealing with the mux and accessing
the lm79?

BTW, do I need the iic stuff?  All I've got for smb in my config file
is:

device          smbus           # Bus support, required for smb below.
device          alpm    1
device          smb


Thanks again,

Drew


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