Kernel driver `i2c-sis645.o'

Status: Beta

Supported adapters:
  * Silicon Integrated Systems Corp (SiS)
    Any combination of these host bridges:
	645, 645DX (aka 646), 648, 650, 651, 655, 735, 745, 746
    and these south bridges:
    	961, 962, 963(L)

Author: Mark M. Hoffman <mhoffman@lightlink.com>

License: GPL


Module Parameters
-----------------

(none)


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

This SMBus only driver is known to work on motherboards with the above named
chipset combinations.  The driver was developed without benefit of a proper
datasheet from SiS.  The SMBus registers are assumed compatible with those of
the SiS630, although they are located in a completely different place.  Thanks
to Alexander Malysh <amalysh@web.de> for providing the SiS630 datasheet (and 
driver).

The command "lspci" as root should produce something like these lines:

00:00.0 Host bridge: Silicon Integrated Systems [SiS]: Unknown device 0645
00:02.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513
00:02.1 SMBus: Silicon Integrated Systems [SiS]: Unknown device 0016

or perhaps this...

00:00.0 Host bridge: Silicon Integrated Systems [SiS]: Unknown device 0645 (rev 02)
00:02.0 ISA bridge: Silicon Integrated Systems [SiS]: Unknown device 0961
00:02.1 SMBus: Silicon Integrated Systems [SiS]: Unknown device 0016

(kernel versions later than 2.4.18 may fill in the "Unknown"s)

If the SMBus line is missing, then the BIOS on the board has disabled the
device.  This driver is capable of enabling it, as long as the kernel has
CONFIG_HOTPLUG enabled.  In that case, the SMBus device will appear in "lspci"
after the driver is loaded.  Note that you need to rebuild lm_sensors AFTER
running "make config" or equivalent on your kernel, otherwise the i2c-sis645
driver will not build in this support.

I suspect that this driver could be made to work for the following SiS chipsets
as well: 635, and 635T.
If anyone owns a board with those chips AND is willing to risk crashing &
burning an otherwise well-behaved kernel in the name of progress... please
contact me at <mhoffman@lightlink.com> or via the project's mailing list:
<sensors@stimpy.netroedge.com>.  Please send bug reports and/or success
stories as well.


TO DOs
-----------
* The driver does not support SMBus block reads/writes; I may add them if a
scenario is found where they're needed.


Thank Yous
-----------
Mark D. Studebaker <mdsxyz123@yahoo.com>
 - design hints and bug fixes
Alexander Maylsh <amalysh@web.de>
 - ditto, plus an important datasheet... almost the one I really wanted
Hans-Günter Lütke Uphues <hg_lu@t-online.de>
 - patch for SiS735
Robert Zwerus <arzie@dds.nl>
 - testing for SiS645DX
Kianusch Sayah Karadji <kianusch@sk-tech.net>
 - patch for SiS645DX/962
Ken Healy
 - patch for Sis655

To anyone else who has written w/ feedback, thanks!

