Dez/2006 

Here are the modified driver for the i2c-bus with the ADM5120.
Now all GPIOs (also the Switch-LEDs) are possible as i2c-bus lines.
The driver can also load multiple times with different lines.
So you can have multiple i2c-buses.
The driver has no more the bug with the level of the GPIO0..8 .
All lines works as "open collector" output now.  
For HIGH-level the line is set to input. You need a pullup-resitor 
for the HIGH-level. You should use a resitor around 2..10kohm to 
the 3.3V Vcc. So you can use 3.3V and 5V I2C-devices in mix without 
risk for the ADM5120. For longer wires you should use a bus driver 
like PCA9515.
With this input-mode for SCL the slave-clock-stretching for 
slower devices are possible.
The clock rate is around 62.5KHz now (old around 32KHz).

Examples : 
"insmod i2c-adm5120"  load the first driver with defaults from 
                      kernelconfig( gpio1 and gpio3)

"insmod i2c-adm5120 scl=8 sda=9" load the fist driver with given lines
                                 (leds 0 and 1 from Switch-port 0)

"insmod -o i2c-adm5120_1 i2c-adm5120 scl=11 sda=12" load second driver with given lines
                                                    (leds 0 and 1 from Switch-port 1)

The second i2c-bus makes a second device under /dev/i2c .
So you have to use for example the device "/dev/i2c/1" for the second bus.

Note : The demo applications LM75 and PCF8574 use "/dev/i2c/0". 
You have to edit the source. The lm_sensors tools can deal with all
buses.

--------------------------------------------------------------------------
Okt/2006

Driver and Tools for I2C-bus over GPIO1 and 3.
See http://www.sunspot.co.uk/Projects/SWEEX/files/data_file/general_IO.html
and http://midge.vlad.org.ua/forum/viewtopic.php?p=2108#2108

The tools are from the lm_sensors-2.7.0-package.
They are compiled with "staging_dir_mipsel/bin/mipsel-linux-gcc" and
then processed with "staging_dir_mipsel/bin/sstrip".