Hi Richard,

sorry for the late reply.

> > I'm curious if there have ever been any attempts to emulate i2c devices
> > under uml in order to facilitate driver development by using stub
> > drivers.
> I know none.

> If there is a use case, why not. :-)
Thanks for your encouraging words ;)

I had a look around and found the nice CONFIG_I2C_STUB driver,
which is described in detail at 
http://www.kernel.org/doc/Documentation/i2c/i2c-stub

"""This module is a very simple fake I2C/SMBus driver.  It implements five
types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, (r/w)
word data, and (r/w) I2C block data."""
which more or less exactly fits my need.

The only thing that was missing was general support for I2C which is dependent 
on CONFIG_HAS_IOMEM which unfortunately isn't available on UML,
but I simply added a || UML to the Kconfig and was now able to build the I2C 
Support, the i2c-dev module (for userspace access) and the i2c-stub driver.

If I  know load the i2c_stub module I have a emulated i2c device ;)

I adapted the stub driver to my needs and was now able to create my own 
emulated i2c device and start with driver and tools development for it ;)


I added the patch, in case you're interested.

Unfortunately some I2C drivers fail to build if CONFIG_HAS_IOMEM = n, but 
don't have that dependency in Kconfig - I simply added it to prevent them from 
inclusion.

Do you think I should try to push this mainline via the i2c subsystem?

Thanks,
Peter