On Mon, Jul 31, 2017 at 6:24 PM, Boris Brezillon
[off-list ref] wrote:

Add core infrastructure to support I3C in Linux and document it.

- I2C backward compatibility has been designed to be transparent to I2C
  drivers and the I2C subsystem. The I3C master just registers an I2C
  adapter which creates a new I2C bus. I'd say that, from a
  representation PoV it's not ideal because what should appear as a
  single I3C bus exposing I3C and I2C devices here appears as 2
  different busses connected to each other through the parenting (the
  I3C master is the parent of the I2C and I3C busses).
  On the other hand, I don't see a better solution if we want something
  that is not invasive.

Can you describe the reasons for making i3c a separate subsystem then,
rather than extending the i2c subsystem to handle both i2c devices as
before and also i3c devices and hosts?

        Arnd