Re: [PATCH 1/4] i2c: introduce i2c-cbus driver

On Thu, Sep 13, 2012 at 12:53:09PM +0200, Wolfram Sang wrote:

On Mon, Sep 03, 2012 at 11:23:22PM +0300, Aaro Koskinen wrote:

quoted

Add i2c driver to enable access to devices behind CBUS on Nokia Internet
Tablets.

The patch also adds CBUS I2C configuration for N8x0 which is one of the
users of this driver.

Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Acked-by: Felipe Balbi <redacted>
Acked-by: Tony Lindgren <redacted>
Signed-off-by: Aaro Koskinen <redacted>

My main question is: what is CBUS? It doesn't look like an I2C/SMBUS
host controller, but some bit-banging protocol? As such, it shouldn't go
to i2c/busses/. And the protocol doesn't look much like I2C, neither.
There is no ACK/NACK/START/STOP, so I wonder if it should be in i2c
after all...

It's some legacy 3-wire bus protocol. Not much info is available,
there's some references to CBUS in i2c spec, so I thought it wouldn't
be a completly wrong place for it...

A.