[i2c] USB to I2C interface

[Mark M. Hoffman]

Hi Till:

* Till Harbaum (Lists) <lists at harbaum.org> [2006-10-25 19:02:39 +0200]:
> i am currently building a very simple USB to I2C interface since i just 
> don't like those parallel interfaces anymore. They are slow, buggy, generate
> too much host cpu load and don't even supply power to your target ...
> 
> Thus i decided to build something similar to my lcd2usb 
> (http://www.harbaum.org/till/lcd2usb) which should result in a device
> smaller and easer to to build than most of the printer port interfaces
> and at a cost of about $5 if you build it on a bread board.

This would be quite welcome.

> Now the question: Do i have to use some "algorithm" driver? I basically
> want to forward every request to a tiny microcontroller so i don't need any
> special algorithm. Do i have to implement some i2c-algo-simple or 
> i2c-algo-direct or however i'll name it or can i make my i2c-usb driver
> to directly interface between the usb core and the usb interface.

The algorithm portion of most I2C bus drivers is trivial.  Have a look at
drivers/i2c/i2c-sis96x, or any of the other "south bridge" bus drivers for
an example.

> Another question will be of course if the resulting driver should be usb-i2c 
> and part of the usb stack or i2c-usb and be part of the i2c stack. I'd prefer
> the latter as most i2c users will understand what a usb interface is but 
> not all usb users will understand the idea of an i2c interface.

IMHO it belongs in drivers/i2c.  The name is pretty generic though.  I would
prefer if you give your hardware a name (e.g. harbaum-usb) and then name the
driver appropriately (i2c-harbaum-usb).

Regards,

-- 
Mark M. Hoffman
mhoffman at lightlink.com