Subject: Re: New i2c framework
To: Nathan J. Williams <>
From: Jason Thorpe <>
List: tech-kern
Date: 07/31/2003 10:38:32
On Thursday, July 31, 2003, at 10:24  AM, Nathan J. Williams wrote:

> Jason Thorpe <> writes:
>> Direct configuration requires being able to deterministically identify
>> a device based on some unique cookie.  I2C does not have that.
>> Chris's suggestion of a hybrid approach using a platform-specific
>> table could be useful, but pure direct configuration like is possible
>> on e.g. SBus or PCI is simply not possible on I2C.
> However, the SMBus 2.0 protocol does, via a somewhat isapnp-like
> mechanism. Is this implementation readily extensible or layerable to a
> SMBus implementaion with direct configuration?

Yes.  One of the reasons the back-end provides the "bus lock" is to 
allow the back-end to potentially attach an "smbus" as well as an "iic".

However, only "iic" is currently implemented at this time, and 
communication with SMBus devices is still possible using vanilla i2c 

[Note, the SMBus devices that I've encountered while doing this work do 
not have an PnP ID mechanism that I can tell.. but these are mostly 
things like fan controllers and whatnot.]

         -- Jason R. Thorpe <>