Subject: Re: "cell-index" vs. "index" vs. no index in I2C device nodes

From: Timur Tabi <[email-masked]>
Date: Thu, 05 Jun 2008 10:17:01 -0500

Stefan Roese wrote:

> So what should we do now? Currently I2C doesn't work at all on 4xx since the 
> driver expects the "index" property and no dts sets this property. Personally 
> I would like to move to using cell-index here, since this seems to be more 
> common. But I could also life with removing the index property and using 
> the "static index" if this is preferred and/or acceptable.

My opinion:

In situations where it doesn't matter which I2C bus is #1 and which one is #2,
then I think the code should just initialize idx based on the order the nodes
are found in the tree.

In situations where it does matter, then we should use cell-index.

The patch I posted ("Update fsl_soc to use cell-index property of I2C nodes")
does both.  If the cell-index property is present, then its value is used in the
call to platform_device_register_simple().  Otherwise, it just keeps count of
each node, and uses that count.

-- 
Timur Tabi
Linux kernel developer at Freescale