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Date: Thu, 05 Jun 2008 10:50:20 -0500
From: Timur Tabi <timur@freescale.com>
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To: Jochen Friedrich <jochen@scram.de>
Subject: Re: "cell-index" vs. "index" vs. no index in I2C device nodes
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Cc: Stefan Roese <sr@denx.de>, linuxppc-dev@ozlabs.org,
	Sean MacLennan <smaclennan@pikatech.com>,
	Scott Wood <scottwood@freescale.com>, Jean Delvare <khali@linux-fr.org>
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Jochen Friedrich wrote:
> Hi Timur,
> 
>> 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.
> 
> that's what I did in i2c-cpm, as well. However, here I use the property
> "linux,i2c-index" instead (see http://patchwork.ozlabs.org/linuxppc/patch?id=18603).

Well, I just don't see the point of having two different properties that say the
same thing.  I'm not an IEE 1275 purist, so I don't think we should be hampered
by old node definitions.  I especially don't like having a property specifically
for indexing I2C nodes that can't be used to enumerate other nodes.

The DMA and SSI controllers on Freescale parts use cell-index to enumerate them.
 It just seems dumb to invent a new property.

Will there ever be a situation where a node will contain "cell-index" and
"linux,i2c-index"?

-- 
Timur Tabi
Linux kernel developer at Freescale