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Date: Wed, 4 Jun 2008 10:43:51 -0500
From: Scott Wood <scottwood@freescale.com>
To: Timur Tabi <timur@freescale.com>
Subject: Re: "cell-index" vs. "index" vs. no index in I2C device nodes
Message-ID: <20080604154351.GB10393@ld0162-tx32.am.freescale.net>
References: <200806041706.21557.sr@denx.de> <4846B39F.3010601@freescale.com>
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Cc: linuxppc-dev@ozlabs.org, Stefan Roese <sr@denx.de>
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On Wed, Jun 04, 2008 at 10:24:15AM -0500, Timur Tabi wrote:
> Stefan Roese wrote:
> > I'm wondering what is currently recommended in the I2C device tree nodes? The 
> > current IBM I2C driver (i2c-ibm_iic.c) checks "index" and most FSL dts files 
> > use "cell-index". Some 4xx dts files implement "cell-index" some have no 
> > index at all.
> > 
> > So what should be used here. Please advise and I'll prepare a patch for it.
> 
> I just posted a patch for the FSL I2C driver to check for cell-index.  I'm under
> the impression that cell-index is the standard for enumerating devices in the
> device tree.

No, it's the standard for correlating devices with portions of a shared
register block elsewhere.  Your use in the I2C node is merely a hack to
deal with Linux wanting to deal with indices rather than pointers,
combined with a lack of a decent way to look up a device struct from the
device node.

-Scott