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Date: Fri, 14 Nov 2014 08:43:01 +0100
From: Valentin Longchamp <valentin.longchamp@keymile.com>
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To: Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH] i2c-qoriq: modified compatibility for correct prescaler
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Cc: Linux device trees <devicetree@vger.kernel.org>, "Boschung,
 Rainer" <Rainer.Boschung@keymile.com>, "Brunck,
 Holger" <Holger.Brunck@keymile.com>, Linux I2C <linux-i2c@vger.kernel.org>,
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On 11/13/2014 01:34 AM, Wolfram Sang wrote:
> 
>> If we wanted to be on the safe side and strict (since we are not sure that the
>> hardware is 100% compatible), we maybe should add a fsl,qoriq-i2c compatible to
>> the driver that does the same as mpc8543-i2c.
> 
> Or you leave the driver as is and use both compatibles:
> 
> compatible = "fsl,qoriq-i2c", "fsl,mpc8543-i2c", "fsl-i2c";
> 
> ?
> 

I like Scott's proposition to add the prescaler in the device tree more. From
the hardware description point of view, it makes more sense: the devices are all
just fsl-i2c, with a different prescaler. I just quote it below as a reminder.

> 
> If we're going to change the device tree I'd rather just add a property
> to say what the prescaler is.

 We would however, leave the boards' device trees that use things like
"fsl,mpc8543-i2c" as is and introduce the prescaler for the others requiring it.


Now the drawback is that the driver would require a change, to parse this
prescaler new prescaler property. Would this be OK from your point of view
Wolfram ? If yes, I will send the patches for it.

Valentin