From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marek.vasut@gmail.com>
Date: Wed, 14 Sep 2011 21:39:29 +0200
Subject: [U-Boot] [PATCH V3+] I2C: mxc_i2c rework
In-Reply-To: <CAFQ4atTS=ptKnNe_ntfA-ypV5Ctw+AeudHG5=pJYYNmju+f-EA@mail.gmail.com>
References: <1310594283-19819-1-git-send-email-marek.vasut@gmail.com>
	<CAFQ4atTS=ptKnNe_ntfA-ypV5Ctw+AeudHG5=pJYYNmju+f-EA@mail.gmail.com>
Message-ID: <201109142139.29539.marek.vasut@gmail.com>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

On Friday, July 29, 2011 08:55:14 AM Jason Hui wrote:
> Hi, Marek,
> 
> On Thu, Jul 14, 2011 at 5:58 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> > Rewrite the mxc_i2c driver.
> >  * This version is much closer to Linux implementation.
> >  * Fixes IPG_PERCLK being incorrectly used as clock source
> >  * Fixes behaviour of the driver on iMX51
> >  * Clean up coding style a bit ;-)
> 
> why you change i2c clock from IPG_PERCLK to IPG_CLK?
> 
> [...]

Ok, I investigated a bit deeper and I suspect the clock.c is the culprit.

Apparently, the PERCLK doesn't run at the frequency the clock.c reports it runs 
on. Therefore, the i2c miscalculates the divider etc -- falling crap model 
(waterfall model).

Anyway, Jason, can you look into that clock problem? I think there are more than 
just perclk miscalculated.

Cheers