From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
Subject: Re: [PATCH] i2c: mxs: Rework the PIO mode operation
Date: Wed, 17 Jul 2013 19:04:00 +0200
Message-ID: <201307171904.00784.marex@denx.de>
References: <201307150405.53110.marex@denx.de> <1UzQet-1Vf4pE0@fwd17.aul.t-online.de>
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Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>, Fabio Estevam <r49496-KZfg59tc24xl57MIdRCFDg@public.gmane.org>, Lucas Stach <l.stach-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>, Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
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Dear to-fleischer-zqRNUXuvxA0b1SvskN2V4Q@public.gmane.org,

> Hi,
> 
> > > Analyze and rework the PIO mode operation. The PIO mode operation
> > > was unreliable on MX28, by analyzing the bus with LA, the checks for
> > > when data were available or were to be sent were wrong.
> > > 
> > > The PIO WRITE has to be completely reworked as it multiple problems.
> > > The MX23 datasheet helped here, see comments in the code for
> > > details.
> > > The problems boil down to:
> > > - RUN bit in CTRL0 must be set after DATA register was written - The
> > > PIO transfer must be 4 bytes long tops, otherwise use
> > > clock stretching.
> > > Both of these fixes are implemented.
> > > 
> > > The PIO READ operation can only be done for up to four bytes as we
> > > are unable to read out the data from the DATA register fast enough.
> > > 
> > > This patch also tries to document the investigation within the code.
> > > 
> > > Signed-off-by: Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
> > > Cc: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> > > Cc: Fabio Estevam <r49496-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> > > Cc: Lucas Stach <l.stach-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > > Cc: Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > > Cc: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
> > > Cc: <to-fleischer-zqRNUXuvxA0b1SvskN2V4Q@public.gmane.org>
> > 
> > I so far got confirmation from ALexandre this patch works. Can someone
> > else test it please? I'd like to roll out a final version to close
> > this issue.
> 
> sorry, I couldn't  test the patch until today on my iMX283 board.
> It works when reading the registers from the temperature sensor TCN75A.
> But it fails when writing less than 7 bytes to the EEPROM (24LC32). Then
> I always get a 'Connection timed out' error in the user space.

Thinking about this, did you correctly configure the EEPROM write sector size? I 
think it's 32 bytes for this device.

Best regards,
Marek Vasut