[PATCH 2/3 V3] i2c: mxs: Rework the PIO mode operation

[marex@denx.de (Marek Vasut)]

Hey Wolfram,

> On Mon, Sep 30, 2013 at 01:23:54AM +0200, Marek Vasut wrote:
> > 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@denx.de>
> 
> Yay, there it is. Thanks, looks good to me. Will wait a few days so
> people can donate Tested-by tags.

Sorry for the delay, things're pretty hectic recently.

Are you coming to ELCE btw ?

Best regards,
Marek Vasut