Re: [PATCH] ARM: at91: sama5d3: reduce TWI internal clock frequency

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Fri, Nov 22, 2013 at 03:51:41PM +0100, Ludovic Desroches wrote:
> Hi Wolfram,
> 
> On Fri, Nov 22, 2013 at 03:33:51PM +0100, Wolfram Sang wrote:
> > On Fri, Nov 22, 2013 at 03:07:08PM +0100, ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org wrote:
> > > From: Ludovic Desroches <ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
> > > 
> > > There are still I2C unexpected behaviors which are solved by reducing TWI
> > > internal frequency.
> > > 
> > > Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> #3.10+
> > > Signed-off-by: Ludovic Desroches <ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
> > 
> > I think the commit message needs more details. Is this a true bugfix
> > because the real bus frequency was too high because of the wrong
> > divider? Is this a workaround which makes things work but will make the
> > bus frequency slower than it should be?
> 
> This fix doesn't concern the i2c bus frequency, only the internal IP frequency.
> 
> TWI has been validated at 66MHz. With some devices, transfer hangs during i2c
> frame transmission. This issue disappears when reducing the internal frequency
> of the IP. Maybe there is some oversampling on i2c signals.
> Unfortunately, I have no clear status about the root cause that's why
> the commit message was imprecise.

This paragraph is a way better commit message IMO :)


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