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

[Ludovic Desroches <ludovic.desroches@atmel.com>]

On Fri, Nov 22, 2013 at 03:58:35PM +0100, Wolfram Sang wrote:
> 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@atmel.com wrote:
> > > > From: Ludovic Desroches <ludovic.desroches@atmel.com>
> > > > 
> > > > There are still I2C unexpected behaviors which are solved by reducing TWI
> > > > internal frequency.
> > > > 
> > > > Cc: <stable@vger.kernel.org> #3.10+
> > > > Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> > > 
> > > 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 :)
> 

Ok I'll update it.

Thanks for the review Wolfram.

Regards

Ludovic