From mboxrd@z Thu Jan 1 00:00:00 1970 From: wsa@the-dreams.de (Wolfram Sang) Date: Fri, 22 Nov 2013 15:58:35 +0100 Subject: [PATCH] ARM: at91: sama5d3: reduce TWI internal clock frequency In-Reply-To: <20131122145141.GB30749@ludovic.desroches@atmel.com> References: <1385129228-11225-1-git-send-email-ludovic.desroches@atmel.com> <20131122143350.GA7420@katana> <20131122145141.GB30749@ludovic.desroches@atmel.com> Message-ID: <20131122145835.GB7420@katana> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 at atmel.com wrote: > > > From: Ludovic Desroches > > > > > > There are still I2C unexpected behaviors which are solved by reducing TWI > > > internal frequency. > > > > > > Cc: #3.10+ > > > Signed-off-by: Ludovic Desroches > > > > 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 :) -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: