From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Subject: Re: [PATCH v2] ARM: at91: sama5d3: reduce TWI internal clock frequency Date: Mon, 2 Dec 2013 09:42:11 +0100 Message-ID: <529C47E3.2010508@atmel.com> References: <1385136523-11962-1-git-send-email-ludovic.desroches@atmel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1385136523-11962-1-git-send-email-ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 22/11/2013 17:08, ludovic.desroches-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org : > From: Ludovic Desroches > > With some devices, transfer hangs during I2C frame transmission. This issue > disappears when reducing the internal frequency of the TWI IP. Even if it is > indicated that internal clock max frequency is 66MHz, it seems we have > oversampling on I2C signals making TWI believe that a transfer in progress > is done. > > This fix has no impact on the I2C bus frequency. > > Cc: #3.10+ > Acked-by: Nicolas Ferre > Signed-off-by: Ludovic Desroches added to at91-3.14-dt branch. thanks, > --- > > v2: update commit message > > arch/arm/mach-at91/sama5d3.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/mach-at91/sama5d3.c b/arch/arm/mach-at91/sama5d3.c > index 4012797..4ee0de5 100644 > --- a/arch/arm/mach-at91/sama5d3.c > +++ b/arch/arm/mach-at91/sama5d3.c > @@ -95,19 +95,19 @@ static struct clk twi0_clk = { > .name = "twi0_clk", > .pid = SAMA5D3_ID_TWI0, > .type = CLK_TYPE_PERIPHERAL, > - .div = AT91_PMC_PCR_DIV2, > + .div = AT91_PMC_PCR_DIV8, > }; > static struct clk twi1_clk = { > .name = "twi1_clk", > .pid = SAMA5D3_ID_TWI1, > .type = CLK_TYPE_PERIPHERAL, > - .div = AT91_PMC_PCR_DIV2, > + .div = AT91_PMC_PCR_DIV8, > }; > static struct clk twi2_clk = { > .name = "twi2_clk", > .pid = SAMA5D3_ID_TWI2, > .type = CLK_TYPE_PERIPHERAL, > - .div = AT91_PMC_PCR_DIV2, > + .div = AT91_PMC_PCR_DIV8, > }; > static struct clk mmc0_clk = { > .name = "mci0_clk", > -- Nicolas Ferre