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 11:56:14 +0100 Message-ID: <529C674E.5050403@atmel.com> References: <1385136523-11962-1-git-send-email-ludovic.desroches@atmel.com> <529C47E3.2010508@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: <529C47E3.2010508-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 02/12/2013 09:42, Nicolas Ferre : > 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. No, sorry, it will go in at91-3.13-fixes! Bye, >> --- >> >> 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