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From: wsa@the-dreams.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: at91: sama5d3: reduce TWI internal clock frequency
Date: Fri, 22 Nov 2013 15:33:51 +0100	[thread overview]
Message-ID: <20131122143350.GA7420@katana> (raw)
In-Reply-To: <1385129228-11225-1-git-send-email-ludovic.desroches@atmel.com>

On Fri, Nov 22, 2013 at 03:07:08PM +0100, ludovic.desroches at 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?

> ---
>  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",
> -- 
> 1.7.9.5
> 
> --
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  reply	other threads:[~2013-11-22 14:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-22 14:07 [PATCH] ARM: at91: sama5d3: reduce TWI internal clock frequency ludovic.desroches at atmel.com
2013-11-22 14:33 ` Wolfram Sang [this message]
2013-11-22 14:51   ` Ludovic Desroches
2013-11-22 14:58     ` Wolfram Sang
2013-11-22 15:07       ` Ludovic Desroches
2013-11-22 15:09         ` Nicolas Ferre
2013-11-22 15:01 ` boris brezillon
2013-11-22 15:11   ` Nicolas Ferre

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