Re: [PATCH 1/3] Blackfin I2C/TWI Driver: make sure we don't end up with a CLKDIV=0

[Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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On Wed, May 27, 2009 at 02:20:08AM -0400, Mike Frysinger wrote:
> From: Michael Hennerich <michael.hennerich-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> 
> Make sure we don't end up with an invalid CLKDIV=0 in case someone
> specifies 20kHz SCL or less (5 * 1024 / 20 = 0x100).
> 
> Signed-off-by: Michael Hennerich <michael.hennerich-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
> Signed-off-by: Bryan Wu <cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> ---
>  drivers/i2c/busses/Kconfig        |    2 +-
>  drivers/i2c/busses/i2c-bfin-twi.c |   11 ++++++++---
>  2 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index f1c6ca7..c8460fa 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -298,7 +298,7 @@ config I2C_BLACKFIN_TWI
>  config I2C_BLACKFIN_TWI_CLK_KHZ
>  	int "Blackfin TWI I2C clock (kHz)"
>  	depends on I2C_BLACKFIN_TWI
> -	range 10 400
> +	range 21 400
>  	default 50
>  	help
>  	  The unit of the TWI clock is kHz.
> diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
> index fc548b3..3ab1f66 100644
> --- a/drivers/i2c/busses/i2c-bfin-twi.c
> +++ b/drivers/i2c/busses/i2c-bfin-twi.c
> @@ -614,6 +614,7 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
>  	struct i2c_adapter *p_adap;
>  	struct resource *res;
>  	int rc;
> +	unsigned int clkhilow;
>  
>  	iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL);
>  	if (!iface) {
> @@ -675,10 +676,14 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
>  	/* Set TWI internal clock as 10MHz */
>  	write_CONTROL(iface, ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
>  
> +	/*
> +	 * We will not end up with a CLKDIV=0 cause no one will specifies

specify

> +	 * 20kHz SCL or less in Kconfig now. (5 * 1024 / 20 = 0x100)
> +	 */
> +	clkhilow = 5 * 1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ;
> +
>  	/* Set Twi interface clock as specified */
> -	write_CLKDIV(iface, ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
> -			<< 8) | ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
> -			& 0xFF));
> +	write_CLKDIV(iface, (clkhilow << 8) | clkhilow);
>  
>  	/* Enable TWI */
>  	write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
> -- 
> 1.6.3.1
> 
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-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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