[i2c] Is review of AT91 patch pending?

Jean Delvare khali at linux-fr.org
Thu Oct 4 10:47:14 CEST 2007


On Wed, 03 Oct 2007 13:25:45 -0700, David Brownell wrote:
> Mark the i2c-at91 driver BROKEN in Kconfig, and explain just
> why it's broken.  (Summary:  hardware design issues.)
> 
> Signed-off-by: David Brownell <dbrownell at users.sourceforge.net>
> ---
>  drivers/i2c/busses/Kconfig |   10 +++++++++-
>  1 files changed, 9 insertions(+), 1 deletion(-)
> 
> --- a/drivers/i2c/busses/Kconfig	2007-09-24 14:11:49.000000000 -0700
> +++ b/drivers/i2c/busses/Kconfig	2007-10-03 13:15:09.000000000 -0700
> @@ -75,11 +75,19 @@ config I2C_AMD8111
>  
>  config I2C_AT91
>  	tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
> -	depends on ARCH_AT91 && EXPERIMENTAL
> +	depends on ARCH_AT91 && EXPERIMENTAL && BROKEN
>  	help
>  	  This supports the use of the I2C interface on Atmel AT91
>  	  processors.
>  
> +	  This driver is BROKEN because the controller which it uses
> +	  will easily trigger RX overrun and TX underrun errors.  Using
> +	  low I2C clock rates may partially work around those issues
> +	  on some systems.  Another serious problem is that there is no
> +	  documented way to issue repeated START conditions, as needed
> +	  to support combined I2C messages.  Use the i2c-gpio driver
> +	  unless your system can cope with those limitations.
> +
>  config I2C_AU1550
>  	tristate "Au1550/Au1200 SMBus interface"
>  	depends on SOC_AU1550 || SOC_AU1200

Patch applied, thank you.

-- 
Jean Delvare



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