[U-Boot] [PATCH 13/17] post/i2c: Add ability to ignore I2C devices

Heiko Schocher hs at denx.de
Thu Sep 30 08:10:48 CEST 2010


Hello Peter,

Peter Tyser wrote:
> Add the ability to not report an I2C POST error for a set of given I2C
> addresses on bootup.  This is useful for the following cases:
> 
> - Some form factors such as XMC and Compact PCI Express have an I2C
>   EEPROM whose address changes based on geographical address.  Eg
>   installed in one slot its EEPROM address is, 0x50, in another its
>   0x51, etc.  This allows multiple devices to have their EEPROMs present
>   on the same I2C bus.  Thus the I2C devices present for an XMC or
>   CPCIe card depend on if and where other cards are installed in the
>   same system.
> 
> - Some cards have optional I2C devices.  Eg one hardware build
>   configuration has different I2C devices than another.
> 
> - Some cards have optional daughtercards with I2C devices on them.
> 
> - I2C EEPROMs address range depends on their size.  Its possible to
>   support differently size EEPROMs by only probing the EEPROM's base
>   address and ignoring the other addresses that are impacted by its
>   size.
> 
> A new I2C_ADDR_IGNORE_LIST define has been added which specifies a list
> of I2C addresses for the I2C POST to ignore.
> 
> Signed-off-by: Peter Tyser <ptyser at xes-inc.com>
> CC: hs at denx.de
> ---
>  post/drivers/i2c.c |   16 ++++++++++++++++
>  1 files changed, 16 insertions(+), 0 deletions(-)

Maybe you can add a little info in the README?

> diff --git a/post/drivers/i2c.c b/post/drivers/i2c.c
> index 2dd128e..9e1fd50 100644
> --- a/post/drivers/i2c.c
> +++ b/post/drivers/i2c.c
> @@ -40,6 +40,20 @@
>  
>  #if CONFIG_POST & CONFIG_SYS_POST_I2C
>  
> +static int i2c_ignore_device(unsigned int chip)
> +{
> +#ifdef I2C_ADDR_IGNORE_LIST

Hmm.. as this is only used in post code, this should be visible
in the defines name, what with:

I2C_POST_ADDR_IGNORE_LIST

?

bye,
Heiko
-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany


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