Re: [PATCH 5/8] powerpc: i2c-mpc: make I2C bus speed configurable

[Grant Likely <grant.likely@secretlab.ca>]

On Wed, Apr 1, 2009 at 1:51 AM, Wolfgang Grandegger <wg@grandegger.com> wrote:
> Grant Likely wrote:
>> The table definition is more verbose this way, but I think it results
>> in more understandable and easier to extend code.  It also adds lets
>> the compiler do more type checking for you.
>
> OK but I don't like the callback function to do the settings. We need
> backward compatibility with old DTS files including the ugly "dfsrr"
> property, right? Then it seems consequent to continue using i2c->flags
> for that purpose and not to introduce another method. If we don't need
> backward compatibility, we could drop the flags completely and just use
> callback functions.

I don't understand why you don't like it.  It's an elegant solution
and it simplifies the code somewhat.  After grabbing the callback
pointer the compatibility code can simply override it.  But I won't
belabor the point or oppose the patch if you stick with the flags
pointer.

>>> --- linux-2.6.orig/arch/powerpc/platforms/52xx/mpc52xx_common.c 2009-03-31 13:25:08.000000000 +0200
>>> +++ linux-2.6/arch/powerpc/platforms/52xx/mpc52xx_common.c      2009-03-31 13:28:54.309718526 +0200
>>> +int fsl_i2c_get_fdr(struct device_node *node, u32 i2c_clock, u32 i2c_flags)
>>> +{
>>> [...]
>>> +}
>>> +EXPORT_SYMBOL(fsl_i2c_get_fdr);
>>
>> does not work on a multiplatform kernel.  Both 8xxx and 52xx support
>> can be selected at the same time.
>
> OK, then we need different functions including stubs.

I've been thinking about this more.  These tables are only ever going
to be used by the i2c_mpc driver and so really they are a part of the
i2c_mpc driver itself.  Putting them into common code doesn't make any
sense because it is not common code.  I will not merge a patch that
puts them into mpc5200 common code.

g.


-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.