Re: [PATCH 2/3] powerpc/esdhc: add property to disable the CMD23

[Chris Ball <cjb@laptop.org>]

Hi,

On Tue, Sep 18 2012, Kumar Gala wrote:
>>>> I've got a mild preference for handling quirk assignment in the DT
>>>> rather than in driver code, so I'd prefer to just push the original
>>>> patch to mmc-next as-is.  Does that sound okay?
>>> 
>>> Why?  I only ask because I agree with Scott that this means you have to
>>> update your device tree to get proper functionality.
>>> 
>> When the new silicon does not support CMD23,
>> if we don't update the device tree, then we must update the SDHC driver.
>> I prefer to add the property in device tree,
>> because we just add this property in new device tree, we don't need more effort to modify driver.
>
> Jerry,
>
> I think doing it driver makes more sense because:
>
> 1. means older device tree's still work
> 2. odds that CMD23 not being supported in future devices is near 0%
>    (Now that we support AutoCMD23 [and thus CMD23] we aren't likely to stop supporting it in future)
> 3. If IP changes you are going to have to update driver anyways for new features
>
> I really think we should NOT utilize device tree for this.

Of course, we could also make both (or perhaps neither) of you happy by
merging both:  if your DT says you don't support cmd23 *or* you hit the
driver's blacklist, we avoid it.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child