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

Hi,

On Tue, Sep 18 2012, Kumar Gala wrote:

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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   [off-list ref]   <http://printf.net/>
One Laptop Per Child