Hi Richard,

On Wed, Sep 21, 2011 at 03:05:44PM +0800, Richard Zhu wrote:

Hi Sascha:
One proposal about how to convert the ahci driver to devicetree in future.
ahci driver system can make a reference to the evolution of the sdhc driver.

You don't need to "convert" ahci driver to devicetree. IIRC,
the current ahci_platform driver should work almost* out of
the box with OF-enabled architectures, as OF subsystem
automatically populates memory and interrupt resources for
platform devices.

Someday you might need to implement OF-specific bindings
(e.g. get some property from the device tree and translate
it into port flags). When/if you'll need it, you can just
add it into the driver.

* Almost: you have to add of_match_table into 'struct
  platform_driver ahci_driver'.

* separate the ahci to ahci common codes, ahci-pci driver and
ahci-platform driver.

Done. Long time ago, actually.

* create kinds of ahci vendor's own ahci platform driver refer to the
sdhci-xxx driver solutions.

I think that this is viable, but personally I would like to
see platforms to just pass port flags and all needed hooks
via platform_data. That is, I'd leave the hooks in the arch/
code. Usually these hooks are very arch-specific (i.e. enable
these and these clocks, etc), so arch/ seems like a perfect
place for such things.

Not a strong opinion though, and if you like to go your route,
I'm also fine with this. It has its own pros (and cons).

Thanks,

-- 
Anton Vorontsov
Email: cbouatmailru@gmail.com