Re: [alsa-devel] [PATCH 1/2] powerpc: add platform registration for ALSA SoC drivers

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

On Wed, Apr 28, 2010 at 7:35 AM, Timur Tabi <timur@freescale.com> wrote:
> On Wed, Apr 28, 2010 at 12:37 AM, Grant Likely
> <grant.likely@secretlab.ca> wrote:
>
>> Why not? =A0Just have the ssi driver probe routine register the fabric
>> device based on the existence of the codec-handle property. =A0It is the
>> best way to go about things with the data that you've got available,
>> and it is no big deal. =A0The relevant fabric driver can then bind
>> against that. =A0You should probably also stuff the ssi device node
>> pointer into the fabric device of_node pointer.
>
> And then where do I put the board-specific initialization code that's
> currently in the fabric driver? =A0The programming information for that
> initialization is not in the device tree.

In the fabric driver; where it is right now.  I'm saying *instantiate*
the device when the ssi driver gets probed.  Use the top level board
name when assigning the name so that the correct asoc machine driver
gets bound to it.

> It sounds to me like you're saying I should take all the code from the
> fabric driver and shove it into the SSI driver, just so that I can
> avoid instantiating a platform driver.

Nope.

> Keep in mind that asoc likes to have a different struct device for the
> fabric driver and the SSI nodes, so I would need to manually create a
> struct device for the fabric device anyway.

You can do it this way too, but this is not what I'm saying.

>> Linux struct device registrations are cheap, and every struct device
>> has a device_node pointer available. =A0It is totally fine to have both
>> the ssi device and the fabric device point to the same device node if
>> that helps solve your problem of finding references to the right
>> things in each driver. =A0(Just as long as only one of them is an
>> of_platform driver).
>
> But I already have it set up like that. =A0The SSI driver is an OF
> driver, and the fabric driver is a platform driver. =A0I might be able
> to move some code from the fabric driver into the SSI driver to make
> it the fabric driver less obnoxious about scanning the device tree.

I'm just saying move the registration of the machine device out of
arch/powerpc platform code and into the ssi driver.  Then you've got a
reasonable place to pass shared data (either the ssi device node or
device instance or name.  Whatever you need) to the machine driver.

g.