Re: [PATCH 3/4] dt: omap3: add generic board file for dt support

[Tony Lindgren <tony@atomide.com>]

* Grant Likely <grant.likely@secretlab.ca> [110716 22:08]:
> 
> The way I see it, you've got two options:
> 
> 1) modify the of_platform_bus_create() to call some kind of
> of_platform_bus_create_omap() for devices that match "ti,omap3-device"
> or something.
> 
> 2) Leave of_platform_bus_create(), and instead us a notifier to attach
> hwmod data to normal platform devices.  omap_device_build() is
> actually pretty simple.  It allocated a device, it attaches
> platform_data and hwmod pointers to the device and registers it.
> omap_device_register() is just a wrapper around
> platform_device_register().
> 
> My preference is definitely #2, but there is a wrinkle in this
> approach.  Unfortunately omap_devices are not simply plain
> platform_devices with extra data attached, an omap_device actually
> embeds the platform_device inside it, which cannot be attached after
> the fact.  I think I had talked with Kevin (cc'd) about eliminating
> the embedding, but I cannot remember clearly on this point.  As long
> as platform_device remains embedded inside struct omap_device, #2
> won't work.
> 
> In either case, looking up the correct hwmod data should be easy for
> any device provided the omap code maintains a lookup table of
> compatible strings and base addresses of devices (much like auxdata).
> In fact, I'd be okay with extending auxdata to include OMAP fields if
> that would be easiest since the whole point of auxdata is to ease the
> transition to DT support.  When a matching device is created, the
> hwmod pointer can easily be attached.  This should work transparently
> for all omap devices, not just the i2c bus.

Well we should be able to automgagically build the omap_device for
each device tree entry.

And then the device driver probe and runtime PM should be able to take
care of the rest for the driver. And then there's no more driver
specific platform init code needed ;)

How about if we just have the hwmod code call omap_device_build for
each device tree entry?

Regards,

Tony