Re: [PATCH v2 00/16] ARM: support for ICP DAS LP-8x4x (with dts)

Arnd Bergmann
2013-12-18T20:50:47Z

On Monday 16 December 2013, Sergei Ianovich wrote:
> On Mon, 2013-12-16 at 18:56 +0100, Arnd Bergmann wrote:
> > Ok, I see. This sounds like some of the other platforms we have with
> > external memory buses. If there is a chance that Linux ever has to
> > program the per-CS settings into the bus controller, I would suggest
> > to represent that as well as a separate node, like this
>
> This is a platform-specific bus (PXA27x). Should it go into pxa27x.dtsi
> rather than machine dts?

Yes, that was the idea.

> > In case there is a driver for the extbus node, I would not make it
> > "simple-bus" but instead add a separate compatible string to match
> > the driver, and let that driver call of_platform_populate
> > to probe the children after the bus is set up.
>
> There seems to be none at the moment. However, some machines need to
> setup these partitions as a part of their initialization. So complete
> migration to DT will require this driver.
>
> In LP-8x4x case everything is setup by the bootloader. So "simple-bus"
> works for me.

Hmm, this is a bit tricky then. I think it would be best to not
use "simple-bus" then, to allow migrating the other platforms later,
but that will be a little more work. Maybe you can register a trivial
driver in the platform code that only calls of_platform_populate on
the device for now?

Arnd