Re: [RFC PATCH dtc] C-based DT schema checker integrated into dtc

[Olof Johansson <olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org>]

On Mon, Nov 4, 2013 at 8:37 AM, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> wrote:

> I had suggested that while talking to someone at the kernel summit,
> basically each driver supplies functions like:
>
> 1) ACPI -> platform data or resources converter
> 2) DT -> platform or resources data converter
> 3) anything else -> platform or resources data converter
> 4) probe()
>
> One of (1)..(3) (depending on device instantiation source) is called to
> translate the data source to platform data or resources, before probe
> (and could indeed handle much of deferred probe I suppose).
>
> (4) is called to actually initialize the device, and always has complete
> pre-parsed platform data/resources available, and does no DT/ACPI/...
> parsing.
>
> I forget who I was talking to, but it was asserted something like this
> had been proposed before, and wasn't accepted. Unfortunately, I don't
> entirely recall why...
>
> It may have been due to the fact I proposed (1) and (2) above being
> separate, rather than identical, due to using some unified API to read
> data from ACPI and DT. That wasn't the most interesting aspect of the
> proposal though. Still, I think conceptually there could be other data
> sources in the future, so we may need to allow different types of
> conversion function at some point, even if the ACPI and DT
> implementations can end up being the same.

I think it might have been me you were talking to. I know Grant
considered something like that when first doing the device tree
enablement, and chose not to do it then but I am not sure what the
motivations were. Given that we have cleaned up a lot of driver
probing already by now, it might be suitable to try again.


-Olof
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