Request review of device tree documentation

Grant Likely grant.likely at secretlab.ca
Sat Jun 12 16:53:59 EST 2010


On Fri, Jun 11, 2010 at 5:47 PM, Dan Malek <ppc6dev at digitaldans.com> wrote:
>
> Hi Grant.
>
> On Jun 11, 2010, at 3:59 PM, Grant Likely wrote:
>
>> I've been doing a bit of work on some introductory level documentation
>> of the flattened device tree.
>
> Wow, I feel empowered to create device trees now :-)
> Seriously, I never understood this well and this is a
> great document.

Hey, thanks!  That's a fantastic compliment!

> I have one source of confusion.  Your first Initial structure
> example uses 'compatible' to describe the machine, the
> paragraph below then mentions the 'model' property,
> and all subsequent examples use model.
>
> Does this mean if I use just the single line in the dts,
> using 'compatible' implies the ARM machine ID?  If I
> have more description I use 'model'?

No, that is just a reflection of a late change I made to the document.
 It should be compatible all the way down.  I was trying to keep
things simple because on a lot of boards both compatible and model
properties will exist in the root node.  I started writing with model,
and then changed it last minute without fixing everything up which is
why the document was confusing.

I've fixed it now if you want to take a look.

I also changed the property in the cpu nodes from model to compatible
so that the exact CPU version can be specified.  This isn't actually
in any spec anywhere, but I need something to properly identify the
different ARM cores.

Mitch, I know you were working on a draft ARM binding a while ago,
have you resurrected it at all?  How do you think the core should be
identified?

Cheers,
g.


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