[RFC] [PATCH] ARM: tegra: emc: device tree bindings

On Wed, Oct 19, 2011 at 8:11 AM, Stephen Warren [off-list ref] wrote:

Olof Johansson wrote at Wednesday, October 19, 2011 9:07 AM:

quoted

On Wed, Oct 19, 2011 at 7:36 AM, Rob Herring [off-list ref] wrote:

...

quoted

quoted

Using the frequency as was previously proposed would work assuming that
is unique.

Someone suggested (off-list) to just use dummy addressing like cpu
nodes do. Sounds reasonable to me.

So:

emc {
? compatible = "tegra20-emc";
? nvidia,use-ram-code;
? emc-tables@<ram-code> {
? ? ?nvidia,ram-code = < <ram-code> >;
? ? ?emc-table@<dummy enumerator> {
? ? ? ? compatible = "tegra20-emc-table";
? ? ? ? clock-frequency = < >;
? ? ? ? nvidia,emc-regs = < >;
? ? ?}
? }

This also avoids having to handle 2-dimensional dummy numbering (i.e.
<ramcode,table-number>) by breaking it in two levels:

Where nvidia,use-ram-code is missing in the emc node, the immediate
child nodes will be scanned for the compatible nodes
Where nvidia,use-ram-code is present, first scan will be of all child
nodes containing an nvidia,ram-code property, then from there treat it
the same as the first case.

In the above, none of the names have meaning, so they can be changed
as needed (but these seem like a reasonably generic and descriptive
name to me).

OK, I'm good with that general structure.

But, as Rob suggests, you may as well use the frequency instead of the
<dummy enumerator> for the unit address of the final tables, right?
The search algorithm might not care, but it'll be easier for humans
to read the resulting dts file.

Sure, anything can probably be used so that's fine with me -- it won't
change the table walking code.


-Olof