Re: [RFC PATCH 6/8] dts: coresight: Clean up the device tree graph bindings
From: Suzuki K Poulose
Date: Tue Jul 03 2018 - 05:44:24 EST
Hi Rob,
On 14/06/18 14:59, Rob Herring wrote:
On Thu, Jun 14, 2018 at 2:53 AM, Suzuki K Poulose
<Suzuki.Poulose@xxxxxxx> wrote:
On 13/06/18 22:07, Matt Sealey wrote:
-----Original Message-----
From: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
So, if the suggestion is to use an existing property "unit", I am fine
with it, if people agree to it.
If we're going to have something sharply different than ACPI I prefer
Rob's idea.
No, the above comment is about using "unit" ( if it is a standard property
for specifying something specific to hardware) instead of "coresight,hwid".
I would prefer to stick to the DT graph bindings, because :
"unit" is not a standard property and I don't like it either.
1) The connections are bi-directional => Well, not necessarily
bi-directional
in terms of the data flow. But the connection information is critical. i.e,
we need information about both the end-points of a connection, which the DT
graph bindings solves.
All we are missing is a way for specifying the "hardware port" number and
the
direction of flow. I don't see why do we need to create something new just
for
these two properties for something that exists today and works reasonably
well
for the usecase.
If you have "in-ports" and "out-ports" nodes, then that gives you
direction and you can use reg for the "hardware port".
in-ports {
port@0 {
reg = <0>;
endpoint {...};
};
port@1 {
reg = <1>;
endpoint {...};
};
};
out-ports {
port@0 {
reg = <0>;
endpoint {...};
};
};
I'll need to check, but dtc may need an update to not warn about this.
I did a quick check with the upstream dtc tool and the above form is
doesn't generate any errors.
Mathieu, Rob,
Shall I proceed with the proposal above ?
Suzuki