On Fri, Jan 13, 2017 at 06:43:52PM +0000, Mark Rutland wrote:

On Fri, Jan 13, 2017 at 04:03:49PM +0000, Will Deacon wrote:

quoted

This patch documents the devicetree binding in use for ARM SPE.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Will Deacon <redacted>
---
 Documentation/devicetree/bindings/arm/spe-pmu.txt | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/spe-pmu.txt

diff --git a/Documentation/devicetree/bindings/arm/spe-pmu.txt b/Documentation/devicetree/bindings/arm/spe-pmu.txt
new file mode 100644
index 000000000000..d6540b491af4
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/spe-pmu.txt

@@ -0,0 +1,20 @@
+* ARMv8.2 Statistical Profiling Extension (SPE) Performance Monitor Units (PMU)
+
+ARMv8.2 introduces the optional Statistical Profiling Extension for collecting
+performance sample data using an in-memory trace buffer.
+
+** SPE Required properties:
+
+- compatible : should be one of:
+	       "arm,arm-spe-pmu-v1"

The second "arm" here doesn't seem to add much. Should that be "armv8.2"
instead?

I don't think armv8.2 is particularly helpful, because that effectively ties
together the SPE version and the architecture version, which I don't think
is strictly required. The reason I added it was so that you could describe
a partner implementation as something like:

  acme,arm-spe-pmu-v1

and know that it was acme's implementation of an ARM architectural feature.

If I drop the second "arm", I was worried that it might conflict with other
namespaces (e.g. acme's signal-processing-element's power-management-unit).

What do you reckon?

Will