Re: [PATCH v2 08/34] dt-bindings: arm: Convert PMU binding to json-schema

On Wed, Dec 05, 2018 at 09:42:04AM -0600, Rob Herring wrote:

On Wed, Dec 5, 2018 at 4:08 AM Will Deacon [off-list ref] wrote:

quoted

On Mon, Dec 03, 2018 at 03:31:57PM -0600, Rob Herring wrote:

quoted

+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - apm,potenza-pmu
+              - arm,armv8-pmuv3
+              - arm,cortex-a73-pmu
+              - arm,cortex-a72-pmu
+              - arm,cortex-a57-pmu
+              - arm,cortex-a53-pmu
+              - arm,cortex-a35-pmu
+              - arm,cortex-a17-pmu
+              - arm,cortex-a15-pmu
+              - arm,cortex-a12-pmu
+              - arm,cortex-a9-pmu
+              - arm,cortex-a8-pmu
+              - arm,cortex-a7-pmu
+              - arm,cortex-a5-pmu
+              - arm,arm11mpcore-pmu
+              - arm,arm1176-pmu
+              - arm,arm1136-pmu
+              - brcm,vulcan-pmu
+              - cavium,thunder-pmu
+              - qcom,scorpion-pmu
+              - qcom,scorpion-mp-pmu
+              - qcom,krait-pmu
+      - items:
+          - const: arm,cortex-a7-pmu
+          - const: arm,cortex-a15-pmu

What do these last two mean?

The first list only allows a single compatible string. This list says
there are 2 and that the compatible property should be:
compatible = "arm,cortex-a7-pmu", "arm,cortex-a15-pmu";

Which shows up here:
arch/arm/boot/dts/sun6i-a31.dtsi:               compatible =
"arm,cortex-a7-pmu", "arm,cortex-a15-pmu";
arch/arm/boot/dts/sun7i-a20.dtsi:               compatible =
"arm,cortex-a7-pmu", "arm,cortex-a15-pmu";

Maybe the dts is wrong and should be fixed?

Yes, that's wrong and you could end up with the kernel exposing the wrong
events to userspace. So I think we can fix the .dts and leave the binding
without this.

quoted

quoted

+required:
+  - compatible

I probably said this before, but I do think that it's a shame to lose the
example binding, especially for something like the PMU where you can
pretty much take an example and bang in your own IRQ numbers to get it
up and running.

I just thought it is so trivial that it didn't add much. I think most
folks would copy-n-paste from an actual dts file which has all the
other nodes you just need to update addresses and irq nums.

True... even more of a reason to fix thise sun* .dts files then!

Will