[RFC PATCH v3 RESEND 09/13] dt-bindings: riscv: Add T-Head PMU extension description

[Yu Chien Peter Lin]

Document the ISA string for T-Head performance monitor extension
which provides counter overflow interrupt mechanism.

Signed-off-by: Yu Chien Peter Lin <peterlin at andestech.com>
---
Changes v2 -> v3:
  - New patch
---
 Documentation/devicetree/bindings/riscv/extensions.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index cc1f546fdbdc..5e9291d258d5 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -246,5 +246,11 @@ properties:
             in commit 2e5236 ("Ztso is now ratified.") of the
             riscv-isa-manual.
 
+        - const: xtheadpmu
+          description:
+            The T-Head performance monitor extension for counter overflow. For more
+            details, see the chapter 12 in the Xuantie C906 user manual.
+            https://github.com/T-head-Semi/openc906/tree/main/doc
+
 additionalProperties: true
 ...
-- 
2.34.1