[PATCH v3] dt-bindings: timer: Add SiFive CLINT2

[Nick Hu <nick.hu@sifive.com>]

Add compatible string and property for the SiFive CLINT v2. The SiFive
CLINT v2 is incompatible with the SiFive CLINT v0 due to differences
in their control methods.

Signed-off-by: Nick Hu <nick.hu@sifive.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
---
- v3 changes:
  - Add the reason for the incompatibility between sifive,clint2 and
    sifive,clint0.
- v2 changes:
  - Don't allow sifive,clint2 by itself. Add '-{}' to the first entry
  - Mark the sifive,fine-ctr-bits as the required property when
    the compatible includes the sifive,clint2

 .../bindings/timer/sifive,clint.yaml          | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
index 76d83aea4e2b..34684cda8b15 100644
--- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
@@ -36,6 +36,12 @@ properties:
               - starfive,jh7110-clint   # StarFive JH7110
               - starfive,jh8100-clint   # StarFive JH8100
           - const: sifive,clint0        # SiFive CLINT v0 IP block
+      - items:
+          - {}
+          - const: sifive,clint2        # SiFive CLINT v2 IP block
+        description:
+          SiFive CLINT v2 is the HRT that supports the Zicntr. The control of sifive,clint2
+          differs from that of sifive,clint0, making them incompatible.
       - items:
           - enum:
               - allwinner,sun20i-d1-clint
@@ -62,6 +68,22 @@ properties:
     minItems: 1
     maxItems: 4095
 
+  sifive,fine-ctr-bits:
+    maximum: 15
+    description: The width in bits of the fine counter.
+
+if:
+  properties:
+    compatible:
+      contains:
+        const: sifive,clint2
+then:
+  required:
+    - sifive,fine-ctr-bits
+else:
+  properties:
+    sifive,fine-ctr-bits: false
+
 additionalProperties: false
 
 required:
-- 
2.17.1