[PATCH v6 1/4] dt-bindings: iommu: mediatek: Fix interrupt count constraint for new SoCs

[Macpaul Lin]

The infra-iommu node in mt8195.dtsi was triggering a CHECK_DTBS error due
to an excessively long 'interrupts' property. The error message was:

  infra-iommu@10315000: interrupts: [[0, 795, 4, 0], [0, 796, 4, 0],
                     [0, 797, 4, 0], [0, 798, 4, 0], [0, 799, 4, 0]]
                     is too long

To address this issue, update the compatbile matching rule for
'interrupts' property. This change allows flexibility in the number
of interrupts for new SoCs like MT8195.
The purpose of these 5 interrupts is also added into description.

Fixes: bca28426805d ("dt-bindings: iommu: mediatek: Convert IOMMU to DT schema")
Signed-off-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
---
 .../bindings/iommu/mediatek,iommu.yaml        | 28 ++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

Changes for v2:
 - commit message: re-formatting and add a description of adding 5 interrupts.
 - add 'description' and 'maxItems: 5' for 'interrupt' property of
   'mt8195-iommu-infra'
 - others keeps 'maxItems: 1'

Changes for v3:
 - Refine the description for 'interrupts' property and fixes the compatible
   matching rules.
 - Refine commit message.

Changes for v4:
  - add missing 'minItems: 5' to 'mediatek,mt8195-iommu-infra'.
    Thanks the explanation from Conor and Krzysztof. 

Changes for v5:
  - Repharse the description for interrupts property of MT8195.

Changes for v6:
  - Remove maxItems for mt8195-iommu-infra.
  - Add 'Reviewed-by' tag from Rob. Thanks for the review.

diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
index ea6b0f5f24de..eeb39f5acf7e 100644
--- a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
+++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
@@ -96,7 +96,16 @@ properties:
     maxItems: 1
 
   interrupts:
-    maxItems: 1
+    description: |
+      Usually, the IOMMU requires only one interrupt.
+
+      The infra IOMMU in MT8195 has five banks: each features one set
+      of APB registers. One for the normal world (set 0), three for the
+      protected world (sets 1-3), and one for the secure world (set 4).
+      and each set has its own interrupt. Therefore, five interrupts
+      are needed.
+    minItems: 1
+    maxItems: 5
 
   clocks:
     items:
@@ -210,6 +219,23 @@ allOf:
       required:
         - mediatek,larbs
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - mediatek,mt8195-iommu-infra
+
+    then:
+      properties:
+        interrupts:
+          minItems: 5
+
+    else:
+      properties:
+        interrupts:
+          maxItems: 1
+
 additionalProperties: false
 
 examples:
-- 
2.45.2