dt-bindings: arm-smmu: add binding for Tegra194 SMMU

Add binding for NVIDIA's Tegra194 SoC SMMU.

Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20200718193457.30046-5-vdumpa@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

Documentation/devicetree/bindings/iommu/arm,smmu.yaml

@@ -44,6 +44,11 @@ properties:
         items:
           - const: marvell,ap806-smmu-500
           - const: arm,mmu-500
+      - description: NVIDIA SoCs that program two ARM MMU-500s identically
+        items:
+          - enum:
+              - nvidia,tegra194-smmu
+          - const: nvidia,smmu-500
       - items:
           - const: arm,mmu-500
           - const: arm,smmu-v2
@@ -61,7 +66,8 @@ properties:
           - cavium,smmu-v2
 
   reg:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
 
   '#global-interrupts':
     description: The number of global interrupts exposed by the device.
@@ -144,6 +150,23 @@ required:
 
 additionalProperties: false
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - nvidia,tegra194-smmu
+    then:
+      properties:
+        reg:
+          minItems: 2
+          maxItems: 2
+    else:
+      properties:
+        reg:
+          maxItems: 1
+
 examples:
   - |+
     /* SMMU with stream matching or stream indexing */