[PATCH v3] dt-bindings: spi: tegra: Document IOMMU property for Tegra234 QSPI

[Vishwaroop A]

Add the 'iommus' property to the Tegra QSPI device tree binding.
The property is needed for Tegra234 when using the internal DMA
controller, and is not supported on other Tegra chips, as DMA is
handled by an external controller.

Signed-off-by: Vishwaroop A <va@xxxxxxxxxx>
---
 .../bindings/spi/nvidia,tegra210-quad.yaml    | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra210-quad.yaml b/Documentation/devicetree/bindings/spi/nvidia,tegra210-quad.yaml
index 48e97e240265..04d3b1a47392 100644
--- a/Documentation/devicetree/bindings/spi/nvidia,tegra210-quad.yaml
+++ b/Documentation/devicetree/bindings/spi/nvidia,tegra210-quad.yaml
@@ -10,9 +10,6 @@ maintainers:
   - Thierry Reding <thierry.reding@xxxxxxxxx>
   - Jonathan Hunter <jonathanh@xxxxxxxxxx>
 
-allOf:
-  - $ref: spi-controller.yaml#
-
 properties:
   compatible:
     enum:
@@ -47,6 +44,9 @@ properties:
       - const: rx
       - const: tx
 
+  iommus:
+    maxItems: 1
+
 patternProperties:
   "@[0-9a-f]+$":
     type: object
@@ -69,6 +69,19 @@ required:
 
 unevaluatedProperties: false
 
+allOf:
+  - $ref: spi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          const: nvidia,tegra234-qspi
+    then:
+      properties:
+        iommus: true
+    else:
+      properties:
+        iommus: false
+
 examples:
   - |
     #include <dt-bindings/clock/tegra210-car.h>
-- 
2.17.1