dt-bindings: iommu: Add Allwinner H6 IOMMU bindings

The Allwinner H6 has introduced an IOMMU. Let's add a device tree binding
for it.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/f3e1633677a9cf9cf36fe3582f0168fae94c1b3e.1589378833.git-series.maxime@cerno.techSigned-off-by: Joerg Roedel <jroedel@suse.de>

Documentation/devicetree/bindings/iommu/allwinner,sun50i-h6-iommu.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iommu/allwinner,sun50i-h6-iommu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner H6 IOMMU Device Tree Bindings
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Maxime Ripard <mripard@kernel.org>
+
+properties:
+  "#iommu-cells":
+    const: 1
+    description:
+      The content of the cell is the master ID.
+
+  compatible:
+    const: allwinner,sun50i-h6-iommu
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - "#iommu-cells"
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+      #include <dt-bindings/interrupt-controller/arm-gic.h>
+      #include <dt-bindings/interrupt-controller/irq.h>
+
+      #include <dt-bindings/clock/sun50i-h6-ccu.h>
+      #include <dt-bindings/reset/sun50i-h6-ccu.h>
+
+      iommu: iommu@30f0000 {
+          compatible = "allwinner,sun50i-h6-iommu";
+          reg = <0x030f0000 0x10000>;
+          interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>;
+          clocks = <&ccu CLK_BUS_IOMMU>;
+          resets = <&ccu RST_BUS_IOMMU>;
+          #iommu-cells = <1>;
+      };
+
+...