dt-bindings: dmaengine: Add doc for tegra gpcdma

Add DT binding document for Nvidia Tegra GPCDMA controller.
Signed-off-by: NRajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: NAkhil R <akhilrajeev@nvidia.com>
Reviewed-by: NJon Hunter <jonathanh@nvidia.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Acked-by: NThierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20220225132044.14478-2-akhilrajeev@nvidia.comSigned-off-by: NVinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/nvidia,tegra186-gpc-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra GPC DMA Controller Device Tree Bindings
+
+description: |
+  The Tegra General Purpose Central (GPC) DMA controller is used for faster
+  data transfers between memory to memory, memory to device and device to
+  memory.
+
+maintainers:
+  - Jon Hunter <jonathanh@nvidia.com>
+  - Rajesh Gumasta <rgumasta@nvidia.com>
+
+allOf:
+  - $ref: "dma-controller.yaml#"
+
+properties:
+  compatible:
+    oneOf:
+      - const: nvidia,tegra186-gpcdma
+      - items:
+          - const: nvidia,tegra194-gpcdma
+          - const: nvidia,tegra186-gpcdma
+
+  "#dma-cells":
+    const: 1
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description:
+      Should contain all of the per-channel DMA interrupts in
+      ascending order with respect to the DMA channel index.
+    minItems: 1
+    maxItems: 31
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: gpcdma
+
+  iommus:
+    maxItems: 1
+
+  dma-coherent: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - resets
+  - reset-names
+  - "#dma-cells"
+  - iommus
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/memory/tegra186-mc.h>
+    #include <dt-bindings/reset/tegra186-reset.h>
+
+    dma-controller@2600000 {
+        compatible = "nvidia,tegra186-gpcdma";
+        reg = <0x2600000 0x210000>;
+        resets = <&bpmp TEGRA186_RESET_GPCDMA>;
+        reset-names = "gpcdma";
+        interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 93 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
+        #dma-cells = <1>;
+        iommus = <&smmu TEGRA186_SID_GPCDMA_0>;
+        dma-coherent;
+    };
+...