dt-bindings: dma: Add bindings for Intel LGM SoC

Add DT bindings YAML schema for DMA controller driver
of Lightning Mountain (LGM) SoC.
Signed-off-by: Amireddy Mallikarjuna reddy <mallikarjunax.reddy@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/f307e9012680a300a4dbaf4c7e0e83ca05fd9459.1606905330.git.mallikarjunax.reddy@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/intel,ldma.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/intel,ldma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Lightning Mountain centralized DMA controllers.
+
+maintainers:
+  - chuanhua.lei@intel.com
+  - mallikarjunax.reddy@intel.com
+
+allOf:
+  - $ref: "dma-controller.yaml#"
+
+properties:
+  compatible:
+    enum:
+      - intel,lgm-cdma
+      - intel,lgm-dma2tx
+      - intel,lgm-dma1rx
+      - intel,lgm-dma1tx
+      - intel,lgm-dma0tx
+      - intel,lgm-dma3
+      - intel,lgm-toe-dma30
+      - intel,lgm-toe-dma31
+
+  reg:
+    maxItems: 1
+
+  "#dma-cells":
+    const: 3
+    description:
+      The first cell is the peripheral's DMA request line.
+      The second cell is the peripheral's (port) number corresponding to the channel.
+      The third cell is the burst length of the channel.
+
+  dma-channels:
+    minimum: 1
+    maximum: 16
+
+  dma-channel-mask:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    items:
+      - const: ctrl
+
+  interrupts:
+    maxItems: 1
+
+  intel,dma-poll-cnt:
+    $ref: /schemas/types.yaml#definitions/uint32
+    description:
+      DMA descriptor polling counter is used to control the poling mechanism
+      for the descriptor fetching for all channels.
+
+  intel,dma-byte-en:
+    type: boolean
+    description:
+      DMA byte enable is only valid for DMA write(RX).
+      Byte enable(1) means DMA write will be based on the number of dwords
+      instead of the whole burst.
+
+  intel,dma-drb:
+    type: boolean
+    description:
+      DMA descriptor read back to make sure data and desc synchronization.
+
+  intel,dma-dburst-wr:
+    type: boolean
+    description:
+      Enable RX dynamic burst write. When it is enabled, the DMA does RX dynamic burst;
+      if it is disabled, the DMA RX will still support programmable fixed burst size of 2,4,8,16.
+      It only applies to RX DMA and memcopy DMA.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    dma0: dma-controller@e0e00000 {
+      compatible = "intel,lgm-cdma";
+      reg = <0xe0e00000 0x1000>;
+      #dma-cells = <3>;
+      dma-channels = <16>;
+      dma-channel-mask = <0xFFFF>;
+      interrupt-parent = <&ioapic1>;
+      interrupts = <82 1>;
+      resets = <&rcu0 0x30 0>;
+      reset-names = "ctrl";
+      clocks = <&cgu0 80>;
+      intel,dma-poll-cnt = <4>;
+      intel,dma-byte-en;
+      intel,dma-drb;
+    };
+  - |
+    dma3: dma-controller@ec800000 {
+      compatible = "intel,lgm-dma3";
+      reg = <0xec800000 0x1000>;
+      clocks = <&cgu0 71>;
+      resets = <&rcu0 0x10 9>;
+      #dma-cells = <3>;
+      intel,dma-poll-cnt = <16>;
+      intel,dma-byte-en;
+      intel,dma-dburst-wr;
+    };