dt-bindings: mtd: Add Nand Flash Controller support for Intel LGM SoC

Add YAML file for dt-bindings to support NAND Flash Controller
on Intel's Lightning Mountain SoC.
Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201110012333.18647-2-vadivel.muruganx.ramuthevar@linux.intel.com

Documentation/devicetree/bindings/mtd/intel,lgm-nand.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/intel,lgm-nand.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Intel LGM SoC NAND Controller Device Tree Bindings
+
+allOf:
+  - $ref: "nand-controller.yaml"
+
+maintainers:
+  - Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
+
+properties:
+  compatible:
+    const: intel,lgm-nand
+
+  reg:
+    maxItems: 6
+
+  reg-names:
+    items:
+      - const: ebunand
+      - const: hsnand
+      - const: nand_cs0
+      - const: nand_cs1
+      - const: addr_sel0
+      - const: addr_sel1
+
+  clocks:
+    maxItems: 1
+
+  dmas:
+    maxItems: 2
+
+  dma-names:
+    items:
+      - const: tx
+      - const: rx
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^nand@[a-f0-9]+$":
+    type: object
+    properties:
+      reg:
+        minimum: 0
+        maximum: 7
+
+      nand-ecc-mode: true
+
+      nand-ecc-algo:
+        const: hw
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - dmas
+  - dma-names
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    nand-controller@e0f00000 {
+      compatible = "intel,lgm-nand";
+      reg = <0xe0f00000 0x100>,
+            <0xe1000000 0x300>,
+            <0xe1400000 0x8000>,
+            <0xe1c00000 0x1000>,
+            <0x17400000 0x4>,
+            <0x17c00000 0x4>;
+      reg-names = "ebunand", "hsnand", "nand_cs0", "nand_cs1",
+        "addr_sel0", "addr_sel1";
+      clocks = <&cgu0 125>;
+      dmas = <&dma0 8>, <&dma0 9>;
+      dma-names = "tx", "rx";
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      nand@0 {
+        reg = <0>;
+        nand-ecc-mode = "hw";
+      };
+    };
+
+...