dt-bindings: nvmem: add binding for QTI SPMI SDAM

QTI SDAM allows PMIC peripherals to access the shared memory that is
available on QTI PMICs. Add documentation for it.
Signed-off-by: Shyam Kumar Thella <sthella@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200116161100.30637-3-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/nvmem/qcom,spmi-sdam.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/qcom,spmi-sdam.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Technologies, Inc. SPMI SDAM DT bindings
+
+maintainers:
+  - Shyam Kumar Thella <sthella@codeaurora.org>
+
+description: |
+  The SDAM provides scratch register space for the PMIC clients. This
+  memory can be used by software to store information or communicate
+  to/from the PBUS.
+
+allOf:
+  - $ref: "nvmem.yaml#"
+
+properties:
+  compatible:
+    enum:
+      - qcom,spmi-sdam
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+  ranges: true
+
+required:
+  - compatible
+  - reg
+  - ranges
+
+patternProperties:
+  "^.*@[0-9a-f]+$":
+    type: object
+
+    properties:
+      reg:
+        maxItems: 1
+        description:
+          Offset and size in bytes within the storage device.
+
+      bits:
+        $ref: /schemas/types.yaml#/definitions/uint32-array
+        maxItems: 1
+        items:
+          items:
+            - minimum: 0
+              maximum: 7
+              description:
+                Offset in bit within the address range specified by reg.
+            - minimum: 1
+              description:
+                Size in bit within the address range specified by reg.
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+examples:
+  - |
+      sdam_1: nvram@b000 {
+          #address-cells = <1>;
+          #size-cells = <1>;
+          compatible = "qcom,spmi-sdam";
+          reg = <0xb000 0x100>;
+          ranges = <0 0xb000 0x100>;
+
+          /* Data cells */
+          restart_reason: restart@50 {
+              reg = <0x50 0x1>;
+              bits = <6 2>;
+          };
+      };
+...