dt-bindings: thermal: sprd: Add the Spreadtrum thermal documentation

Add the Spreadtrum thermal documentation.
Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/444e45ce0a9b390b2502dfcefd1ddb36948fa8e1.1582013101.git.baolin.wang7@gmail.com

Documentation/devicetree/bindings/thermal/sprd-thermal.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/sprd-thermal.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spreadtrum thermal sensor controller bindings
+
+maintainers:
+  - Orson Zhai <orsonzhai@gmail.com>
+  - Baolin Wang <baolin.wang7@gmail.com>
+  - Chunyan Zhang <zhang.lyra@gmail.com>
+
+properties:
+  compatible:
+    const: sprd,ums512-thermal
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: enable
+
+  nvmem-cells:
+    maxItems: 2
+    description:
+      Reference to nvmem nodes for the calibration data.
+
+  nvmem-cell-names:
+    maxItems: 2
+    items:
+      - const: thm_sign_cal
+      - const: thm_ratio_cal
+
+  "#thermal-sensor-cells":
+    const: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^([a-z]*-)?sensor(-section)?@[0-9]+$":
+    type: object
+    description:
+      Represent one thermal sensor.
+
+    properties:
+      reg:
+        description: Specify the sensor id.
+        maxItems: 1
+
+      nvmem-cells:
+        maxItems: 1
+        description:
+          Reference to an nvmem node for the calibration data.
+
+      nvmem-cell-names:
+        const: sen_delta_cal
+
+    required:
+      - reg
+      - nvmem-cells
+      - nvmem-cell-names
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - nvmem-cells
+  - nvmem-cell-names
+  - "#thermal-sensor-cells"
+  - "#address-cells"
+  - "#size-cells"
+
+examples:
+  - |
+        ap_thm0: thermal@32200000 {
+                compatible = "sprd,ums512-thermal";
+                reg = <0 0x32200000 0 0x10000>;
+                clock-names = "enable";
+                clocks = <&aonapb_gate 32>;
+                #thermal-sensor-cells = <1>;
+                nvmem-cells = <&thm0_sign>, <&thm0_ratio>;
+                nvmem-cell-names = "thm_sign_cal", "thm_ratio_cal";
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                prometheus-sensor@0 {
+                        reg = <0>;
+                        nvmem-cells = <&thm0_sen0>;
+                        nvmem-cell-names = "sen_delta_cal";
+                };
+
+                ank-sensor@1 {
+                        reg = <1>;
+                        nvmem-cells = <&thm0_sen1>;
+                        nvmem-cell-names = "sen_delta_cal";
+                };
+        };
+...