dt-bindings: (hwmon/sbtsi_temp) Add SB-TSI hwmon driver bindings

Document device tree bindings for AMD SB-TSI emulated temperature
sensor.
Signed-off-by: Kun Yi <kunyi@google.com>
Link: https://lore.kernel.org/r/20201211215427.3281681-4-kunyi@google.comReviewed-by: Rob Herring <robh@kernel.org>
[groeck: Fixed subject]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/amd,sbtsi.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/amd,sbtsi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: >
+  Sideband interface Temperature Sensor Interface (SB-TSI) compliant
+  AMD SoC temperature device
+
+maintainers:
+  - Kun Yi <kunyi@google.com>
+  - Supreeth Venkatesh <supreeth.venkatesh@amd.com>
+
+description: |
+  SB Temperature Sensor Interface (SB-TSI) is an SMBus compatible
+  interface that reports AMD SoC's Ttcl (normalized temperature),
+  and resembles a typical 8-pin remote temperature sensor's I2C interface
+  to BMC. The emulated thermal sensor can report temperatures in increments
+  of 0.125 degrees, ranging from 0 to 255.875.
+
+properties:
+  compatible:
+    enum:
+      - amd,sbtsi
+
+  reg:
+    maxItems: 1
+    description: |
+      I2C bus address of the device as specified in Section 6.3.1 of the
+      SoC register reference. The SB-TSI address is normally 98h for socket
+      0 and 90h for socket 1, but it could vary based on hardware address
+      select pins.
+      \[open source SoC register reference\]
+        https://www.amd.com/system/files/TechDocs/56255_OSRR.pdf
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        sbtsi@4c {
+                compatible = "amd,sbtsi";
+                reg = <0x4c>;
+        };
+    };
+...