dt-bindings: soc: mediatek: add mtk svs dt-bindings

Document the binding for enabling mtk svs on MediaTek SoC.
Signed-off-by: Roger Lu <roger.lu@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20220516004311.18358-2-roger.lu@mediatek.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/soc/mediatek/mtk-svs.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/mediatek/mtk-svs.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek Smart Voltage Scaling (SVS) Device Tree Bindings
+
+maintainers:
+  - Roger Lu <roger.lu@mediatek.com>
+  - Matthias Brugger <matthias.bgg@gmail.com>
+  - Kevin Hilman <khilman@kernel.org>
+
+description: |+
+  The SVS engine is a piece of hardware which has several
+  controllers(banks) for calculating suitable voltage to
+  different power domains(CPU/GPU/CCI) according to
+  chip process corner, temperatures and other factors. Then DVFS
+  driver could apply SVS bank voltage to PMIC/Buck.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt8183-svs
+
+  reg:
+    maxItems: 1
+    description: Address range of the MTK SVS controller.
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description: Main clock for MTK SVS controller to work.
+
+  clock-names:
+    const: main
+
+  nvmem-cells:
+    minItems: 1
+    description:
+      Phandle to the calibration data provided by a nvmem device.
+    items:
+      - description: SVS efuse for SVS controller
+      - description: Thermal efuse for SVS controller
+
+  nvmem-cell-names:
+    items:
+      - const: svs-calibration-data
+      - const: t-calibration-data
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - nvmem-cells
+  - nvmem-cell-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8183-clk.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        svs@1100b000 {
+            compatible = "mediatek,mt8183-svs";
+            reg = <0 0x1100b000 0 0x1000>;
+            interrupts = <GIC_SPI 127 IRQ_TYPE_LEVEL_LOW>;
+            clocks = <&infracfg CLK_INFRA_THERM>;
+            clock-names = "main";
+            nvmem-cells = <&svs_calibration>, <&thermal_calibration>;
+            nvmem-cell-names = "svs-calibration-data", "t-calibration-data";
+        };
+    };