dt-bindings: dsp: mediatek: Add mt8186 dsp document

This patch adds mt8186 dsp document. The dsp is used for Sound Open
Firmware driver node. It includes registers, clocks, memory regions,
and mailbox for dsp.
Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220622062245.21021-4-tinghan.shen@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/dsp/mediatek,mt8186-dsp.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dsp/mediatek,mt8186-dsp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek mt8186 DSP core
+
+maintainers:
+  - Tinghan Shen <tinghan.shen@mediatek.com>
+
+description: |
+  MediaTek mt8186 SoC contains a DSP core used for
+  advanced pre- and post- audio processing.
+
+properties:
+  compatible:
+    const: mediatek,mt8186-dsp
+
+  reg:
+    items:
+      - description: Address and size of the DSP config registers
+      - description: Address and size of the DSP SRAM
+      - description: Address and size of the DSP secure registers
+      - description: Address and size of the DSP bus registers
+
+  reg-names:
+    items:
+      - const: cfg
+      - const: sram
+      - const: sec
+      - const: bus
+
+  clocks:
+    items:
+      - description: mux for audio dsp clock
+      - description: mux for audio dsp local bus
+
+  clock-names:
+    items:
+      - const: audiodsp
+      - const: adsp_bus
+
+  power-domains:
+    maxItems: 1
+
+  mboxes:
+    items:
+      - description: mailbox for receiving audio DSP requests.
+      - description: mailbox for transmitting requests to audio DSP.
+
+  mbox-names:
+    items:
+      - const: rx
+      - const: tx
+
+  memory-region:
+    items:
+      - description: dma buffer between host and DSP.
+      - description: DSP system memory.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - power-domains
+  - mbox-names
+  - mboxes
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8186-clk.h>
+    dsp@10680000 {
+        compatible = "mediatek,mt8186-dsp";
+        reg = <0x10680000 0x2000>,
+              <0x10800000 0x100000>,
+              <0x1068b000 0x100>,
+              <0x1068f000 0x1000>;
+        reg-names = "cfg", "sram", "sec", "bus";
+        clocks = <&topckgen CLK_TOP_AUDIODSP>,
+                 <&topckgen CLK_TOP_ADSP_BUS>;
+        clock-names = "audiodsp",
+                      "adsp_bus";
+        power-domains = <&spm 6>;
+        mbox-names = "rx", "tx";
+        mboxes = <&adsp_mailbox0>, <&adsp_mailbox1>;
+    };