dt-bindings: mmc: spacemit,sdhci: add support for K1 SoC

Add support for the SD/eMMC Host Controller found in SpacemiT K1 SoC,
The controller supports data transmission of MMC, SDIO, SD protocol.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250509-20-k1-sdhci-v3-1-526c35feaa20@gentoo.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml

@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/spacemit,sdhci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SpacemiT SDHCI Controller
+
+maintainers:
+  - Yixun Lan <dlan@gentoo.org>
+
+allOf:
+  - $ref: mmc-controller.yaml#
+
+properties:
+  compatible:
+    const: spacemit,k1-sdhci
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: core clock, used by internal controller
+      - description: io clock, output for SD, SDIO, eMMC device
+
+  clock-names:
+    items:
+      - const: core
+      - const: io
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    mmc@d4281000 {
+      compatible = "spacemit,k1-sdhci";
+      reg = <0xd4281000 0x200>;
+      interrupts = <101>;
+      interrupt-parent = <&plic>;
+      clocks = <&clk_apmu 10>, <&clk_apmu 13>;
+      clock-names = "core", "io";
+    };