riscv: dts: sophgo: add sdcard support for milkv duo

Add sdhci dt node in SoC dtsi and enable it in milkv duo dts.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>

arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo.dts

@@ -33,6 +33,14 @@
 	clock-frequency = <25000000>;
 };
 
+&sdhci0 {
+	status = "okay";
+	bus-width = <4>;
+	no-1-8-v;
+	no-mmc;
+	no-sdio;
+};
+
 &uart0 {
 	status = "okay";
 };

arch/riscv/boot/dts/sophgo/cv18xx.dtsi

@@ -4,6 +4,7 @@
  * Copyright (C) 2023 Inochi Amaoto <inochiama@outlook.com>
  */
 
+#include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/reset/sophgo,cv1800b-reset.h>
 
@@ -47,6 +48,13 @@
 		#clock-cells = <0>;
 	};
 
+	sdhci_clk: sdhci-clock {
+		compatible = "fixed-clock";
+		clock-frequency = <375000000>;
+		clock-output-names = "sdhci_clk";
+		#clock-cells = <0>;
+	};
+
 	soc {
 		compatible = "simple-bus";
 		interrupt-parent = <&plic>;
@@ -188,6 +196,15 @@
 			status = "disabled";
 		};
 
+		sdhci0: mmc@4310000 {
+			compatible = "sophgo,cv1800b-dwcmshc";
+			reg = <0x4310000 0x1000>;
+			interrupts = <36 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&sdhci_clk>;
+			clock-names = "core";
+			status = "disabled";
+		};
+
 		plic: interrupt-controller@70000000 {
 			reg = <0x70000000 0x4000000>;
 			interrupts-extended = <&cpu0_intc 11>, <&cpu0_intc 9>;