Document: dw_mmc-k3: add document of hi6220 mmc

Add bindings for hi6220 mmc support
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt

@@ -13,6 +13,10 @@ Required Properties:
 
 * compatible: should be one of the following.
   - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extensions.
+  - "hisilicon,hi6220-dw-mshc": for controllers with hi6220 specific extensions.
+
+Optional Properties:
+- hisilicon,peripheral-syscon: phandle of syscon used to control peripheral.
 
 Example:
 
@@ -42,3 +46,27 @@ Example:
 		cap-mmc-highspeed;
 		cap-sd-highspeed;
 	};
+
+	/* for Hi6220 */
+
+	dwmmc_1: dwmmc1@f723e000 {
+		compatible = "hisilicon,hi6220-dw-mshc";
+		num-slots = <0x1>;
+		bus-width = <0x4>;
+		disable-wp;
+		cap-sd-highspeed;
+		sd-uhs-sdr12;
+		sd-uhs-sdr25;
+		card-detect-delay = <200>;
+		hisilicon,peripheral-syscon = <&ao_ctrl>;
+		reg = <0x0 0xf723e000 0x0 0x1000>;
+		interrupts = <0x0 0x49 0x4>;
+		clocks = <&clock_sys HI6220_MMC1_CIUCLK>, <&clock_sys HI6220_MMC1_CLK>;
+		clock-names = "ciu", "biu";
+		cd-gpios = <&gpio1 0 1>;
+		pinctrl-names = "default", "idle";
+		pinctrl-0 = <&sd_pmx_func &sd_clk_cfg_func &sd_cfg_func>;
+		pinctrl-1 = <&sd_pmx_idle &sd_clk_cfg_idle &sd_cfg_idle>;
+		vqmmc-supply = <&ldo7>;
+		vmmc-supply = <&ldo10>;
+	};