修改MT7620 DTS支持USB

    首先确定硬件有USB，这个得检查板子是否引出了usb口，一把来说mt7620的板子是引出了的。

    文件修改：在./openwrt/garget/linux/ramips/dts/目录下，确定MT7620a.dts文件是否有如下内容，status = “okay”很重要。

 ehci@101c0000 {
        status = "okay";
    };

    ohci@101c1000 {
        status = "okay";
    };

    接着，还是在./openwrt/garget/linux/ramips/dts/目录下，将文件 mt7620a.dtsi 如下内容：

ehci@101c0000 {
        compatible = "ralink,rt3xxx-ehci";
        reg = <0x101c0000 0x1000>;

        interrupt-parent = <&intc>;
        interrupts = <18>;

        status = "disabled";
    };

    ohci@101c1000 {
        compatible = "ralink,rt3xxx-ohci";
        reg = <0x101c1000 0x1000>;

        interrupt-parent = <&intc>;
        interrupts = <18>;

        status = "disabled";
    };

status = “disabled”注释掉，更改成这样：

    ehci@101c0000 {
        compatible = "ralink,rt3xxx-ehci";
        reg = <0x101c0000 0x1000>;

        interrupt-parent = <&intc>;
        interrupts = <18>;

        #status = "disabled";
    };

    ohci@101c1000 {
        compatible = "ralink,rt3xxx-ohci";
        reg = <0x101c1000 0x1000>;

        interrupt-parent = <&intc>;
        interrupts = <18>;

        #status = "disabled";
    };

执行make menuconfig ，添加USB相关支持

Kernel modules —> USB Support —> <*> kmod-usb-core.  
Kernel modules —> USB Support —> <*> kmod-usb-ohci.  
Kernel modules —> USB Support —> <*> kmod-usb-uhci.  
Kernel modules —> USB Support —> <*> kmod-usb-storage.
Kernel modules —> USB Support —> <*> kmod-usb-storage-extras.
Kernel modules —> USB Support —> <*> kmod-usb2. 

重新编译就行了。