.../arch/arm/boot/dts/imx28-tx28.dts
reg_usb1_vbus: regulator@1 {
compatible = "regulator-fixed";
reg = <1>;
regulator-name = "usb1_vbus";
regulator-min-microvolt = <5000000>;
regulator-max-microvolt = <5000000>;
//gpio = <&gpio3 27 GPIO_ACTIVE_HIGH>;
enable-active-high;
};