arch/arm/boot/dts/bcm2835-rpi-b-plus.dts

/dts-v1/;
#include "bcm2835-rpi.dtsi"

/ {
	compatible = "raspberrypi,model-b-plus", "brcm,bcm2835";
	model = "Raspberry Pi Model B+";

	leds {
		act {
			gpios = <&gpio 47 0>;
		};

		pwr {
			label = "PWR";
			gpios = <&gpio 35 0>;
			default-state = "keep";
			linux,default-trigger = "default-on";
		};
	};
};

&gpio {
	pinctrl-0 = <&gpioout &alt0 &i2s_alt0 &alt3>;

	/* I2S interface */
	i2s_alt0: i2s_alt0 {
		brcm,pins = <18 19 20 21>;
		brcm,function = <BCM2835_FSEL_ALT0>;
	};
};