An i2c gate is useful to e.g. reduce the digital noise for RF tuners connected
to the i2c bus. Gates are similar to arbitrators in that you need to perform
some kind of operation to access the i2c bus past the arbitrator/gate, but
there are no competing masters to consider for gates and therefore there is
no arbitration happening for gates.

Common i2c gate properties.

- i2c-gate child node

Required properties for the i2c-gate child node:
- #address-cells = <1>;
- #size-cells = <0>;

Optional properties for i2c-gate child node:
- Child nodes conforming to i2c bus binding


Example :

	/*
	   An Invensense mpu9150 at address 0x68 featuring an on-chip Asahi
	   Kasei ak8975 compass behind a gate.
	 */

	mpu9150@68 {
		compatible = "invensense,mpu9150";
		reg = <0x68>;
		interrupt-parent = <&gpio1>;
		interrupts = <18 1>;

		i2c-gate {
			#address-cells = <1>;
			#size-cells = <0>;

			ax8975@c {
				compatible = "ak,ak8975";
				reg = <0x0c>;
			};
		};
	};