xref: /freebsd/sys/contrib/device-tree/Bindings/i2c/i2c-gate.txt (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1An i2c gate is useful to e.g. reduce the digital noise for RF tuners connected
2to the i2c bus. Gates are similar to arbitrators in that you need to perform
3some kind of operation to access the i2c bus past the arbitrator/gate, but
4there are no competing masters to consider for gates and therefore there is
5no arbitration happening for gates.
6
7Common i2c gate properties.
8
9- i2c-gate child node
10
11Required properties for the i2c-gate child node:
12- #address-cells = <1>;
13- #size-cells = <0>;
14
15Optional properties for i2c-gate child node:
16- Child nodes conforming to i2c bus binding
17
18
19Example :
20
21	/*
22	   An Invensense mpu9150 at address 0x68 featuring an on-chip Asahi
23	   Kasei ak8975 compass behind a gate.
24	 */
25
26	mpu9150@68 {
27		compatible = "invensense,mpu9150";
28		reg = <0x68>;
29		interrupt-parent = <&gpio1>;
30		interrupts = <18 1>;
31
32		i2c-gate {
33			#address-cells = <1>;
34			#size-cells = <0>;
35
36			ax8975@c {
37				compatible = "ak,ak8975";
38				reg = <0x0c>;
39			};
40		};
41	};
42