xref: /OK3568_Linux_fs/kernel/Documentation/devicetree/bindings/i2c/i2c-gate.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunAn i2c gate is useful to e.g. reduce the digital noise for RF tuners connected
2*4882a593Smuzhiyunto the i2c bus. Gates are similar to arbitrators in that you need to perform
3*4882a593Smuzhiyunsome kind of operation to access the i2c bus past the arbitrator/gate, but
4*4882a593Smuzhiyunthere are no competing masters to consider for gates and therefore there is
5*4882a593Smuzhiyunno arbitration happening for gates.
6*4882a593Smuzhiyun
7*4882a593SmuzhiyunCommon i2c gate properties.
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun- i2c-gate child node
10*4882a593Smuzhiyun
11*4882a593SmuzhiyunRequired properties for the i2c-gate child node:
12*4882a593Smuzhiyun- #address-cells = <1>;
13*4882a593Smuzhiyun- #size-cells = <0>;
14*4882a593Smuzhiyun
15*4882a593SmuzhiyunOptional properties for i2c-gate child node:
16*4882a593Smuzhiyun- Child nodes conforming to i2c bus binding
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunExample :
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun	/*
22*4882a593Smuzhiyun	   An Invensense mpu9150 at address 0x68 featuring an on-chip Asahi
23*4882a593Smuzhiyun	   Kasei ak8975 compass behind a gate.
24*4882a593Smuzhiyun	 */
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun	mpu9150@68 {
27*4882a593Smuzhiyun		compatible = "invensense,mpu9150";
28*4882a593Smuzhiyun		reg = <0x68>;
29*4882a593Smuzhiyun		interrupt-parent = <&gpio1>;
30*4882a593Smuzhiyun		interrupts = <18 1>;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun		i2c-gate {
33*4882a593Smuzhiyun			#address-cells = <1>;
34*4882a593Smuzhiyun			#size-cells = <0>;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun			ax8975@c {
37*4882a593Smuzhiyun				compatible = "ak,ak8975";
38*4882a593Smuzhiyun				reg = <0x0c>;
39*4882a593Smuzhiyun			};
40*4882a593Smuzhiyun		};
41*4882a593Smuzhiyun	};
42