Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-gate.txt b/Documentation/devicetree/bindings/i2c/i2c-gate.txt
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index 000000000..1846d236e
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+++ b/Documentation/devicetree/bindings/i2c/i2c-gate.txt
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+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>;
+			};
+		};
+	};