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authorPeter Rosin <peda@axentia.se>2016-07-08 12:12:17 +0200
committerPeter Rosin <peda@axentia.se>2016-08-25 22:11:00 +0200
commite8813c15be0a9e7f2c79c58d3329d92bcf056ecc (patch)
tree4d8f0b29bcd34446ddf619edd4b089040428e4d6 /Documentation/devicetree/bindings/i2c
parent374f8436ff3a450a2f95a0c1910a0b17212cede1 (diff)
downloadblackbird-op-linux-e8813c15be0a9e7f2c79c58d3329d92bcf056ecc.tar.gz
blackbird-op-linux-e8813c15be0a9e7f2c79c58d3329d92bcf056ecc.zip
dt-bindings: i2c: add support for 'i2c-arb' subnode
This gets rid of the need for a pointless 'reg' property for i2c arbitrators. I.e. this new and more compact style some-arbitrator { i2c-arb { #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; instead of the old some-arbitrator { #address-cells = <1>; #size-cells = <0>; i2c@0 { reg = <0>; #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Peter Rosin <peda@axentia.se>
Diffstat (limited to 'Documentation/devicetree/bindings/i2c')
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt8
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-arb.txt35
2 files changed, 37 insertions, 6 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt
index 71191ff0e781..248a155414c2 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt
@@ -44,8 +44,7 @@ Required properties:
- our-claim-gpio: The GPIO that we use to claim the bus.
- their-claim-gpios: The GPIOs that the other sides use to claim the bus.
Note that some implementations may only support a single other master.
-- Standard I2C mux properties. See i2c-mux.txt in this directory.
-- Single I2C child bus node at reg 0. See i2c-mux.txt in this directory.
+- I2C arbitration bus node. See i2c-arb.txt in this directory.
Optional properties:
- slew-delay-us: microseconds to wait for a GPIO to go high. Default is 10 us.
@@ -63,8 +62,6 @@ Example:
i2c-arbitrator {
compatible = "i2c-arb-gpio-challenge";
- #address-cells = <1>;
- #size-cells = <0>;
i2c-parent = <&{/i2c@12CA0000}>;
@@ -74,8 +71,7 @@ Example:
wait-retry-us = <3000>;
wait-free-us = <50000>;
- i2c@0 {
- reg = <0>;
+ i2c-arb {
#address-cells = <1>;
#size-cells = <0>;
diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb.txt b/Documentation/devicetree/bindings/i2c/i2c-arb.txt
new file mode 100644
index 000000000000..59abf9277bdc
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-arb.txt
@@ -0,0 +1,35 @@
+Common i2c arbitration bus properties.
+
+- i2c-arb child node
+
+Required properties for the i2c-arb child node:
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Optional properties for i2c-arb child node:
+- Child nodes conforming to i2c bus binding
+
+
+Example :
+
+ /*
+ An NXP pca9541 I2C bus master selector at address 0x74
+ with a NXP pca8574 GPIO expander attached.
+ */
+
+ arb@74 {
+ compatible = "nxp,pca9541";
+ reg = <0x74>;
+
+ i2c-arb {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ gpio@38 {
+ compatible = "nxp,pca8574";
+ reg = <0x38>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ };
+ };
+ };
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