From e8813c15be0a9e7f2c79c58d3329d92bcf056ecc Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Fri, 8 Jul 2016 12:12:17 +0200 Subject: [PATCH] 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 Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- .../bindings/i2c/i2c-arb-gpio-challenge.txt | 8 ++--- Documentation/devicetree/bindings/i2c/i2c-arb.txt | 35 ++++++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 38 insertions(+), 6 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt index 71191ff..248a155 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 0000000..59abf92 --- /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; + }; + }; + }; diff --git a/MAINTAINERS b/MAINTAINERS index 0bbe4b1..cde3e72 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5667,6 +5667,7 @@ S: Maintained F: Documentation/i2c/i2c-topology F: Documentation/i2c/muxes/ F: Documentation/devicetree/bindings/i2c/i2c-mux* +F: Documentation/devicetree/bindings/i2c/i2c-arb* F: drivers/i2c/i2c-mux.c F: drivers/i2c/muxes/ F: include/linux/i2c-mux.h -- 2.7.4