[PATCH v2 2/8] dt-bindings: i2c: add support for 'i2c-arb' subnode
From: Peter Rosin <hidden>
Date: 2016-08-15 19:15:23
Also in:
linux-i2c, lkml
Subsystem:
i2c muxes, i2c subsystem host drivers, open firmware and flattened device tree bindings, the rest · Maintainers:
Peter Rosin, Andi Shyti, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
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 <redacted>
Signed-off-by: Peter Rosin <redacted>
---
.../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 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; + }; + }; + };
diff --git a/MAINTAINERS b/MAINTAINERS
index 20bb1d00098c..1a61e2f5a0a9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS@@ -5660,6 +5660,7 @@ 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
--
2.1.4
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