diff mbox

[2/7] dt-bindings: i2c: add support for 'i2c-arb' subnode

Message ID 1469609010-23049-3-git-send-email-peda@axentia.se
State Not Applicable, archived
Headers show

Commit Message

Peter Rosin July 27, 2016, 8:43 a.m. UTC 
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-mux {
			#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>;
			};
		};
	};

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 .../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

Comments

Rob Herring July 29, 2016, 9:24 p.m. UTC | #1 
On Wed, Jul 27, 2016 at 10:43:25AM +0200, Peter Rosin wrote:
> 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-mux {

You mean i2c-arb here?

> 			#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>;
> 			};
> 		};
> 	};
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  .../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

Otherwise,

Acked-by: Rob Herring <robh@kernel.org>
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diff mbox

Patch

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 8c20323d1277..543052305a09 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5524,6 +5524,7 @@  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