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SubjectRe: [PATCH v2 3/8] dt-bindings: i2c: add support for 'i2c-gate' subnode
On Mon, Aug 15, 2016 at 03:40:26PM +0200, Peter Rosin wrote:
> Handle i2c gates similarly to how i2c arbitrators are handled.
> This gets rid of a pointless 'reg' property for i2c gates.
>
> I.e. this new and more compact style
>
> some-gate {
> i2c-gate {
> #address-cells = <1>;
> #size-cells = <0>;
>
> some-i2c-device@50 {
> reg = <0x50>;
> };
> };
> };
>
> instead of the old
>
> some-gate {
> #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>
> ---
> Documentation/devicetree/bindings/i2c/i2c-gate.txt | 41 ++++++++++++++++++++++
> MAINTAINERS | 1 +
> 2 files changed, 42 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gate.txt
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-gate.txt b/Documentation/devicetree/bindings/i2c/i2c-gate.txt
> new file mode 100644
> index 000000000000..0b057fb2a15a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-gate.txt
> @@ -0,0 +1,41 @@
> +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@0c {

Drop the leading 0. With that,

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

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