linux-kernel - Re: [PATCH v2 3/8] dt-bindings: i2c: add support for 'i2c-gate' subnode

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Date:	Tue, 16 Aug 2016 08:57:51 -0500
From:	Rob Herring <robh@...nel.org>
To:	Peter Rosin <peda@...ntia.se>
Cc:	linux-kernel@...r.kernel.org, Wolfram Sang <wsa@...-dreams.de>,
	Mark Rutland <mark.rutland@....com>,
	Guenter Roeck <linux@...ck-us.net>,
	"David S. Miller" <davem@...emloft.net>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
	Crestez Dan Leonard <leonard.crestez@...el.com>
Subject: Re: [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@...ntia.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@...nel.org>