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Subject: Re: [RFC PATCH v5 1/6] dt-bindings: exynos-bus: Add documentation
 for interconnect properties
To:     georgi.djakov@linaro.org, cw00.choi@samsung.com, krzk@kernel.org
Cc:     a.swigon@samsung.com, myungjoo.ham@samsung.com,
        inki.dae@samsung.com, sw0312.kim@samsung.com,
        b.zolnierkie@samsung.com, m.szyprowski@samsung.com,
        linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org
From:   Sylwester Nawrocki <s.nawrocki@samsung.com>
Message-ID: <e8e00988-af5d-7022-f66d-89a2cb0f74cf@samsung.com>
Date:   Mon, 1 Jun 2020 10:19:45 +0200
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Cc: Rob, devicetree ML

On 29.05.2020 18:31, Sylwester Nawrocki wrote:
> Add documentation for new optional properties in the exynos bus nodes:
> samsung,interconnect-parent, #interconnect-cells.
> These properties allow to specify the SoC interconnect structure which
> then allows the interconnect consumer devices to request specific
> bandwidth requirements.
> 
> Signed-off-by: Artur Świgoń <a.swigon@samsung.com>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> ---
> Changes for v5:
>  - exynos,interconnect-parent-node renamed to samsung,interconnect-parent
> ---
>  Documentation/devicetree/bindings/devfreq/exynos-bus.txt | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> index e71f752..e0d2daa 100644
> --- a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -51,6 +51,11 @@ Optional properties only for parent bus device:
>  - exynos,saturation-ratio: the percentage value which is used to calibrate
>  			the performance count against total cycle count.
> 
> +Optional properties for interconnect functionality (QoS frequency constraints):
> +- samsung,interconnect-parent: phandle to the parent interconnect node; for
> +  passive devices should point to same node as the exynos,parent-bus property.
> +- #interconnect-cells: should be 0
> +
>  Detailed correlation between sub-blocks and power line according to Exynos SoC:
>  - In case of Exynos3250, there are two power line as following:
>  	VDD_MIF |--- DMC
> @@ -185,8 +190,9 @@ Example1:
>  	----------------------------------------------------------
> 
>  Example2 :
> -	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
> -	is listed below:
> +	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi is
> +	listed below. An interconnect path "bus_lcd0 -- bus_leftbus -- bus_dmc"
> +	is defined for demonstration purposes.
> 
>  	bus_dmc: bus_dmc {
>  		compatible = "samsung,exynos-bus";
> @@ -376,12 +382,15 @@ Example2 :
>  	&bus_dmc {
>  		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
>  		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
> +		#interconnect-cells = <0>;
>  		status = "okay";
>  	};
> 
>  	&bus_leftbus {
>  		devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
>  		vdd-supply = <&buck3_reg>;
> +		samsung,interconnect-parent = <&bus_dmc>;
> +		#interconnect-cells = <0>;
>  		status = "okay";
>  	};
> 
> @@ -392,6 +401,8 @@ Example2 :
> 
>  	&bus_lcd0 {
>  		devfreq = <&bus_leftbus>;
> +		samsung,interconnect-parent = <&bus_leftbus>;
> +		#interconnect-cells = <0>;
>  		status = "okay";
>  	};
> 
> --
> 2.7.4