linux-kernel - Re: [PATCH v7 1/6] dt-bindings: devfreq: Add documentation for the interconnect properties

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Message-ID: <2213a69c-1483-6840-28a4-ab7ca84d55bb@samsung.com>
Date:   Tue, 3 Nov 2020 18:40:18 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Sylwester Nawrocki <s.nawrocki@...sung.com>,
        georgi.djakov@...aro.org, krzk@...nel.org
Cc:     devicetree@...r.kernel.org, robh+dt@...nel.org,
        a.swigon@...sung.com, myungjoo.ham@...sung.com,
        inki.dae@...sung.com, sw0312.kim@...sung.com,
        b.zolnierkie@...sung.com, m.szyprowski@...sung.com,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v7 1/6] dt-bindings: devfreq: Add documentation for the
 interconnect properties

Hi Sylwester,

This patch contains one typo.

On 10/30/20 9:51 PM, Sylwester Nawrocki wrote:
> Add documentation for new optional properties in the exynos bus nodes:
> interconnects, #interconnect-cells, samsung,data-clock-ratio.
> 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@...sung.com>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
> ---
> Changes for v7:
>  - bus-width property replaced with samsung,data-clock-ratio,
>  - the interconnect consumer bindings used instead of vendor specific
>    properties
> 
> Changes for v6:
>  - added dts example of bus hierarchy definition and the interconnect
>    consumer,
>  - added new bus-width property.
> 
> Changes for v5:
>  - exynos,interconnect-parent-node renamed to samsung,interconnect-parent
> ---
>  .../devicetree/bindings/devfreq/exynos-bus.txt     | 68 +++++++++++++++++++++-
>  1 file changed, 66 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> index e71f752..e34175c 100644
> --- a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -51,6 +51,16 @@ 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):
> +- #interconnect-cells: should be 0.
> +- interconnects: as documented in ../interconnect.txt, describes a path
> +  at the higher level interconnects used by this interconnect provider.
> +  If this interconnect provider is a parent of a top level interconnect
> +  provider the property contains only one phandle.
> +
> +- samsung,data-clock-ratio: ratio of the data troughput in B/s to minimum data

s/troughput/throughput

> +   clock frequency in Hz, default value is 8 when this property is missing.
> +
>  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
> @@ -135,7 +145,7 @@ Detailed correlation between sub-blocks and power line according to Exynos SoC:
>  		|--- PERIC (Fixed clock rate)
>  		|--- FSYS  (Fixed clock rate)
>  
> -Example1:
> +Example 1:
>  	Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
>  	power line (regulator). The MIF (Memory Interface) AXI bus is used to
>  	transfer data between DRAM and CPU and uses the VDD_MIF regulator.
> @@ -184,7 +194,7 @@ Example1:
>  	|L5   |200000 |200000  |400000 |300000 |       ||1000000 |
>  	----------------------------------------------------------
>  
> -Example2 :
> +Example 2:
>  	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
>  	is listed below:
>  
> @@ -419,3 +429,57 @@ Example2 :
>  		devfreq = <&bus_leftbus>;
>  		status = "okay";
>  	};
> +
> +Example 3:
> +	An interconnect path "bus_display -- bus_leftbus -- bus_dmc" on
> +	Exynos4412 SoC with video mixer as an interconnect consumer device.
> +
> +	soc {
> +		bus_dmc: bus_dmc {
> +			compatible = "samsung,exynos-bus";
> +			clocks = <&clock CLK_DIV_DMC>;
> +			clock-names = "bus";
> +			operating-points-v2 = <&bus_dmc_opp_table>;
> +			samsung,data-clock-ratio = <4>;
> +			#interconnect-cells = <0>;
> +		};
> +
> +		bus_leftbus: bus_leftbus {
> +			compatible = "samsung,exynos-bus";
> +			clocks = <&clock CLK_DIV_GDL>;
> +			clock-names = "bus";
> +			operating-points-v2 = <&bus_leftbus_opp_table>;
> +			#interconnect-cells = <0>;
> +			interconnects = <&bus_dmc>;
> +		};
> +
> +		bus_display: bus_display {
> +			compatible = "samsung,exynos-bus";
> +			clocks = <&clock CLK_ACLK160>;
> +			clock-names = "bus";
> +			operating-points-v2 = <&bus_display_opp_table>;
> +			#interconnect-cells = <0>;
> +			interconnects = <&bus_leftbus &bus_dmc>;

About adding two icc_node, I queried you on patch2.

> +		};
> +
> +		bus_dmc_opp_table: opp_table1 {
> +			compatible = "operating-points-v2";
> +			/* ... */
> +		}
> +
> +		bus_leftbus_opp_table: opp_table3 {
> +			compatible = "operating-points-v2";
> +			/* ... */
> +		};
> +
> +		bus_display_opp_table: opp_table4 {
> +			compatible = "operating-points-v2";
> +			/* .. */
> +		};
> +
> +		&mixer {
> +			compatible = "samsung,exynos4212-mixer";
> +			interconnects = <&bus_display &bus_dmc>;
> +			/* ... */
> +		};
> +	};
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics