Re: [PATCH v2 09/19] PM / devfreq: exynos: Update documentation for bus devices using passive governor

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On 09.12.2015 13:08, Chanwoo Choi wrote:
> This patch updates the documentation for passive bus devices and adds the
> detailed example of Exynos3250.
> 
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
>  .../devicetree/bindings/devfreq/exynos-bus.txt     | 244 ++++++++++++++++++++-
>  1 file changed, 241 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> index 54a1f9c46c88..c4fdc70f8eac 100644
> --- a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -13,18 +13,23 @@ SoC has the different sub-blocks. So, this difference should be specified
>  in devicetree file instead of each device driver. In result, this driver
>  is able to support the bus frequency for all Exynos SoCs.
>  
> -Required properties for bus device:
> +Required properties for all bus devices:
>  - compatible: Should be "samsung,exynos-bus".
>  - clock-names : the name of clock used by the bus, "bus".
>  - clocks : phandles for clock specified in "clock-names" property.
>  - #clock-cells: should be 1.
>  - operating-points-v2: the OPP table including frequency/voltage information
>    to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
> +
> +Required properties for only parent bus device:

Maybe:
"Required properties only for parent bus devices:"

In this binding documentation file the idea of "parent" is not
explained. I now it is related to passive devfreq governor but looking
at the binding itself it is a new idea, not covered here.

>  - vdd-supply: the regulator to provide the buses with the voltage.
>  - devfreq-events: the devfreq-event device to monitor the curret utilization
>    of buses.
>  
> -Optional properties for bus device:
> +Required properties for only passive bus device:

"Required properties only for passive bus devices:"

> +- devfreq: the parent bus device.
> +
> +Optional properties for only parent bus device:
>  - exynos,saturation-ratio: the percentage value which is used to calibrate
>                     the performance count againt total cycle count.
>  
> @@ -33,7 +38,20 @@ Example1:
>  	power line (regulator). The MIF (Memory Interface) AXI bus is used to
>  	transfer data between DRAM and CPU and uses the VDD_MIF regualtor.
>  
> -	- power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
> +	- MIF (Memory Interface) block
> +	: VDD_MIF |--- DMC (Dynamic Memory Controller)
> +
> +	- INT (Internal) block
> +	: VDD_INT |--- LEFTBUS (parent device)
> +		  |--- PERIL
> +		  |--- MFC
> +		  |--- G3D
> +		  |--- RIGHTBUS
> +		  |--- FSYS
> +		  |--- LCD0
> +		  |--- PERIR
> +		  |--- ISP
> +		  |--- CAM
>  
>  	- MIF bus's frequency/voltage table
>  	-----------------------
> @@ -46,6 +64,24 @@ Example1:
>  	|L5| 400000 |875000   |
>  	-----------------------
>  
> +	- INT bus's frequency/voltage table
> +	----------------------------------------------------------
> +	|Block|LEFTBUS|RIGHTBUS|MCUISP |ISP    |PERIL  ||VDD_INT |
> +	| name|       |LCD0    |       |       |       ||        |
> +	|     |       |FSYS    |       |       |       ||        |
> +	|     |       |MFC     |       |       |       ||        |
> +	----------------------------------------------------------
> +	|Mode |*parent|passive |passive|passive|passive||        |
> +	----------------------------------------------------------
> +	|Lv   |Frequency                               ||Voltage |
> +	----------------------------------------------------------
> +	|L1   |50000  |50000   |50000  |50000  |50000  ||900000  |
> +	|L2   |80000  |80000   |80000  |80000  |80000  ||900000  |
> +	|L3   |100000 |100000  |100000 |100000 |100000 ||1000000 |
> +	|L4   |134000 |134000  |200000 |200000 |       ||1000000 |
> +	|L5   |200000 |200000  |400000 |300000 |       ||1000000 |
> +	----------------------------------------------------------
> +
>  Example2 :
>  	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
>  	are listed below:
> @@ -84,6 +120,167 @@ Example2 :
>  		};
>  	};
>  
> +	bus_leftbus: bus_leftbus {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_GDL>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_leftbus_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_rightbus: bus_rightbus {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_GDR>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_leftbus_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_lcd0: bus_lcd0 {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_ACLK_160>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_leftbus_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_fsys: bus_fsys {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_ACLK_200>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_leftbus_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_mcuisp: bus_mcuisp {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_ACLK_400_MCUISP>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_mcuisp_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_isp: bus_isp {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu CLK_DIV_ACLK_266>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_isp_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_peril: bus_perir {


Peril or perir?

Best regards,
Krzysztof