linux-kernel - Re: [PATCH v3 3/4] Documentation: devicetree: add PPMU events description

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Date:   Tue, 30 Apr 2019 15:16:04 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Lukasz Luba <l.luba@...tner.samsung.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     b.zolnierkie@...sung.com, krzk@...nel.org, robh+dt@...nel.org,
        mark.rutland@....com, kyungmin.park@...sung.com,
        m.szyprowski@...sung.com, s.nawrocki@...sung.com,
        myungjoo.ham@...sung.com, kgene@...nel.org,
        willy.mh.wolff.ml@...il.com
Subject: Re: [PATCH v3 3/4] Documentation: devicetree: add PPMU events
 description

Hi Lukasz,

On 19. 4. 19. 오후 10:48, Lukasz Luba wrote:
> Extend the documenation by events description with new 'event-data-type'
> field. Add example how the event might be defined in DT.
> 
> Signed-off-by: Lukasz Luba <l.luba@...tner.samsung.com>
> ---
>  .../devicetree/bindings/devfreq/event/exynos-ppmu.txt  | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt b/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
> index 3e36c1d..47feb5f 100644
> --- a/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
> +++ b/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
> @@ -145,3 +145,21 @@ Example3 : PPMUv2 nodes in exynos5433.dtsi are listed below.
>  			reg = <0x104d0000 0x2000>;
>  			status = "disabled";
>  		};
> +
> +The 'event' type specified in the PPMU node defines 'event-name'
> +which also contains 'id' number and optionally 'event-data-type'.
> +
> +Example:
> +
> +		events {
> +			ppmu_leftbus_0: ppmu-event0-leftbus {
> +				event-name = "ppmu-event0-leftbus";
> +				event-data-type = <PPMU_RO_DATA_CNT>;
> +			};
> +		};
> +
> +The 'event-data-type' defines the type of data which shell be counted
> +by the counter. You can check include/dt-bindings/pmu/exynos_ppmu.h for
> +all possible type, i.e. count read requests, count write data in bytes,
> +etc. This field is optional and when it is missing, the driver code will
> +use default data type.
> 

How about editing it as following?

--- a/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
+++ b/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
@@ -10,14 +10,23 @@ The Exynos PPMU driver uses the devfreq-event class to provide event data
 to various devfreq devices. The devfreq devices would use the event data when
 derterming the current state of each IP.
 
-Required properties:
+Required properties for PPMU device:
 - compatible: Should be "samsung,exynos-ppmu" or "samsung,exynos-ppmu-v2.
 - reg: physical base address of each PPMU and length of memory mapped region.
 
-Optional properties:
+Optional properties for PPMU device:
 - clock-names : the name of clock used by the PPMU, "ppmu"
 - clocks : phandles for clock specified in "clock-names" property
 
+Required properties for 'events' child node of PPMU device:
+- event-name : the unique event name among PPMU device
+Optional properties for 'events' child node of PPMU device:
+- event-data-type : Define the type of data which shell be counted
+by the counter. You can check include/dt-bindings/pmu/exynos_ppmu.h for
+all possible type, i.e. count read requests, count write data in bytes,
+etc. This field is optional and when it is missing, the driver code
+will use default data type.
+
 Example1 : PPMUv1 nodes in exynos3250.dtsi are listed below.
 
                ppmu_dmc0: ppmu_dmc0@...a0000 {
@@ -145,3 +154,16 @@ Example3 : PPMUv2 nodes in exynos5433.dtsi are listed below.
                        reg = <0x104d0000 0x2000>;
                        status = "disabled";
                };
+
+Example4 : 'event-data-type' in exynos4412-ppmu-common.dtsi are listed below.
+
+       &ppmu_dmc0 {
+               status = "okay";
+               events {
+                       ppmu_dmc0_3: ppmu-event3-dmc0 {
+                               event-name = "ppmu-event3-dmc0";
+                               event-data-type = <(PPMU_RO_DATA_CNT |
+                                               PPMU_WO_DATA_CNT)>;
+                       };
+               };
+       };


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics