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Commit 6d96302f authored by Chanwoo Choi's avatar Chanwoo Choi Committed by MyungJoo Ham
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PM / devfreq: event: Add documentation for exynos-ppmu devfreq-event driver 



This patch adds the documentation for Exynos PPMU (Platform Performance
Monitoring Unit) devfreq-event driver.

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent e6ee3192

Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt

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* Samsung Exynos PPMU (Platform Performance Monitoring Unit) device



The Samsung Exynos SoC has PPMU (Platform Performance Monitoring Unit) for

each IP. PPMU provides the primitive values to get performance data. These

PPMU events provide information of the SoC's behaviors so that you may

use to analyze system performance, to make behaviors visible and to count

usages of each IP (DMC, CPU, RIGHTBUS, LEFTBUS, CAM interface, LCD, G3D, MFC).

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:

- compatible: Should be "samsung,exynos-ppmu".

- reg: physical base address of each PPMU and length of memory mapped region.



Optional properties:

- clock-names : the name of clock used by the PPMU, "ppmu"

- clocks : phandles for clock specified in "clock-names" property

- #clock-cells: should be 1.



Example1 : PPMU nodes in exynos3250.dtsi are listed below.



		ppmu_dmc0: ppmu_dmc0@106a0000 {

			compatible = "samsung,exynos-ppmu";

			reg = <0x106a0000 0x2000>;

			status = "disabled";

		};



		ppmu_dmc1: ppmu_dmc1@106b0000 {

			compatible = "samsung,exynos-ppmu";

			reg = <0x106b0000 0x2000>;

			status = "disabled";

		};



		ppmu_cpu: ppmu_cpu@106c0000 {

			compatible = "samsung,exynos-ppmu";

			reg = <0x106c0000 0x2000>;

			status = "disabled";

		};



		ppmu_rightbus: ppmu_rightbus@112a0000 {

			compatible = "samsung,exynos-ppmu";

			reg = <0x112a0000 0x2000>;

			clocks = <&cmu CLK_PPMURIGHT>;

			clock-names = "ppmu";

			status = "disabled";

		};



		ppmu_leftbus: ppmu_leftbus0@116a0000 {

			compatible = "samsung,exynos-ppmu";

			reg = <0x116a0000 0x2000>;

			clocks = <&cmu CLK_PPMULEFT>;

			clock-names = "ppmu";

			status = "disabled";

		};



Example2 : Events of each PPMU node in exynos3250-rinato.dts are listed below.



	&ppmu_dmc0 {

		status = "okay";



		events {

			ppmu_dmc0_3: ppmu-event3-dmc0 {

				event-name = "ppmu-event3-dmc0";

			};



			ppmu_dmc0_2: ppmu-event2-dmc0 {

				event-name = "ppmu-event2-dmc0";

			};



			ppmu_dmc0_1: ppmu-event1-dmc0 {

				event-name = "ppmu-event1-dmc0";

			};



			ppmu_dmc0_0: ppmu-event0-dmc0 {

				event-name = "ppmu-event0-dmc0";

			};

		};

	};



	&ppmu_dmc1 {

		status = "okay";



		events {

			ppmu_dmc1_3: ppmu-event3-dmc1 {

				event-name = "ppmu-event3-dmc1";

			};

		};

	};



	&ppmu_leftbus {

		status = "okay";



		events {

			ppmu_leftbus_3: ppmu-event3-leftbus {

				event-name = "ppmu-event3-leftbus";

			};

		};

	};



	&ppmu_rightbus {

		status = "okay";



		events {

			ppmu_rightbus_3: ppmu-event3-rightbus {

				event-name = "ppmu-event3-rightbus";

			};

		};

	};