[RFC PATCHv3 4/7] devfreq: event: Add documentation for exynos-ppmu devfreq-event driver

[Chanwoo Choi]

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

Cc: MyungJoo Ham <myungjoo.ham at samsung.com>
Cc: Kyungmin Park <kyungmin.park at samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi at samsung.com>
---
 .../bindings/devfreq/event/exynos-ppmu.txt         | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt

diff --git a/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt b/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
new file mode 100644
index 0000000..f7e50e5
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt
@@ -0,0 +1,56 @@
+
+* Samsung Exynos PPMU (Performance Profiling Monitoring Unit) device
+
+The Samsung Exynos SoC have PPMU (Performance Profiling Monitoring Unit) for
+each IPs. PPMU provides the primitive values to get performance data. These
+events provide useful information about the behavior of the SoC that you can
+use when analyzing system performance, and made visible and can be counted
+using login in each IP (DMC, CPU, RIGHTBUS, LEFTBUS, CAM interface, LCD, G3D,
+MFC). The Exynos PPMU driver use the devfreq-event class to provide event data
+to various devfreq device. The devfreq device 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.
+
+Example : Examples of PPMU nodes are listed below.
+
+		ppmu_dmc0: ppmu_dmc0 at 106a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106a0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_dmc1: ppmu_dmc1 at 106b0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106b0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_cpu: ppmu_cpu at 106c0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106c0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_rightbus: ppmu_rightbus at 112a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x112a0000 0x2000>;
+			clocks = <&cmu CLK_PPMURIGHT>;
+			clock-names = "ppmu";
+			status = "disabled";
+		};
+
+		ppmu_leftbus: ppmu_leftbus0 at 116a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x116a0000 0x2000>;
+			clocks = <&cmu CLK_PPMULEFT>;
+			clock-names = "ppmu";
+			status = "disabled";
+		};
-- 
1.8.5.5