[PATCH v2 3/4] Documentation: devicetree: add PPMU events description

[Lukasz Luba <l.luba@partner.samsung.com>]

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@partner.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.
-- 
2.7.4