Documentation: devicetree: add PPMU events description

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>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
This commit is contained in:
Lukasz Luba 2019-06-05 11:12:35 +02:00 committed by Chanwoo Choi
parent fcbd8037f7
commit 3b7b37846b
1 changed files with 24 additions and 2 deletions

View File

@ -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@106a0000 {
@ -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)>;
};
};
};