[PATCH V3 4/6] dt-bindings: csky: Add csky PMU bindings

[Mao Han <han_mao@c-sky.com>]

This patch adds the documentation to describe that how to add pmu node in
dts.

Signed-off-by: Mao Han <han_mao@c-sky.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Guo Ren <guoren@kernel.org>
CC: linux-csky@vger.kernel.org
---
 Documentation/devicetree/bindings/csky/pmu.txt | 38 ++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/csky/pmu.txt

diff --git a/Documentation/devicetree/bindings/csky/pmu.txt b/Documentation/devicetree/bindings/csky/pmu.txt
new file mode 100644
index 0000000..4046b3b
--- /dev/null
+++ b/Documentation/devicetree/bindings/csky/pmu.txt
@@ -0,0 +1,38 @@
+============================
+C-SKY Performance Monitor Units
+============================
+
+C-SKY 8xx series cores often have a PMU for counting cpu and cache events.
+The C-SKY PMU representation in the device tree should be done as under:
+
+==============================
+PMU node bindings definition
+==============================
+
+	Description: Describes PMU
+
+	PROPERTIES
+
+	- compatible
+		Usage: required
+		Value type: <string>
+		Definition: must be "csky,csky-pmu"
+	- interrupts
+		Usage: required
+		Value type: <u32>
+		Definition: must be pmu irq num defined by soc
+	- reg-io-width
+		Usage: optional
+		Value type: <u32>
+		Definition: the width of pmu counter
+
+Examples:
+---------
+
+        pmu {
+                compatible = "csky,csky-pmu";
+                interrupts = <0x17 IRQ_TYPE_EDGE_RISING>;
+                interrupt-parent = <&intc>;
+		reg-io-width = <0x30>;
+        };
+
-- 
2.7.4