dt-bindings: csky: Add csky PMU bindings

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>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>

diff --git a/Documentation/devicetree/bindings/csky/pmu.txt b/Documentation/devicetree/bindings/csky/pmu.txt
new file mode 100644 (file)
index 0000000..728d05c
--- /dev/null
+++ b/Documentation/devicetree/bindings/csky/pmu.txt
@@ -0,0 +1,38 @@
+===============================
+C-SKY Performance Monitor Units
+===============================
+
+C-SKY Performance Monitor is designed for ck807/ck810/ck860 SMP soc and
+it could count cpu's events for helping analysis performance issues.
+
+============================
+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 IRQ_TYPE_XXX>
+               Definition: must be pmu irq num defined by soc
+       - count-width
+               Usage: optional
+               Value type: <u32>
+               Definition: the width of pmu counter
+
+Examples:
+---------
+#include <dt-bindings/interrupt-controller/irq.h>
+
+       pmu: performace-monitor {
+               compatible = "csky,csky-pmu";
+               interrupts = <23 IRQ_TYPE_EDGE_RISING>;
+               interrupt-parent = <&intc>;
+               count-width = <48>;
+        };