add ufs node document for Hisilicon.

Signed-off-by: Li Wei <redacted>
---
 Documentation/devicetree/bindings/ufs/ufs-hisi.txt | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/ufs/ufs-hisi.txt

diff --git a/Documentation/devicetree/bindings/ufs/ufs-hisi.txt b/Documentation/devicetree/bindings/ufs/ufs-hisi.txt
new file mode 100644
index 000000000000..175693e47d6b
--- /dev/null
+++ b/Documentation/devicetree/bindings/ufs/ufs-hisi.txt

@@ -0,0 +1,43 @@
+* Hisilicon Universal Flash Storage (UFS) Host Controller
+
+UFS nodes are defined to describe on-chip UFS hardware macro.
+Each UFS Host Controller should have its own node.
+
+Required properties:
+- compatible        : compatible list, contains one of the following -
+					"hisilicon,hi3660-ufs", "jedec,ufs-1.1" for hisi ufs
+					host controller present on Hi36xx chipset.
+- reg               : should contain UFS register address space & UFS SYS CTRL register address,
+- interrupt-parent  : interrupt device
+- interrupts        : interrupt number
+- clocks	        : List of phandle and clock specifier pairs
+- clock-names       : List of clock input name strings sorted in the same
+					order as the clocks property. "ref_clk", "phy_clk" is optional
+- freq-table-hz		: Array of <min max> operating frequencies stored in the same
+                          order as the clocks property. If this property is not
+			  defined or a value in the array is "0" then it is assumed
+			  that the frequency is set by the parent clock or a
+			  fixed rate clock source.