It was previously required but not documented.
Add the text to the binding along with the new "dmas" addition.

Signed-off-by: Yuan Yao <redacted>
---
 Documentation/devicetree/bindings/serial/fsl-lpuart.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
index 6e1cbbf..9666f97 100644
--- a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
+++ b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt

@@ -4,6 +4,8 @@ Required properties:
 - compatible : Should be "fsl,<soc>-lpuart"
 - reg : Address and length of the register set for the device
 - interrupts : Should contain uart interrupt
+- clocks : phandle + clock specifier pairs, one for each entry in clock-names
+- clock-names : should contain: "ipg" - the uart clock
 
 Optional properties:
 - dmas: Generic dma devicetree binding as described

@@ -19,6 +21,8 @@ uart0: serial at 40027000 {
 		compatible = "fsl,vf610-lpuart";
 		reg = <0x40027000 0x1000>;
 		interrupts = <0 61 0x00>;
+		clocks = <&clks VF610_CLK_UART0>;
+		clock-names = "ipg";
 		dmas = <&edma0 0 2>,
 			<&edma0 0 3>;
 		dma-names = "rx","tx";