diff --git a/arch/arm/boot/dts/microchip/sam9x7.dtsi b/arch/arm/boot/dts/microchip/sam9x7.dtsi
index 29950159bb94..d3f7238eda85 100644
--- a/arch/arm/boot/dts/microchip/sam9x7.dtsi
+++ b/arch/arm/boot/dts/microchip/sam9x7.dtsi
@@ -166,6 +166,7 @@ flx4: flexcom@f0000000 {
 			uart4: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <13 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -234,6 +235,7 @@ flx5: flexcom@f0004000 {
 			uart5: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <14 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -375,6 +377,7 @@ flx11: flexcom@f0020000 {
 			uart11: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <32 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -424,6 +427,7 @@ flx12: flexcom@f0024000 {
 			uart12: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <33 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -595,6 +599,7 @@ flx6: flexcom@f8010000 {
 			uart6: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <9 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -644,6 +649,7 @@ flx7: flexcom@f8014000 {
 			uart7: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <10 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -693,6 +699,7 @@ flx8: flexcom@f8018000 {
 			uart8: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <11 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -742,6 +749,7 @@ flx0: flexcom@f801c000 {
 			uart0: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <5 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -810,6 +818,7 @@ flx1: flexcom@f8020000 {
 			uart1: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <6 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -878,6 +887,7 @@ flx2: flexcom@f8024000 {
 			uart2: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <7 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -946,6 +956,7 @@ flx3: flexcom@f8028000 {
 			uart3: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <8 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -1067,6 +1078,7 @@ flx9: flexcom@f8040000 {
 			uart9: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <15 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
@@ -1116,6 +1128,7 @@ flx10: flexcom@f8044000 {
 			uart10: serial@200 {
 				compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
 				reg = <0x200 0x200>;
+				atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
 				interrupts = <16 IRQ_TYPE_LEVEL_HIGH 7>;
 				dmas = <&dma0
 					(AT91_XDMAC_DT_MEM_IF(0) |
