diff --git a/arch/arm/boot/dts/r8a7778.dtsi b/arch/arm/boot/dts/r8a7778.dtsi
index 05db0ccad7a6..10d996d2941f 100644
--- a/arch/arm/boot/dts/r8a7778.dtsi
+++ b/arch/arm/boot/dts/r8a7778.dtsi
@@ -367,6 +367,30 @@
 		status = "disabled";
 	};
 
+	hscif0: serial@ffe48000 {
+		compatible = "renesas,hscif-r8a7778",
+			     "renesas,rcar-gen1-hscif", "renesas,hscif";
+		reg = <0xffe48000 96>;
+		interrupts = <GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&mstp0_clks R8A7778_CLK_HSCIF0>,
+			 <&cpg_clocks R8A7778_CLK_S>, <&scif_clk>;
+		clock-names = "fck", "brg_int", "scif_clk";
+		power-domains = <&cpg_clocks>;
+		status = "disabled";
+	};
+
+	hscif1: serial@ffe49000 {
+		compatible = "renesas,hscif-r8a7778",
+			     "renesas,rcar-gen1-hscif", "renesas,hscif";
+		reg = <0xffe49000 96>;
+		interrupts = <GIC_SPI 119 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&mstp0_clks R8A7778_CLK_HSCIF1>,
+			 <&cpg_clocks R8A7778_CLK_S>, <&scif_clk>;
+		clock-names = "fck", "brg_int", "scif_clk";
+		power-domains = <&cpg_clocks>;
+		status = "disabled";
+	};
+
 	mmcif: mmc@ffe4e000 {
 		compatible = "renesas,mmcif-r8a7778", "renesas,sh-mmcif";
 		reg = <0xffe4e000 0x100>;
@@ -535,6 +559,8 @@
 				 <&cpg_clocks R8A7778_CLK_P>,
 				 <&cpg_clocks R8A7778_CLK_P>,
 				 <&cpg_clocks R8A7778_CLK_P>,
+				 <&cpg_clocks R8A7778_CLK_S>,
+				 <&cpg_clocks R8A7778_CLK_S>,
 				 <&cpg_clocks R8A7778_CLK_P>,
 				 <&cpg_clocks R8A7778_CLK_P>,
 				 <&cpg_clocks R8A7778_CLK_P>,
@@ -551,6 +577,7 @@
 				R8A7778_CLK_SCIF0 R8A7778_CLK_SCIF1
 				R8A7778_CLK_SCIF2 R8A7778_CLK_SCIF3
 				R8A7778_CLK_SCIF4 R8A7778_CLK_SCIF5
+				R8A7778_CLK_HSCIF0 R8A7778_CLK_HSCIF1
 				R8A7778_CLK_TMU0 R8A7778_CLK_TMU1
 				R8A7778_CLK_TMU2 R8A7778_CLK_SSI0
 				R8A7778_CLK_SSI1 R8A7778_CLK_SSI2
@@ -560,6 +587,7 @@
 			clock-output-names =
 				"i2c0", "i2c1", "i2c2", "i2c3", "scif0",
 				"scif1", "scif2", "scif3", "scif4", "scif5",
+				"hscif0", "hscif1",
 				"tmu0", "tmu1", "tmu2", "ssi0", "ssi1",
 				"ssi2", "ssi3", "sru", "hspi";
 		};
diff --git a/include/dt-bindings/clock/r8a7778-clock.h b/include/dt-bindings/clock/r8a7778-clock.h
index f6b07c5399de..d0bff9ec5c66 100644
--- a/include/dt-bindings/clock/r8a7778-clock.h
+++ b/include/dt-bindings/clock/r8a7778-clock.h
@@ -30,6 +30,8 @@
 #define R8A7778_CLK_SCIF3	23
 #define R8A7778_CLK_SCIF4	22
 #define R8A7778_CLK_SCIF5	21
+#define R8A7778_CLK_HSCIF0	19
+#define R8A7778_CLK_HSCIF1	18
 #define R8A7778_CLK_TMU0	16
 #define R8A7778_CLK_TMU1	15
 #define R8A7778_CLK_TMU2	14