arm64: dts: renesas: r8a77980: add CAN-FD support

Define the generic R8A77980 part of the CAN-FD device node.

Based on the original (and large) patch by Vladimir Barinov.
Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
[simon: consistently use tabs for indentation]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77980.dtsi

@@ -38,6 +38,13 @@ L2_CA53: cache-controller {
 		};
 	};
 
+	/* External CAN clock - to be overridden by boards that provide it */
+	can_clk: can {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <0>;
+	};
+
 	extal_clk: extal {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
@@ -170,6 +177,30 @@ hscif3: serial@e66a0000 {
 			status = "disabled";
 		};
 
+		canfd: can@e66c0000 {
+			compatible = "renesas,r8a77980-canfd",
+				     "renesas,rcar-gen3-canfd";
+			reg = <0 0xe66c0000 0 0x8000>;
+			interrupts = <GIC_SPI 29 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 30 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&cpg CPG_MOD 914>,
+				 <&cpg CPG_CORE R8A77980_CLK_CANFD>,
+				 <&can_clk>;
+			clock-names = "fck", "canfd", "can_clk";
+			assigned-clocks = <&cpg CPG_CORE R8A77980_CLK_CANFD>;
+			assigned-clock-rates = <40000000>;
+			power-domains = <&sysc R8A77980_PD_ALWAYS_ON>;
+			status = "disabled";
+
+			channel0 {
+				status = "disabled";
+			};
+
+			channel1 {
+				status = "disabled";
+			};
+		};
+
 		avb: ethernet@e6800000 {
 			compatible = "renesas,etheravb-r8a77980",
 				     "renesas,etheravb-rcar-gen3";