arm64: dts: renesas: r8a77970: add CAN-FD support

Define the generic R8A77970 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>
Acked-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77970.dtsi

@@ -68,6 +68,13 @@ psci {
 		method = "smc";
 	};
 
+	/* External CAN clock - to be overridden by boards that provide it */
+	can_clk: can {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <0>;
+	};
+
 	/* External SCIF clock - to be overridden by boards that provide it */
 	scif_clk: scif {
 		compatible = "fixed-clock";
@@ -381,6 +388,31 @@ hscif3: serial@e66a0000 {
 			status = "disabled";
 		};
 
+		canfd: can@e66c0000 {
+			compatible = "renesas,r8a77970-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 R8A77970_CLK_CANFD>,
+				 <&can_clk>;
+			clock-names = "fck", "canfd", "can_clk";
+			assigned-clocks = <&cpg CPG_CORE R8A77970_CLK_CANFD>;
+			assigned-clock-rates = <40000000>;
+			power-domains = <&sysc R8A77970_PD_ALWAYS_ON>;
+			resets = <&cpg 914>;
+			status = "disabled";
+
+			channel0 {
+				status = "disabled";
+			};
+
+			channel1 {
+				status = "disabled";
+			};
+		};
+
 		avb: ethernet@e6800000 {
 			compatible = "renesas,etheravb-r8a77970",
 				     "renesas,etheravb-rcar-gen3";