arm64: dts: renesas: r8a77990: Add BRG support to SCIF2

Add the device node for the external SCIF_CLK, and describe the clock
inputs for the Baud Rate Generator for External Clock (BRG) for SCIF2,
which can increase serial clock accuracy.

The presence of the SCIF_CLK crystal and its clock frequency depend on
the actual board.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[geert: Enhance patch description]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

1 files changed, 12 insertions, 2 deletions

diff --git a/arch/arm64/boot/dts/renesas/r8a77990.dtsi b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
index e2c2d1480a68..6198768264be 100644
--- a/arch/arm64/boot/dts/renesas/r8a77990.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
@@ -63,6 +63,13 @@
                 method = "smc";
         };
 
+        /* External SCIF clock - to be overridden by boards that provide it */
+        scif_clk: scif {
+                compatible = "fixed-clock";
+                #clock-cells = <0>;
+                clock-frequency = <0>;
+        };
+
         soc: soc {
                 compatible = "simple-bus";
                 interrupt-parent = <&gic>;
@@ -412,8 +419,11 @@
                                      "renesas,rcar-gen3-scif", "renesas,scif";
                         reg = <0 0xe6e88000 0 64>;
                         interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
-                        clocks = <&cpg CPG_MOD 310>;
-                        clock-names = "fck";
+                        clocks = <&cpg CPG_MOD 310>,
+                                 <&cpg CPG_CORE R8A77990_CLK_S3D1C>,
+                                 <&scif_clk>;
+                        clock-names = "fck", "brg_int", "scif_clk";
+
                         power-domains = <&sysc R8A77990_PD_ALWAYS_ON>;
                         resets = <&cpg 310>;
                         status = "disabled";