arm64: dts: renesas: rzg2ul-smarc: Add support for enabling MTU3

Add support for PMOD_MTU3 macro to enable MTU3 node on RZ/G2UL SMARC
EVK.

The MTU3a PWM pins on PMOD0 are muxed with SPI1. Disable SPI1, when
PMOD_MTU3 macro is enabled.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230727081848.100834-6-biju.das.jz@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts

@@ -17,6 +17,17 @@
 #define SW_SW0_DEV_SEL	1
 #define SW_ET0_EN_N	1
 
+/*
+ * To enable MTU3a PWM on PMOD0,
+ *  - Set DIP-Switch SW1-3 to On position.
+ *  - Set PMOD_MTU3 macro to 1.
+ */
+#define PMOD_MTU3	0
+
+#if (PMOD_MTU3 && !SW_ET0_EN_N)
+#error "Cannot set as both PMOD_MTU3 and !SW_ET0_EN_N are mutually exclusive"
+#endif
+
 #include "r9a07g043u.dtsi"
 #include "rzg2ul-smarc-som.dtsi"
 #include "rzg2ul-smarc.dtsi"

arch/arm64/boot/dts/renesas/rzg2ul-smarc-pinfunction.dtsi

@@ -50,6 +50,12 @@ i2c1_pins: i2c1 {
 		input-enable;
 	};
 
+	mtu3_pins: mtu3 {
+		mtu2-pwm {
+			pinmux = <RZG2L_PORT_PINMUX(4, 0, 4)>; /* MTIOC2A */
+		};
+	};
+
 	scif0_pins: scif0 {
 		pinmux = <RZG2L_PORT_PINMUX(6, 4, 6)>, /* TxD */
 			 <RZG2L_PORT_PINMUX(6, 3, 6)>; /* RxD */

arch/arm64/boot/dts/renesas/rzg2ul-smarc.dtsi

@@ -28,6 +28,19 @@ wm8978: codec@1a {
 	};
 };
 
+#if PMOD_MTU3
+&mtu3 {
+	pinctrl-0 = <&mtu3_pins>;
+	pinctrl-names = "default";
+
+	status = "okay";
+};
+
+&spi1 {
+	status = "disabled";
+};
+#endif
+
 #if (SW_ET0_EN_N)
 &ssi1 {
 	pinctrl-0 = <&ssi1_pins>;