riscv: dts: starfive: jh7100-common: Setup pinmux and enable gmac

Add pinmux configuration for DWMAC found on the JH7100 based boards and
enable the related DT node, providing a basic PHY configuration.
Co-developed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/boot/dts/starfive/jh7100-common.dtsi

@@ -72,7 +72,91 @@ wifi_pwrseq: wifi-pwrseq {
 	};
 };
 
+&gmac {
+	pinctrl-names = "default";
+	pinctrl-0 = <&gmac_pins>;
+	phy-mode = "rgmii-id";
+	status = "okay";
+
+	mdio: mdio {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "snps,dwmac-mdio";
+	};
+};
+
 &gpio {
+	gmac_pins: gmac-0 {
+		gtxclk-pins {
+			pins = <PAD_FUNC_SHARE(115)>;
+			bias-pull-up;
+			drive-strength = <35>;
+			input-enable;
+			input-schmitt-enable;
+			slew-rate = <0>;
+		};
+		miitxclk-pins {
+			pins = <PAD_FUNC_SHARE(116)>;
+			bias-pull-up;
+			drive-strength = <14>;
+			input-enable;
+			input-schmitt-disable;
+			slew-rate = <0>;
+		};
+		tx-pins {
+			pins = <PAD_FUNC_SHARE(117)>,
+			       <PAD_FUNC_SHARE(119)>,
+			       <PAD_FUNC_SHARE(120)>,
+			       <PAD_FUNC_SHARE(121)>,
+			       <PAD_FUNC_SHARE(122)>,
+			       <PAD_FUNC_SHARE(123)>,
+			       <PAD_FUNC_SHARE(124)>,
+			       <PAD_FUNC_SHARE(125)>,
+			       <PAD_FUNC_SHARE(126)>;
+			bias-pull-up;
+			drive-strength = <35>;
+			input-disable;
+			input-schmitt-disable;
+			slew-rate = <0>;
+		};
+		rxclk-pins {
+			pins = <PAD_FUNC_SHARE(127)>;
+			bias-pull-up;
+			drive-strength = <14>;
+			input-enable;
+			input-schmitt-disable;
+			slew-rate = <6>;
+		};
+		rxer-pins {
+			pins = <PAD_FUNC_SHARE(129)>;
+			bias-pull-up;
+			drive-strength = <14>;
+			input-enable;
+			input-schmitt-disable;
+			slew-rate = <0>;
+		};
+		rx-pins {
+			pins = <PAD_FUNC_SHARE(128)>,
+			       <PAD_FUNC_SHARE(130)>,
+			       <PAD_FUNC_SHARE(131)>,
+			       <PAD_FUNC_SHARE(132)>,
+			       <PAD_FUNC_SHARE(133)>,
+			       <PAD_FUNC_SHARE(134)>,
+			       <PAD_FUNC_SHARE(135)>,
+			       <PAD_FUNC_SHARE(136)>,
+			       <PAD_FUNC_SHARE(137)>,
+			       <PAD_FUNC_SHARE(138)>,
+			       <PAD_FUNC_SHARE(139)>,
+			       <PAD_FUNC_SHARE(140)>,
+			       <PAD_FUNC_SHARE(141)>;
+			bias-pull-up;
+			drive-strength = <14>;
+			input-enable;
+			input-schmitt-enable;
+			slew-rate = <0>;
+		};
+	};
+
 	i2c0_pins: i2c0-0 {
 		i2c-pins {
 			pinmux = <GPIOMUX(62, GPO_LOW,