boards: xiao_esp32c6: add i2c0 port

- Add i2c0 port support on xiao_esp32c6

Signed-off-by: Romain Pelletant <romain.pelletant@fullfreqs.com>

boards/seeed/xiao_esp32c6/doc/index.rst

@@ -36,6 +36,8 @@ The Zephyr ``xiao_esp32c6`` board target supports the following hardware feature
 +------------+------------+-------------------------------------+
 | SPI Master | on-chip    | spi                                 |
 +------------+------------+-------------------------------------+
+| I2C        | on-chip    | i2c                                 |
++------------+------------+-------------------------------------+
 | Watchdog   | on-chip    | watchdog                            |
 +------------+------------+-------------------------------------+
 | LEDC       | on-chip    | pwm                                 |

boards/seeed/xiao_esp32c6/seeed_xiao_connector.dtsi

@@ -24,5 +24,6 @@
 	};
 };
 
+xiao_i2c: &i2c0 {};
 xiao_spi: &spi2 {};
 xiao_serial: &uart0 {};

boards/seeed/xiao_esp32c6/xiao_esp32c6-pinctrl.dtsi

@@ -31,4 +31,14 @@
 			output-low;
 		};
 	};
+
+	i2c0_default: i2c0_default {
+		group1 {
+			pinmux = <I2C0_SDA_GPIO22>,
+				 <I2C0_SCL_GPIO23>;
+			bias-pull-up;
+			drive-open-drain;
+			output-high;
+		};
+	};
 };

boards/seeed/xiao_esp32c6/xiao_esp32c6.dts

@@ -55,6 +55,13 @@
 	status = "okay";
 };
 
+&i2c0 {
+	status = "okay";
+	clock-frequency = <I2C_BITRATE_FAST>;
+	pinctrl-0 = <&i2c0_default>;
+	pinctrl-names = "default";
+};
+
 &spi2 {
 	#address-cells = <1>;
 	#size-cells = <0>;

boards/seeed/xiao_esp32c6/xiao_esp32c6.yaml

@@ -11,6 +11,7 @@ supported:
   - dma
   - spi
   - entropy
+  - i2c
 testing:
   ignore_tags:
     - bluetooth