[PATCH] arm64: dts: mediatek: mt8395-radxa-nio-12l: Enable I2C3 on 40-pin header

[Ricardo Pardini via B4 Relay]

From: Ricardo Pardini <ricardo at pardini.net>

I2C3 (SDA3/SCL3 on GPIO14/GPIO15) is routed to the 40-pin GPIO header,
exposed on the blue-colored pins 27 (SCL3) and 28 (SDA3). Enable the
controller, add the corresponding pin configuration in the pinctrl node
so users can use external I2C devices.

Signed-off-by: Ricardo Pardini <ricardo at pardini.net>
---
The Radxa NIO 12L exposes I2C3 (SDA3/SCL3, GPIO14/GPIO15) on its 40-pin
GPIO header, on the blue-coloured pins 27 (SCL3) and 28 (SDA3).

Enable the I2C3 controller, add the matching pinctrl configuration and run
the bus at 400 kHz, matching the other I2C buses already enabled on this
board.

Tested using a SD1306 I2C OLED display.
---
 arch/arm64/boot/dts/mediatek/mt8395-radxa-nio-12l.dts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt8395-radxa-nio-12l.dts b/arch/arm64/boot/dts/mediatek/mt8395-radxa-nio-12l.dts
index bf91305e8e4a5..03a2f2e746475 100644
--- a/arch/arm64/boot/dts/mediatek/mt8395-radxa-nio-12l.dts
+++ b/arch/arm64/boot/dts/mediatek/mt8395-radxa-nio-12l.dts
@@ -371,6 +371,14 @@ it5205_sbu_mux: endpoint {
 	};
 };
 
+/* Exposed on 40-pin header (blue-colored pins 27:SCL3 28:SDA3) */
+&i2c3 {
+	clock-frequency = <400000>;
+	pinctrl-0 = <&i2c3_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+};
+
 &i2c4 {
 	clock-frequency = <400000>;
 	pinctrl-0 = <&i2c4_pins>;
@@ -789,6 +797,16 @@ pins-bus {
 		};
 	};
 
+	i2c3_pins: i2c3-pins {
+		pins-bus {
+			pinmux = <PINMUX_GPIO14__FUNC_SDA3>,
+				 <PINMUX_GPIO15__FUNC_SCL3>;
+			bias-pull-up = <1000>;
+			drive-strength = <6>;
+			drive-strength-microamp = <1000>;
+		};
+	};
+
 	i2c4_pins: i2c4-pins {
 		pins-bus {
 			pinmux = <PINMUX_GPIO16__FUNC_SDA4>,

---
base-commit: 8cd9520d35a6c38db6567e97dd93b1f11f185dc6
change-id: 20260624-nio-12l-add-i2c-40-pin-19e0482fd835

Best regards,
--  
Ricardo Pardini <ricardo at pardini.net>