[PATCH] arm64: dts: rockchip: Add the fan tachometers to Kobol Helios64

[Igor Velkov via B4 Relay]

From: Igor Velkov <iav@xxxxxx>

The tachometer outputs of both fan connectors reach the SoC through
open-drain buffers, on GPIO4_C5 for P7 and GPIO4_C7 for P6, but the fan
nodes do not describe them. pwm-fan therefore registers no fan1_input.

Describe each line as the fan's interrupt. The board pulls both lines
up, so configure the pins without internal bias.

Tested on 7.3-rc6: fan1_input reads 0 with the fans stopped and rises
with the duty cycle, to about 3500 rpm at full speed on both fans.

Assisted-by: LLM
Signed-off-by: Igor Velkov <iav@xxxxxx>
---
Schematic, sheets 30 and 36:
https://wiki.kobol.io/helios64/files/schematics/Helios64_Schematics_Rev1.2.pdf
---
 arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts b/arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts
index d146e5075b4f..63ad79b4c8ac 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts
@@ -74,6 +74,10 @@ fan1 {
 		compatible = "pwm-fan";
 		pwms = <&pwm0 0 40000 0>;
 		cooling-levels = <0 80 170 255>;
+		interrupt-parent = <&gpio4>;
+		interrupts = <RK_PC5 IRQ_TYPE_EDGE_FALLING>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&fan1_sense>;
 	};
 
 	fan2 {
@@ -81,6 +85,10 @@ fan2 {
 		compatible = "pwm-fan";
 		pwms = <&pwm1 0 40000 0>;
 		cooling-levels = <0 80 170 255>;
+		interrupt-parent = <&gpio4>;
+		interrupts = <RK_PC7 IRQ_TYPE_EDGE_FALLING>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&fan2_sense>;
 	};
 
 	gpio-keys {
@@ -493,6 +501,16 @@ user1_btn: user1-btn {
 		};
 	};
 
+	fan {
+		fan1_sense: fan1-sense {
+			rockchip,pins = <4 RK_PC5 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+
+		fan2_sense: fan2-sense {
+			rockchip,pins = <4 RK_PC7 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+	};
+
 	gmac {
 		gphy_reset: gphy-reset {
 			rockchip,pins = <3 RK_PB7 RK_FUNC_GPIO &pcfg_output_low>;

---
base-commit: 1892b1ccccb9d546903ad6a61ffb9e388acdec80
change-id: 20261006-helios64-fan-tach-2db24b132105

Best regards,
-- 
Igor Velkov <iav@xxxxxx>