[PATCH RFC 4/4] arm64: dts: broadcom: bcm2712-rpi-5-b: Add RP1 fan tachometer node

[Andrea della Porta]

Add the hwmon fan node for the Raspberry Pi 5 to expose the cooling fan
speed (RPM) to userspace.

The fan tachometer is managed internally by the RP1 PWM controller.
This node uses the 'raspberrypi,pwm-tachometer' property to link the
rp1-fan hwmon driver to the existing RP1 PWM controller, enabling
RPM reporting via sysfs.

Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
---
 arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
index 748be8f1ee9e2..9bc6d0e9da1b5 100644
--- a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
+++ b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
@@ -16,6 +16,11 @@ / {
 	aliases {
 		ethernet0 = &rp1_eth;
 	};
+
+	fan-tach {
+		compatible = "raspberrypi,rp1-fan";
+		raspberrypi,pwm-tachometer = <&rp1_pwm1>;
+	};
 };
 
 &pcie2 {
-- 
2.35.3