// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) /* * Device Tree Overlay for the PWM controlled blower fan in connector J3:FAN * on R-Car V4H ES3.0 Sparrow Hawk board * * Copyright (C) 2025 Marek Vasut * * Example usage: * * # Localize hwmon sysfs directory that matches the PWM fan, * # enable the PWM fan, and configure the fan speed manually. * r8a779g3-sparrow-hawk$ grep -H . /sys/class/hwmon/hwmon?/name * /sys/class/hwmon/hwmon0/name:sensor1_thermal * /sys/class/hwmon/hwmon1/name:sensor2_thermal * /sys/class/hwmon/hwmon2/name:sensor3_thermal * /sys/class/hwmon/hwmon3/name:sensor4_thermal * /sys/class/hwmon/hwmon4/name:pwmfan * ^ ^^^^^^ * * # Select mode 2 , enable fan PWM and regulator and keep them enabled. * # For details, see Linux Documentation/hwmon/pwm-fan.rst * r8a779g3-sparrow-hawk$ echo 2 > /sys/class/hwmon/hwmon4/pwm1_enable * * # Configure PWM fan speed in range 0..255 , 0 is stopped , 255 is full speed . * # Fan speed 101 is about 2/5 of the PWM fan speed: * r8a779g3-sparrow-hawk$ echo 101 > /sys/class/hwmon/hwmon4/pwm1 */ /dts-v1/; /plugin/; /* * Override default PWM fan settings. For a list of available properties, * see schema Documentation/devicetree/bindings/hwmon/pwm-fan.yaml . */ &fan { /* Available cooling levels */ cooling-levels = <0 50 100 150 200 255>; /* Four pulses of tacho signal per one revolution */ pulses-per-revolution = <4>; /* PWM period: 100us ~= 10 kHz */ pwms = <&pwm0 0 100000>; };