1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2/* 3 * Device Tree Overlay for the PWM controlled blower fan in connector J3:FAN 4 * on R-Car V4H ES3.0 Sparrow Hawk board 5 * 6 * Copyright (C) 2025 Marek Vasut <marek.vasut+renesas@mailbox.org> 7 * 8 * Example usage: 9 * 10 * # Localize hwmon sysfs directory that matches the PWM fan, 11 * # enable the PWM fan, and configure the fan speed manually. 12 * r8a779g3-sparrow-hawk$ grep -H . /sys/class/hwmon/hwmon?/name 13 * /sys/class/hwmon/hwmon0/name:sensor1_thermal 14 * /sys/class/hwmon/hwmon1/name:sensor2_thermal 15 * /sys/class/hwmon/hwmon2/name:sensor3_thermal 16 * /sys/class/hwmon/hwmon3/name:sensor4_thermal 17 * /sys/class/hwmon/hwmon4/name:pwmfan 18 * ^ ^^^^^^ 19 * 20 * # Select mode 2 , enable fan PWM and regulator and keep them enabled. 21 * # For details, see Linux Documentation/hwmon/pwm-fan.rst 22 * r8a779g3-sparrow-hawk$ echo 2 > /sys/class/hwmon/hwmon4/pwm1_enable 23 * 24 * # Configure PWM fan speed in range 0..255 , 0 is stopped , 255 is full speed . 25 * # Fan speed 101 is about 2/5 of the PWM fan speed: 26 * r8a779g3-sparrow-hawk$ echo 101 > /sys/class/hwmon/hwmon4/pwm1 27 */ 28 29/dts-v1/; 30/plugin/; 31 32/* 33 * Override default PWM fan settings. For a list of available properties, 34 * see schema Documentation/devicetree/bindings/hwmon/pwm-fan.yaml . 35 */ 36&fan { 37 /* Available cooling levels */ 38 cooling-levels = <0 50 100 150 200 255>; 39 /* Four pulses of tacho signal per one revolution */ 40 pulses-per-revolution = <4>; 41 /* PWM period: 100us ~= 10 kHz */ 42 pwms = <&pwm0 0 100000>; 43}; 44