r8a779g3-sparrow-hawk-fan-pwm.dtso

 1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 2/*
 3 * Device Tree Overlay for the PWM controlled blower fan on 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$ ls -1 /sys/devices/platform/pwm-fan/hwmon/hwmon?/pwm?_enable
13 * /sys/devices/platform/pwm-fan/hwmon/hwmon4/pwm1_enable
14 *
15 * # Select mode 2 , enable fan PWM and regulator and keep them enabled.
16 * # For details, see Linux Documentation/hwmon/pwm-fan.rst
17 * r8a779g3-sparrow-hawk$ echo 2 > /sys/devices/platform/pwm-fan/hwmon/hwmon4/pwm1_enable
18 *
19 * # Configure PWM fan speed in range 0..255 , 0 is stopped , 255 is full speed .
20 * # Fan speed 101 is about 2/5 of the PWM fan speed:
21 * r8a779g3-sparrow-hawk$ echo 101 > /sys/devices/platform/pwm-fan/hwmon/hwmon4/pwm1
22 */
23
24/dts-v1/;
25/plugin/;
26
27/*
28 * Override default PWM fan settings. For a list of available properties,
29 * see schema Documentation/devicetree/bindings/hwmon/pwm-fan.yaml .
30 */
31&fan {
32	/* Available cooling levels */
33	cooling-levels = <0 50 100 150 200 255>;
34	/* Four pulses of tacho signal per one revolution */
35	pulses-per-revolution = <4>;
36	/* PWM period: 100us ~= 10 kHz */
37	pwms = <&pwm0 0 100000>;
38};