r8a779g3-sparrow-hawk-fan-argon40.dtso

 1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 2/*
 3 * Device Tree Overlay for the Argon40 HAT blower fan on connector CN7
 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-ext/hwmon/hwmon?/pwm?_enable
13 * /sys/devices/platform/pwm-fan-ext/hwmon/hwmon0/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-ext/hwmon/hwmon0/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-ext/hwmon/hwmon0/pwm1
22 */
23
24/dts-v1/;
25/plugin/;
26
27&{/} {
28	pwm-fan-ext {
29		compatible = "pwm-fan";
30		#cooling-cells = <2>;
31		/* PWM period: 33us ~= 30 kHz */
32		pwms = <&pwmhat 0 33334 0>;
33		/* Available cooling levels */
34		cooling-levels = <0 50 100 150 200 255>;
35		fan-shutdown-percent = <100>;
36	};
37};
38
39/* Page 31 / IO_CN */
40&i2c3 {
41	#address-cells = <1>;
42	#size-cells = <0>;
43	clock-frequency = <400000>;
44	status = "okay";
45
46	pwmhat: pwm@1a {
47		compatible = "argon40,fan-hat";
48		reg = <0x1a>;
49		#pwm-cells = <3>;
50	};
51};