1 files changed, 43 insertions, 0 deletions
diff --git a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-pwm.dtso b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-pwm.dtso
new file mode 100644
index 000000000000..50d53c8d76c5
--- /dev/null
+++ b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-pwm.dtso
@@ -0,0 +1,43 @@
+// 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 <marek.vasut+renesas@mailbox.org>
+ *
+ * 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>;
+};