arm64: dts: renesas: r8a779g3: Add Retronix R-Car V4H Sparrow Hawk board support

Add Retronix R-Car V4H Sparrow Hawk board based on Renesas R-Car V4H ES3.0
(R8A779G3) SoC. This is a single-board computer with single gigabit ethernet,
DSI-to-eDP bridge, DSI and two CSI2 interfaces, audio codec, two CANFD ports,
micro SD card slot, USB PD supply, USB 3.0 ports, M.2 Key-M slot for NVMe SSD,
debug UART and JTAG.

Tested-by: Kuninori Morimoto <[email protected]>
Tested-by: Niklas Söderlund <[email protected]>
Signed-off-by: Marek Vasut <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>

Author: Marek Vasut

arch/arm64/boot/dts/renesas/Makefile

@@ -94,6 +94,10 @@ dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g2-white-hawk-single.dtb
 r8a779g2-white-hawk-single-ard-audio-da7212-dtbs := r8a779g2-white-hawk-single.dtb white-hawk-ard-audio-da7212.dtbo
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g2-white-hawk-single-ard-audio-da7212.dtb
 
+dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk.dtb
+r8a779g3-sparrow-hawk-fan-pwm-dtbs := r8a779g3-sparrow-hawk.dtb r8a779g3-sparrow-hawk-fan-pwm.dtbo
+dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-fan-pwm.dtb
+
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-white-hawk-single.dtb
 r8a779g3-white-hawk-single-ard-audio-da7212-dtbs := r8a779g3-white-hawk-single.dtb white-hawk-ard-audio-da7212.dtbo
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-white-hawk-single-ard-audio-da7212.dtb

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 <[email protected]>
+ *
+ * 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>;
+};