arm64: dts: renesas: sparrow-hawk: Add overlay for Argon40 fan HAT

Add a DT overlay to bind the Argon40 fan HAT on the Retronix R-Car V4H
Sparrow Hawk board.  Fan RPM control and full RPM on reboot has been
tested.

Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20250907161130.218470-1-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/arch/arm64/boot/dts/renesas/Makefile b/arch/arm64/boot/dts/renesas/Makefile
index dd45927dbe691999b14eba0b44e35fcec85df366..6fbd6cb480d8868d2d570721b8e6ad8620b0e621 100644 (file)
--- a/arch/arm64/boot/dts/renesas/Makefile
+++ b/arch/arm64/boot/dts/renesas/Makefile
@@ -108,6 +108,9 @@ dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-camera-j2-imx219.dtb
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-camera-j2-imx462.dtbo
 r8a779g3-sparrow-hawk-camera-j2-imx462-dtbs := r8a779g3-sparrow-hawk.dtb r8a779g3-sparrow-hawk-camera-j2-imx462.dtbo
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-camera-j2-imx462.dtb
+dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-fan-argon40.dtbo
+r8a779g3-sparrow-hawk-fan-argon40-dtbs := r8a779g3-sparrow-hawk.dtb r8a779g3-sparrow-hawk-fan-argon40.dtbo
+dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-fan-argon40.dtb
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g3-sparrow-hawk-fan-pwm.dtbo
 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

diff --git a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-argon40.dtso b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-argon40.dtso
new file mode 100644 (file)
index 0000000..c730ef3
--- /dev/null
+++ b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-argon40.dtso
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/*
+ * Device Tree Overlay for the Argon40 HAT blower fan on connector CN7
+ * 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$ ls -1 /sys/devices/platform/pwm-fan-ext/hwmon/hwmon?/pwm?_enable
+ * /sys/devices/platform/pwm-fan-ext/hwmon/hwmon0/pwm1_enable
+ *
+ * # 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/devices/platform/pwm-fan-ext/hwmon/hwmon0/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/devices/platform/pwm-fan-ext/hwmon/hwmon0/pwm1
+ */
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+       pwm-fan-ext {
+               compatible = "pwm-fan";
+               #cooling-cells = <2>;
+               /* PWM period: 33us ~= 30 kHz */
+               pwms = <&pwmhat 0 33334 0>;
+               /* Available cooling levels */
+               cooling-levels = <0 50 100 150 200 255>;
+               fan-shutdown-percent = <100>;
+       };
+};
+
+/* Page 31 / IO_CN */
+&i2c3 {
+       #address-cells = <1>;
+       #size-cells = <0>;
+       clock-frequency = <400000>;
+       status = "okay";
+
+       pwmhat: pwm@1a {
+               compatible = "argon40,fan-hat";
+               reg = <0x1a>;
+               #pwm-cells = <3>;
+       };
+};