[PATCH v2 2/2] arm64: dts: freescale: imx93-phyboard-nash: Add pwm-fan overlay

[Primoz Fiser <primoz.fiser@norik.com>]

Add overlay to support PWM fan on the phyBOARD-Nash-i.MX93 board. Fan
can be connected to the FAN (X48) connector on the board and will be
controlled according to the following CPU temperature trips table:

 - bellow 50 degrees - fan is off (<1% duty cycle)
 - between 50 and 58 degrees - low fan speed (~35% duty cycle)
 - between 58 and 65 degrees - fan medium speed (~60% duty cycle)
 - above 65 degrees - fan at full speed (>99% duty cycle)

The output frequency of PWM signal is set to 25 kHz.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Alberto Merciai <alb3rt0.m3rciai@gmail.com>
---
Changes in v2:
- add Reviewed-by: tag

Link to v1: https://lore.kernel.org/all/20251007084028.1125185-2-primoz.fiser@norik.com/

 arch/arm64/boot/dts/freescale/Makefile        |  2 +
 .../imx93-phyboard-nash-pwm-fan.dtso          | 75 +++++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 arch/arm64/boot/dts/freescale/imx93-phyboard-nash-pwm-fan.dtso

diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index 33151065684f..e5c71dd7f4f3 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -359,11 +359,13 @@ dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-segin.dtb
 
 imx93-phyboard-nash-jtag-dtbs += imx93-phyboard-nash.dtb imx93-phyboard-nash-jtag.dtbo
 imx93-phyboard-nash-peb-wlbt-07-dtbs += imx93-phyboard-nash.dtb imx93-phyboard-nash-peb-wlbt-07.dtbo
+imx93-phyboard-nash-pwm-fan-dtbs += imx93-phyboard-nash.dtb imx93-phyboard-nash-pwm-fan.dtbo
 imx93-phyboard-segin-peb-eval-01-dtbs += imx93-phyboard-segin.dtb imx93-phyboard-segin-peb-eval-01.dtbo
 imx93-phyboard-segin-peb-wlbt-05-dtbs += imx93-phyboard-segin.dtb imx93-phyboard-segin-peb-wlbt-05.dtbo
 imx93-phycore-rpmsg-dtbs += imx93-phyboard-nash.dtb imx93-phyboard-segin.dtb imx93-phycore-rpmsg.dtbo
 dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-nash-jtag.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-nash-peb-wlbt-07.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-nash-pwm-fan.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-segin-peb-eval-01.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx93-phyboard-segin-peb-wlbt-05.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx93-phycore-rpmsg.dtb
diff --git a/arch/arm64/boot/dts/freescale/imx93-phyboard-nash-pwm-fan.dtso b/arch/arm64/boot/dts/freescale/imx93-phyboard-nash-pwm-fan.dtso
new file mode 100644
index 000000000000..d1adf04d56d9
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx93-phyboard-nash-pwm-fan.dtso
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (C) 2025 PHYTEC Messtechnik GmbH
+ * Author: Primoz Fiser <primoz.fiser@norik.com>
+ */
+
+#include <dt-bindings/pwm/pwm.h>
+#include "imx93-pinfunc.h"
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+	fan0: pwm-fan {
+		compatible = "pwm-fan";
+		#cooling-cells = <2>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_fan>;
+		cooling-levels = <1 90 150 200 255>;
+		pwms = <&tpm6 1 40000 PWM_POLARITY_INVERTED>;
+	};
+
+	thermal-zones {
+		cpu-thermal {
+			trips {
+				cpu_low: cpu-low {
+					hysteresis = <3000>;
+					temperature = <50000>;
+					type = "active";
+				};
+
+				cpu_med: cpu-med {
+					hysteresis = <3000>;
+					temperature = <58000>;
+					type = "active";
+				};
+
+				cpu_high: cpu-high {
+					hysteresis = <3000>;
+					temperature = <65000>;
+					type = "active";
+				};
+			};
+
+			cooling-maps {
+				map1 {
+					cooling-device = <&fan0 1 1>;
+					trip = <&cpu_low>;
+				};
+
+				map2 {
+					cooling-device = <&fan0 2 2>;
+					trip = <&cpu_med>;
+				};
+
+				map3 {
+					cooling-device = <&fan0 4 4>;
+					trip = <&cpu_high>;
+				};
+			};
+		};
+	};
+};
+
+&tpm6 {
+	status = "okay";
+};
+
+&iomuxc {
+	pinctrl_fan: fangrp {
+		fsl,pins = <
+			MX93_PAD_GPIO_IO23__TPM6_CH1	0x31e
+		>;
+	};
+};
-- 
2.34.1