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# T2 SDE: package/*/linux/sifive-fans.patch.disabled
# Copyright (C) 2021 - 2022 The T2 SDE Project
# 
# This Copyright note is generated by scripts/Create-CopyPatch,
# more information can be found in the files COPYING and README.
# 
# This patch file is dual-licensed. It is available under the license the
# patched project is licensed under, as long as it is an OpenSource license
# as defined at http://www.opensource.org/ (e.g. BSD, X11) or under the terms
# of the GNU General Public License version 2 as used by the T2 SDE.
# --- T2-COPYRIGHT-NOTE-END ---

Let's implement some minimal viable HiFive Unmatched PWM fan control.

Signed-off-by: René Rebe <rene@exactcode.com>

--- ./arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts.vanilla	2024-04-01 18:58:55.930393689 +0200
+++ ./arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts	2024-04-01 20:32:34.682852300 +0200
@@ -47,6 +47,18 @@
 		gpios = <&gpio 2 GPIO_ACTIVE_LOW>;
 	};
 
+	fan1 {
+		compatible = "pwm-fan";
+		pwms = <&pwm1 2 7812500 PWM_POLARITY_INVERTED>;
+		active-low;
+	};
+
+	fan2 {
+		compatible = "pwm-fan";
+		pwms = <&pwm1 3 7812500 PWM_POLARITY_INVERTED>;
+		active-low;
+	};
+
 	led-controller-1 {
 		compatible = "pwm-leds";
 
--- ./drivers/hwmon/pwm-fan.c.vanilla	2024-04-01 20:38:04.170820553 +0200
+++ ./drivers/hwmon/pwm-fan.c	2024-04-01 20:57:57.418705578 +0200
@@ -45,6 +45,7 @@
 	enum pwm_fan_enable_mode enable_mode;
 	bool regulator_enabled;
 	bool enabled;
+	bool active_low;
 
 	int tach_count;
 	struct pwm_fan_tach *tachs;
@@ -207,6 +208,9 @@
 
 		period = state->period;
 		state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
+		if (ctx->active_low)
+			state->duty_cycle = state->period - state->duty_cycle;
+
 		ret = pwm_apply_might_sleep(ctx->pwm, state);
 		if (ret)
 			return ret;
@@ -476,6 +480,7 @@
 {
 	struct thermal_cooling_device *cdev;
 	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
 	struct pwm_fan_ctx *ctx;
 	struct device *hwmon;
 	int ret;
@@ -526,6 +532,7 @@
 	}
 
 	ctx->enable_mode = pwm_disable_reg_enable;
+	ctx->active_low = of_property_read_bool(np, "active-low");
 
 	/*
 	 * Set duty cycle to maximum allowed and enable PWM output as well as