#!/usr/bin/env bash

# gpufan -- sets manual fan speed on AMD Radeon GPU. For 5.x / 6.x Linux Kernel users running AMDGPU driver...
# Author: Ben @ LostGeek . NET
# Created 09/20/2025

# 	READ ME! How to use:
# save as /usr/local/bin/gpufan then chmod +x
# running "gpufan" will give temperature & fan rpm. gpufan followed by a number (1-100)
# will manually set speed. "gpufan auto" will restore auto / driver control.

# Detect hwmon directory automatically
hwmon_path=$(find /sys/class/drm/card0/device/hwmon/ -name "pwm1" -printf '%h\n' | head -n1)
[[ -z "$hwmon_path" ]] && { echo "GPU hwmon path not found."; exit 1; }

pwm_file="$hwmon_path/pwm1"
mode_file="$hwmon_path/pwm1_enable"
fan_file="$hwmon_path/fan1_input"
temp_file="$hwmon_path/temp2_input"   # Use temp2_input as GPU temperature

get_status() {
    pwm=$(<"$pwm_file")
    mode=$(<"$mode_file")
    
    # Read fan RPM, leave blank if not available
    if [[ -f "$fan_file" ]]; then
        fan_rpm=$(<"$fan_file" 2>/dev/null)
        [[ -z "$fan_rpm" ]] && fan_rpm="N/A"
    else
        fan_rpm="N/A"
    fi

    # Read GPU temperature
    if [[ -f "$temp_file" ]]; then
        temp_raw=$(<"$temp_file")
        temp=$(( temp_raw / 1000 ))
    else
        temp="N/A"
    fi

    percent=$(( pwm * 100 / 255 ))

    case "$mode" in
        0) mode_str="Disabled" ;;
        1) mode_str="Manual" ;;
        2) mode_str="Auto" ;;
        *) mode_str="Unknown($mode)" ;;
    esac

    echo "Fan speed: $percent% (pwm=$pwm/255, RPM=$fan_rpm) | Mode: $mode_str | GPU Temp: ${temp}°C"
}

if [[ -z "$1" ]]; then
    # No argument → status
    get_status
elif [[ "$1" == "auto" ]]; then
    echo "Returning fan control to driver (auto)..."
    echo 2 | sudo tee "$mode_file" >/dev/null
    get_status
elif [[ "$1" =~ ^[0-9]+$ ]] && (( $1 >= 1 && $1 <= 100 )); then
    pwm=$(( $1 * 255 / 100 ))
    echo "Setting fan to $1% (pwm=$pwm)..."
    echo 1 | sudo tee "$mode_file" >/dev/null
    echo $pwm | sudo tee "$pwm_file" >/dev/null
    get_status
else
    echo "Usage: gpu [<1-100>] | [auto] | [status]"
    exit 1
fi