[Unit]
Description=Fan PWM Control
After=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/bash -c 'echo 0 > /sys/class/pwm/pwmchip0/export && \
                        echo 40000 > /sys/class/pwm/pwmchip0/pwm0/period && \
                        echo 28000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle && \
                        echo 1 > /sys/class/pwm/pwmchip0/pwm0/enable'
ExecStop=/bin/bash -c 'echo 0 > /sys/class/pwm/pwmchip0/pwm0/enable && \
                       echo 0 > /sys/class/pwm/pwmchip0/unexport'

[Install]
WantedBy=multi-user.target