答：这里只给出了PWM的输出设置，这些无法使用，还需要按照实际pin脚修改dts添加PWM节点。
echo 100000 > /sys/class/pwm/pwmchip0/pwm0/period
echo 50000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
echo 0 > /sys/class/pwm/pwmchip1/export
echo 100000 > /sys/class/pwm/pwmchip1/pwm0/period
echo 50000 > /sys/class/pwm/pwmchip1/pwm0/duty_cycle
echo 0 > /sys/class/pwm/pwmchip2/export
echo 100000 > /sys/class/pwm/pwmchip2/pwm0/period
echo 50000 > /sys/class/pwm/pwmchip2/pwm0/duty_cycle
echo 0 > /sys/class/pwm/pwmchip3/export
echo 100000 > /sys/class/pwm/pwmchip3/pwm0/period
echo 50000 > /sys/class/pwm/pwmchip3/pwm0/duty_cycle
