following Instuction only works for Linux kernel 3.11 or greater
PWM devices are listed under /sys/class/pwm
root@MBaXXX:~ cd /sys/class/pwm // enter pwm folder in sysfs root@MBaXXX:/sys/class/pwm cd pwmchip<pwmchipnr> // enter the desired pwmchip folder root@MBaXXX:/sys/your/path/to/pwmchip/pwmchip<pwmchipnr> echo <pwmnr> > export // export device PWM<pwmnr> root@MBaXXX:/sys/your/path/to/pwmchip/pwmchip<pwmchipnr> cd pwm<pwmnr> // enter exported pwm device folder