PWM period

I want to use two servos with pins 8_13 and 8_19. How can I change the period? I tried editing the dts file and compiling with
dtc -O dtb -o bone_pwm_P8_13-00A0.dtbo -b 0 -@ bone_pwm_P8_13-00A0.dts, but the period remains the same. Is there something else that need to be done? I not sure it actually compiles, because the command line returns instantly.

If you are using device tree based approach, then refer this link!topic/beagleboard/4R91_v9WBEY

I hope this can help you.