I have cape-universal set up:
0: PF---- -1
1: PF---- -1
2: PF---- -1
3: PF---- -1
4: P-O-L- 0 Override Board Name,00A0,Override Manuf,univ-emmc
root@beaglebone:~# config-pin -q p8.13
P8_13 Mode: pwm
So I configure pwm for pwmchip4 :
sh -c "echo 0 > /sys/class/pwm/pwmchip4/export"
and now I have duty_cycle, period, etc in: /sys/devices/platform/ocp/48304000.epwmss/48304200.pwm/pwm/pwmchip4/pwm0
When the machine reboots all that is gone. Why?