I wish to control PWM_A, PWM_B and PWM_C on an armStoneA9r2, that, according to the GPIO reference card, are associated with /sys/class/gpio# 42, 125, 126 mapped on feature pins 28, 30, 32.
On general linux forums, I've seen it should be possible to control PWM outputs by setting values on sysfs parameters such as duty_cycle, polarity, enable.
But I can't find any of them on the sysfs treee on the pwm subfolder.
On my board (among the others) the most likely entries I have are:
But can't set any of those values, as I catch errors. (Permission denied).
Looking in other paths under /sys/class/pwm/pwmchip# I've not found any suitable file I can set.
am I missing something?
Thanks and BR,