I’m having problems with PWM under the latest 3.13 kernel (built as per the instructions provided @ http://www.eewiki.net/display/linuxonarm/BeagleBone+Black) with a Debian root filesystem.The Device tree seems to support 3 PWM channels on P9_14, P9_16 (ehprwm1a&b) & P9_42 (ecap0). But when i take a peek at the contents of the “/sys/devices/ocp.#/pwm_test_P9_14.#/” directory I do not see the ‘period’, ‘duty’, ‘run’ or ‘polarity’ files needed to control the PWM channels.
Is PWM supported in the 3.13 Kernel yet?
Thanks!
Hussam
I retried accessing PWM in the latest 3.13 kernel…with no luck. Is PWM still not supported in 3.13 (under /sys/devices/ocp.#/pwm_test_P9_14.#/) or is there simply a new way to access PWM that I’m not aware of ?
Hussam
If properly enabled in dtb file during booting, you can always use any peripherals in AM335X SoC.
Refer https://github.com/chunsj/nxctrl/blob/master/pwm-test.c, which uses /dev/mem for control
pwm. Of course this code does not provide sysfs interface.
Thanks Sungjin!
I’ll take a look a your code…I’m still curious as to what exactly happened to the pwm sysfs interface in the 3.13 kernel though. If anyone knows please let me/us know
Thanks!