Paul, This link explains how sysfs works with the PWM driver:
http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/Documentation/pwm.txt#n48 The PWM chip and channel number are determined by the device tree. If you 'cat /sys/kernel/debug/pwm', do you see PWM_P9_14 listed? More information: http://hipstercircuits.com/enable-pwm-on-beaglebone-with-device-tree-overlays/ On Thu, Nov 21, 2013 at 10:41 AM, Paul Mikesell <[email protected]> wrote: > Hi, > > I'm using a BeagleBone RevA6 with the latest Angstrom (as of a few days > ago at least). > > I'm able to get pwm pins up and running via the capemgr and the helpful > dts files for the various pwms in the /lib/firmware dir. I can echo various > duty and period values into the corresponding > /sys/devices/ocp.2/pwm_test_PX_YY.ZZ/{duty,period} files and control > servos. This all seems fine. > > From my (possibly flawed) understanding, the better way to do this is to > explicitly export the pwms via the /sys/class/pwm/export special file. What > I don't understand is how are these pwms numbered from the export > perspective? That is, how do I know what number to cat into > /sys/class/pwm/export to correspond to, for example, P9_14 when configured > as ehrpwm1A? > > I understand that for gpios there are 32 gpios per chip, so gpio 1[18] > = (1 * 32) + 18 = 50, and that seems to work. Is there some corresponding > relationship for pwms? > > > -P > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
