Hello Thierry & Fabrice, >> Still, it is possible to send uevent (KOBJ_CHANGE) on pwmchipN device, >> to notify of a change, e.g. pwmX channel being exported/unexported.
I tested this patch, and I am happy to report that it works with the udev rule that Raspbian (Raspberry Pi's Debian derivative) has in place: SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\ chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\ chown -R root:gpio /sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770 /sys/devices/platform/soc/*.pwm/pwm/pwmchip*\ '" So while I can't comment on the uevent semantics, it would solve what the original patch attempted to enable (non-root use of pwm). Tested-by: Gottfried Haider <gottfried.hai...@gmail.com> Best, Gottfried