This is on BBB Linux beaglebone 4.14.108-ti-r108 On this new kernel I can see that cape_universal is being used in /boot/uEnv.txt so all, or quite of pwm's are on in /sys/class/pwm/pwmchip#
Some of the pwms like GPIO 71 P8-46 used to be on pwmchip6/pwm1 but now exporting 1 > gpiochip6 says no device. Based on this utility https://redypis.org/addons/bb_pins.php which uses the bash array from config_pin I can see that p8_46 is on 0x3:ehrpwm2B which is EHRPWM2 (ePWM2) which is pwmchip6 channel B so export 1 (B) should work but now does not . Furthermore more going to chips 6 folder and exporting 0 or un-exporting makes the gpio-6.0 going on and off which is fine, but any attempt to write onto it fails marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 100000 ./duty_cycle 100000 ./duty_cycle marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 100000 > ./duty_cycle -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 100000 > enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 1 > enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ config-pin P8.46 pwm marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 1 > enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 0 > enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 0 > ./enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 10000 > enable -bash: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 10000 ./duty_cycle 10000 ./duty_cycle marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ echo 10000 > ./duty_cycle marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ sudo echo 1 > enable [sudo] password for marius: echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ sudo echo on > enable echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ sudo echo default > enable echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ sudo echo okay > enable echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ sudo echo true > enable echo: write error: Invalid argument marius@beaglebone:/sys/class/pwm/pwmchip6/pwm-6:0$ uname -a Is there any updated information or I have to look into the dts file and figure it out ? Is there any way to find the mapping from the sys filesystem between the KERNEL GPIO# -- PX.Y (rail name) and /sys/class/pwm/pwm-X.Y Thank you. -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/baaa91a8-b2c7-4274-a7c7-487cea1bb698%40googlegroups.com.
