I think I have it figured out. If you disable the ecap devices, the dual channel populate normally. e.g. 0,2,4. But when you do have ecap enabled, that's when things start to get squirrely. But at least it's not completely random. There are or seem to be patterns when you have both ecap enabled. My file structure looked exactly the same as your above where you had ecap enabled.
On Fri, Sep 29, 2017 at 2:17 PM, Robert Nelson <robertcnel...@gmail.com> wrote: > On Fri, Sep 29, 2017 at 3:19 PM, William Hermans <yyrk...@gmail.com> > wrote: > > Robert, > > > > Ok I think I see what you mean now( fully ). With universal IO and the > > generic startup script enabled. I did see something similar to what you > were > > saying. However, if one disables both universal IO, and the generic > startup > > script, then writes their own custom overlay for all 3 of the PWM chips > that > > are dual channel. You get a structure like this: > > > > root@wgd:~# ls /sys/class/pwm/pwmchip*/ |grep pwm > > /sys/class/pwm/pwmchip0/: > > npwm > > /sys/class/pwm/pwmchip2/: > > npwm > > /sys/class/pwm/pwmchip4/: > > npwm > > > > This is consistent across multiple images on the same board. In this > case a > > 4G beaglebone black( rev C ). But at the same time as you can see from > the > > output above. The two PWM channels for each PWM chip are not enabled. In > > Jessie, these are populated automatically at boot. How can I make that > > happen in stretch ? I could write a script, but I think that is done > > automatically through cape_manager in Jessie ? > > What's happening in v4.4.x, the pwm's are now in the correct order, if > you look at v4.4.x: (pwm came before ecap) > > #4.4.88-ti-r129 > pwmchip0 -> ../../devices/platform/ocp/48300000.epwmss/48300200.pwm/ > pwm/pwmchip0 > pwmchip2 -> ../../devices/platform/ocp/48302000.epwmss/48302200.pwm/ > pwm/pwmchip2 > pwmchip4 -> ../../devices/platform/ocp/48304000.epwmss/48304200.pwm/ > pwm/pwmchip4 > pwmchip6 -> ../../devices/platform/ocp/48300000.epwmss/48300100.ecap/ > pwm/pwmchip6 > pwmchip7 -> ../../devices/platform/ocp/48304000.epwmss/48304100.ecap/ > pwm/pwmchip7 > > In v4.9.x: (since ecap are considered pwm's) they are now in the order > of the register address: > > pwmchip0 -> ../../devices/platform/ocp/48300000.epwmss/48300100.ecap/ > pwm/pwmchip0 > pwmchip1 -> ../../devices/platform/ocp/48300000.epwmss/48300200.pwm/ > pwm/pwmchip1 > pwmchip3 -> ../../devices/platform/ocp/48302000.epwmss/48302200.pwm/ > pwm/pwmchip3 > pwmchip5 -> ../../devices/platform/ocp/48304000.epwmss/48304100.ecap/ > pwm/pwmchip5 > pwmchip6 -> ../../devices/platform/ocp/48304000.epwmss/48304200.pwm/ > pwm/pwmchip6 > > In your case, you only want the dual mode "pwm", (48300200.pwm, > 48302200.pwm, 48304200.pwm), you shouldn't blindly enable the > "pwmchip0,2,4" as they are dynamic. You should grep the symlink > first. > > Ps, watch out for v4.11.x too: > > #v4.4.x/v4.9.x > /sys/class/pwm/pwmchip1/: > drwxr-xr-x 3 root root 0 Sep 29 21:06 pwm0 > drwxr-xr-x 3 root root 0 Sep 29 21:06 pwm1 > > #v4.11.x+ > > /sys/class/pwm/pwmchip1/: > drwxrwxr-x 3 root pwm 0 Sep 29 21:10 pwm-1:0 > drwxrwxr-x 3 root pwm 0 Sep 29 21:10 pwm-1:1 > > (ps, this last change is good thing, notice that udev correctly added > the "root:pwm" rule.. ;) ) > > Regards, > > -- > Robert Nelson > https://rcn-ee.com/ > -- 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/CALHSORpeFHTD5q2WrPaQeLwCQ4D0D%2B_Yr0fTL4FuEZ_hvx%2BwLQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
