Enable PWM on BBB Debian 4.1 Jessie

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21

We could also add the alias to the am33xx.dtsi:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am33xx.dtsi#n20

like:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=70f97128a158a596aeb82140ffacc8c18657baee

Yeah, but would that help with the given problem with what Mark is currently facing ? Look at the two capes, and base address, and mode each pwm chip is placed in.

22

Mark,
Quite honestly, I have no idea how both of those capes you’re showing data on work. Each peripheral module between the two have different base addresses. Offset width, I can understand being different, but device module base address ? . . .I’m confused.

23

Robert:
I tried it. What should I see? It looks like I get yet another ordering of the aliases.

universaln

0 lrwxrwxrwx 1 root root 0 Feb 8 19:32 pwmchip0 → …/…/devices/platform/ocp/48300000.epwmss/48300200.ehrpwm/pwm/pwmchip0

0 lrwxrwxrwx 1 root root 0 Feb 8 19:32 pwmchip2 → …/…/devices/platform/ocp/48302000.epwmss/48302200.ehrpwm/pwm/pwmchip2

0 lrwxrwxrwx 1 root root 0 Feb 8 19:32 pwmchip4 → …/…/devices/platform/ocp/48300000.epwmss/48300100.ecap/pwm/pwmchip4

0 lrwxrwxrwx 1 root root 0 Feb 8 19:32 pwmchip5 → …/…/devices/platform/ocp/48304000.epwmss/48304100.ecap/pwm/pwmchip5

0 lrwxrwxrwx 1 root root 0 Feb 8 19:32 pwmchip6 → …/…/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip6

cape-emmc

0 lrwxrwxrwx 1 root root 0 Feb 8 19:01 pwmchip0 → …/…/devices/platform/ocp/48300000.epwmss/48300100.ecap/pwm/pwmchip0

0 lrwxrwxrwx 1 root root 0 Feb 8 19:01 pwmchip1 → …/…/devices/platform/ocp/48304000.epwmss/48304100.ecap/pwm/pwmchip1

0 lrwxrwxrwx 1 root root 0 Feb 8 19:01 pwmchip2 → …/…/devices/platform/ocp/48300000.epwmss/48300200.ehrpwm/pwm/pwmchip2

0 lrwxrwxrwx 1 root root 0 Feb 8 19:01 pwmchip4 → …/…/devices/platform/ocp/48302000.epwmss/48302200.ehrpwm/pwm/pwmchip4

0 lrwxrwxrwx 1 root root 0 Feb 8 19:01 pwmchip6 → …/…/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip6

New universaln (4.1-ti-pwm)

0 lrwxrwxrwx 1 root root 0 Feb 9 08:57 pwmchip0 → …/…/devices/platform/ocp/48300000.epwmss/48300200.ehrpwm/pwm/pwmchip0

0 lrwxrwxrwx 1 root root 0 Feb 9 08:57 pwmchip2 → …/…/devices/platform/ocp/48302000.epwmss/48302200.ehrpwm/pwm/pwmchip2

0 lrwxrwxrwx 1 root root 0 Feb 9 08:57 pwmchip4 → …/…/devices/platform/ocp/48300000.epwmss/48300100.ecap/pwm/pwmchip4

0 lrwxrwxrwx 1 root root 0 Feb 9 08:57 pwmchip5 → …/…/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip5

0 lrwxrwxrwx 1 root root 0 Feb 9 08:57 pwmchip7 → …/…/devices/platform/ocp/48304000.epwmss/48304100.ecap/pwm/pwmchip7

–Mark

24

Thanks for testing Mark, looks like we need to patch the ecap/ehrpwm
driver to utilze the alias..

I'm going to be out of the lab today and tomorrow, so i'll take a look
at this thursday morning..

Regards,

25

Thanks for the help Robert. I’e hacked around the problem for the short term.

–Mark