Re: BeagleBone Black Overlay: Missing file in newer kernel

[Drew Fustini]

On Wed, Dec 6, 2017 at 12:06 PM, Shivanand Pattanshetti wrote:
> Hi,
>
> I am trying to get encoder input using eQEP on the BBB. I am running the
> Ubuntu 16.04 image downloaded from rcn-ee website.
>
> ubuntu@arm:/sys/firmware/devicetree/base/bone_capemgr$ uname -r
> 4.9.54-ti-r68
> ubuntu@arm:~$ ls -ltr /sys/devices/platform/bone_capemgr
> total 0
> -rw-r--r-- 1 root root 4096 Dec 6 17:29 uevent
> lrwxrwxrwx 1 root root 0 Dec 6 17:29 subsystem -> ../../../bus/platform
> drwxr-xr-x 2 root root 0 Dec 6 17:30 power
> lrwxrwxrwx 1 root root 0 Dec 6 17:30 of_node ->
> ../../../firmware/devicetree/base/bone_capemgr
> -r--r--r-- 1 root root 4096 Dec 6 17:30 modalias
> -rw-r--r-- 1 root root 4096 Dec 6 17:30 driver_override
> lrwxrwxrwx 1 root root 0 Dec 6 17:30 driver ->
> ../../../bus/platform/drivers/bone_capemgr
> ubuntu@arm:~$ ls -ltr /sys/firmware/devicetree/base/bone_capemgr/
> total 0
> -r--r--r-- 1 root root 16 Dec 6 17:53 compatible
> -r--r--r-- 1 root root 20 Dec 6 17:53 nvmem-cells
> -r--r--r-- 1 root root 4 Dec 6 17:53 #slots
> -r--r--r-- 1 root root 5 Dec 6 17:53 status
> drwxr-xr-x 4 root root 0 Dec 6 17:53 baseboardmaps
> -r--r--r-- 1 root root 13 Dec 6 17:53 name
> -r--r--r-- 1 root root 34 Dec 6 17:53 nvmem-cell-names
> ubuntu@arm:~$ cat /sys/firmware/devicetree/base/bone_capemgr/#slots
> �ubuntu@arm:~$
>
>
> I tried following the readme on
> https://github.com/beagleboard/bb.org-overlays, but there is no 'slots' file
> anywhere! Could you help me?
>
> Thank you!!
>
> Shivanand Pattanshetti

Hi Shivanand, sorry for the delay. I just noticed this email from you.

I'm replying to the beagleboard.org community mailing list and bcc'ing
you as others may benefit from this discussion.

My guess is that your system has u-boot overlays enabled:
https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays

The cape manager kernel driver is incompatible with u-boot overlays so
Robert Nelson has disabled the slots file:
https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Where_did_the_slots_file_go.3F

If you have further questions, then please post the contents of your
/boot/uEnv.txt

thanks,
drew