Kernel 3.13 and above: How to enable dcan_1 and GPIOs
Marco Steger
Hi folks!
For some reasons (mainly the kernel support for IEEE 802.11s) I need to use Debian (kernel 3.13 or higher; I’m currently running 3.16.1-bone4) on my BBB. For my project, I will also use the CAN interface of the BBB and some IO pins (mainly for LEDs and switches...).
This is my first BBB project so I searched the web for the easiest / best solution for using the GPIO pins of my BBBs.
In many tutorials about BBB GPIO and can-bus the use of the capemgr is suggested. But as you all know there is no capemgr in 3.16.
Now I would
really need your help to find the best way to enable the can-bus (dcan_1) and
also control some other GPIO pins. Can I do this from userspace some how? Or do
I have to reconfigure and rebuild the kernel?
@GPIO pins: I think the easiest solution is to use "echo [GPIO No.] > /sys/class/gpio/export" and then set the value & direction etc. using echo. Am I right here?
Thanks a
lot for your help and hints,
Marco
Marco Steger
Hi again!
I spent some more hours on how to enable the d_can interfaces on my BBB.
I found Robert Nelsons "Really Simple Cape Manager" (RSCM) here [1].
This looks very promising at first. There is a folder for 3.13-bone and the
README says that
3.13-rc6-bone2 should be installed.
I'm currently working on 3.16.1-bone4. As far as I understand the idea behind
Robert’s RSCM I would need the original
.dts file of my BBB. Than add the needed lines to enable d_can1 (to enable d_can0
I would have to disable I2C2. Am I right?). The build a dtb file using dtc
(patched by Robert … he is present everywhere on the BBB I think! J) .
Finally I can move this
file to /boot/dtbs/3.16.1-bone4/ on my BBB (replace the existing dtb file(s).
But where can I find the dts file of my BBB? I wasn’t able to locate it on my board. Can I use the dts file from 3.13? Can I (permanently) damage my BBB when playing around here?
Would be great if someone
can help me!!!
[1] https://github.com/RobertCNelson/rscm
Jason Lange
https://groups.google.com/forum/#!topic/beagleboard/WuCvPyi9bqk
suggests that you might be more interested in this:
http://elinux.org/Beagleboard:Capes_3.8_to_3.14#Custom_dtb
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Jason Lange
Marco Steger
Hi Jason!
Thanks for your help! The dtb-rebuilder looks like a very promising solution for me. Although, in
Robert's GitHub repo is just a branch for kernel "3.14-ti". So a very
similar question then in my last post: Can I use the scripts and the dts file
also on my 3.16-bone4 kernel?
Do you think that it would be possible to permanently damage my BBB, if I try
to use the scripts on my 3.16 BBB?
If this is possible, then I think (or more hope :) ) it would be really easy to enable
d_can1:
1.) Like suggested in [1] I would take the am335x-boneblack.dtb file.
2.) It looks like that includes can be added easily:
|
/* can1: P9_24, P9_26 */ |
|
#include "am335x-can1.dtsi" (Already there) |
|
#include "am335x-boneblack-can1.dts" (add this line; But I’m not sure if .dts files can be included like .dtsi file?!) |
|
/* #include "am335x-bone-can1.dtsi" */ |
3.) Build dtb file using dtb-rebuilder.
4.) Copy to /boot/dtbs/ dir.
5.) reboot
Would be great if you can help me once more here!
[1] http://elinux.org/Beagleboard:Capes_3.8_to_3.14#Custom_dtb
Robert Nelson
>
> Hi Jason!
>
> Thanks for your help! The dtb-rebuilder looks like a very promising solution for me. Although, in Robert's GitHub repo is just a branch for kernel "3.14-ti". So a very similar question then in my last post: Can I use the scripts and the dts file also on my 3.16-bone4 kernel?
> Do you think that it would be possible to permanently damage my BBB, if I try to use the scripts on my 3.16 BBB?
branch contains a lot of patches that are both heading and hitting
mainline. Many post "3.16".. Lot's of the can patches have been
posted this last month for review for "3.19"..
>
> If this is possible, then I think (or more hope :) ) it would be really easy to enable d_can1:
>
> 1.) Like suggested in [1] I would take the am335x-boneblack.dtb file.
>
> 2.) It looks like that includes can be added easily:
>
>
> /* can1: P9_24, P9_26 */
>
> #include "am335x-can1.dtsi" (Already there)
>
> #include "am335x-boneblack-can1.dts" (add this line; But I’m not sure if .dts files can be included like .dtsi file?!)
>
> /* #include "am335x-bone-can1.dtsi" */
un-comment the 2nd line (pinmux) aka:
/* can1: P9_24, P9_26 */
#include "am335x-can1.dtsi"
The first include is the device "perhiperal" the second include is the pinmux.
Regards,
--
Robert Nelson
http://www.rcn-ee.com/
Marco Steger
Hi Robert,
thanks for your comments.
Yes and No... It'll boot, but not everything will work, ...
1.) Downloaded your DTB-rebuilder "
git clone -b 3.14-ti https://github.com/RobertCNelson/dtb-rebuilder.git"2.) Uncommented line 53 (/* #include "am335x-bone-can1.dtsi" */) in file dtb-rebuilder/src/arm/am335x-boneblack.dts.
3.) make
4.) copied the am335x-boneblack.dtb file to /boot/dtbs/3.16.1-bone4/
5.) Reboot. Without result. After running modprobe can; modprobe can-dev; modprobe can-raw there was no CAN interface when typing ifconfig -a
6.) So I checked the uEnv file in /boot dir. There was a line "#dtb="
7.) Then I uncommented this line and used dtb=/boot/dtbs/3.16.1-bone4/am335x-boneblack.dtb
8.) After reboot all 4 LEDs stay lid and after lets say 30 seconds its seems that the board reboots again.
What did I wrong here? Any ideas?
In the meantime I will reflash my board and start again... :)
Hope you can help me once again!
Thanks a lot!!!
Robert Nelson
>
> Hi Robert,
> thanks for your comments.
>>
>> Yes and No... It'll boot, but not everything will work, ...
>
> I'm not that sure about that. I just tried this and the BBB doesn't boot
> afterwards. But maybe I did a bad mistake. Here my steps:
>
> 1.) Downloaded your DTB-rebuilder "
>
> git clone -b 3.14-ti https://github.com/RobertCNelson/dtb-rebuilder.git"
>
> 2.) Uncommented line 53 (/* #include "am335x-bone-can1.dtsi" */) in file
> dtb-rebuilder/src/arm/am335x-boneblack.dts.
> 3.) make
> 4.) copied the am335x-boneblack.dtb file to /boot/dtbs/3.16.1-bone4/
> 5.) Reboot. Without result. After running modprobe can; modprobe can-dev;
> modprobe can-raw there was no CAN interface when typing ifconfig -a
The can "pinmux" relies on this patchset in my v3.14.x tree:
https://github.com/RobertCNelson/ti-linux-kernel-dev/tree/ti-linux-3.14.y/patches/beaglebone/pinmux-helper
> 6.) So I checked the uEnv file in /boot dir. There was a line "#dtb="
> 7.) Then I uncommented this line and used
> dtb=/boot/dtbs/3.16.1-bone4/am335x-boneblack.dtb
path to the lookup function in u-boot so user's don't break their boot
via ^^^^that^^^)
> 8.) After reboot all 4 LEDs stay lid and after lets say 30 seconds its seems
> that the board reboots again.
>
> What did I wrong here? Any ideas?
>
> In the meantime I will reflash my board and start again... :)
Robert Nelson
Right now i'm mainly focusing on the "v3.14-ti" branch, as a stepping
stone off "v3.8.x"
Otherwise, i'm staying in sync with mainline, as dt "overlay's" are
getting so close:
http://www.spinics.net/lists/devicetree/msg59480.html
Marco Steger
I reflashed my board, updated the kernel to 3.16.1-bon4, installed the dtc using [1] and downloaded dtb-rebuilder via [2]. But still wasn't able to enable CAN1...
> 4.) copied the am335x-boneblack.dtb file to /boot/dtbs/3.16.1-bone4/
> 5.) Reboot. Without result. After running modprobe can; modprobe can-dev;
> modprobe can-raw there was no CAN interface when typing ifconfig -a
Do you have can enabled?
The can "pinmux" relies on this patchset in my v3.14.x tree:
https://github.com/RobertCNelson/ti-linux-kernel-dev/tree/ti-linux-3.14.y/patches/beaglebone/pinmux-helper
I hope I got you rigth here. I went to the github repo from above and look at the file "0011-pinmux-helper-can1.patch ". In this patch file there is just one change in file "am335x-bone-common-pinmux.dtsi":
- pinctrl-single,pins = <0x180 0x32>; }; /* Mode 2, Pull-Up, RxActive */ //This line changes to
+ pinctrl-single,pins = <0x180 0x12>; }; /* Mode 2, Pull-Up, RxActive */ //this one
So I looked into this file on my BBB (dtb-rebuilder/src/arm/am335x-bone-common-pinmux.dtsi) and the change <0x180 0x12> was already there. Finally I uncommented line 53 (/* #include "am335x-bone-can1.dtsi" */) in file dtb-rebuilder/src/arm/am335x-boneblack.dts.
Then make and copy the dtb-file to the /boot/dbts/... dir.
> 6.) So I checked the uEnv file in /boot dir. There was a line "#dtb="
> 7.) Then I uncommented this line and used
> dtb=/boot/dtbs/3.16.1-bone4/am335x-boneblack.dtb
Yuck, don't do that, just the file name.. (i need to add the exact
path to the lookup function in u-boot so user's don't break their boot
via ^^^^that^^^)
Thanks for that hint. Now I just use "dtb=am335x-boneblack.dtb". And the board restarts without problems
After running the modprobe steps (can, can-dev, can-raw) I checked if I can see the can interface now using ifconfig -a but still there is no can0 interface.
What did I miss? Do you have any ideas or hints for me?
Best regards and thanks again for your help,
Marco
Jason Lange
Marco Steger
@Robert: Is there a plan to add dtb-rebuilder also to 3.16 kernel?
[1] http://elinux.org/Beagleboard:Capes_3.8_to_3.14#Custom_dtb
--Hi Marco,
About the patch: I think I made a mistake and changed a similar line by hand. I wasn't checking too carefully because I'm not actually using can0 -- I just wanted to tell you that it was going to work so you could stop wasting your time. I reverted the repo to be sure, and now I can't find the line. Probably a "git pull" is all you need to ensure you have the latest and greatest code.Cheers.
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Robert Nelson
> Hi Jason, Hi all,
>
> thanks for your hints. So I just used "apt-get install
> linux-image-3.14.25-ti-r37"
> like you preferred and it works like a charm ... After one reboot the can0
> interface was there! :)
> -> So for everyone who needs a kernel >3.8: Use kernel 3.14.25-ti-r37 and
> dtb-builder. For more information see [1].
>
> So I will use this configurations for some tests with can0.
> @Robert: Is there a plan to add dtb-rebuilder also to 3.16 kernel?
Specifically:
https://lkml.org/lkml/2014/11/24/806
Which is one of the really really big frameworks that's in our v3.8.x
kernel but not in mainline.
But yeah, when that drops i'll extend the dtb-rebuilder, because it's
very useful, and depending on the above patch-set i may restructure
things..