trouble with image bone-debian-8.5 / 2016-06-05

[TJF]

capemgr doesn't load device tree overlays: dmesg reports

...

[  200.132514] bone-pinmux-helper ocp:pruio-08: could not find pctldev for node /ocp/interrupt-controller@48200000, deferring probe

but node name is

 ocp/48200000.interrupt-controller

 

[Rahul K Singh]

try this path for latest image:

/sys/devices/platform/ocp/

[TJF]

Thanks for your answer, Rahul. Unfortunatelly you didn't understand the problem.

In the path you mentioned, the bone-pinmux-helper looks for a node named

interrupt-controller@48200000

and failed to find it, obviously because its name is now

48200000.interrupt-controller

This has to get fixed in the kernel source.

[Wally Bkg]

Why all these changes to /sys/devices tree?
Its ugly and will remain ugly no matter what they do with the names, but these changes break existing code and documentation to what benefit?

[John Syne]

What was ugly was the original board files with duplicate code in the kernel source for each platform. Anyway, why is this ugly? It is simply a device address and a label. The driver needs this information, so you can either hard code it (not a good idea because it leads to duplicate code) or you can define it in the device tree. Same thing for gpio numbers, interrupts, dma channels, etc. Take the time to understand the format and it won’t seem so confusing.

Regards,
John

> On Jun 20, 2016, at 5:42 AM, Wally Bkg <wb666...@gmail.com> wrote:
>
> Why all these changes to /sys/devices tree?
> Its ugly and will remain ugly no matter what they do with the names, but these changes break existing code and documentation to what benefit?
>

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[TJF]

Am Montag, 20. Juni 2016 18:09:36 UTC+2 schrieb john3909:

It is simply a device address and a label. The driver needs this information, so you can either hard code it (not a good idea because it leads to duplicate code) or you can define it in the device tree. Same thing for gpio numbers, interrupts, dma channels, etc. Take the time to understand the format and it won’t seem so confusing.

If it is that easy, why do kernel developers have the same problems like Wally Bkg and myself, and problems of this kind are everywhere?

Guys like Derek Molloy spend a lot of effort in writing good tutorials. And most documentations are outdated with the next small kernel update?

Names in /sys should never change! OK, sometimes it needs a clean-up. But that should only happen when the major kernel version number changes. And a clear documentation is obligatory.

BR

[John Syne]

Because Devicetree is new and there is an effort to achieve consistency between all architectures. Remember, devicetree started on the PowerPC platform and it was only when Linus complained about the code duplication and conflicts between ARM platforms that Devicetree was adopted by the ARM community. There are still architectures who still have board files so expect more churn as these architectures adopt devicetree. In addition, as companies like TI mainstream their patches, they are also making changes to the devicetree, so it will be some time before this settles down. 

Regards,

John

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[Robert Nelson]

No one is forcing you to upgrade either..

We go out of our way to allow you to install almost any kernel version.

3.8.13-boneX -> 4.7.X

Regards,

--
Robert Nelson
https://rcn-ee.com/