WiringPi on Odroid C2: No Revision in /proc/cpuinfo

Help & Support Hardware
1

Dear all,

I tried to use wiringPi under CE to make use of the Odroid’s gpio. I cross compiled it and obviously got a working binary. At least it launches and displays version info, help, etc.

Still it won’t access the gpio. This seems to be the case as the data under /proc/cpuinfo do not contain a line labeled „Revision“ which I guess is present in other operating systems. Is there a reason why this line is missing in CE? Any way to add it?

Also I tried forcing the program to just ignore the line and use „Revision : 0200“, which I think should be the correct entry for a C2. Unfortunately that only gets me the next error „Segmentation fault“ and still no working program. :frowning:

Here’s what I changed in ./wiringPi/wiringPi/wiringPi.c in Hardkernel’s wiringPi on github

added in line 304:
fgets ( line, 120, "Revision        : 0200\n");
2

What is the output of cat /proc/cpuinfo? Isn’t there “Hardware :”?

3

Yes, „Hardware : xxx“ is there, but no „Revision : xxx“.

Processor       : AArch64 Processor rev 4 (aarch64)
processor       : 0
processor       : 1
processor       : 2
processor       : 3
Features        : fp asimd evtstrm crc32 wp half thumb fastmult vfp edsp neon vfpv3 tlsi vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

Hardware        : ODROID-C2
Serial          : 1f0c000046333444444644343532bf20

Since WiringPi origins from the RPi, it’s looking for that line. No idea though, why Hardkernel didn’t remove that in their fork in the first place.

Anyways, as I wrote I tried to bypass it and hardcoded the revision into WiringPi, but it still won’t run. That’s a pity cause the gpio is one fine feature that could be put to great use.

4

Could you please specify the problem with logs or code where you stuck if possible?

5

On line 304 after fclose just put
sprintf(line, "Revision : 020b\n");
or maybe just 0200.

6

This solves one error, but brings up another one.

I added it to line 304 in …/wiringPi.c :

…
while (fgets (line, 120, cpuFd) != NULL)
        if (strncmp (line, "Revision", 8) == 0)
                break ;
fclose (cpuFd) ;
sprintf(line, "Revision : 020b\n");
if (strncmp (line, "Revision", 8) != 0)
        wiringPiFailure (WPI_FATAL, "No \"Revision\" line") ;
…

Compiled and launched on the C2 I get ERROR : file not found.(boardrev)
At least it’s a new error for a change…

7

This is not really an error. It just shows that file /sys/class/odroid/boardrev doesn’t exist and it sets revision to 1. WiringPi should work anyway.