Unable to get BusPirate to show up as i2c bus

[ggiraudon]

Hi Tony,

If built your module as per your instructions except for 2 small variations ;

• in include/linux/tty.h 25 was already used (kernel 4.9.0.9) so I used 26 instead
• in sys-utils/ldattach.c I also used 26

Everything compiles normally and I am able to load the module without any issues.
I can confirm that the buspirate is connected properly and working. I can manually set it to i2c mode via picocom and run a scan for addresses successfully.

If I run "ldattach BUSPIRATE /dev/ttyUSB0" everything seems to work correctly.
Howevever, if i then run "i2cdetect -l" , I get no output.

If I run "ldattach -d BUSPIRATE /dev/ttyUSB0" I get the following :

root@slam:~# ldattach -d BUSPIRATE /dev/ttyUSB0
ldattach: opened /dev/ttyUSB0
ldattach: set to raw 0 ---: cflag=0xb0
ldattach: line discipline set to 26

which seems correct.
But I still get no output out of "i2cdetect -l"

I was wondering : do I have to recompile my kernel with the changes to include/linux/tty.h (I dont think so... but I just want to make sure).
If that isnt the case, would you have any pointers as to what I might be doing wrong ? Is there anything I can do to troubleshoot this further ?

Thanks in advance

MadBeggar

[tonyhutter]

Hmm, everything looks ok. You shouldn't need to recompile the kernel. Did you try running sudo i2cdetect -l?

[ggiraudon]

I'm actually running all commands as root so that wouldnt be the issue.
I'm going to try adding a few more printk() in the module code to see what gets called...

[ggiraudon]

I figured out one part of my puzzle : the module "i2c_dev" wasnt loaded.
I can now see my device and scan successfully.
However, when I tried to make a read, I get timeouts on the code side.
On the kernel side, here's what I have :

[21340.101273] buspirate: module loaded
[21585.301256] i2c i2c-1: Got 1 bytes spurious data
[21585.459275] i2c i2c-1: Got 1 bytes spurious data
[21585.732359] i2c i2c-1: Got 1 bytes spurious data
[21585.762390] i2c i2c-1: Got 1 bytes spurious data
[21585.810245] i2c i2c-1: Got 1 bytes spurious data
[21585.842121] i2c i2c-1: Got 1 bytes spurious data
[21586.336709] i2c i2c-1: Got 1 bytes spurious data
[21616.079662] i2c i2c-1: Got 1 bytes spurious data
[21616.364853] i2c i2c-1: Got 1 bytes spurious data
[21616.494197] i2c i2c-1: Got 1 bytes spurious data
[21617.387647] i2c i2c-1: Got 1 bytes spurious data
[21622.333853] i2c i2c-1: Got 1 bytes spurious data
[21632.416124] i2c i2c-1: Got 1 bytes spurious data
[21633.247491] i2c i2c-1: Got 1 bytes spurious data
[21633.325451] i2c i2c-1: Got 1 bytes spurious data
[21633.453085] i2c i2c-1: Got 1 bytes spurious data
[21633.503053] i2c i2c-1: Got 1 bytes spurious data
[21723.921792] i2c i2c-1: Got 1 bytes spurious data
[21724.001752] i2c i2c-1: Got 1 bytes spurious data
[21724.112934] i2c i2c-1: Got 1 bytes spurious data
[21724.496242] i2c i2c-1: Got 1 bytes spurious data
[21724.672892] i2c i2c-1: Got 1 bytes spurious data

Any ideas ?

[ggiraudon]

Is there a way to see the output of dev_dbg( ) ?

[tonyhutter]

You could try setting /proc/sys/kernel/printk
https://elinux.org/Debugging_by_printing#Log_Levels