I considered having a lock file that each script accesses, to control access to the i2c bus, but that seems like a lot of overhead, probably worse that my time slot solution.

Taking a brief look at the code, it appears that what HiPi::Device::I2C is doing is an ioctl on the /dev/i2c* device file, and my guess would be that the Linux kernel doesn't guarantee those to be atomic when there are multiple writers. But I also don't see your issue with a lock file, since I2C writes should be pretty quick - why not just flock the object's filehandle? I don't have an RPi with an I2C device handy to test, but I'd suggest just trying something like this:

use Fcntl qw/:flock/;
...
my $i2c = HiPi::Device::I2C->new(...);
...
flock($i2c->fh, LOCK_EX) or die "flock: $!";
$i2c->bus_write(...);
flock($i2c->fh, LOCK_UN) or die "flock: $!";

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In reply to Re: i2c bus contention by haukex
in thread i2c bus contention by anita2R

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