Linux Device Drivers Development

Capturing using the sysfs trigger

Capturing data using the sysfs trigger consists of sending a set of command few sysfs files. Let's enumerate what we should do to achieve that:

1. Create the trigger: Before the trigger can be assigned to any device, it should be created:

 # echo 0 > /sys/devices/iio_sysfs_trigger/add_trigger

Here, 0 corresponds to the index we need to assign to the trigger. After this command, the trigger directory will be available under /sys/bus/iio/devices/, as trigger0.

2. Assign the trigger to the device: A trigger is uniquely identified by its name, which we can use in order to tie the device to the trigger. Since we used 0 as the index, the trigger will be named sysfstrig0:

# echo sysfstrig0 > /sys/bus/iio/devices/iio:device0/trigger/current_trigger ...