active_scan_mask

[Henk <iio-developer@freedom.nl>]

Dear all,

I created a custom IIO device in FPGA which in fact contains a bunch of 
ADC channels which I can acquire and stream to disk. I use analog 
devices' libiio and specifically their iio_readdev application together 
with my custom FPGA design and custom iio kernel driver.

Question: what mechanism is updating the indio_dev->active_scan_mask field.

With the iio_readdev application I can add command arguments where I can 
activate the channels that I want to retrieve (voltage0 voltage1 
...etc). When I use 8 channels as command argument in iio_readdev then 
the active_scan_mask seems to be updated with the enabled channels. When 
adding even more channels the field is extended. However, when trying to 
acquire new data and dropping some of the channel arguments then the 
active_scan_mask field does not seem to revert back to the less enabled 
(or requested) channels.

So.. I am searching which mechanisms updates that field with the aim to 
fix that bug.

Any help is appreciated.

Kind regards

Henk