Day36 Log - IIO Triggered Buffer Integration

Summary

Successfully integrated:

• IIO trigger
• triggered buffer
• IRQ-driven sampling
• user-space controlled data flow

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Achievements

• DRDY IRQ triggers IIO pipeline
• Buffer streaming works via /dev/iio:device0
• Multi-channel frame validated
• User-space control confirmed

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Issues Encountered

1. Missing IIO modules

Unknown symbol iio_push_to_buffers

Fix:

modprobe industrialio-triggered-buffer
modprobe kfifo_buf

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2. Duplicate scan index

Duplicate scan index 0

Fix:

• add unique scan_index per channel

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3. Module stuck (File exists)

Cause:

• incomplete cleanup
• refcount mismatch

Fix:

• reboot system

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4. Module in use

rmmod: module in use

Fix:

echo 0 > buffer/enable
echo "" > trigger/current_trigger

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5. Trigger misuse

Cause:

• directly calling buffer handler from IRQ

Fix:

• use proper trigger flow

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Observations

1. User-space control is critical

• buffer must be manually enabled
• trigger must be explicitly bound

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2. Driver must remain passive

• no auto-start
• no hidden configuration

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3. Debugging requires layered approach

IRQ → trigger → buffer → userspace

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Key Insight

IIO is not just a driver API, but a data pipeline framework.

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Reflection

This stage represents a major shift:

driver-centric → system-centric

The driver no longer "serves data directly", but participates in a larger pipeline controlled by user space.

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Next Plan

• add timestamp support
• improve buffer parsing
• explore trigger types
• test high-frequency sampling

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