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Day39 Log - IIO Capability Exposure

📅 Summary

Implemented capability exposure for sampling frequency.

✅ Achievements

  • Added mapping table for sampling frequency
  • Separated hardware register values from user-visible Hz
  • Implemented sampling_frequency_available
  • Switched validation to table-based lookup
  • Verified behavior with FIFO + trigger buffer

🔍 Observations

Capability Output

0 1 2 4 8 16 32 64 128

Valid Write

echo 16 > sampling_frequency

Result:

  • Success

Invalid Write

echo 3 > sampling_frequency

Result:

  • Rejected with -EINVAL

Integration Test

  • FIFO mode works as expected
  • Trigger buffer unaffected
  • No regression from Day38

⚠️ Notes

  • 0 is defined as:
  • disable periodic sampling
  • does NOT imply one-shot
  • one-shot behavior to be designed later

🧠 Learnings

  • Capability exposure improves usability
  • Table-based design avoids duplicated logic
  • Kernel prefers explicit capability reporting over trial-and-error

🚀 Next Steps

  • Mode design (FIFO / DRDY / idle)
  • One-shot acquisition design
  • Further abstraction of control plane