fix(pa01): Optimize key matrix polling with split-cycle scanning

[richardclli]

Developed by opencode + deepseek-v4

Split the 4-column matrix scan across 4 poll cycles (1 I2C read + 1 write per cycle instead of 4 reads + 4 writes). The output for each column is set in one cycle and read in the next (10ms later), eliminating the 10us settling delay.

Interrupt-driven caching: when no pin-change interrupt occurs between polls, the I2C read is skipped and per-column cached results are reused. A forced full rescan every 250ms catches key releases that may not trigger an interrupt.

Replaced #7394 and #7315

v2.11 version is at #7409

Summary by CodeRabbit

• Bug Fixes
  • Improved key scanning to an incremental, cached column-based poll for faster, non-blocking input updates and periodic background scans when idle.
  • Added consecutive-I2C-error tracking and automatic recovery (bus reinitialization) with writes routed through the same tracking to improve communication robustness.

[coderabbitai]

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📝 Walkthrough

Walkthrough

Refactors key matrix polling from a blocking full-matrix scan to an incremental, cached per-column scanner with idle-driven scheduling and ent_mask handling. Adds consecutive I2C error tracking that deinitializes/reinitializes the I2C bus after a configurable failure threshold; AW9523B device reinitialization/output-state restoration is not included here.

Changes

Key Matrix Incremental Scan

Layer / File(s)	Summary
Scan state infrastructure and cached reading radio/src/targets/pa01/key_driver.cpp	Introduces scan configuration and persistent per-column cache/state plus read_col_to_keys() to decode a column; pollKeys() now computes ent_mask each call and may return cached results when suspendI2CTasks is set.
Progressive scan scheduling and result computation radio/src/targets/pa01/key_driver.cpp	Replaces blocking full-matrix read with progressive per-column updates gated by syncelem.ui8ReadInProgress: schedules reads with bsp_get_shouldReadKeys()/IDLE_FORCE_SCAN, updates one cached column per call, drives next column output, recomputes full result from col_cache + ent_mask, stores it in syncelem, and refreshes fct_state[].

I2C Error Recovery for AW9523B

Layer / File(s)

Summary

Consecutive I2C error tracking and recovery mechanism radio/src/targets/pa01/bsp_io.cpp

Adds delays_driver.h/debug.h; implements a consecutive-failure counter and _track_i2c_error() that triggers _recover_i2c() after a threshold. _recover_i2c() deinitializes and reinitializes the I2C bus (with delay and TRACE); AW9523B device reinitialization/output-state restoration is not performed in these changes. bsp_input_read() updates inputState only on successful reads, and output writes route results through the same tracker.

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: optimizing key matrix polling through split-cycle scanning across multiple poll cycles.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The pull request description provides a clear summary of changes, technical rationale, and references to related PRs.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch richardclli/fix-pa01-keyboard-scanning

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@radio/src/targets/pa01/bsp_io.cpp`:
- Around line 81-84: The three post-init calls aw9523b_write(&i2c_exp,
BSP_OUT_MASK, BSP_KEY_OUT1 | BSP_KEY_OUT2 | BSP_KEY_OUT3 | BSP_KEY_OUT4),
aw9523b_set_direction(&i2c_exp, 0xFFFF, BSP_IN_MASK) and
bsp_output_clear(BSP_U6_SELECT) currently ignore return values; update this
block to check each return like the rest of bsp_io_init() (use BSP_CHECK or
equivalent error handling), and bail/log on failure before logging "I2C recovery
complete" so the device cannot reach an inconsistent state.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 123f361e-6ab9-4892-8b92-9dc800b0bb60

📥 Commits

Reviewing files that changed from the base of the PR and between a9bd6d9 and 7ad0780.

📒 Files selected for processing (2)

• radio/src/targets/common/arm/stm32/stm32_i2c_driver.cpp
• radio/src/targets/pa01/bsp_io.cpp