fix(pl18u): Reinit I2C when touch screen not working

[richardclli]

PL18U can have touch screen unresponsive, and need I2C reinit to make it work again.

This PR will fix all similar symptom in all Flysky radios supported in pl18 target.

A bug is discovered in stm32_i2c_driver that will make reinit i2c bus not working in other color touch screen (opencode + deepseek did this, yeah)

Summary by CodeRabbit

• Bug Fixes

  • Strengthened I2C peripheral driver cleanup with enhanced memory clearing during deinitialization to prevent resource leaks and stale state.
  • Improved touch panel driver with an active I2C bus reinitialization sequence, including timing control and diagnostic logging for more reliable recovery.

• Tests

  • Added a disabled debugging block for future I2C reinitialization testing and diagnostics.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds and zeroes the I2C handle Init after deinit; enables touch driver _i2c_reInit() to deinit, delay 1 ms, and reinit with trace logs; adds a compile-disabled polling counter in touchPanelRead() for optional reinit triggering.

Changes

STM32 I2C Driver Cleanup and Touch Reinitialization

Layer / File(s)	Summary
STM32 I2C driver handle cleanup radio/src/targets/common/arm/stm32/stm32_i2c_driver.cpp	Adds <cstring> header and introduces memset to zero the I2C handle's Init structure after successful HAL_I2C_DeInit() call.
Touch driver I2C reinitialization radio/src/targets/pl18/touch_driver.cpp	_i2c_reInit() actively deinitializes the I2C bus, logs start/end, delays 1 ms, reinitializes it, and returns on failure. touchPanelRead() gains a compile-disabled (#if 0) counter/polling block that can trigger _i2c_reInit() for testing.

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description provides context about the touch screen issue and the bug fix, but does not follow the template structure with required sections like 'Fixes #' issue reference and 'Summary of changes'.	Add the required template sections: include a 'Fixes #' reference to link the related issue, and structure the description with a clear 'Summary of changes' section following the repository template.
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 (3 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title 'fix(pl18u): Reinit I2C when touch screen not working' directly describes the main change: implementing I2C reinitialization to recover unresponsive touch screens on PL18U devices.

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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-pl18-touch-dead

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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/pl18/touch_driver.cpp`:
- Around line 173-180: The TRACE call always reports "I2C reinit: bus reset
complete" even if deinit or re-init failed; update _i2c_reInit() to check the
return value of i2c_deinit(TOUCH_I2C_BUS) and the result of _i2c_init() and only
emit the success TRACE when both succeed, otherwise log an error/TRACE with the
failure reason and propagate/return an error code; specifically modify the block
around i2c_deinit, delay_ms(1), and _i2c_init() (references: i2c_deinit,
_i2c_init, and the surrounding TRACE calls) to conditionally log success or
failure and avoid masking recovery failures.

🪄 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: 4d0c0c70-f4c9-4e23-85a2-a837cb459f13

📥 Commits

Reviewing files that changed from the base of the PR and between 00d7544 and d66b80d.

📒 Files selected for processing (2)

• radio/src/targets/common/arm/stm32/stm32_i2c_driver.cpp
• radio/src/targets/pl18/touch_driver.cpp

[richardclli]

@pfeerick Need to wait for Flysky confirm if this can fix the problem, I can hardly reproduce touch screen dead.