prevent NFC driver crash on repeated deinitialization

[TychoVrahe]

Spi deinit causes the crash when receiving NULL instance.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: f23f1948-cf77-4b6a-9540-d2822a554611

📥 Commits

Reviewing files that changed from the base of the PR and between 972dd51 and 7b271ae.

📒 Files selected for processing (1)

• core/embed/io/nfc/st25/nfc.c

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Walkthrough

The nfc_deinit() function in the NFC driver was changed to guard SPI de-initialization. Instead of unconditionally calling HAL_SPI_DeInit() on the driver's SPI handle, it now checks that drv->hspi.Instance is non-NULL before invoking HAL_SPI_DeInit(), avoiding de-initialization when the SPI peripheral was never initialized or its instance was cleared.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

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.
Description check	❓ Inconclusive	The PR description is minimal and vague. While it mentions the core issue (SPI deinit crash with NULL instance), it lacks the structured information recommended by the template.	Enhance the description with more context: explain the issue scenario, the fix approach, testing steps, and whether QA testing is needed per the template guidelines.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: preventing NFC driver crash on repeated deinitialization, which matches the code change that adds a NULL check before SPI deinitialization.
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.

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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 tychovrahe/nfc/deinit_fix

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[github-actions]

en main(all)

model	device_test	click_test	persistence_test
T2T1	test(all) main(all)	test(all) main(all)	test(all) main(all)
T3B1	test(all) main(all)	test(all) main(all)	test(all) main(all)
T3T1	test(all) main(all)	test(all) main(all)	test(all) main(all)
T3W1	test(all) main(all)	test(all) main(all)	test(all) main(all)

Latest CI run: 25058975892