fix(t22): use PB15 and PJ12 for red LED due to USART1_RX DFU overlap

[3djc]

Fixes #7534 (or at least support the required hardware change, technical details in the issue itself)

Summary of changes:

To fix an issue of buddy been unable to flash T22, there needs to be an hardware change. Red led pin will be moved from the troublemaking PB15 in current T22 boards to PJ12 in future boards.

This software change supports the red led operation for both old and new boards (old still remains non buddy flashable)

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds a second red LED GPIO (LED_RED2_GPIO) for the T22 target, defined as GPIOJ pin 12, and wires it into the shared LED driver's initialization, off, and red-on functions alongside the existing red LED.

Changes

Second Red LED GPIO Support

Layer / File(s)	Summary
LED_RED2_GPIO macro definition radio/src/targets/t22/hal.h	Adds a new macro mapping LED_RED2_GPIO to GPIO_PIN(GPIOJ, 12).
LED driver wiring for second red LED radio/src/boards/generic_stm32/led_driver.cpp	ledInit(), ledOff(), and ledRed() are updated to conditionally initialize, clear, and set LED_RED2_GPIO alongside the existing red LED GPIO.

Estimated code review effort: 1 (Trivial) | ~5 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The GPIO/LED compatibility update matches the T22 flashing issue's hardware workaround and keeps both board variants supported.
Out of Scope Changes check	✅ Passed	The changes are limited to the T22 LED driver and GPIO definition, with no obvious unrelated additions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The title clearly matches the main change: T22 red LED GPIO mapping updated for old and new boards.
Description check	✅ Passed	The description follows the template with a Fixes reference and a summary of the hardware-compatibility change.

✨ 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 3djc/fix-t22-dfu-flash

Warning

Review ran into problems

🔥 Problems

Git: Failed to clone repository. Please run the @coderabbitai full review command to re-trigger a full review. If the issue persists, set path_filters to include or exclude specific files.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[pfeerick]

Ouch! Well, at least you can still do UF2 :-O