Pass TELEM_RAK12500_ADDRESS to the RAK12500 I2C probe (iteration branch)

[ptr727]

Branch renamed, PR re-opened. This branch was fix/rak12500-i2c-address and carried
#7, including the note recording that
CodeRabbit never reviewed it. It was renamed to work/rak12500-i2c-address to match this fork's
convention — work/* is the iteration log, fix/* is the squashed branch that goes upstream —
and GitHub closed #7 on the rename rather than following it. Nothing in the code changed; the
head is still 89e73970.

The bug

src/helpers/sensors/EnvironmentSensorManager.cpp defines the RAK12500's I2C address inside an
#ifndef, which is the file's convention for "a variant may override this":

#ifndef TELEM_RAK12500_ADDRESS
#define TELEM_RAK12500_ADDRESS   0x42     //RAK12500 Ublox GPS via i2c
#endif

The probe then never passes it:

if (ublox_GNSS.begin(Wire) == true){

SFE_UBLOX_GNSS::begin is declared
bool begin(TwoWire &wirePort = Wire, uint8_t deviceAddress = 0x42, ...), so the address actually
probed is the library's own default, not the macro.

grep -rn TELEM_RAK12500_ADDRESS src/ variants/ platformio.ini examples/ returns only the two
lines of the definition itself. It is the one TELEM_*_ADDRESS in this file that nothing consumes
— every other one reaches its probe through the sensor table (TELEM_AHTX_ADDRESS,
TELEM_BME280_ADDRESS, TELEM_SHT4X_ADDRESS, …) or a driver constructor (TELEM_INA219_ADDRESS,
TELEM_INA226_ADDRESS).

Why it is latent, and why it is still worth fixing

No variant in the tree overrides the macro, and the library's default is also 0x42, so nothing
diverges today. The defect is that the knob exists and does nothing: a variant that overrode it —
which the #ifndef invites — would silently probe one address while every other reference to the
macro named another, and the symptom would be a GPS that is simply not detected.

The fix

if (ublox_GNSS.begin(Wire, TELEM_RAK12500_ADDRESS) == true){

This is the only ublox_GNSS.begin call site in the tree.

Verification

• Signature confirmed against the pinned library
  (SparkFun_u-blox_GNSS_Arduino_Library.h:715), not assumed.
• RAK_4631_repeater builds. The RAK_WISBLOCK_GPS block is compiled into that env
  (ENV_INCLUDE_GPS && RAK_BOARD && !RAK_WISMESH_TAG), confirmed by the ublox_GNSS symbol and
  the SparkFun translation unit in the resulting ELF, so the changed line is actually built.
• Not verified on hardware. The RAK4631 available here carries a CASIC receiver on the UART
  rather than a u-blox on I2C, so it takes the serial fallback and never reaches this line. A
  board with an actual RAK12500 would be needed to exercise it, and since the address is unchanged
  in-tree the observable behaviour would be identical either way.

Notes

This is a detection change rather than a reporting one, which is why it was kept out of the
hwinfo PR (#5) when CodeRabbit raised it there. Independent of that branch and of #6.

Not upstream yet — this is the fork bake.

Summary by CodeRabbit

• Bug Fixes
  • Improved RAK12500 GNSS initialization by using the configured I2C address, helping ensure reliable device communication.

[coderabbitai]

Important

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[Copilot]

🟢 Approval recommended

The change is minimal, matches the intended configuration behavior, and no issues were found in the updated call site.

Pull request overview

This PR fixes a latent configuration bug in the RAK12500 (u-blox GNSS over I2C) detection path by ensuring the variant-overridable TELEM_RAK12500_ADDRESS macro is actually used when probing the device.

Changes:

• Pass TELEM_RAK12500_ADDRESS as the I2C address argument to ublox_GNSS.begin(...) during RAK12500 initialization.

File summaries

File	Description
src/helpers/sensors/EnvironmentSensorManager.cpp	Uses the configured (and variant-overridable) RAK12500 I2C address in the GNSS probe call.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite

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[ptr727]

Squashed onto upstream/dev cdd04077 as fix/rak12500-i2c-address @ 85f016be and filed upstream as meshcore-dev/MeshCore#3434. The clean branch's diff against upstream/dev is byte-identical to this branch's diff against 0ec5ed5f. This branch stays the iteration log: upstream review feedback lands here first, then gets re-squashed onto the clean branch.