lora/lora-sx127x-pycom: Add unified SX1272/SX1276 LoRa driver

[ddtdanilo]

Summary

Add lora-sx127x-pycom: a unified SX1272/SX1276 LoRa radio driver for micropython-lib.

The existing lora-sx127x package only supports SX1276 (version register 0x12); this driver also handles SX1272 (0x22), which has a different register layout for bandwidth encoding, coding rate bits, CRC location, and RSSI calculation offsets.

This package is consumed by the Pycom LoPy (SX1272) and LoPy4 (SX1276) board definitions in micropython/micropython#19026.

Testing

• All files pass ruff check and ruff format
• Hardware tests (driver init, config, TX power, validation) available in esp32/boards: Add Pycom LoPy and LoPy4 board definitions with SX127x LoRa driver micropython#19026

Related

• LoRaWAN MAC layer: lora/lora-lorawan: Add LoRaWAN 1.0.x MAC layer #1111 (split out per @projectgus's request)
• Boards consuming this package: esp32/boards: Add Pycom LoPy and LoPy4 board definitions with SX127x LoRa driver micropython#19026 (PYCOM_LOPY, PYCOM_LOPY4)

[projectgus]

This looks really exciting, thanks @ddtdanilo! Had always hoped the LoRa micropython-lib support would be enough for someone to build a LoRaWAN driver.

Do you mind moving the lorawan support into its own PR, please? There's a lot of new code here, and it will be easier to review and merge these independently.

[ddtdanilo]

Hi @projectgus — thanks for the review!

I've split the LoRaWAN MAC layer into its own PR as you suggested:

➡️ #1111 (lora-lorawan)

This PR (#1102) now contains only the lora-sx127x-pycom driver. The two are independently reviewable and mergeable. Force-pushed add-pycom-lora to keep just the driver commit (c9c9d04); the MAC commit is on add-pycom-lorawan for #1111.

Let me know if you'd like any further changes to either one.