drivers: lora: deadlock in sx126x lora driver

[mjm987]

Describe the bug
The sx126x lora driver uses a busy loop in drivers/lora/sx126x.c::SX126xWaitOnBusy() which stalls the system endless in case ...

• the device does not work correctly eg. when the battery is weak.
• the busy line is disconnected eg. by a bad connection.

Unfortunately the problem is not visible in the Log unless CONFIG_LORA_LOG_LEVEL_DBG is set.

To Reproduce
Steps to reproduce the behavior:

1. set CONFIG_LORA=y in prj.conf .
2. define a lora device node in the device tree.
3. build and flash on a board without sx126x or with disconnected busy line.
4. the system hangs on reboot without error log in console and without executing main() .

Expected behavior
The polling in SX126xWaitOnBusy() should have a timeout after which the polling will be aborted and error message is visible in the log.

Impact

• main() thread not executed at all in case of lora hardware problem.
• Freezing of system if a lora device hardware problem occures during runtime.

Environment (please complete the following information):

• all Zephyr releases (tested at v4.1)

[rijesha]

I have the same issue. Here are a couple more references to the issue:
Lora-net/LoRaMac-node#1048
Lora-net/LoRaMac-node#1270

They say asserting the CS pin (sending another spi message) will cause the radio to start responding again.

#89241 also looks like it may fix the issue. That driver seems to have timeouts built in.

I am using ncs, so will just manually put a loop count to 1000 or something like that as a timeout until a fix makes it way there.