Added error checking to can_filter() for Classic CAN

[GewoonMaarten]

Summary of changes

Previously the function always returned 1 even when the configuration was illegal. I added a small check to HAL_CAN_ConfigFilter(...).

Impact of changes

Very small impact. The function was already pretty robust, but I felt that always returning 1 wasn't very nice.

Documentation

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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[ciarmcom]

@GewoonMaarten, thank you for your changes.
@ARMmbed/mbed-os-maintainers please review.

[jeromecoutant]

Hi @GewoonMaarten

Do you have a real CAN setup working with that patch ?

[GewoonMaarten]

@jeromecoutant Yes, I have two NUCLEO-L432KC boards connected via a diode CAN bus. I have this function which gets called at the beginning of the main function.

CAN can(CAN_RX_PIN, CAN_TX_PIN);
void configure_can_bus()
{
  printf("configure_can_bus()\n");

  can.frequency(CAN_FREQUENCY);
  can.mode(CAN::Normal);
  
  if (!can.filter(NODE_ID, NODE_MASK, CANStandard, 0))
  {
    printf("[ERROR] can.filter() error\n");
    return;
  }
}

[0xc0170]

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