STM32 can_init_freq() ignores frequency and uses 100000 instead

[bikeNomad]

Description of defect

Attempts to create an mbed::CAN object passing in the CAN bit rate don't properly set the frequency. Instead, the CAN port is always opened at 100000 bps.

Target(s) affected by this defect ?

All STM32 parts with CAN peripherals.

Toolchain(s) (name and version) displaying this defect ?

All

What version of Mbed-os are you using (tag or sha) ?

mbed-os-5.15

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

mbed-cli 1.10.1

How is this defect reproduced ?

Create an mbed::CAN object using the three-argument constructor and pass in a frequency argument other than 100000:

CAN myCAN(PIN_CAN_RX, PIN_CAN_TX, 500000);

This is due to mbed-os/targets/TARGET_STM/can_api.c containing this code:

void can_init_freq(can_t *obj, PinName rd, PinName td, int hz)
{
    CANName can_rd = (CANName)pinmap_peripheral(rd, PinMap_CAN_RD);
    CANName can_td = (CANName)pinmap_peripheral(td, PinMap_CAN_TD);
    int peripheral = (int) pinmap_merge(can_rd, can_td);

    int function_rd = (int)pinmap_find_function(rd, PinMap_CAN_RD);
    int function_td = (int)pinmap_find_function(td, PinMap_CAN_TD);

    const can_pinmap_t static_pinmap = {peripheral, rd, function_rd, td, function_td};

    CAN_INIT_FREQ_DIRECT(obj, &static_pinmap, 100000);
}

As you can see, the hz argument is ignored and 100000 is used instead.

[ciarmcom]

Internal Jira reference: https://jira.arm.com/browse/MBOTRIAGE-2473

[0xc0170]

cc @ARMmbed/team-st-mcd

[jeromecoutant]

Hi

@mprse

I understand that for CAN, there are 2 API for init:

CAN::CAN(PinName rd, PinName td) :
can_init(&_can, rd, td);
CAN::CAN(PinName rd, PinName td, int hz) :
can_init_freq(&_can, rd, td, hz);

Before #11892, in each target API:

• can_init_freq is setting CAN with the expected frequency
• can_init is only calling can_init_freq with the default frequency

Now with #11892

• can_init is now calling CAN_INIT_DIRECT
• can_init_freq is now calling CAN_INIT_FREQ_DIRECT
  We miss the frequency setting

[mprse]

@jeromecoutant @bikeNomad Yes, this is a bug.

The fix can be found here: PR #12113.
Please review.

[jeromecoutant]

As #12113 is merged, we close close this one
Thx