stm32/can: add option to enable deep-sleep per device

[vincent-d]

Contribution description

Deep-sleep was based on using rx pin as external interrupt to be able to
wake up from stop mode. If rx pin cannot be used as interrupt or user
does not need to wake up from stop from the CAN, an option is now
present. If en_deep_sleep_wake_up is set to false, setting the device to
sleep simply unblocks stop mode. Otherwise the behavior is unchanged.

[benpicco]

Why not extend the bit field below? (line 130)

[vincent-d]

The bitfield was using uint8_t as the base type and there were already eight bits in it. Also, the bits in the bit field correspond to a setting in the config register.

[aabadie]

How can we test this ? I don't find any board that provides a default can configuration. The tests/candev application is also missing non native initialization code. This is out of the scope of this PR but would help if someone wants to try CAN on STM32.

[vincent-d]

@aabadie tests/candev is improved in #14909 so it can be used more easily with non-native devices. tests/conn_can might also be a good candidate for testing.

Normally, the nucleo-f413zh provides a CAN configuration, but I must admit this is not straightforward, as a default can_params.h is shared for all stm32 CPUs. You would also need a transceiver.

[aabadie]

So I guess the default can_params should be updated as well:

RIOT/cpu/stm32/include/can_params.h

Lines 30 to 31 in c6fe777

	/** Default STM32 CAN devices config */
	static const can_conf_t candev_conf[] = {

the nucleo-f413zh provides a CAN configuration

There's nothing related to CAN at this level.

[fjmolinas]

So I guess the default can_params should be updated as well:

RIOT/cpu/stm32/include/can_params.h

Lines 30 to 31 in c6fe777

	/** Default STM32 CAN devices config */
	static const can_conf_t candev_conf[] = {

the nucleo-f413zh provides a CAN configuration

There's nothing related to CAN at this level.

@vincent-d this one looks good, do you mind adding the default config as well?

[vincent-d]

Added en_deep_sleep_wake_up  in default can configs and rebased.

[fjmolinas]

All good, mind if I ask was what the use case for this is?

[fjmolinas]

ACK.

[vincent-d]

All good, mind if I ask was what the use case for this is?

On stm32, EXTIs are a bit annoying...for instance, you cannot configure PA1 and PB1 as an external interrupt pin at the same time (there are 15 lines for EXTI, shared among ports).
We had such a conflict with the CAN RX pin on one of our CAN controllers. But on the other controller, we need to be able to wake up from stop mode, and the only way of doing it is to configure the RX pin as an external interrupt. So we needed a way to enable or disable the change of configuration of the RX pin.