boards/common/nrf52xxxdk: Expose LEDs via saul_pwm

[maribu]

Contribution description

As the title says. This allows dimming the LEDs instead of only turning them on and off.

Testing procedure

make BOARD=nrf52840dk PROGRAMMER=openocd -C examples/saul

[...]

help
2021-12-14 20:34:02,723 # help
2021-12-14 20:34:02,725 # Command              Description
2021-12-14 20:34:02,728 # ---------------------------------------
2021-12-14 20:34:02,732 # reboot               Reboot the node
2021-12-14 20:34:02,736 # version              Prints current RIOT_VERSION
2021-12-14 20:34:02,741 # pm                   interact with layered PM subsystem
2021-12-14 20:34:02,747 # ps                   Prints information about running threads.
2021-12-14 20:34:02,753 # saul                 interact with sensors and actuators using SAUL
> saul
2021-12-14 20:34:03,742 # saul
2021-12-14 20:34:03,743 # ID	Class		Name
2021-12-14 20:34:03,745 # #0	SENSE_BTN	Button 1
2021-12-14 20:34:03,747 # #1	SENSE_BTN	Button 2
2021-12-14 20:34:03,748 # #2	SENSE_BTN	Button 3
2021-12-14 20:34:03,750 # #3	SENSE_BTN	Button 4
2021-12-14 20:34:03,752 # #4	ACT_DIMMER	LED 1
2021-12-14 20:34:03,754 # #5	ACT_DIMMER	LED 2
2021-12-14 20:34:03,756 # #6	ACT_DIMMER	LED 3
2021-12-14 20:34:03,758 # #7	ACT_DIMMER	LED 4
2021-12-14 20:34:03,760 # #8	SENSE_TEMP	NRF_TEMP
> saul write 4 1
2021-12-14 20:34:09,340 # saul write 4 1
2021-12-14 20:34:09,342 # Writing to device #4 - LED 1
2021-12-14 20:34:09,344 # Data:	              1 
2021-12-14 20:34:09,347 # data successfully written to device #4
> saul write 4 100
2021-12-14 20:34:14,456 # saul write 4 100
2021-12-14 20:34:14,458 # Writing to device #4 - LED 1
2021-12-14 20:34:14,463 # Data:	            100 
2021-12-14 20:34:14,465 # data successfully written to device #4
> saul write 4 50
2021-12-14 20:34:17,740 # saul write 4 50
2021-12-14 20:34:17,742 # Writing to device #4 - LED 1
2021-12-14 20:34:17,744 # Data:	             50 
2021-12-14 20:34:17,748 # data successfully written to device #4
> saul write 4 20
2021-12-14 20:34:20,106 # saul write 4 20
2021-12-14 20:34:20,108 # Writing to device #4 - LED 1
2021-12-14 20:34:20,110 # Data:	             20 
2021-12-14 20:34:20,114 # data successfully written to device #4
> saul write 4 10
2021-12-14 20:34:21,785 # saul write 4 10
2021-12-14 20:34:21,788 # Writing to device #4 - LED 1
2021-12-14 20:34:21,790 # Data:	             10 
2021-12-14 20:34:21,793 # data successfully written to device #4
> saul write 5 10
2021-12-14 20:34:24,725 # saul write 5 10
2021-12-14 20:34:24,727 # Writing to device #5 - LED 2
2021-12-14 20:34:24,729 # Data:	             10 
2021-12-14 20:34:24,732 # data successfully written to device #5
> saul write 6 10
2021-12-14 20:34:27,183 # saul write 6 10
2021-12-14 20:34:27,186 # Writing to device #6 - LED 3
2021-12-14 20:34:27,188 # Data:	             10 
2021-12-14 20:34:27,191 # data successfully written to device #6
> saul write 7 10
2021-12-14 20:34:29,919 # saul write 7 10
2021-12-14 20:34:29,921 # Writing to device #7 - LED 4
2021-12-14 20:34:29,923 # Data:	             10 
2021-12-14 20:34:29,929 # data successfully written to device #7
> saul write 7 100
2021-12-14 20:34:32,382 # saul write 7 100
2021-12-14 20:34:32,389 # Writing to device #7 - LED 4
2021-12-14 20:34:32,390 # Data:	            100 
2021-12-14 20:34:32,392 # data successfully written to device #7
> saul write 7 255
2021-12-14 20:34:36,024 # saul write 7 255
2021-12-14 20:34:36,026 # Writing to device #7 - LED 4
2021-12-14 20:34:36,028 # Data:	            255 
2021-12-14 20:34:36,031 # data successfully written to device #7
> saul write 7 256
2021-12-14 20:34:40,222 # saul write 7 256
2021-12-14 20:34:40,225 # Writing to device #7 - LED 4
2021-12-14 20:34:40,227 # Data:	            256 
2021-12-14 20:34:40,230 # error: failure to write to device #7
> saul write 7 255
2021-12-14 20:34:45,455 # saul write 7 255
2021-12-14 20:34:45,458 # Writing to device #7 - LED 4
2021-12-14 20:34:45,460 # Data:	            255 
2021-12-14 20:34:45,463 # data successfully written to device #7
> 2021-12-14 20:35:17,711 # Exiting Pyterm

Note: The LEDs were dimmed as expected.

Issues/PRs references

None

[maribu]

Doxygen group defined here:

RIOT/boards/common/nrf52xxxdk/include/periph_conf_common.h

Lines 9 to 19 in 0afed1d

	/**
	* @defgroup boards_common_nrf52xxxdk NRF52 DK common
	* @ingroup boards_common_nrf52
	* @{
	*
	* @file
	* @brief Peripheral configuration for the nRF52 DK
	*
	* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
	*
	*/

So it was indeed missorted before

[chrysn]

I was about to complain about this relying on the boards to set up their PWM with matching pins, but as the PWM setup is done in the same module, that's fine. (A comment in periph_conf_common.h indicating that this assignment is relied on by the pwm_params might be useful.)

I don't have any of the boards, you indicated you tested it on nrf52840dk. Any others you have at hand? (Not insisting on further checks though, as the PWM channels were already configured and thus, if it's broken after this commit it was before as well).

[fjmolinas]

Kconfig change is missing, please re-add ci label when addressed.

[chrysn]

That CI check is worth its weight in gold. (Metaphorically speaking, assigning some arbitrary weight to the check). Without that, Kconfig migration would be a whack-a-mole. I think I should just put it in my commit hooks.

[maribu]

In fact, this would have not been caught by Murdock, since SAUL is not yet fully modeled. Nice catch!

[chrysn]

I trust your test (in combination with the PWMs already being configured for these pins). ACK.

[maribu]

Thanks for the quick review!