samples: basic: fade_led: Add stm32_min_dev.overlay with 4 LEDs

[GomaaMohamed]

Add a Device Tree overlay for the STM32 Minimum Development Board
(Blue) to the fade_led sample, enabling PWM-based LED fading on
PA8 (Timer 1, Channel 1), PA9 (Timer 1, Channel 2), PA0 (Timer 2,
Channel 1), and PA1 (Timer 2, Channel 2). The overlay sets a 20 ms
and a prescaler of 10000 to ensure compatibility with the
STM32F103C8’s timer constraints. Pin configurations include
maximum slew rate and pull-up bias for reliable PWM output. Tested
on the stm32_min_dev board, confirming all four LEDs fade correctly
without errors.

[github-actions]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[GomaaMohamed]

@nashif @kartben Thank you for being assigned to review this PR. I’ve submitted a Device Tree overlay for the STM32 Minimum Development Board (Blue) to the fade_led sample and confirmed all CI tests have passed. Could you please begin the initial review when you have a moment? I’d be happy to address any questions or provide clarifications. Thanks!

[kartben]

Hi @GomaaMohamed - board overlays added to code samples are meant to enable hardware features that are actually readily available on the board. Unless I am mistaken, this board does NOT have these 4 LEDs and this overlay effectively corresponds to some custom wiring/breadboarding you did?

[kartben]

Hi @GomaaMohamed - board overlays added to code samples are meant to enable hardware features that are actually readily available on the board. Unless I am mistaken, this board does NOT have these 4 LEDs and this overlay effectively corresponds to some custom wiring/breadboarding you did?

Yes, all the four Leds are custom. Do you just need the Leds are already on the board?

yes, otherwise the overlay is not really useful, right? If everyone adds overlays for whatever custom setup they have, it just doesn't scale :) Luckily there is hopefully more than enough examples already of how to configure PWM LEDs on STM32 if people look at the devicetree files of the dozens of Nucleo boards and DKs in the tree. Hope this makes sense?

[GomaaMohamed]

Hi @GomaaMohamed - board overlays added to code samples are meant to enable hardware features that are actually readily available on the board. Unless I am mistaken, this board does NOT have these 4 LEDs and this overlay effectively corresponds to some custom wiring/breadboarding you did?

Yes, all the four Leds are custom. Do you just need the Leds are already on the board?

yes, otherwise the overlay is not really useful, right? If everyone adds overlays for whatever custom setup they have, it just doesn't scale :) Luckily there is hopefully more than enough examples already of how to configure PWM LEDs on STM32 if people look at the devicetree files of the dozens of Nucleo boards and DKs in the tree. Hope this makes sense?

Thank you for clarifying this point.
Could I use this Pull Request to add any another future contribution to avoid waiting for response from maintainers? Or it must be closed?

[kartben]

Could I use this Pull Request to add any another future contribution to avoid waiting for response from maintainers? Or it must be closed?

It should be closed yes. If you do other contributions in the future it might be a different set of maintainers that will be you main point of contact depending on what files/area you change :)