[Core] Adjust PWM hardware audio driver for RP2040

[KarlK90]

Description

WIP Working but depends on ~~https://github.com/ChibiOS/ChibiOS-Contrib/pull/328~~ (merged!) and https://github.com/qmk/qmk_firmware/pull/17706

Types of Changes

• [x] Core
• [ ] Bugfix
• [x] New feature
• [x] Enhancement/optimization
• [ ] Keyboard (addition or update)
• [ ] Keymap/layout/userspace (addition or update)
• [x] Documentation

Issues Fixed or Closed by This PR

Checklist

• [x] My code follows the code style of this project: C, Python
• [x] I have read the PR Checklist document and have made the appropriate changes.
• [x] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[Jpe230]

Sweet! Just tested this PR on my trusty Adafruit Macropad and can confirm that it is working amazingly -- albeit a little too loud for my taste but nonetheless amazing job as always!

[yoichiro]

@KarlK90 Thank you for writing this code set to support the audio feature on RP2040 chip! I can't wait merging this pull request because I would like to use the audio feature on the Lunakey Pico keyboard which was designed by me and is using Raspberry Pi Pico. Therefore, I tried testing this code by using my keyboard. The diff I created is the following:

https://github.com/yoichiro/qmk_firmware/commit/247705834f295a166beae72e3b64b208c055c64f

The circuit design of the Lunakey Pico is the following. The speaker is connected to the GP8 pin.

When compiling the code set with the qmk command, I got the following output including Compiling: platforms/chibios/drivers/audio_pwm_hardware.c. That is, I believe that the built result has an audio feature.

...
Compiling: quantum/process_keycode/process_audio.c                                                  [OK]
Compiling: quantum/process_keycode/process_clicky.c                                                 [OK]
Compiling: quantum/audio/audio.c                                                                    [OK]
Compiling: platforms/chibios/drivers/audio_pwm_hardware.c                                           [OK]
Compiling: quantum/audio/voices.c                                                                   [OK]
Compiling: quantum/audio/luts.c                                                                     [OK]
Compiling: quantum/process_keycode/process_music.c                                                  [OK]
...

I wrote the uf2 file and restarted my keyboard, unfortunately I was not able to hear any sounds.

I have already confirmed that the speaker worked normally with KMK firmware. Did I forget to write something? Could you give me an advice to work the audio feature on my keyboard with your code?

[yoichiro]

@Jpe230 Could you share me your code which you tried the audio feature using your keyboard?

[Jpe230]

@Jpe230 Could you share me your code which you tried the audio feature using your keyboard?

Sure, here it is

[yoichiro]

Finally, I can hear the sound from my keyboard using the code: https://github.com/yoichiro/qmk_firmware/commit/65a383e3a982236618f7ae6f56b769fea0329b6c The cause is wrong combination of PWMn and Channel. It is necessary to use the PWM4 and the Channel A (= 1) for GP8.

See: https://discordapp.com/channels/440868230475677696/1032861820228227132

I think that the diff of this pull request looks good to me and has comfirm that this code works normally. Thank you for the great contribution!

[yoichiro]

@KarlK90 Congrats!