PDM_PCM-read, irq and set gain function implementation

[NikhitaR-IFX]

Summary

In this PR, all the below functions are implemented but yet to be fully tested.

• PDM_PCM.irq()
• PDM_PCM.readinto()
• PDM_PCM.set_gain()

In the source file, you will find 4 sections:

1. PDM_PCM higher level MPY functions --> at some point this should move to extmod/ and the functions in this are port independent
2. Port-specific private functions for DMA and PDM_PCM support
3. MPY bindings for the module
4. Implementation to support stream protocol

Test Status:

All the testin so far is being done manually and is later when successful to be added to HIL.

• PDM_PCM.set_gain() atleast does the job of setting the values and this is ensured as cyhal api is supposed to throw an error if we try to set unacceptable values.
• PDM_PCM.irq() sets the callback fine.
• PDM_PCM.readinto() is waiting for the interrupt trigger forever. I suspect the buffer configurations.

Note: Based on further testing, I feel changes would happen only to following functions and you may ignore if needed while reviewing the same:

• fill_appbuf_from_ringbuf()
• fill_appbuf_from_ringbuf_non_blocking()

Also I am aware there are printf()/mp_printf() statements in the beginning of every function, but only to help with debugging. This will be replaced later by mplogger_print().

[jaenrig-ifx]

All good, with the structure and the API :)

Only the comments on the documentation. Which is generated here:
https://ifx-micropython.readthedocs.io/en/pdm-read-blocking/psoc6/quickref.html#pdm-pcm

Without tests passing, I will postpone a deeper of the code functionality.

[jaenrig-ifx]

The headlines need to have 1 level lower (Methods, Constructor, etc.)

[jaenrig-ifx]

And to keep consistency with the rest of the classes, I would name this "PDM-PDM bus"

[NikhitaR-IFX]

Noted

[IFX-Anusha]

Looks Good!

[ramya-subramanyam]

Looks good!