Re: [PATCH v2 2/2] mfd: Add initial synology microp driver

[Danilo Krummrich]

On Mon Mar 9, 2026 at 1:52 PM CET, Markus Probst wrote:
> Yes. I will split it into multiple drivers using the aux bus in the
> next revision.

Independent of the other discussion whether this belongs into the kernel in the
first place, reading over the cover letter and commit message I understood the
following.

  "Synology uses a microcontroller in their NAS devices connected to a serial
  port [...]" controlling LEDs, fan speeds, a beeper, etc.

  I.e. it muliplexes several physical functions that belong to different
  subsystems, such as hwmon, input, etc. over a single serial port.

This sounds like a textbook candidate for MFD to me.

I.e. there is a very loose coupling of the different functions that make up for
entirely independent drivers, except that they share the same serial port
connection.

Whereas the auxiliary bus is more for very complicated devices to be broken down
into more managable (sometimes optional) sub-domains, where the corresponding
drivers usually have driver specific APIs to interact with each other.

- Danilo