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

[Danilo Krummrich]

On Mon Mar 9, 2026 at 4:15 PM CET, Lee Jones wrote:
> On Mon, 09 Mar 2026, Markus Probst wrote:
>
>> On Mon, 2026-03-09 at 14:32 +0100, Danilo Krummrich wrote:
>> > 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.
>
> Then you do not know what a textbook candidate for MFD is. :)
>
> What part of the MFD API does this device utilise?

I did *not* say this driver - as in the code that was posted - is a textbook
example for MFD.

I said that the hardware that is supposed to be fully supported eventually is a
textbook candidate for an MFD driver, i.e. it should use things like
devm_mfd_add_devices().

I think this was obvious from what I wrote above.