Re: [PATCH v6 0/2] add support for MCP998X

[Guenter Roeck]

On 10/4/25 07:11, Jonathan Cameron wrote:
> On Tue, 30 Sep 2025 16:31:29 +0300
> <victor.duicu@xxxxxxxxxxxxx> wrote:
>
> > From: Victor Duicu <victor.duicu@xxxxxxxxxxxxx>
> >
> > Add support for Microchip MCP998X/33 and MCP998XD/33D Multichannel
> > Automotive Temperature Monitor Family.
> >
> > The chips in the family have different numbers of external channels,
> > ranging from 1 (MCP9982) to 4 channels (MCP9985). Reading diodes in
> > anti-parallel connection is supported by MCP9984/85/33 and
> > MCP9984D/85D/33D. Dedicated hardware shutdown circuitry is present
> > only in MCP998XD and MCP9933D.
> >
> > This driver was submitted in the IIO subsystem because the chips could use
> > interrupts to handle threshold events.
>
> This reasoning isn't particularly strong as hwmon has support for events etc.
> This device is also 'slow' so I'm not immediately seeing a strong reason why
> IIO is the right choice.

Correct. hwmon supports both events and udev events.

> After some recent feedback from Guenter I'm keen to get a clearer set
> of reasoning when I take a temperature monitoring chip into IIO.
>
> Also asking that we +CC Guenter for his input on devices where the decision
> isn't clear cut.

IMO this _is_ (or should be) clear cut: This is a hardware monitoring device.
It should be a hardware monitoring driver. FWIW, writing one should be
straightforward (including interrupt/event support).

Guenter