Re: [PATCH 2/2] iio: temperature: ltc2983: Add support for ADT7604

From: Nuno Sá

Date: Fri May 08 2026 - 12:15:43 EST


On Fri, May 08, 2026 at 02:48:39PM +0000, Stan, Liviu wrote:
> On Fri, May 08, 2026 Nuno Sá wrote:
> > > On Fri, 8 May 2026 Jonathan Cameron wrote:
> > > > > Will defer this to Jonathan but if we can have a real of the coverage
> > > > > given the temperature, I guess this is ok. Given that I think we don't have
> > > > > a better channel (unless we add one?) for this. Or just extended_info...
> > > > >
> > > >
> > > > I have no idea what coverage percentage means in this case.
> > > > Can you provide some more details or a reference? Google isn't giving me
> > > > anything useful.
> > >
> > > A leak detector is a sensor like the raindrop detection modules, whose
> > > resistance decreases as more of its surface is contacted by liquid. In this case,
> > > for example, if half of the sensor's surface is in contact with a liquid, the
> > > ADT7604 should, with an appropiate user-provided resistance-vs-coverage
> > > table, report 50% coverage in the IIO channel.
> >
> > And, AFAIU, depending on the coverage the resistance changes and that's
> > how we get into the indirect temperature variations?
>
> If I understand your comment correctly, you're implying that there are indirect
> temperature variations caused by resistance changes, and that's what the chip is
> measuring? The chip does not measure any actual temperature for this sensor
> type, the value in the temperature result register bank is solely a result of the
> chip's interpolation of the user-defined custom table.
>

I meant that's what the table is trying to accomplish? That's why I kind
of put it as "indirect". My understanding was the chip does not measure
any temperature as well.

- Nuno Sá

> Liviu