Re: [PATCH v2 2/2] iio: light: Add support for APDS9306 Light Sensor

[Matti Vaittinen]

On 11/6/23 14:04, Subhajit Ghosh wrote:
> On 6/11/23 21:43, Jonathan Cameron wrote:
> > On Tue, 31 Oct 2023 19:08:08 +1030
> > Subhajit Ghosh <subhajit.ghosh@xxxxxxxxxxxxxx> wrote:
> >
> > > > Scale on the intensity channel is interesting...  What are the units?
> > > > There tend not to be any well defined units for intensity (as opposed
> > > > to illuminance).  There may be gain on the signal, but it won't be 
> > > > in untils
> > > > that map directly to a scale userspace should apply.  This is one of 
> > > > the
> > > > rare reasons for using the HARDWARE_GAIN element of the ABI.
> > > >
> > > > A tricky corner however as relationship between raw value and 
> > > > hardwaregain
> > > > is not tightly defined (as it can be really weird!)
> > > Hi Jonathan,
> > >
> > > Thank you for taking time for reviewing and clearing all my tiny 
> > > doubts and
> > > queries especially for the dt and versioning part. Much appreciated.
> > >
> > > In the above case, should I not expose scale for the "clear" channel? 
> > > Rather,
> > > how should I expose the "clear" channel to userspace?
> > What is the scale?  What units to you get after applying it?
> The scale is in Lux. The output after applying is Lux.

Hi Subhajit,

I am by no means an expert here but maybe you could check if the channel 
should be of type 'illuminance'? (To me 'Lux' sounds like an unit of 
illuminance rather than intensity).

Yours,
	-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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