Re: [PATCH] iio: Add driver for TLA202x ADCs

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 21 Jan 2019 10:49:17 +0100
Ibtsam Ul-Haq <ibtsam.haq.0x01@gmail.com> wrote:

> Hi,
> 
> Thanks a lot for the review. I shall apply all these in the v2, I do
> have just one question, below.
> 
> > > > +
> > > > +static int tla2024_of_find_chan(struct tla2024 *priv, struct device_node *ch)
> > > > +{
> > > > +   u16 chan_idx = 0;
> > > > +   u32 tmp_p, tmp_n;
> > > > +   int ainp, ainn;
> > > > +   int ret;
> > > > +
> > > > +   ret = of_property_read_u32_index(ch, "single-ended", 0, &tmp_p);  
> > There is now (only very recently) a generic description in DT for
> > acpi channels.  Please look at that:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/tree/Documentation/devicetree/bindings/iio/adc/adc.txt?h=togreg&id=00426e99789357dbff7e719a092ce36a3ce49d94
> >
> > It is minimalist.  If it is single ended, you can tell that by the absence
> > of diff-channels.
> >  
> 
> How should we specify which single ended channel to use? For example,
> say I want to configure the driver for reading single-ended values
> only from input pin AIN3. When we only signify a single-ended channel
> by the absence of "diff-channels", where should the "3" be specified?

Fair question.  Stefan, what do you think makes sense?
(obviously others welcome but my guess is Stefan has thought about this
more than most ;)

Jonathan



> 
> > If the binding needs additional elements (it probably does)
> > then propose them for that generic binding.  We are trying to move
> > away from each driver doing it's own thing given all this stuff is
> > pretty generic!
> >  
> 
> Sorry for trimming the message. Gmail was otherwise blocking my
> outbound message, and I could not find any other way to get it
> through.
> 
> Best regards,
> Ibtsam Haq