Re: [PATCH v6 2/2] iio: amplifiers: adl8113: add driver support

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 12 Dec 2025 10:41:07 +0000
"Miclaus, Antoniu" <Antoniu.Miclaus@analog.com> wrote:

> Hi,
> > 
> > Could do this as something like:
> > 
> > 	st->gain_configs[i++] = (struct adl8113_gain_config) {
> > 		.path = ADL8113_INTERNAL_AMP,
> > 		.gain_db = 14,
> > 	};
> > 
> > 	st->gain_configs[i++] = (struct adl8113_gain_config) {
> > 		.path = ADL8113_INTERNAL_BYPASS,
> > 		.gain_db = -2,
> > 	};
> > 
> > etc.
> >   
> > > +	i++;
> > > +
> > > +	/* Always include internal bypass (-2dB insertion loss) */
> > > +	st->gain_configs[i].path = ADL8113_INTERNAL_BYPASS;
> > > +	st->gain_configs[i].gain_db = -2;
> > > +	i++;
> > > +
> > > +	/* Add external bypass A if configured */
> > > +	if (!device_property_read_u32(dev, "adi,external-bypass-a-gain-db",
> > > +				      &external_a_gain)) {
> > > +		st->gain_configs[i].path = ADL8113_EXTERNAL_A;
> > > +		st->gain_configs[i].gain_db = external_a_gain;
> > > +		i++;
> > > +	}
> > > +
> > > +	/* Add external bypass B if configured */
> > > +	if (!device_property_read_u32(dev, "adi,external-bypass-b-gain-db",
> > > +				      &external_b_gain)) {
> > > +		st->gain_configs[i].path = ADL8113_EXTERNAL_B;
> > > +		st->gain_configs[i].gain_db = external_b_gain;
> > > +		i++;
> > > +	}
> > > +
> > > +	/*
> > > +	 * If there's a free external bypass path, add one with INT_MIN gain
> > > +	 * to represent "nothing connected" for testing purposes  
> > 
> > I don't follow this one.  What sort of testing purpose?  Something we want
> > in a real system?  
> This addition was suggested by David in v4. But I can revert it in the next series.
Ok. I looked back and found it.  I don't mind this feature with
more explanation.  However, I'm not sure it's actually useful other than for
replicating figure 121 on the datasheet which I can't really see as particularly
useful for testing.  Mind you I've no real idea how these are used :)

Jonathan

> 
> Regards,
> Antoniu