Re: [PATCH v5 3/5] iio: adc: ad7949: add support for internal vref

From: Andy Shevchenko
Date: Mon Aug 16 2021 - 04:07:43 EST


On Fri, Aug 13, 2021 at 11:51 PM Liam Beguin <liambeguin@xxxxxxxxx> wrote:
> On Mon Aug 9, 2021 at 3:42 PM EDT, Jonathan Cameron wrote:

...

> > > > > + /* Read channel specific information form the devicetree */

from

> > > > > + device_for_each_child_node(dev, child) {
> > > > > + ret = fwnode_property_read_u32(child, "reg", &i);
> > > > > + if (ret) {
> > > > > + dev_err(dev, "missing reg property in %pfw\n", child);
> > > > > + fwnode_handle_put(child);
> > > > > + return ret;
> > > > > + }
> > > > > +
> > > > > + ad7949_chan = &ad7949_adc->channels[i];
> > > > > +
> > > > > + ret = fwnode_property_read_u32(child, "adi,internal-ref-microvolt", &tmp);
> > > > > + if (ret < 0 && ret != -EINVAL) {
> > > > > + dev_err(dev, "invalid internal reference in %pfw\n", child);
> > > > > + fwnode_handle_put(child);
> > > > > + return ret;
> > > > > + }

> After getting access to another setup to run more tests, I noticed
> that setting the reference per channel isn't really feasible.

Is it a hardware limitation?

--
With Best Regards,
Andy Shevchenko