Re: [PATCH v2 2/2] iio: adc: ti-ads1015: Add support for label
From: Jonathan Cameron
Date: Fri Sep 04 2026 - 22:02:23 EST
On Thu, 3 Sep 2026 22:03:55 +0300
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:
> On Thu, Sep 03, 2026 at 06:16:27PM +0300, Flaviu Nistor wrote:
> > On Thu, Sep 3, 2026 at 9:18 AM, Andy Shevchenko wrote:
>
> ...
>
> > Since the iio core exposes in sysfs the in_volatagex_label
> > for all channels, there are 3 situations:
>
> > 3. The channel is not defined in the dts (in_voltagex_label is still visible
> > in the sysfs), and reading the label will cause "(null)\n" to be printed in
> > the console (as indicated also by Sashiko boot), since the default "" value
> > is not assigned during device_for_each_child_node_scoped(). I think this is
> > not an issue since is just the way sysfs_emit() handles an NULL string.
>
> Is this current state of affairs?
>
> If so, the patch must not change that — it's an ABI now and (null) is valid
> response from the user space point of view.
>
> > What would you prefer? Any further suggestions?
>
Unfortunately we never defined what should happen this way explicitly.
In practice assumption is that this is a corner case we probably won't
see. People don't tend to want to label just one random pin, they tend
to label the lot.
So go with whatever is most common in other drivers,
Jonathan