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Date: Sat, 5 Sep 2026 03:01:14 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Flaviu Nistor <flaviu.nistor@gmail.com>, Andy Shevchenko
 <andy@kernel.org>, David Lechner <dlechner@baylibre.com>, Nuno Sa
 <nuno.sa@analog.com>, Krzysztof Kozlowski <krzk+dt@kernel.org>, Rob Herring
 <robh@kernel.org>, Conor Dooley <conor+dt@kernel.org>, Daniel Baluta
 <daniel.baluta@nxp.com>, Antoniu Miclaus <antoniu.miclaus@analog.com>,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-iio@vger.kernel.org
Subject: Re: [PATCH v2 2/2] iio: adc: ti-ads1015: Add support for label
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On Thu, 3 Sep 2026 22:03:55 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> 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: =20
>=20
> ...
>=20
> > Since the iio core exposes in sysfs the in_volatagex_label
> > for all channels, there are 3 situations: =20
>=20
> > 3. The channel is not defined in the dts (in_voltagex_label is still vi=
sible
> > in the sysfs), and reading the label will cause "(null)\n" to be printe=
d in
> > the console (as indicated also by Sashiko boot), since the default "" v=
alue
> > is not assigned during device_for_each_child_node_scoped(). I think thi=
s is
> > not an issue since is just the way sysfs_emit() handles an NULL string.=
 =20
>=20
> Is this current state of affairs?
>=20
> If so, the patch must not change that =E2=80=94 it's an ABI now and (null=
) is valid
> response from the user space point of view.
>=20
> > What would you prefer? Any further suggestions? =20
>=20
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. =20

So go with whatever is most common in other drivers,

Jonathan