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Date: Thu, 5 Feb 2026 20:18:44 +0000
From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>, Rob Herring <robh@kernel.org>,
 Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley
 <conor+dt@kernel.org>, kernel@pengutronix.de, linux-kernel@vger.kernel.org,
 linux-iio@vger.kernel.org, devicetree@vger.kernel.org, Andy Shevchenko
 <andy@kernel.org>, David Lechner <dlechner@baylibre.com>, Nuno
 =?UTF-8?B?U8Oh?= <nuno.sa@analog.com>, David Jander <david@protonic.nl>
Subject: Re: [PATCH v5 06/13] iio: dac: ds4424: use device match data for
 chip info
Message-ID: <20260205201844.01efba05@jic23-huawei>
In-Reply-To: <aYNVndcMVRj3JsKL@smile.fi.intel.com>
References: <20260204140045.390677-1-o.rempel@pengutronix.de>
	<20260204140045.390677-7-o.rempel@pengutronix.de>
	<aYNVndcMVRj3JsKL@smile.fi.intel.com>
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On Wed, 4 Feb 2026 16:20:13 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Wed, Feb 04, 2026 at 03:00:38PM +0100, Oleksij Rempel wrote:
> > Refactor the driver to use device match data instead of checking ID enu=
ms
> > in a switch statement.
> >=20
> > Define a `ds4424_chip_info` structure to hold variant-specific attribut=
es
> > (currently just the channel count) and attach it directly to the I2C and
> > OF device ID tables.
> >=20
> > This simplifies the probe function and makes it easier to add support f=
or
> > new variants like DS4402/DS4404. =20
>=20
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> with a hope that we get rid an I=C2=B2C ID requirement at some point.
>=20
> ...
>=20
> > +struct ds4424_chip_info {
> > +	u8 num_channels; =20
>=20
> If you wish, you can provide name here that will go to ->name field.
> Linker dedups string literals, so it will be just an additional runtime
> pointer.

I'd prefer we did this now.  That avoids any future issue where we get
subtle mismatches between DT compatibles listed and the i2c_device_id
names.

We've been bitten by bugs around this before, hence tend to push names
into the chip_info structure instead of using id->name.  IIRC correctly
the fun starts when we have a fallback compatible.

Jonathan


>=20
> > +}; =20
>=20