RE: [PATCH v4 1/5] spi: allow ancillary devices to share parent's chip selects

[Miclaus, Antoniu]

--
Antoniu Miclăuş

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
> Sent: Tuesday, February 24, 2026 12:09 PM
> To: Miclaus, Antoniu <Antoniu.Miclaus@xxxxxxxxxx>
> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>; Hennerich, Michael
> <Michael.Hennerich@xxxxxxxxxx>; Jonathan Cameron <jic23@xxxxxxxxxx>;
> David Lechner <dlechner@xxxxxxxxxxxx>; Sa, Nuno <Nuno.Sa@xxxxxxxxxx>;
> Andy Shevchenko <andy@xxxxxxxxxx>; Rob Herring <robh@xxxxxxxxxx>;
> Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; Olivier Moysan <olivier.moysan@xxxxxxxxxxx>; Mark
> Brown <broonie@xxxxxxxxxx>; Sebastian Reichel
> <sebastian.reichel@xxxxxxxxxxxxx>; linux-iio@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> spi@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 1/5] spi: allow ancillary devices to share parent's chip
> selects
> 
> [External]
> 
> On Mon, Feb 23, 2026 at 06:21:00PM +0200, Antoniu Miclaus wrote:
> > When registering an ancillary SPI device, the current code flags a chip
> > select conflict with the parent device. This happens because the
> > ancillary device intentionally uses one of the parent's chip selects,
> > but __spi_add_device() checks against all existing devices including
> > the parent.
> >
> > Allow this by passing the parent device pointer to __spi_add_device()
> > and skipping the conflict check when the existing device is the parent.
> 
> Isn't this already applied?
Don't think so.
V2: https://patchwork.kernel.org/project/linux-iio/patch/bcb1eb34fc5e86fd5dbb4472ad1d3ea3cf3e9779.1770393792.git.antoniu.miclaus@xxxxxxxxxx/
V3: https://patchwork.kernel.org/project/linux-iio/patch/20260213144742.16394-2-antoniu.miclaus@xxxxxxxxxx/
> 
> --
> With Best Regards,
> Andy Shevchenko
>