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

[Miclaus, Antoniu]

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
> Sent: Tuesday, February 24, 2026 1:24 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 Tue, Feb 24, 2026 at 11:12:57AM +0000, Miclaus, Antoniu wrote:
> > > -----Original Message-----
> > > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
> > > Sent: Tuesday, February 24, 2026 12:09 PM
> > > 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://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-
> iio/patch/bcb1eb34fc5e86fd5dbb4472ad1d3ea3cf3e9779.1770393792.git.
> antoniu.miclaus@xxxxxxxxxx/__;!!A3Ni8CS0y2Y!_3N9p4aNfQTLDj_PhmYtKj
> tvDUb_XuD11NL_A9Q_MXJ-
> oIMK_bwwRFi8Cc_RFNuRKMFw48sWYPfFKfzH_mLYVjz4Rtk9HYs$
> > V3:
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-
> iio/patch/20260213144742.16394-2-
> antoniu.miclaus@xxxxxxxxxx/__;!!A3Ni8CS0y2Y!_3N9p4aNfQTLDj_PhmYtKj
> tvDUb_XuD11NL_A9Q_MXJ-
> oIMK_bwwRFi8Cc_RFNuRKMFw48sWYPfFKfzH_mLYVjz4Y3O1A3U$
> 
> https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git
> /broonie/spi.git/commit/?h=for-
> 7.1&id=ffef4123043c5bb29e61052a41e577ae1ee6837a__;!!A3Ni8CS0y2Y!_
> 3N9p4aNfQTLDj_PhmYtKjtvDUb_XuD11NL_A9Q_MXJ-
> oIMK_bwwRFi8Cc_RFNuRKMFw48sWYPfFKfzH_mLYVjz4-hW_q-o$
> 
> Will be part of today's Linux Next IIUC.

Oh, thanks! Was tracking it on patchwork and saw it was not accepted.

> --
> With Best Regards,
> Andy Shevchenko
>