Re: [PATCH v1 01/11] arm64: dts: freescale: imx8mm-verdin: Add SPI alias

[Francesco Dolcini <francesco@dolcini.it>]

Hello Frank,

On Thu, Nov 12, 2026 at 09:41:31AM -0600, Frank Li wrote:
> On Thu, Nov 12, 2026 at 04:02:23PM +0100, Francesco Dolcini wrote:
> > From: Francesco Dolcini <francesco.dolcini@toradex.com>
> >
> > The Verdin family pinout defines the SoM interfaces and their
> > numbering, SPI_1 being the SPI bus available to the carrier board,
> > implemented by ecspi2 on Verdin iMX8MM.
> >
> > imx8mm.dtsi numbers ecspi2 as spi1, so the Linux bus number in sysfs
> > and the spidev name do not match the Verdin interface. Add a spi0
> > alias in the SoM dtsi and delete the inherited spi1, so ecspi2 is
> > bus 0, zero-based with SPI_1 being spi0, and carries a single alias.
> > ecspi3, internal to the SoM with the CAN controller and the TPM, keeps
> > the spi2 alias inherited from the SoC.
> >
> > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
> > ---
> >  arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
> > index 1ac9d000d415..0369803a4d46 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
> > @@ -16,6 +16,8 @@ chosen {
> >  	aliases {
> >  		rtc0 = &rtc_i2c;
> >  		rtc1 = &snvs_rtc;
> > +		spi0 = &ecspi2;
> > +		/delete-property/ spi1;
> 
> Can you avoid delete property for new platform?

Unfortunately this is needed. 

The included imx8mm.dtsi has

  spi1 = &ecspi2;

so, without the /delete-property/ we will have both

  spi0 = &ecspi2;
  spi1 = &ecspi2;

and what is happening with that is implementation dependent, and this
would not be ok.

The original issue is that imx8mm.dtsi should not define the aliases in
the first place, unfortunately removing it now is no longer possible,
it will introduce regressions everywhere [0][1].

This issue, and the reason I have the delete-property, is already
explained in the commit message.

Francesco

[0] https://lore.kernel.org/all/20250425-dts-imx-aliases-ethernet-v1-0-15b9d5cca611@linaro.org/
[1] https://lore.kernel.org/all/aca3addbe510c58524af8d3fd069fe2ae4b1cd24.camel@pengutronix.de/