Re: [PATCH] arm64: dts: renesas: sparrow-hawk: Add overlay for WaveShare 2CH CANFD HAT

[Marek Vasut]

On 9/9/26 9:56 AM, Geert Uytterhoeven wrote:

Hello Geert,

> On Tue, 8 Sept 2026 at 19:02, Marek Vasut <marek.vasut@xxxxxxxxxxx> wrote:
> > On 9/8/26 2:02 PM, Geert Uytterhoeven wrote:
> > > > +&pfc {
> > > > +       msiof0_pins: spi-ws-2ch-canfd0 {        /* SPI_0 */
> > >
> > > Node name should be "msiof0".
> >
> > Do we also have to fix up
> > arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts this:
> >
> > "
> >    755         msiof1_pins: sound {
> >                             ^^^^^
> > "
> > ?
>
> Might be a good idea, to increase consistency.

Submitted as

[PATCH] arm64: dts: renesas: sparrow-hawk: Align MSIOF1 PFC node name 
with label

> > But I wonder, shouldn't the DTOs contain unique pinmux node names, which
> > cannot accidentally overlap with the base DT or other DTO node names ?
>
> In general, the answer is yes.
> In this case it is about pin control subnodes. If the base DTS already
> uses msiof0, its original user needs to be disabled by the overlay
> anyway.

The original DTS does not use MSIOF0 .

I think the proper solution here would be DT connector ?

> > > > +               groups = "msiof0_clk", "msiof0_txd", "msiof0_rxd";
> > > > +               function = "msiof0";
> > > > +       };
> > > > +};
> > > > +
> > > > +/*
> > > > + * PWM1 uses PWM1_B pin configuration for pin GP2_13. This conflicts
> > > > + * with SPI_1 CE_1 signal which is also on pin GP2_13. Disable PWM1
> > > > + * in case this hat is in use.
> > > > + */
> > > > +&pwm1 {
> > > > +       status = "disabled";
> > > > +};
> > >
> > > Please move this node disabling pwm1 to the top, for compatibility
> > > with dynamic DT overlays.
> > Could you expand on that a bit ? What difference does the placement of
> > this node make within the DTSO ? Please pardon my ignorance.
>
> In case of a dynamic overlay, pwm1 must be disabled before SPI_1 is
> probed.  Otherwise the latter will fail with -EBUSY due to the
> conflicting pin being still in use.

TIL, thank you.

--
Best regards,
Marek Vasut