RE: [EXT] Re: [PATCH 2/2] arm64: dts: freescale: add i.MX952 FRDM Board support device tree

> 
> On Mon, Jul 20, 2026 at 03:03:20PM +0800, Joseph Guo wrote:
> > On 7/20/2026 2:55 PM, [email protected] wrote:
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> > >
> > > Thank you for your contribution! Sashiko AI review found 2 potential
> issue(s) to consider:
> > > - [High] Shared GPIO requested exclusively by two CAN transceivers
> causes probe failure for the second transceiver.
> > > - [Low] Use of undocumented, downstream-only device tree property
> `fsl,cd-gpio-wakeup-disable`.
> > > --
> > >
> > > --- Patch [2]: [PATCH 2/2] arm64: dts: freescale: add i.MX952 FRDM
> > > Board support device tree --- commit
> > > 8bbcb28d08a05e0f4c57023333492b4e023f7caf
> > > Author: Joseph Guo <[email protected]>
> > >
> > > arm64: dts: freescale: add i.MX952 FRDM Board support device tree
> > >
> > > Add basic device tree support for i.MX952 FRDM Board. The
> > > board-common hardware description is placed in imx952-frdm.dtsi so
> > > that it can be shared with future i.MX952-based FRDM derivative boards.
> > >
> > >> diff --git a/arch/arm64/boot/dts/freescale/imx952-frdm.dtsi
> > >> b/arch/arm64/boot/dts/freescale/imx952-frdm.dtsi
> > >> new file mode 100644
> > >> index 0000000000000..b9ef6bec2bd5a
> > >> --- /dev/null
> > >> +++ b/arch/arm64/boot/dts/freescale/imx952-frdm.dtsi
> > >> @@ -0,0 +1,727 @@
> > > [ ... ]
> > >> +     flexcan2_phy: can-phy0 {
> > >> +             compatible = "nxp,tja1051";
> > >> +             #phy-cells = <0>;
> > >> +             max-bitrate = <8000000>;
> > >> +             silent-gpios = <&pcal6416 6 GPIO_ACTIVE_HIGH>;
> > >> +     };
> > >> +
> > >> +     flexcan3_phy: can-phy1 {
> > >> +             compatible = "nxp,tja1051";
> > >> +             #phy-cells = <0>;
> > >> +             max-bitrate = <8000000>;
> > >> +             silent-gpios = <&pcal6416 6 GPIO_ACTIVE_HIGH>;
> > >
> > > [Severity: High]
> > > Does this cause a probe failure for the second transceiver?
> > >
> > > The first PHY node successfully requests this GPIO line, taking
> > > exclusive ownership. Because the phy-can-transceiver driver uses
> > > standard exclusive requests (without
> GPIOD_FLAGS_BIT_NONEXCLUSIVE),
> > > the second request for the exact same GPIO line fails with -EBUSY.
> > >
> > > This prevents the flexcan3_phy and the flexcan3 controller from
> > > probing and functioning.
> > >
> >
> > This two CAN PHY did share same pin as their silent-gpio on hardware.
> 
> Hardware share gpio, but driver may not handle this case. Are you sure
> 
> flexcan3_phy probed if can-phy0 already probed?
> 
> Frank
> 
Hi Frank,

root@imx952-15x15-lpddr5-frdm:~# ls /sys/bus/platform/drivers/flexcan/
421d0000.can  42220000.can  bind  module  uevent  unbind
root@imx952-15x15-lpddr5-frdm:~# ls /sys/bus/platform/drivers/can-transceiver-phy/
bind  can-phy0  can-phy1  module  uevent  unbind

From the log I think both can-phy probe successfully.

Regards,
Joseph

> >
> > The same design on i.MX95 15x15 FRDM. This should be fine.
> >
> > Regards,
> > Joseph
> >
> > >> +     };
> > > [ ... ]
> > >> +&usdhc2 {
> > >> +     bus-width = <4>;
> > >> +     cd-gpios = <&gpio3 0 GPIO_ACTIVE_LOW>;
> > >> +     pinctrl-0 = <&pinctrl_usdhc2>, <&pinctrl_usdhc2_gpio>;
> > >> +     pinctrl-1 = <&pinctrl_usdhc2_100mhz>, <&pinctrl_usdhc2_gpio>;
> > >> +     pinctrl-2 = <&pinctrl_usdhc2_200mhz>, <&pinctrl_usdhc2_gpio>;
> > >> +     pinctrl-3 = <&pinctrl_usdhc2>, <&pinctrl_usdhc2_gpio>;
> > >> +     pinctrl-names = "default", "state_100mhz", "state_200mhz", "sleep";
> > >> +     vmmc-supply = <&reg_usdhc2_vmmc>;
> > >> +     fsl,cd-gpio-wakeup-disable;
> > >
> > > [Severity: Low]
> > > Is this out-of-tree vendor property invalid in the upstream kernel?
> > >
> > > The property fsl,cd-gpio-wakeup-disable does not exist in any
> > > upstream device tree bindings (such as fsl-imx-esdhc.yaml) and is
> > > not handled by any driver code in the upstream Linux tree. This acts
> > > as dead code and will trigger `make dtbs_check` validation warnings.
> > >
> > >> +     status = "okay";
> > >> +};
> > >
> > > --
> > > Sashiko AI review *
> > > https://sashiko.dev/#/patchset/20260720-imx952_frdm-v1-0-
> 6d145eaaa5c
> > > [email protected]?part=2
> >
> > --
> > Best Regards,
> > Joseph