Re: [PATCH v1 1/1] arm64: dts: imx8mn-evk: Pass GPIO_OPEN_DRAIN flag on i2c3 GPIOs

[Peng Fan <peng.fan@oss.nxp.com>]

On Thu, Oct 15, 2026 at 01:12:40PM +0200, Stefano Radaelli wrote:
>On Thu, Oct 15, 2026 at 07:02:48PM +0800, Peng Fan wrote:
>> On Thu, Oct 15, 2026 at 10:11:49AM +0200, Stefano Radaelli wrote:
>> >From: Stefano Radaelli <stefano.r@variscite.com>
>> >
>> >scl-gpios and sda-gpios need GPIO_OPEN_DRAIN flag, otherwise the
>> >following run-time warning is seen:
>> >
>> >gpio-146 (scl): enforced open drain please flag it properly in DT/ACPI DSDT/board file
>> >
>> >Signed-off-by: Stefano Radaelli <stefano.r@variscite.com>
>> >---
>> > arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> >diff --git a/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
>> >index 3e590afa4fab..036afa0f6990 100644
>> >--- a/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
>> >+++ b/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
>> >@@ -287,8 +287,8 @@ &i2c3 {
>> > 	pinctrl-names = "default", "gpio";
>> > 	pinctrl-0 = <&pinctrl_i2c3>;
>> > 	pinctrl-1 = <&pinctrl_i2c3_gpio>;
>> >-	scl-gpios = <&gpio5 18 GPIO_ACTIVE_HIGH>;
>> >-	sda-gpios = <&gpio5 19 GPIO_ACTIVE_HIGH>;
>> >+	scl-gpios = <&gpio5 18 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
>> >+	sda-gpios = <&gpio5 19 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
>> 
>> I think ODE should be configured for pinctrl_i2c3_gpio.
>> 
>> Regards
>> Peng
>
>Hi Peng,
>
>I followed the same approach used in commit
>2b1d5d054d29e08926f05cfa30e34d149644585e, as well as in the other i.MX
>DTS files that use GPIO_OPEN_DRAIN for I2C bus recovery.
>
>Even in imx8mn-evk.dtsi itself, I2C2 uses the same configuration,
>with GPIO_OPEN_DRAIN specified in the GPIO properties and without
>ODE enabled in the pinctrl.
>
>Wouldn't introducing a different configuration for I2C3 create some
>inconsistency and potentially cause confusion?
>
>If enabling ODE in the pinctrl is the preferred approach, wouldn't it
>make more sense to address this in a separate follow-up patch, updating
>the existing I2C recovery pinctrl configurations consistently across the
>affected DTS files?
>
>What do you think?

w/o GPIO_OPEN_DRAIN, there is risk that GPIO emulated I2C is not using
open drain mode.

Enabling ODE in pad will not make the warning disappear (:, so still need
the flag.

It is fine to add the flag in your path.

I will fixes all the wrong usage for the GPIO I2C pad settings.

Regards
Peng

>
>Best Regards,
>Stefano
>
>