Re: [PATCH 2/3] ARM: dts: imx6ulz-bsh-smm-m2: Enable uart2

Peng Fan
2025-05-22T08:57:34Z

On Fri, May 16, 2025 at 12:11:54PM +0200, Michael Nazzareno Trimarchi wrote:
>Hi
>
>
>On Fri, May 16, 2025 at 4:56???AM Peng Fan <peng.fan@oss.nxp.com> wrote:
>>
>> On Wed, May 14, 2025 at 09:05:34AM +0200, Dario Binacchi wrote:
>> >From: Wolfgang Birkner <wolfgang.birkner@bshg.com>
>> >
>> >uart2 is used as wake up source.
>> >
>> >Signed-off-by: Wolfgang Birkner <wolfgang.birkner@bshg.com>
>> >Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
>> >---
>> >
>> > arch/arm/boot/dts/nxp/imx/imx6ulz-bsh-smm-m2.dts | 4 ++++
>> > 1 file changed, 4 insertions(+)
>> >
>> >diff --git a/arch/arm/boot/dts/nxp/imx/imx6ulz-bsh-smm-m2.dts b/arch/arm/boot/dts/nxp/imx/imx6ulz-bsh-smm-m2.dts
>> >index 5c32d1e3675c..fff21f28c552 100644
>> >--- a/arch/arm/boot/dts/nxp/imx/imx6ulz-bsh-smm-m2.dts
>> >+++ b/arch/arm/boot/dts/nxp/imx/imx6ulz-bsh-smm-m2.dts
>> >@@ -37,6 +37,10 @@ &snvs_poweroff {
>> > status = "okay";
>> > };
>> >
>> >+&uart2 {
>> >+ status = "okay";
>> >+};
>>
>> No need pinctrl settings?
>>
>
>We found out that in imx6ulz, if we don't enable wakeup on uart2 (or
>other uarts that do not conflict on pinout) we are not able to wake up
>from uart4, which is the console.
>According to the TRM and the code everything look fine but the real
>result it's we stuck in suspend
>
>Here is how we are able to resume.
>
>uart2
>echo enabled > wakeup
>uart4
>echo enabled > wakeup

No idea.

But at least put some info in commit log to describe why set uart2 as okay.

Thanks,
Peng

>
>Michael
>
>> Regards,
>> Peng
>>
>> >+
>> > &uart3 {
>> > pinctrl-names = "default";
>> > pinctrl-0 = <&pinctrl_uart3>;
>> >--
>> >2.43.0
>> >
>> >base-commit: e9565e23cd89d4d5cd4388f8742130be1d6f182d
>> >branch: bsh-202505-imx6ulz_smm_m2
>>
>>
>
>
>--
>Michael Nazzareno Trimarchi
>Co-Founder & Chief Executive Officer
>M. +39 347 913 2170
>michael@amarulasolutions.com
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