Re: [PATCH] arm64: dts: imx8mp-phyboard-pollux: add PEB-WLBT-07 expansion board

[Primoz Fiser <primoz.fiser@norik.com>]

Hi,

On 8/27/26 10:10, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Missing `post-power-on-delay-ms` in the MMC power sequence for the NXP IW612 Wi-Fi/BT module.
> --
> 
> commit 60b0b6fcfb75ad1ee4054d84dfea3d70e8467993
> Author: Primoz Fiser <primoz.fiser@norik.com>
> 
> arm64: dts: imx8mp-phyboard-pollux: add PEB-WLBT-07 expansion board
> 
> Add support for PEB-WLBT-07 which is an expansion board that provides WiFi 6
> and Bluetooth 5.4 LE functionality. It features the u-blox MAYA-W2 module
> with the NXP IW612 chipset.
> 
> [ ... ]
> 
>> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-peb-wlbt-07.dtso b/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-peb-wlbt-07.dtso
>> new file mode 100644
>> index 0000000000000..008b6f9f46e59
>> --- /dev/null
>> +++ b/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-peb-wlbt-07.dtso
>> @@ -0,0 +1,76 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
>> +/*
>> +* Copyright (C) 2026 PHYTEC Messtechnik GmbH
>> +*/
>> +
>> +#include <dt-bindings/clock/imx8mp-clock.h>
>> +#include <dt-bindings/gpio/gpio.h>
>> +#include <dt-bindings/interrupt-controller/irq.h>
>> +#include "imx8mp-pinfunc.h"
>> +
>> +/dts-v1/;
>> +/plugin/;
>> +
>> +&{/} {
>> +	usdhc1_pwrseq: pwr-seq {
>> +		compatible = "mmc-pwrseq-simple";
>> +		reset-gpios = <&gpio2 7 GPIO_ACTIVE_LOW>;
>> +	};
> 
> [Severity: Medium]
> Is it possible that the usdhc1_pwrseq node needs a post-power-on-delay-ms
> property here?
> 
> When the MMC core powers up the SDIO bus, it deasserts the reset GPIO and
> immediately proceeds to probe the module with no explicit delay. If the
> SDIO host controller probes the IW612 module immediately after the reset
> deassertion and the hardware is not yet stabilized, could this cause SDIO
> enumeration failures during device boot or resume?
> 
> Other in-tree configurations for the IW61x chipset, such as those in
> imx8mm-var-som-wifi-bt-iw61x.dtsi, explicitly configure a delay like
> post-power-on-delay-ms = <100>. While there might be an on-board hardware
> RC delay on the MAYA-W2 module that mitigates the missing software delay,
> adding the explicit software delay might be necessary to guarantee stability.

The same PEB-WLBT-07 expansion board on i.MX93 also doesn't use
post-power-on-delay-ms property, see
arch/arm64/boot/dts/freescale/imx93-phyboard-nash-peb-wlbt-07.dtso.

So far no issues without post-power-on-delay-ms property.

I would like to avoid adding such properties "just in case" for now.

Thanks,
BR,
Primoz


> 
> [ ... ]
> 

-- 
Primoz Fiser
phone: +386-41-390-545
email: primoz.fiser@norik.com
--
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