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From:   Krzysztof Kozlowski <krzk@kernel.org>
Date:   Mon, 12 Oct 2020 08:52:42 +0200
Message-ID: <CAJKOXPdwsoN1Dnqs9gZTibqoy5vRTPwpLLmohHoguSCiq+UWHA@mail.gmail.com>
Subject: Re: [PATCH 1/3] arm64: dts: imx8mm: Correct WDOG_B pin configuration
To:     Anson Huang <Anson.Huang@nxp.com>
Cc:     robh+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de,
        kernel@pengutronix.de, festevam@gmail.com, aford173@gmail.com,
        daniel.baluta@nxp.com, shengjiu.wang@nxp.com, peter.chen@nxp.com,
        alifer.wsdm@gmail.com, abel.vesa@nxp.com, yibin.gong@nxp.com,
        jun.li@nxp.com, l.stach@pengutronix.de, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux-imx@nxp.com
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On Fri, 9 Oct 2020 at 09:52, Anson Huang <Anson.Huang@nxp.com> wrote:
>
> Different revision of i.MX8MM EVK boards may have different external
> pull up registor design, some are enabled while some are NOT, to make
> sure the WDOG_B pin works properly, better to enable internal pull up
> resistor. Since enabling internal pull up resistor is NOT harmful and
> having benefit of flexibility on different board design, just enable
> it for all i.MX8MM boards.
>
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
>  arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi | 2 +-
>  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi        | 2 +-
>  arch/arm64/boot/dts/freescale/imx8mm-var-som.dtsi    | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi
> index 6de86a4..a941301 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi
> @@ -398,7 +398,7 @@
>
>                 pinctrl_wdog: wdoggrp {
>                         fsl,pins = <
> -                               MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B            0xc6
> +                               MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B            0x166

Enabling pull up makes sense but you change other bits - disable
Schmitt input and enable open drain. This change is not documented /
explained in commit msg.

Best regards,
Krzysztof