Message-ID: <24c7e160-762d-61f9-1745-4d91a29ff0d6@linaro.org>
Date:   Fri, 27 Jan 2023 17:23:44 +0100
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From:   Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH v2 1/5] arm64: dts: meson: bananapi-m5: switch VDDIO_C pin
 to OPEN_DRAIN
Content-Language: en-US
To:     Christian Hewitt <christianshewitt@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20230127142221.3718184-1-christianshewitt@gmail.com>
 <20230127142221.3718184-2-christianshewitt@gmail.com>
Organization: Linaro Developer Services
In-Reply-To: <20230127142221.3718184-2-christianshewitt@gmail.com>
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Precedence: bulk

On 27/01/2023 15:22, Christian Hewitt wrote:
> For proper warm (re)boot from SD card the BPI-M5 board requires TFLASH_VDD_EN
> and VDDIO_C pins to be switched to high impedance mode. This can be achieved
> using OPEN_DRAIN instead of ACTIVE_HIGH to leave the GPIO pins in input mode
> and retain high state (pin has the pull-up).
> 
> This change is inspired by meson-sm1-odroid.dtsi where OPEN_DRAIN has been
> used to resolve similar problems with the Odroid C4 board (TF_IO in the C4
> dts is the equivalent regulator).
> 
> Fixes: 976e920183e4 ("arm64: dts: meson-sm1: add Banana PI BPI-M5 board dts")
> Suggested-by: Neil Armstrong <neil.armstrong@linaro.org>
> Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
> ---
>   arch/arm64/boot/dts/amlogic/meson-sm1-bananapi-m5.dts | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-bananapi-m5.dts b/arch/arm64/boot/dts/amlogic/meson-sm1-bananapi-m5.dts
> index 028220ed45ad..3c1267a7ffef 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-sm1-bananapi-m5.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-sm1-bananapi-m5.dts
> @@ -123,7 +123,7 @@ vddio_c: regulator-vddio_c {
>   		regulator-min-microvolt = <1800000>;
>   		regulator-max-microvolt = <3300000>;
>   
> -		enable-gpio = <&gpio_ao GPIOE_2 GPIO_ACTIVE_HIGH>;
> +		enable-gpio = <&gpio_ao GPIOE_2 GPIO_OPEN_DRAIN>;
>   		enable-active-high;
>   		regulator-always-on;
>   

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>