Re: [PATCH v2] arm64: dts: meson: switch TFLASH_VDD_EN pin to open drain on Odroid-C4

From: Neil Armstrong <narmstrong@baylibre.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
	linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Kevin Hilman <khilman@baylibre.com>,
	Dongjin Kim <tobetter@gmail.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Jerome Brunet <jbrunet@baylibre.com>
Subject: Re: [PATCH v2] arm64: dts: meson: switch TFLASH_VDD_EN pin to open drain on Odroid-C4
Date: Mon, 25 Jan 2021 19:37:33 +0100	[thread overview]
Message-ID: <3375145a-a9cc-3559-33fc-a0e0b2d5e977@baylibre.com> (raw)
In-Reply-To: <20210122055218.27241-1-m.szyprowski@samsung.com>

On 22/01/2021 06:52, Marek Szyprowski wrote:
> For the proper reboot Odroid-C4 board requires to switch TFLASH_VDD_EN
> pin to the high impedance mode, otherwise the board is stuck in the
> middle of loading early stages of the bootloader from SD card.
> 
> This can be achieved by using the OPEN_DRAIN flag instead of the
> ACTIVE_HIGH, what will leave the pin in input mode to achieve high state
> (pin has the pull-up) and solve the issue.
> 
> Suggested-by: Neil Armstrong <narmstrong@baylibre.com>
> Fixes: 326e57518b0d ("arm64: dts: meson-sm1: add support for Hardkernel ODROID-C4")
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
> Here is a discussion on u-boot's mailing list that inspired this patch:
> https://lists.denx.de/pipermail/u-boot/2020-December/435295.html
> 
> Changelog:
> v2:
> - fixed typo in the commit message
> 
> v1: https://lore.kernel.org/linux-amlogic/20201218102228.16211-1-m.szyprowski@samsung.com/
> - initial version
> ---
>  arch/arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts
> index cf5a98f0e47c..a712273c905a 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts
> @@ -52,7 +52,7 @@
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  
> -		gpio = <&gpio_ao GPIOAO_3 GPIO_ACTIVE_HIGH>;
> +		gpio = <&gpio_ao GPIOAO_3 GPIO_OPEN_DRAIN>;
>  		enable-active-high;
>  		regulator-always-on;
>  	};
> 

Hi Kevin,

The same fix was pushed on u-boot and solves the issue.

Could you take it for fixes ?

Acked-by: Neil Armstrong <narmstrong@baylibre.com>

Neil

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