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

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

[Marek Szyprowski]

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 if the
ACTIVE_HIGH, what will leave the pin in input 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>
---
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
---
 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;
 	};
-- 
2.17.1


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

[Martin Blumenstingl]

Hi Marek,

thank you for this patch!

On Fri, Dec 18, 2020 at 11:23 AM Marek Szyprowski
<m.szyprowski@samsung.com> 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 if the
I think this should read "instead of ACTIVE_HIGH"

> ACTIVE_HIGH, what will leave the pin in input 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
I'm used to datasheets not being up-to-date. but now also the
schematics don't seem to match the actual HW? :-(


Best regards,
Martin

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