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SubjectRe: [PATCH] arm64: dts: meson: fix PHY deassert timing requirements
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On Tue 01 Dec 2020 at 01:25, Stefan Agner <stefan@agner.ch> wrote:

> According to the datasheet (Rev. 1.4, page 30) the RTL8211F requires
> at least 50ms "for internal circuits settling time" before accessing
> the PHY registers. This fixes an issue where the Ethernet link doesn't
> come up when using ip link set down/up:
> [ 29.360965] meson8b-dwmac ff3f0000.ethernet eth0: Link is Down
> [ 34.569012] meson8b-dwmac ff3f0000.ethernet eth0: PHY [0.0:00] driver [RTL8211F Gigabit Ethernet] (irq=31)
> [ 34.676732] meson8b-dwmac ff3f0000.ethernet: Failed to reset the dma
> [ 34.678874] meson8b-dwmac ff3f0000.ethernet eth0: stmmac_hw_setup: DMA engine initialization failed
> [ 34.687850] meson8b-dwmac ff3f0000.ethernet eth0: stmmac_open: Hw setup failed
>
> Fixes: 658e4129bb81 ("arm64: dts: meson: g12b: odroid-n2: add the Ethernet PHY reset line")
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi
> index 6982632ae646..a5652caacb27 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi
> @@ -413,7 +413,7 @@ external_phy: ethernet-phy@0 {
> max-speed = <1000>;
>
> reset-assert-us = <10000>;
> - reset-deassert-us = <30000>;
> + reset-deassert-us = <50000>;
> reset-gpios = <&gpio GPIOZ_15 (GPIO_ACTIVE_LOW | GPIO_OPEN_DRAIN)>;
>
> interrupt-parent = <&gpio_intc>;

Thanks for sharing this is Stefan,
The title of your patch should probably be modified to show that it
addresses the odroid n2 only, as it stands.

I have checked the RTL8211F doc I have, v1.9, and this one mention
"72ms at least - not including the 1.0V supply rise time" before
accessing the PHY registers :/ ... so 80ms maybe ?

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