ARM: dts: sunxi: Banana Pi: increase startup-delay for the GMAC PHY regulator

On the LeMaker Banana Pi, probing the external ethernet PHY connected
to the SoC's internal GMAC module sometimes fails. The PHY power
supply is handled via a GPIO-controlled regulator, and the existing
regulator startup-delay of 50000us is too short to make sure that the
PHY is always fully powered up when it is queried by phylib. Tests
have shown that to provide a reliable PHY detection, the startup-delay
has to be increased to at least 60000us. To have a certain safety margin
and to cater for manufacturing variations between different boards,
the delay gets set to 100000us as discussed on the linux-arm-kernel
mailinglist.

Signed-off-by: Karsten Merker <merker@debian.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

diff --git a/arch/arm/boot/dts/sun7i-a20-bananapi.dts b/arch/arm/boot/dts/sun7i-a20-bananapi.dts
index 3de847d..1cf1214 100644 (file)
--- a/arch/arm/boot/dts/sun7i-a20-bananapi.dts
+++ b/arch/arm/boot/dts/sun7i-a20-bananapi.dts
@@ -207,7 +207,7 @@
                regulator-name = "gmac-3v3";
                regulator-min-microvolt = <3300000>;
                regulator-max-microvolt = <3300000>;
-               startup-delay-us = <50000>;
+               startup-delay-us = <100000>;
                enable-active-high;
                gpio = <&pio 7 23 0>;
        };