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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2024-10-31 10:29:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-27 11:05:36 +0100 |
| commit | ee195051be2db6b82980053e45c7e892019c22ab (patch) | |
| tree | d4d88f7dbdae94c018ba64af824e8f58dc6a6a40 | |
| parent | 1a233520de8cb614cdd087c1c0475aba3476c0b4 (diff) | |
| download | linux-ee195051be2db6b82980053e45c7e892019c22ab.tar.gz linux-ee195051be2db6b82980053e45c7e892019c22ab.tar.bz2 linux-ee195051be2db6b82980053e45c7e892019c22ab.zip | |
ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms
commit 929d8490f8790164f5f63671c1c58d6c50411cb2 upstream.
Commit b9bf5612610aa7e3 ("ARM: dts: am335x-bone-common: Increase MDIO
reset deassert time") already increased the MDIO reset deassert delay
from 6.5 to 13 ms, but this may still cause Ethernet PHY probe failures:
SMSC LAN8710/LAN8720 4a101000.mdio:00: probe with driver SMSC LAN8710/LAN8720 failed with error -5
On BeagleBone Black Rev. C3, ETH_RESETn is controlled by an open-drain
AND gate. It is pulled high by a 10K resistor, and has a 4.7µF
capacitor to ground, giving an RC time constant of 47ms. As it takes
0.7RC to charge the capacitor above the threshold voltage of a CMOS
input (VDD/2), the delay should be at least 33ms. Considering the
typical tolerance of 20% on capacitors, 40ms would be safer. Add an
additional safety margin and settle for 50ms.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/9002a58daa1b2983f39815b748ee9d2f8dcc4829.1730366936.git.geert+renesas@glider.be
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm/boot/dts/am335x-bone-common.dtsi | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/boot/dts/am335x-bone-common.dtsi b/arch/arm/boot/dts/am335x-bone-common.dtsi index a9f28a097987..c455c91fe3b3 100644 --- a/arch/arm/boot/dts/am335x-bone-common.dtsi +++ b/arch/arm/boot/dts/am335x-bone-common.dtsi @@ -384,7 +384,7 @@ /* Support GPIO reset on revision C3 boards */ reset-gpios = <&gpio1 8 GPIO_ACTIVE_LOW>; reset-assert-us = <300>; - reset-deassert-us = <13000>; + reset-deassert-us = <50000>; }; }; |