On 2024-07-05 23:49:56 +0200, Marek Vasut wrote:

On 7/3/24 11:36 AM, Niklas Söderlund wrote:

quoted

On 2024-07-03 10:24:26 +0200, Geert Uytterhoeven wrote:

quoted

Niklas: commit 54bf0c27380b95a2 ("arm64: dts: renesas: r8a779g0: Use
MDIO node for all AVB devices") did keep the reset-gpios property in
the PHY node. I guess it should be moved one level up?

It's possible to have a rest-gpios property both in the mdio node and
the phy node. The former resets the whole bus while the later a single
PHY, at least that's my understanding.

My understanding of reset GPIO in the MDIO node is that it is used in case
there might be multiple PHYs with shared reset GPIO on the same MDIO bus.
Like on the NXP iMX28 .

There is a use-case for a single PHY on the MDIO bus too, at least in 
Linux as I understand it. If the boot process leave the PHY in a bad 
state which prevents it from being probed. A GPIO reset in the MDIO node 
is used when the MDIO bus is registered thus resetting all (in this 
use-case the one) PHYs which later allows them to be probed. A GPIO 
reset on the PHY node is only used after a PHY have been probed, at 
least that is my understanding.

This is the use-case for adding a MDIO node to the AVB driver and 
WhiteHawk.

-- 
Kind Regards,
Niklas Söderlund