Re: [PATCH] net: mdiobus: Prevent spike on MDIO bus reset signal

On Tue, Jan 26, 2021 at 08:33:37AM +0100, Mike Looijmans wrote:

The mdio_bus reset code first de-asserted the reset by allocating with
GPIOD_OUT_LOW, then asserted and de-asserted again. In other words, if
the reset signal defaulted to asserted, there'd be a short "spike"
before the reset.

Instead, directly assert the reset signal using GPIOD_OUT_HIGH, this
removes the spike and also removes a line of code since the signal
is already high.

Hi Mike

Did you look at the per PHY reset? mdiobus_register_gpiod() gets the
GPIO with GPIOD_OUT_LOW. mdiobus_register_device() then immediately
sets it high.

So it looks like it suffers from the same problem.

   Andrew