RE: [RFC PATCH 4/8] xilinx: tsn: Add Ethernet MAC (EMAC) and MDIO support to the TSN driver

[Neeli, Srinivas]

[Public]

Hi,

> -----Original Message-----
> From: Andrew Lunn <andrew@xxxxxxx>
> Sent: Friday, February 20, 2026 8:33 PM
> To: Neeli, Srinivas <srinivas.neeli@xxxxxxx>
> Cc: andrew+netdev@xxxxxxx; davem@xxxxxxxxxxxxx;
> edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; Simek,
> Michal <michal.simek@xxxxxxx>; robh@xxxxxxxxxx; krzk+dt@xxxxxxxxxx;
> conor+dt@xxxxxxxxxx; richardcochran@xxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; git (AMD-Xilinx) <git@xxxxxxx>
> Subject: Re: [RFC PATCH 4/8] xilinx: tsn: Add Ethernet MAC (EMAC) and MDIO
> support to the TSN driver
>
> > > > +           tsn_mdio_mdc_enable(emac);
> > >
> > > It is unusual to stop MDC. I suspect some PHYs will not like this.
> > > What is your reason for doing this.
> > >
> > The intention is to reduce power consumption by gating  the clock when it is
> not required.
>
> There is only one other MDIO bus driver that i know of which disables the
> clock between transactions. And it does it because the board has ageing
> problems, and if the clock it left ticking all the time, the magic smoke eventually
> escapes.
>
> How many different PHYs have you tested this with? How good a feeling do
> you have this is not going to cause problems? How much power do you
> actually save?
>
>        Andrew
>
This change was expected to provide some power savings when the clock is disabled.
Since I have not validated this through practical measurements and have tested it with only one PHY, I have decided to drop the change.
Thanks for the guidance.

Thanks
Neeli Srinivas