Subject: Re: [PATCH net-next 0/5] net: cadence: macb: add IEEE 802.3az EEE support

From: "Russell King (Oracle)" <[email-masked]>
Date: Mon, 23 Feb 2026 09:14:09 +0000

On Mon, Feb 23, 2026 at 10:04:07AM +0100, Nicolai Buchwitz wrote:
> Add Energy Efficient Ethernet (IEEE 802.3az) support to the Cadence GEM
> (macb) driver. The GEM MAC has hardware LPI registers but no built-in
> idle timer, so the driver implements software-managed TX LPI using a
> delayed_work timer, as recommended by Microchip's GMAC documentation.
> 
> The series is structured as follows:
> 
>   1. Register definitions: LPI counter offsets (0x270-0x27c), TXLPIEN
>      bitfield (NCR bit 19), and a MACB_CAPS_EEE capability flag.
> 
>   2. LPI statistics: Expose the four hardware EEE counters (RX/TX LPI
>      transitions and time) through ethtool -S, accumulated in software
>      since they are clear-on-read.
> 
>   3. TX LPI engine: A delayed_work-based idle timer that enters LPI
>      after 250ms of TX inactivity and wakes before transmit with a
>      conservative 50us PHY wake delay. LPI entry is deferred 1 second
>      after link-up per IEEE 802.3az.
> 
>   4. ethtool EEE ops: get_eee/set_eee delegating to phylink for PHY
>      negotiation; the MAC-level TXLPIEN is controlled only from the
>      phylink mac_link_up/mac_link_down callbacks.

This needs a rewrite - phylink has EEE support now, with new callbacks
and configuration. There is no need to use the obsolete (and incorrect)
phy_init_eee() anymore.

Please see:

e9f03a6a879b net: phylink: add support for notifying PCS about EEE

and

03abf2a7c654 net: phylink: add EEE management

Thanks.

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