Re: [PATCH net-next 5/9] net: dsa: microchip: implement .support_eee() only if needed

[Paolo Abeni]

On 5/26/26 11:47 AM, Bastien Curutchet (Schneider Electric) wrote:
> diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
> index a39541d29ad5..e0b3724a7558 100644
> --- a/drivers/net/dsa/microchip/ksz9477.c
> +++ b/drivers/net/dsa/microchip/ksz9477.c
> @@ -1909,6 +1909,54 @@ void ksz9477_phylink_mac_link_up(struct phylink_config *config,
>  	ksz9477_duplex_flowctrl(dev, port, duplex, tx_pause, rx_pause);
>  }
>  
> +/**
> + * ksz9477_support_eee - Determine Energy Efficient Ethernet (EEE) support for a
> + *                       port
> + * @ds: Pointer to the DSA switch structure
> + * @port: Port number to check
> + *
> + * This function also documents devices where EEE was initially advertised but
> + * later withdrawn due to reliability issues, as described in official errata
> + * documents. These devices are explicitly listed to record known limitations,
> + * even if there is no technical necessity for runtime checks.
> + *
> + * Returns: true if the internal PHY on the given port supports fully
> + * operational EEE, false otherwise.
> + */
> +static bool ksz9477_support_eee(struct dsa_switch *ds, int port)
> +{
> +	struct ksz_device *dev = ds->priv;
> +
> +	if (!dev->info->internal_phy[port])
> +		return false;
> +
> +	switch (dev->chip_id) {
> +	case KSZ8563_CHIP_ID:
> +	case KSZ9563_CHIP_ID:
> +	case KSZ9893_CHIP_ID:
> +		return true;
> +	default:
> +		/* KSZ8567R Errata DS80000752C Module 4 */
> +		/* KSZ9477S Errata DS80000754A Module 4 */
> +		/* KSZ9567S Errata DS80000756A Module 4 */
> +		/* KSZ9896C Errata DS80000757A Module 3 */
> +		/* KSZ9897R Errata DS80000758C Module 4 */

Sashiko noted that errata:

		/* KSZ879x/KSZ877x/KSZ876x Errata DS80000687C Module 2 */

has been lost above.

> diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
> index f8f220242f7a..4cbbcf7993c9 100644
> --- a/drivers/net/dsa/microchip/lan937x_main.c
> +++ b/drivers/net/dsa/microchip/lan937x_main.c
> @@ -915,7 +915,6 @@ const struct dsa_switch_ops lan937x_switch_ops = {
>  	.port_txtstamp		= ksz_port_txtstamp,
>  	.port_rxtstamp		= ksz_port_rxtstamp,
>  	.port_setup_tc		= ksz_setup_tc,
> -	.support_eee		= ksz_support_eee,
>  	.set_mac_eee		= ksz_set_mac_eee,

Sashiko noted that `set_mac_eee` usage is gated by `support_eee` presence,
you may want to remove even the set callback.

/P