Re: [PATCH net-next v2 2/4] net: phy: c45: add genphy_c45_config_master_slave()

[Nicolai Buchwitz]

Hi Javen

On 4.6.2026 09:42, javen wrote:
> From: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
>
> Add a generic helper to configure forced master/slave mode for Clause 
> 45
> PHYs using the 10GBASE-T AN control register.
>
> Signed-off-by: Javen Xu <javen_xu@xxxxxxxxxxxxxx>

> [...]

> +/**
> + * genphy_c45_config_master_slave - Configure Master/Slave setting for 
> C45 PHYs
> + * @phydev: target phy_device struct
> + *
> + * Description: Configures the Master/Slave manual setting in the
> + * 10GBASE-T control register (MMD 7, Register 0x0020) according to
> + * IEEE 802.3 standards.
> + */

Please document the return value (0 = unchanged, 1 = changed, <0 errno), 
like
it is done for genphy_c45_an_config_aneg().

> +int genphy_c45_config_master_slave(struct phy_device *phydev)
> +{
> +	u16 val = 0;
> +
> +	switch (phydev->master_slave_set) {
> +	case MASTER_SLAVE_CFG_MASTER_FORCE:
> +		val = MDIO_AN_10GBT_CTRL_MS_ENABLE | MDIO_AN_10GBT_CTRL_MS_VALUE;
> +		break;
> +	case MASTER_SLAVE_CFG_SLAVE_FORCE:
> +		val = MDIO_AN_10GBT_CTRL_MS_ENABLE;
> +		break;
> +	case MASTER_SLAVE_CFG_UNKNOWN:
> +	case MASTER_SLAVE_CFG_MASTER_PREFERRED:
> +	case MASTER_SLAVE_CFG_SLAVE_PREFERRED:
> +	default:
> +		break;
> +	}

Per IEEE 802.3 (45.2.7.10.3), 7.32.13 (port type) is a copy of 9.10 /
CTL1000_PREFER_MASTER, like it is done in c22's 
genphy_setup_master_slave().

So set it for MASTER_PREFERRED, clear it for SLAVE_PREFERRED and leave 
UNKNOWN/UNSUPPORTED
untouched (return 0). Use -EOPNOTSUPP only for default.

> [...]

Thanks,
Nicolai