Re: [PATCH net-next 04/11] net: stmmac: add stmmac_get_phy_intf_sel()

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi Russell,

On 03/11/2025 12:50, Russell King (Oracle) wrote:
> Provide a function to translate the PHY interface mode to the
> phy_intf_sel pin configuration for dwmac1000 and dwmac4 cores that
> support multiple interfaces. We currently handle MII, GMII, RGMII,
> SGMII, RMII and REVMII, but not TBI, RTBI nor SMII as drivers do not
> appear to use these three and the driver doesn't currently support
> these.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

First, thanks for this work !

[...]

> +int stmmac_get_phy_intf_sel(phy_interface_t interface)
> +{
> +	int phy_intf_sel = -EINVAL;
> +
> +	if (interface == PHY_INTERFACE_MODE_MII ||
> +	    interface == PHY_INTERFACE_MODE_GMII)
> +		phy_intf_sel = PHY_INTF_SEL_GMII_MII;
> +	else if (phy_interface_mode_is_rgmii(interface))
> +		phy_intf_sel = PHY_INTF_SEL_RGMII;
> +	else if (interface == PHY_INTERFACE_MODE_SGMII)
> +		phy_intf_sel = PHY_INTF_SEL_SGMII;
> +	else if (interface == PHY_INTERFACE_MODE_RMII)
> +		phy_intf_sel = PHY_INTF_SEL_RMII;
> +	else if (interface == PHY_INTERFACE_MODE_REVMII)
> +		phy_intf_sel = PHY_INTF_SEL_REVMII;
> +
> +	return phy_intf_sel;
> +}
> +EXPORT_SYMBOL_GPL(stmmac_get_phy_intf_sel);

Nothng wrong with your code, this is out of curiosity.

I'm wondering how we are going to support cases like socfpga (and
probably some other) where the PHY_INTF_SEL_xxx doesn't directly
translate to the phy_interface, i.e.  when you have a PCS or other
IP that serialises the MAC interface ?

for socfpga for example, we need to set the PHY_INTF_SEL to GMII_MII
when we want to use SGMII / 1000BaseX, but we do set it to RGMII when
we need to output RGMII.

Do you have a plan in mind for that ? (maybe a .get_phy_intf_sel() ops ?)

Maxime