Subject: Re: [PATCH net-next 3/4] net: phy: Add helper to derive the number of ports from a phy mode

From: Andrew Lunn <[email-masked]>
Date: Thu, 28 Jul 2022 23:32:36 +0200

> +int phy_interface_num_ports(phy_interface_t interface)
> +{
> +	switch (interface) {
> +	case PHY_INTERFACE_MODE_NA:
> +	case PHY_INTERFACE_MODE_INTERNAL:
> +		return 0;

I've not yet looked at how this is used. Returning 0 could have
interesting effects i guess? INTERNAL clearly does have some sort of
path between the MAC and the PHY, so i think 1 would be a better
value. NA is less clear, it generally means Don't touch. But again,
there still needs to be a path between the MAC and PHY, otherwise
there would not be any to touch.

Why did you pick 0?

> +
> +	case PHY_INTERFACE_MODE_MII:
> +	case PHY_INTERFACE_MODE_GMII:
> +	case PHY_INTERFACE_MODE_TBI:
> +	case PHY_INTERFACE_MODE_REVMII:
> +	case PHY_INTERFACE_MODE_RMII:
> +	case PHY_INTERFACE_MODE_REVRMII:
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +	case PHY_INTERFACE_MODE_RTBI:
> +	case PHY_INTERFACE_MODE_XGMII:
> +	case PHY_INTERFACE_MODE_XLGMII:
> +	case PHY_INTERFACE_MODE_MOCA:
> +	case PHY_INTERFACE_MODE_TRGMII:
> +	case PHY_INTERFACE_MODE_USXGMII:
> +	case PHY_INTERFACE_MODE_SGMII:
> +	case PHY_INTERFACE_MODE_SMII:
> +	case PHY_INTERFACE_MODE_1000BASEX:
> +	case PHY_INTERFACE_MODE_2500BASEX:
> +	case PHY_INTERFACE_MODE_5GBASER:
> +	case PHY_INTERFACE_MODE_10GBASER:
> +	case PHY_INTERFACE_MODE_25GBASER:
> +	case PHY_INTERFACE_MODE_10GKR:
> +	case PHY_INTERFACE_MODE_100BASEX:
> +	case PHY_INTERFACE_MODE_RXAUI:
> +	case PHY_INTERFACE_MODE_XAUI:
> +		return 1;
> +	case PHY_INTERFACE_MODE_QSGMII:
> +	case PHY_INTERFACE_MODE_QUSGMII:
> +		return 4;
> +
> +	default:
> +		return 0;
> +	}
> +}

Have you tried without a default: ? I _think_ gcc will then warn about
missing enum values, which will help future developers when they add
further values to the enum.

	Andrew