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Date:   Thu, 28 Jul 2022 23:32:36 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     davem@davemloft.net, Rob Herring <robh+dt@kernel.org>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, thomas.petazzoni@bootlin.com,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org, Horatiu.Vultur@microchip.com,
        Allan.Nielsen@microchip.com, UNGLinuxDriver@microchip.com
Subject: Re: [PATCH net-next 3/4] net: phy: Add helper to derive the number
 of ports from a phy mode
Message-ID: <YuMAdACnRKsL8/xD@lunn.ch>
References: <20220728145252.439201-1-maxime.chevallier@bootlin.com>
 <20220728145252.439201-4-maxime.chevallier@bootlin.com>
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> +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