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Date:   Thu, 28 Jul 2022 14:44:47 -0700
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Subject: Re: [PATCH net-next 3/4] net: phy: Add helper to derive the number of
 ports from a phy mode
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To:     Andrew Lunn <andrew@lunn.ch>,
        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,
        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
References: <20220728145252.439201-1-maxime.chevallier@bootlin.com>
 <20220728145252.439201-4-maxime.chevallier@bootlin.com>
 <YuMAdACnRKsL8/xD@lunn.ch>
From:   Florian Fainelli <f.fainelli@gmail.com>
In-Reply-To: <YuMAdACnRKsL8/xD@lunn.ch>
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On 7/28/22 14:32, Andrew Lunn wrote:
>> +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?

I would agree that returning 1 is a more sensible default to avoid breaking users of that function. However this makes me wonder, in what case will we break the following common meaning:

- Q -> quad
- P -> penta
- O -> octal

Is the helper really needed in the sense that the phy_interface_t enumeration is explicit enough thanks to or because of its name?
--
Florian