netdev - Re: [PATCH net-next 10/24] net: dsa: mt7530: empty default case on mt7530_setup

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Message-ID: <ZEfuIHET4Nva0hj4@makrotopia.org>
Date:   Tue, 25 Apr 2023 16:13:36 +0100
From:   Daniel Golle <daniel@...rotopia.org>
To:     arinc9.unal@...il.com
Cc:     Sean Wang <sean.wang@...iatek.com>,
        Landen Chao <Landen.Chao@...iatek.com>,
        DENG Qingfang <dqfext@...il.com>, Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Russell King <linux@...linux.org.uk>,
        Arınç ÜNAL <arinc.unal@...nc9.com>,
        Richard van Schagen <richard@...terhints.com>,
        Richard van Schagen <vschagen@...com>,
        Frank Wunderlich <frank-w@...lic-files.de>,
        Bartel Eerdekens <bartel.eerdekens@...stell8.be>,
        erkin.bozoglu@...ont.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH net-next 10/24] net: dsa: mt7530: empty default case on
 mt7530_setup_port5()

On Tue, Apr 25, 2023 at 11:29:19AM +0300, arinc9.unal@...il.com wrote:
> From: Arınç ÜNAL <arinc.unal@...nc9.com>
> 
> There're two code paths for setting up port 5:
> 
> mt7530_setup()
> -> mt7530_setup_port5()
> 
> mt753x_phylink_mac_config()
> -> mt753x_mac_config()
>    -> mt7530_mac_config()
>       -> mt7530_setup_port5()
> 
> On the first code path, priv->p5_intf_sel is either set to
> P5_INTF_SEL_PHY_P0 or P5_INTF_SEL_PHY_P4 when mt7530_setup_port5() is run.
> 
> On the second code path, priv->p5_intf_sel is set to P5_INTF_SEL_GMAC5 when
> mt7530_setup_port5() is run.
> 
> Empty the default case which will never run but is needed nonetheless to
> handle all the remaining enumeration values.

If the default: case is really just unreachable code because of the
sound reasoning you presented above, then you should just remove it.

> 
> Tested-by: Arınç ÜNAL <arinc.unal@...nc9.com>
> Signed-off-by: Arınç ÜNAL <arinc.unal@...nc9.com>
> ---
>  drivers/net/dsa/mt7530.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index aab9ebb54d7d..b3db68d6939a 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -933,9 +933,7 @@ static void mt7530_setup_port5(struct dsa_switch *ds, phy_interface_t interface)
>  		val &= ~MHWTRAP_P5_DIS;
>  		break;
>  	default:
> -		dev_err(ds->dev, "Unsupported p5_intf_sel %d\n",
> -			priv->p5_intf_sel);
> -		goto unlock_exit;
> +		break;

I suppose you can also rather just remove the default: case alltogether
instead of keeping it and making it a no-op.

>  	}
>  
>  	/* Setup RGMII settings */
> @@ -965,7 +963,6 @@ static void mt7530_setup_port5(struct dsa_switch *ds, phy_interface_t interface)
>  	dev_dbg(ds->dev, "Setup P5, HWTRAP=0x%x, intf_sel=%s, phy-mode=%s\n",
>  		val, p5_intf_modes(priv->p5_intf_sel), phy_modes(interface));
>  
> -unlock_exit:
>  	mutex_unlock(&priv->reg_mutex);
>  }
>  
> -- 
> 2.37.2
>