Re: [PATCH net-next 10/24] net: dsa: mt7530: empty default case on mt7530_setup_port5()

[Arınç ÜNAL]

On 25.04.2023 18:13, Daniel Golle wrote:
> On Tue, Apr 25, 2023 at 11:29:19AM +0300, arinc9.unal@xxxxxxxxx wrote:
> > From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> >
> > 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.

The compiler prints warnings if all enumeration values are not handled.

  CC      drivers/net/dsa/mt7530.o
  CC      drivers/net/dsa/mt7530-mdio.o
  CC      drivers/net/dsa/mt7530-mmio.o
drivers/net/dsa/mt7530.c: In function ‘mt7530_setup_port5’:
drivers/net/dsa/mt7530.c:919:9: warning: enumeration value ‘P5_DISABLED’ 
not handled in switch [-Wswitch]
  919 |         switch (priv->p5_intf_sel) {
      |         ^~~~~~

> > Tested-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > ---
> >   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.

I make use of the default case with ("net: dsa: mt7530: rename 
p5_intf_sel and use only for MT7530 switch") so I'd rather keep this.

Arınç