[PATCH net-next] net: dsa: mt7530: do not set MT7530_P5_DIS when PHY muxing is being used

[Andrew Lunn]

On Sat, Apr 27, 2024 at 02:24:42PM +0300, Arınç ÜNAL via B4 Relay wrote:
> From: Arınç ÜNAL <arinc.unal at arinc9.com>
> 
> When the PHY muxing feature is in use, port 5 won't be defined in the
> device tree. Because of this, the type member of the dsa_port structure for
> this port will be assigned DSA_PORT_TYPE_UNUSED. The dsa_port_setup()
> function calls ds->ops->port_disable() when the port type is
> DSA_PORT_TYPE_UNUSED.
> 
> The MT7530_P5_DIS bit is unset when PHY muxing is being used.
> mt7530_port_disable() which is assigned to ds->ops->port_disable() is
> called afterwards. Currently, mt7530_port_disable() sets MT7530_P5_DIS
> which breaks network connectivity when PHY muxing is being used.
> 
> Therefore, do not set MT7530_P5_DIS when PHY muxing is being used.
> 
> Fixes: 377174c5760c ("net: dsa: mt7530: move MT753X_MTRAP operations for MT7530")
> Reported-by: Daniel Golle <daniel at makrotopia.org>
> Signed-off-by: Arınç ÜNAL <arinc.unal at arinc9.com>
> ---
> Hello.
> 
> I've sent this to net-next as the patch it fixes is on the current
> development cycle.
> ---
>  drivers/net/dsa/mt7530.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 2b9f904a98f0..07b6da3ae97c 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1220,7 +1220,7 @@ mt7530_port_disable(struct dsa_switch *ds, int port)
>  	if (priv->id != ID_MT7530 && priv->id != ID_MT7621)
>  		return;
>  
> -	if (port == 5)
> +	if (port == 5 && priv->p5_mode == GMAC5)
>  		mt7530_set(priv, MT753X_MTRAP, MT7530_P5_DIS);


It might be worth a comment. It is not obvious that
priv->p5_mode == GMAC5 means the PHY MUX is being used.
mt7530_setup_port5() thinks it is sufficiently obscure that
it comments each case.

	Andrew