Re: [PATCH net-next v2 10/10] net: stmmac: Add DW XPCS specified via "pcs-handle" support

[Serge Semin]

On Sun, Jun 02, 2024 at 05:36:24PM +0300, Serge Semin wrote:
> Recently the DW XPCS DT-bindings have been introduced and the DW XPCS
> driver has been altered to support the DW XPCS registered as a platform
> device. In order to have the DW XPCS DT-device accessed from the STMMAC
> driver let's alter the STMMAC PCS-setup procedure to support the
> "pcs-handle" property containing the phandle reference to the DW XPCS
> device DT-node. The respective fwnode will be then passed to the
> xpcs_create_fwnode() function which in its turn will create the DW XPCS
> descriptor utilized in the main driver for the PCS-related setups.
> 
> Signed-off-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index 807789d7309a..dc040051aa53 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -497,15 +497,22 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>  
>  int stmmac_pcs_setup(struct net_device *ndev)
>  {
> +	struct fwnode_handle *devnode, *pcsnode;
>  	struct dw_xpcs *xpcs = NULL;
>  	struct stmmac_priv *priv;
>  	int addr, mode, ret;
>  
>  	priv = netdev_priv(ndev);
>  	mode = priv->plat->phy_interface;
> +	devnode = priv->plat->port_node;
>  
>  	if (priv->plat->pcs_init) {
>  		ret = priv->plat->pcs_init(priv);

> +	} else if (fwnode_property_present(devnode, "pcs-handle")) {
> +		pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0);
> +		xpcs = xpcs_create_fwnode(pcsnode, mode);
> +		fwnode_handle_put(pcsnode);
> +		ret = PTR_ERR_OR_ZERO(xpcs);

Just figured, we might wish to be a bit more portable in the
"pcs-handle" property semantics implementation seeing there can be at
least three different PCS attached:
DW XPCS
Lynx PCS
Renesas RZ/N1 MII

Any suggestion of how to distinguish the passed handle? Perhaps
named-property, phandle argument, by the compatible string or the
node-name?

-Serge(y)

>  	} else if (priv->plat->mdio_bus_data &&
>  		   priv->plat->mdio_bus_data->has_xpcs) {
>  		addr = priv->plat->mdio_bus_data->xpcs_addr;
> @@ -515,10 +522,8 @@ int stmmac_pcs_setup(struct net_device *ndev)
>  		return 0;
>  	}
>  
> -	if (ret) {
> -		dev_warn(priv->device, "No xPCS found\n");
> -		return ret;
> -	}
> +	if (ret)
> +		return dev_err_probe(priv->device, ret, "No xPCS found\n");
>  
>  	priv->hw->xpcs = xpcs;
>  
> -- 
> 2.43.0
>