net: dsa: add support for phylink mac_select_pcs()

Add DSA support for the phylink mac_select_pcs() method so DSA drivers
can return provide phylink with the appropriate PCS for the PHY
interface mode.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -788,6 +788,9 @@ struct dsa_switch_ops {
 	void	(*phylink_validate)(struct dsa_switch *ds, int port,
 				    unsigned long *supported,
 				    struct phylink_link_state *state);
+	struct phylink_pcs *(*phylink_mac_select_pcs)(struct dsa_switch *ds,
+						      int port,
+						      phy_interface_t iface);
 	int	(*phylink_mac_link_state)(struct dsa_switch *ds, int port,
 					  struct phylink_link_state *state);
 	void	(*phylink_mac_config)(struct dsa_switch *ds, int port,

net/dsa/port.c

@@ -1053,6 +1053,20 @@ static void dsa_port_phylink_mac_pcs_get_state(struct phylink_config *config,
 	}
 }
 
+static struct phylink_pcs *
+dsa_port_phylink_mac_select_pcs(struct phylink_config *config,
+				phy_interface_t interface)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+	struct phylink_pcs *pcs = NULL;
+
+	if (ds->ops->phylink_mac_select_pcs)
+		pcs = ds->ops->phylink_mac_select_pcs(ds, dp->index, interface);
+
+	return pcs;
+}
+
 static void dsa_port_phylink_mac_config(struct phylink_config *config,
 					unsigned int mode,
 					const struct phylink_link_state *state)
@@ -1119,6 +1133,7 @@ static void dsa_port_phylink_mac_link_up(struct phylink_config *config,
 
 static const struct phylink_mac_ops dsa_port_phylink_mac_ops = {
 	.validate = dsa_port_phylink_validate,
+	.mac_select_pcs = dsa_port_phylink_mac_select_pcs,
 	.mac_pcs_get_state = dsa_port_phylink_mac_pcs_get_state,
 	.mac_config = dsa_port_phylink_mac_config,
 	.mac_an_restart = dsa_port_phylink_mac_an_restart,