net: phylink: rename mac_link_state() op to mac_pcs_get_state()

Rename the mac_link_state() method to mac_pcs_get_state() to make it
clear that it should be returning the MACs PCS current state, which
is used for inband negotiation rather than just reading back what the
MAC has been configured for. Update the documentation to explicitly
mention that this is for inband.

We drop the return value as well; most of phylink doesn't check the
return value and it is not clear what it should do on error - instead
arrange for state->link to be false.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 6e93c36..46ac9ba 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -429,19 +429,22 @@ void dsa_port_phylink_validate(struct phylink_config *config,
 }
 EXPORT_SYMBOL_GPL(dsa_port_phylink_validate);
 
-int dsa_port_phylink_mac_link_state(struct phylink_config *config,
-				    struct phylink_link_state *state)
+void dsa_port_phylink_mac_pcs_get_state(struct phylink_config *config,
+					struct phylink_link_state *state)
 {
 	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
 	struct dsa_switch *ds = dp->ds;
 
-	/* Only called for SGMII and 802.3z */
-	if (!ds->ops->phylink_mac_link_state)
-		return -EOPNOTSUPP;
+	/* Only called for inband modes */
+	if (!ds->ops->phylink_mac_link_state) {
+		state->link = 0;
+		return;
+	}
 
-	return ds->ops->phylink_mac_link_state(ds, dp->index, state);
+	if (ds->ops->phylink_mac_link_state(ds, dp->index, state) < 0)
+		state->link = 0;
 }
-EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_link_state);
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_pcs_get_state);
 
 void dsa_port_phylink_mac_config(struct phylink_config *config,
 				 unsigned int mode,
@@ -510,7 +513,7 @@ EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_link_up);
 
 const struct phylink_mac_ops dsa_port_phylink_mac_ops = {
 	.validate = dsa_port_phylink_validate,
-	.mac_link_state = dsa_port_phylink_mac_link_state,
+	.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,
 	.mac_link_down = dsa_port_phylink_mac_link_down,