[PATCH net-next 2/5] net: dsa: mark DSA phylink as legacy_pre_march2020

[Russell King (Oracle)]

The majority of DSA drivers do not make use of the PCS support, and
thus operate in legacy mode. In order to preserve this behaviour in
future, we need to set the legacy_pre_march2020 flag so phylink knows
this may require the legacy calls.

There are some DSA drivers that do make use of PCS support, and these
will continue operating as before - legacy_pre_march2020 will not
prevent split-PCS support enabling the newer phylink behaviour.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
Resent with the correct cover-letter message-ID.

 net/dsa/port.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/dsa/port.c b/net/dsa/port.c
index 6d5ebe61280b..3b8d18e5b72c 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -1094,6 +1094,13 @@ int dsa_port_phylink_create(struct dsa_port *dp)
 	if (err)
 		mode = PHY_INTERFACE_MODE_NA;
 
+	/* Presence of phylink_mac_link_state or phylink_mac_an_restart is
+	 * an indicator of a legacy phylink driver.
+	 */
+	if (ds->ops->phylink_mac_link_state ||
+	    ds->ops->phylink_mac_an_restart)
+		dp->pl_config.legacy_pre_march2020 = true;
+
 	if (ds->ops->phylink_get_caps)
 		ds->ops->phylink_get_caps(ds, dp->index, &dp->pl_config);
 
-- 
2.30.2