[PATCH net-next 12/17] net: dsa: Make mdio bus optional

[Andrew Lunn]

The switch may want to instantiate its own MDIO bus. Only do it
centrally if the switch has not already created one, and the read op
is implemented.

Signed-off-by: Andrew Lunn <and...@lunn.ch>
---
 net/dsa/dsa.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 221ebde4318d..6c314f300424 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -340,17 +340,18 @@ static int dsa_switch_setup_one(struct dsa_switch *ds, 
struct device *parent)
        if (ret < 0)
                goto out;
 
-       ds->slave_mii_bus = devm_mdiobus_alloc(parent);
-       if (ds->slave_mii_bus == NULL) {
-               ret = -ENOMEM;
-               goto out;
-       }
-       dsa_slave_mii_bus_init(ds);
-
-       ret = mdiobus_register(ds->slave_mii_bus);
-       if (ret < 0)
-               goto out;
+       if (!ds->slave_mii_bus && drv->phy_read) {
+               ds->slave_mii_bus = devm_mdiobus_alloc(parent);
+               if (!ds->slave_mii_bus) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               dsa_slave_mii_bus_init(ds);
 
+               ret = mdiobus_register(ds->slave_mii_bus);
+               if (ret < 0)
+                       goto out;
+       }
 
        /*
         * Create network devices for physical switch ports.
@@ -493,7 +494,8 @@ static void dsa_switch_destroy(struct dsa_switch *ds)
                dsa_cpu_dsa_destroy(ds->ports[port].dn);
        }
 
-       mdiobus_unregister(ds->slave_mii_bus);
+       if (ds->slave_mii_bus && ds->drv->phy_read)
+               mdiobus_unregister(ds->slave_mii_bus);
 }
 
 #ifdef CONFIG_PM_SLEEP
-- 
2.8.1