mdio: mux: Enhanced MDIO mux framework for integrated multiplexers

An integrated multiplexer uses same address space for
"muxed bus selection" and "generation of mdio transaction"
hence its good to register parent bus from mux driver.

Hence added a mechanism where mux driver could register a
parent bus and pass it down to framework via mdio_mux_init api.

Signed-off-by: Pramod Kumar <pramod.kumar@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 10 deletions

diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
index 5c81d6faf304..dbd4ecc205dc 100644
--- a/drivers/net/phy/mdio-mux.c
+++ b/drivers/net/phy/mdio-mux.c
@@ -89,7 +89,8 @@ static int parent_count;
 int mdio_mux_init(struct device *dev,
                   int (*switch_fn)(int cur, int desired, void *data),
                   void **mux_handle,
-                  void *data)
+                  void *data,
+                  struct mii_bus *mux_bus)
 {
         struct device_node *parent_bus_node;
         struct device_node *child_bus_node;
@@ -101,10 +102,21 @@ int mdio_mux_init(struct device *dev,
         if (!dev->of_node)
                 return -ENODEV;
 
-        parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
+        if (!mux_bus) {
+                parent_bus_node = of_parse_phandle(dev->of_node,
+                                                   "mdio-parent-bus", 0);
 
-        if (!parent_bus_node)
-                return -ENODEV;
+                if (!parent_bus_node)
+                        return -ENODEV;
+
+                parent_bus = of_mdio_find_bus(parent_bus_node);
+                if (!parent_bus) {
+                        ret_val = -EPROBE_DEFER;
+                        goto err_parent_bus;
+                }
+        } else {
+                parent_bus = mux_bus;
+        }
 
         pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
         if (pb == NULL) {
@@ -112,11 +124,6 @@ int mdio_mux_init(struct device *dev,
                 goto err_parent_bus;
         }
 
-        parent_bus = of_mdio_find_bus(parent_bus_node);
-        if (parent_bus == NULL) {
-                ret_val = -EPROBE_DEFER;
-                goto err_parent_bus;
-        }
 
         pb->switch_data = data;
         pb->switch_fn = switch_fn;
@@ -177,7 +184,8 @@ int mdio_mux_init(struct device *dev,
         put_device(&pb->mii_bus->dev);
 
 err_parent_bus:
-        of_node_put(parent_bus_node);
+        if (!mux_bus)
+                of_node_put(parent_bus_node);
         return ret_val;
 }
 EXPORT_SYMBOL_GPL(mdio_mux_init);