[PATCH V2 net-next 2/2] net: bgmac: support MDIO described in DT

["Rafał Miłecki" <zajec5@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

Check ethernet controller DT node for "mdio" subnode and use it with
of_mdiobus_register() when present. That allows specifying MDIO and its
PHY devices in a standard DT based way.

This is required for BCM53573 SoC support. That family is sometimes
called Northstar (by marketing?) but is quite different from it. It uses
different CPU(s) and many different hw blocks.

One of shared blocks in BCM53573 is Ethernet controller. Switch however
is not SRAB accessible (as it Northstar) but is MDIO attached.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
V2: Update commit message to reference BCM53573. I thought it's worth it
    after Florian's question.
    Florian suggested I may need of_node_put() but it doesn't seem that
    of_get_child_by_name() or of_mdiobus_register() inc. any refcount.
---
 drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c b/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
index 6ce80cbcb48e..086739e4f40a 100644
--- a/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
+++ b/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
@@ -10,6 +10,7 @@
 
 #include <linux/bcma/bcma.h>
 #include <linux/brcmphy.h>
+#include <linux/of_mdio.h>
 #include "bgmac.h"
 
 static bool bcma_mdio_wait_value(struct bcma_device *core, u16 reg, u32 mask,
@@ -211,6 +212,7 @@ struct mii_bus *bcma_mdio_mii_register(struct bgmac *bgmac)
 {
 	struct bcma_device *core = bgmac->bcma.core;
 	struct mii_bus *mii_bus;
+	struct device_node *np;
 	int err;
 
 	mii_bus = mdiobus_alloc();
@@ -229,7 +231,9 @@ struct mii_bus *bcma_mdio_mii_register(struct bgmac *bgmac)
 	mii_bus->parent = &core->dev;
 	mii_bus->phy_mask = ~(1 << bgmac->phyaddr);
 
-	err = mdiobus_register(mii_bus);
+	np = of_get_child_by_name(core->dev.of_node, "mdio");
+
+	err = of_mdiobus_register(mii_bus, np);
 	if (err) {
 		dev_err(&core->dev, "Registration of mii bus failed\n");
 		goto err_free_bus;
-- 
2.26.2