net: davinci_mdio: allow to create phys from dt

This patch allows to create PHYs from DT in case
if they are explicitly defined. The of_mdiobus_register() is
used for such purposes.

For backward compatibility, call  of_mdiobus_register() only in case
if at least one PHY's child is defined in DT, otherwise rollback to
mdiobus_register().

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 2 deletions

diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c
index 735dc53d4b01..2791f6f2db11 100644
--- a/drivers/net/ethernet/ti/davinci_mdio.c
+++ b/drivers/net/ethernet/ti/davinci_mdio.c
@@ -38,6 +38,7 @@
 #include <linux/davinci_emac.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_mdio.h>
 #include <linux/pinctrl/consumer.h>
 
 /*
@@ -95,6 +96,10 @@ struct davinci_mdio_data {
         struct mii_bus  *bus;
         bool            suspended;
         unsigned long   access_time; /* jiffies */
+        /* Indicates that driver shouldn't modify phy_mask in case
+         * if MDIO bus is registered from DT.
+         */
+        bool            skip_scan;
 };
 
 static void __davinci_mdio_reset(struct davinci_mdio_data *data)
@@ -144,6 +149,9 @@ static int davinci_mdio_reset(struct mii_bus *bus)
         dev_info(data->dev, "davinci mdio revision %d.%d\n",
                  (ver >> 8) & 0xff, ver & 0xff);
 
+        if (data->skip_scan)
+                return 0;
+
         /* get phy mask from the alive register */
         phy_mask = __raw_readl(&data->regs->alive);
         if (phy_mask) {
@@ -369,8 +377,17 @@ static int davinci_mdio_probe(struct platform_device *pdev)
                 goto bail_out;
         }
 
-        /* register the mii bus */
-        ret = mdiobus_register(data->bus);
+        /* register the mii bus
+         * Create PHYs from DT only in case if PHY child nodes are explicitly
+         * defined to support backward compatibility with DTs which assume that
+         * Davinci MDIO will always scan the bus for PHYs detection.
+         */
+        if (dev->of_node && of_get_child_count(dev->of_node)) {
+                data->skip_scan = true;
+                ret = of_mdiobus_register(data->bus, dev->of_node);
+        } else {
+                ret = mdiobus_register(data->bus);
+        }
         if (ret)
                 goto bail_out;