1 files changed, 26 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/fsl_soc.c b/arch/powerpc/sysdev/fsl_soc.c
index 01b884b25696..26ecb96f9731 100644
--- a/arch/powerpc/sysdev/fsl_soc.c
+++ b/arch/powerpc/sysdev/fsl_soc.c
@@ -223,6 +223,8 @@ static int gfar_mdio_of_init_one(struct device_node *np)
         if (ret)
                 return ret;
 
+        /* The gianfar device will try to use the same ID created below to find
+         * this bus, to coordinate register access (since they share).  */
         mdio_dev = platform_device_register_simple("fsl-gianfar_mdio",
                         res.start&0xfffff, &res, 1);
         if (IS_ERR(mdio_dev))
@@ -394,6 +396,30 @@ static int __init gfar_of_init(void)
                         of_node_put(mdio);
                 }
 
+                /* Get MDIO bus controlled by this eTSEC, if any.  Normally only
+                 * eTSEC 1 will control an MDIO bus, not necessarily the same
+                 * bus that its PHY is on ('mdio' above), so we can't just use
+                 * that.  What we do is look for a gianfar mdio device that has
+                 * overlapping registers with this device.  That's really the
+                 * whole point, to find the device sharing our registers to
+                 * coordinate access with it.
+                 */
+                for_each_compatible_node(mdio, NULL, "fsl,gianfar-mdio") {
+                        if (of_address_to_resource(mdio, 0, &res))
+                                continue;
+
+                        if (res.start >= r[0].start && res.end <= r[0].end) {
+                                /* Get the ID the mdio bus platform device was
+                                 * registered with.  gfar_data.bus_id is
+                                 * different because it's for finding a PHY,
+                                 * while this is for finding a MII bus.
+                                 */
+                                gfar_data.mdio_bus = res.start&0xfffff;
+                                of_node_put(mdio);
+                                break;
+                        }
+                }
+
                 ret =
                     platform_device_add_data(gfar_dev, &gfar_data,
                                              sizeof(struct