net: phy: extend fixed driver with fixed_phy_register()

The existing fixed_phy_add() function has several drawbacks that
prevents it from being used as is for OF-based declaration of fixed
PHYs:

 * The address of the PHY on the fake bus needs to be passed, while a
   dynamic allocation is desired.

 * Since the phy_device instantiation is post-poned until the next
   mdiobus scan, there is no way to associate the fixed PHY with its
   OF node, which later prevents of_phy_connect() from finding this
   fixed PHY from a given OF node.

To solve this, this commit introduces fixed_phy_register(), which will
allocate an available PHY address, add the PHY using fixed_phy_add()
and instantiate the phy_device structure associated with the provided
OF node.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 72 insertions, 0 deletions

diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
index e41546da105e..d60d875cb445 100644
--- a/drivers/net/phy/fixed.c
+++ b/drivers/net/phy/fixed.c
@@ -21,6 +21,7 @@
 #include <linux/phy_fixed.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #define MII_REGS_NUM 29
 
@@ -203,6 +204,66 @@ err_regs:
 }
 EXPORT_SYMBOL_GPL(fixed_phy_add);
 
+void fixed_phy_del(int phy_addr)
+{
+        struct fixed_mdio_bus *fmb = &platform_fmb;
+        struct fixed_phy *fp, *tmp;
+
+        list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
+                if (fp->addr == phy_addr) {
+                        list_del(&fp->node);
+                        kfree(fp);
+                        return;
+                }
+        }
+}
+EXPORT_SYMBOL_GPL(fixed_phy_del);
+
+static int phy_fixed_addr;
+static DEFINE_SPINLOCK(phy_fixed_addr_lock);
+
+int fixed_phy_register(unsigned int irq,
+                       struct fixed_phy_status *status,
+                       struct device_node *np)
+{
+        struct fixed_mdio_bus *fmb = &platform_fmb;
+        struct phy_device *phy;
+        int phy_addr;
+        int ret;
+
+        /* Get the next available PHY address, up to PHY_MAX_ADDR */
+        spin_lock(&phy_fixed_addr_lock);
+        if (phy_fixed_addr == PHY_MAX_ADDR) {
+                spin_unlock(&phy_fixed_addr_lock);
+                return -ENOSPC;
+        }
+        phy_addr = phy_fixed_addr++;
+        spin_unlock(&phy_fixed_addr_lock);
+
+        ret = fixed_phy_add(PHY_POLL, phy_addr, status);
+        if (ret < 0)
+                return ret;
+
+        phy = get_phy_device(fmb->mii_bus, phy_addr, false);
+        if (!phy || IS_ERR(phy)) {
+                fixed_phy_del(phy_addr);
+                return -EINVAL;
+        }
+
+        of_node_get(np);
+        phy->dev.of_node = np;
+
+        ret = phy_device_register(phy);
+        if (ret) {
+                phy_device_free(phy);
+                of_node_put(np);
+                fixed_phy_del(phy_addr);
+                return ret;
+        }
+
+        return 0;
+}
+
 static int __init fixed_mdio_bus_init(void)
 {
         struct fixed_mdio_bus *fmb = &platform_fmb;
diff --git a/include/linux/phy_fixed.h b/include/linux/phy_fixed.h
index 509d8f5f984e..4f2478b47136 100644
--- a/include/linux/phy_fixed.h
+++ b/include/linux/phy_fixed.h
@@ -9,15 +9,26 @@ struct fixed_phy_status {
         int asym_pause;
 };
 
+struct device_node;
+
 #ifdef CONFIG_FIXED_PHY
 extern int fixed_phy_add(unsigned int irq, int phy_id,
                          struct fixed_phy_status *status);
+extern int fixed_phy_register(unsigned int irq,
+                              struct fixed_phy_status *status,
+                              struct device_node *np);
 #else
 static inline int fixed_phy_add(unsigned int irq, int phy_id,
                                 struct fixed_phy_status *status)
 {
         return -ENODEV;
 }
+static inline int fixed_phy_register(unsigned int irq,
+                                     struct fixed_phy_status *status,
+                                     struct device_node *np)
+{
+        return -ENODEV;
+}
 #endif /* CONFIG_FIXED_PHY */
 
 /*