[PATCHv2 1/3] net: phy: prevent linking breakage

[Alexandre Belloni]

phy_register_fixup{,_for_uid,_for_id} are called from arch/, quite
often, there is no protection to check whether CONFIG_PHYLIB=y which is
the only case where this would work. Having phylib as a module or not
compiled at all will result in that kind of linking failure:

arch/arm/mach-at91/built-in.o: In function `ksz9021rn_phy_fixup':
:(.text+0x1174): undefined reference to `mdiobus_write'
:(.text+0x1188): undefined reference to `mdiobus_write'
:(.text+0x119c): undefined reference to `mdiobus_write'
:(.text+0x11b0): undefined reference to `mdiobus_write'
arch/arm/mach-at91/built-in.o: In function `sama5_dt_device_init':
:(.init.text+0x1e34): undefined reference to `phy_register_fixup_for_uid'

Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
---
 drivers/net/phy/phy_device.c |  6 ++++++
 include/linux/phy.h          | 33 ++++++++++++++++++++++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3657b4a..df36367 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -64,6 +64,11 @@ static int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 			     u32 flags, phy_interface_t interface);
 
 /*
+ *  phy_register_fixup{,_for_uid,_for_id} are called from arch/ so this won't
+ *  work unless phylib is compiled in the kernel.
+ */
+#ifdef CONFIG_PHYLIB
+/*
  * Creates a new phy_fixup and adds it to the list
  * @bus_id: A string which matches phydev->dev.bus_id (or PHY_ANY_ID)
  * @phy_uid: Used to match against phydev->phy_id (the UID of the PHY)
@@ -109,6 +114,7 @@ int phy_register_fixup_for_id(const char *bus_id,
 	return phy_register_fixup(bus_id, PHY_ANY_UID, 0xffffffff, run);
 }
 EXPORT_SYMBOL(phy_register_fixup_for_id);
+#endif /* CONFIG_PHYLIB */
 
 /*
  * Returns 1 if fixup matches phydev in bus_id and phy_uid.
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 9e11039..2cc3383 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -556,12 +556,39 @@ int phy_start_interrupts(struct phy_device *phydev);
 void phy_print_status(struct phy_device *phydev);
 void phy_device_free(struct phy_device *phydev);
 
+/*
+ *  phy_register_fixup{,_for_uid,_for_id} are called from arch/ so this won't
+ *  work unless phylib is compiled in the kernel.
+ *  Defining stubs allows to prevent linking errors.
+ */
+#ifdef CONFIG_PHYLIB
 int phy_register_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask,
-		int (*run)(struct phy_device *));
+		       int (*run)(struct phy_device *));
 int phy_register_fixup_for_id(const char *bus_id,
-		int (*run)(struct phy_device *));
+			      int (*run)(struct phy_device *));
 int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask,
-		int (*run)(struct phy_device *));
+			       int (*run)(struct phy_device *));
+#else
+static inline int phy_register_fixup(const char *bus_id, u32 phy_uid,
+				     u32 phy_uid_mask,
+				     int (*run)(struct phy_device *))
+{
+	return -ENOTSUPP;
+}
+
+static inline int phy_register_fixup_for_id(const char *bus_id,
+					    int (*run)(struct phy_device *))
+{
+	return -ENOTSUPP;
+}
+
+static inline int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask,
+					     int (*run)(struct phy_device *))
+{
+	return -ENOTSUPP;
+}
+#endif /* CONFIG_PHYLIB */
+
 int phy_scan_fixups(struct phy_device *phydev);
 
 int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable);
-- 
1.8.1.2