net: phy: Add general dummy stubs for MMD register access

For some phy devices, even though they don't support the MMD extended
register access, it does have some side effect if we are trying to
read/write the MMD registers via indirect method. So introduce general
dummy stubs for MMD register access which these devices can use to avoid
such side effect.

Fixes: b6b5e8a69118 ("gianfar: Disable EEE autoneg by default")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index fe16f58940922395871fbd0afaee731a82e9819c..74664a6c0cdc31092e9aee5f189ac053d116846e 100644 (file)
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1673,6 +1673,23 @@ int genphy_config_init(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(genphy_config_init);
 
+/* This is used for the phy device which doesn't support the MMD extended
+ * register access, but it does have side effect when we are trying to access
+ * the MMD register via indirect method.
+ */
+int genphy_read_mmd_unsupported(struct phy_device *phdev, int devad, u16 regnum)
+{
+       return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(genphy_read_mmd_unsupported);
+
+int genphy_write_mmd_unsupported(struct phy_device *phdev, int devnum,
+                                u16 regnum, u16 val)
+{
+       return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(genphy_write_mmd_unsupported);
+
 int genphy_suspend(struct phy_device *phydev)
 {
        return phy_set_bits(phydev, MII_BMCR, BMCR_PDOWN);

diff --git a/include/linux/phy.h b/include/linux/phy.h
index b260fb336b25d0346b62e913846047b84aff291f..7c4c2379e0103186258b6ec26441411d5cb84d13 100644 (file)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -984,6 +984,10 @@ static inline int genphy_no_soft_reset(struct phy_device *phydev)
 {
        return 0;
 }
+int genphy_read_mmd_unsupported(struct phy_device *phdev, int devad,
+                               u16 regnum);
+int genphy_write_mmd_unsupported(struct phy_device *phdev, int devnum,
+                                u16 regnum, u16 val);
 
 /* Clause 45 PHY */
 int genphy_c45_restart_aneg(struct phy_device *phydev);