net: phy: smsc: Re-enable EDPD mode for LAN87xx

This patch re-enables Energy Detect Power Down (EDPD) mode for the
LAN8710/LAN8720.  EDPD mode was disabled in a previous commit,
(b629820d18fa65cc598390e4b9712fd5f83ee693), because it was causing the
PHY to not be able to detect a link when cold started without a cable
connected.

The LAN8710/LAN8720 requires a minimum of 2 link pulses within 64ms of
each other in order to set the ENERGYON bit and exit EDPD mode.  If a
link partner does send the pulses within this interval, the PHY will
remained powered down.

This workaround will manually toggle the PHY on/off upon calls to
read_status in order to generate link test pulses if the link is down.
If a link partner is present, it will respond to the pulses, which will
cause the ENERGYON bit to be set and will cause the EDPD mode to be
exited.

Signed-off-by: Patrick Trantham <patrick.trantham@fuel7.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 26 deletions

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index 88e3991464e7..16dceed29d8c 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -56,35 +56,52 @@ static int smsc_phy_config_init(struct phy_device *phydev)
         return smsc_phy_ack_interrupt (phydev);
 }
 
-static int lan87xx_config_init(struct phy_device *phydev)
+static int lan911x_config_init(struct phy_device *phydev)
 {
-        /*
-         * Make sure the EDPWRDOWN bit is NOT set. Setting this bit on
-         * LAN8710/LAN8720 PHY causes the PHY to misbehave, likely due
-         * to a bug on the chip.
-         *
-         * When the system is powered on with the network cable being
-         * disconnected all the way until after ifconfig ethX up is
-         * issued for the LAN port with this PHY, connecting the cable
-         * afterwards does not cause LINK change detection, while the
-         * expected behavior is the Link UP being detected.
-         */
-        int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);
-        if (rc < 0)
-                return rc;
-
-        rc &= ~MII_LAN83C185_EDPWRDOWN;
-
-        rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS, rc);
-        if (rc < 0)
-                return rc;
-
         return smsc_phy_ack_interrupt(phydev);
 }
 
-static int lan911x_config_init(struct phy_device *phydev)
+/*
+ * The LAN8710/LAN8720 requires a minimum of 2 link pulses within 64ms of each
+ * other in order to set the ENERGYON bit and exit EDPD mode.  If a link partner
+ * does send the pulses within this interval, the PHY will remained powered
+ * down.
+ *
+ * This workaround will manually toggle the PHY on/off upon calls to read_status
+ * in order to generate link test pulses if the link is down.  If a link partner
+ * is present, it will respond to the pulses, which will cause the ENERGYON bit
+ * to be set and will cause the EDPD mode to be exited.
+ */
+static int lan87xx_read_status(struct phy_device *phydev)
 {
-        return smsc_phy_ack_interrupt(phydev);
+        int err = genphy_read_status(phydev);
+
+        if (!phydev->link) {
+                /* Disable EDPD to wake up PHY */
+                int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);
+                if (rc < 0)
+                        return rc;
+
+                rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,
+                               rc & ~MII_LAN83C185_EDPWRDOWN);
+                if (rc < 0)
+                        return rc;
+
+                /* Sleep 64 ms to allow ~5 link test pulses to be sent */
+                msleep(64);
+
+                /* Re-enable EDPD */
+                rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);
+                if (rc < 0)
+                        return rc;
+
+                rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,
+                               rc | MII_LAN83C185_EDPWRDOWN);
+                if (rc < 0)
+                        return rc;
+        }
+
+        return err;
 }
 
 static struct phy_driver smsc_phy_driver[] = {
@@ -187,8 +204,8 @@ static struct phy_driver smsc_phy_driver[] = {
 
         /* basic functions */
         .config_aneg    = genphy_config_aneg,
-        .read_status    = genphy_read_status,
-        .config_init    = lan87xx_config_init,
+        .read_status    = lan87xx_read_status,
+        .config_intr    = smsc_phy_config_intr,
 
         /* IRQ related */
         .ack_interrupt  = smsc_phy_ack_interrupt,