diff options
| author | Igor Plyatov | 2015-08-14 20:11:02 +0300 |
|---|---|---|
| committer | David S. Miller | 2015-08-17 14:27:23 -0700 |
| commit | 776829de90c5972895db398993ddfa9417ff8b01 (patch) | |
| tree | 7a04ac57c817c75c666d866527daa35fb4241176 /drivers/net | |
| parent | a27cc68b9bb25f16b37f9800e977927a2275e7e6 (diff) | |
net: phy: workaround for buggy cable detection by LAN8700 after cable plugging
* Due to HW bug, LAN8700 sometimes does not detect presence of energy in the
Ethernet cable in Energy Detect Power-Down mode (e.g while EDPWRDOWN bit is
set, the ENERGYON bit does not asserted sometimes). This is a common bug of
LAN87xx family of PHY chips.
* The lan87xx_read_status() was improved to acquire ENERGYON bit. Its previous
algorythm still not reliable on 100 % and sometimes skip cable plugging.
Signed-off-by: Igor Plyatov <plyatov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/phy/smsc.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c index c0f6479e19d4..d64f01623bd1 100644 --- a/drivers/net/phy/smsc.c +++ b/drivers/net/phy/smsc.c @@ -91,19 +91,18 @@ 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. + * The LAN87xx suffers from rare absence of the ENERGYON-bit when Ethernet cable + * plugs in while LAN87xx is in Energy Detect Power-Down mode. This leads to + * unstable detection of plugging in Ethernet cable. + * This workaround disables Energy Detect Power-Down mode and waiting for + * response on link pulses to detect presence of plugged Ethernet cable. + * The Energy Detect Power-Down mode is enabled again in the end of procedure to + * save approximately 220 mW of power if cable is unplugged. */ static int lan87xx_read_status(struct phy_device *phydev) { int err = genphy_read_status(phydev); + int i; if (!phydev->link) { /* Disable EDPD to wake up PHY */ @@ -116,8 +115,16 @@ static int lan87xx_read_status(struct phy_device *phydev) if (rc < 0) return rc; - /* Sleep 64 ms to allow ~5 link test pulses to be sent */ - msleep(64); + /* Wait max 640 ms to detect energy */ + for (i = 0; i < 64; i++) { + /* Sleep to allow link test pulses to be sent */ + msleep(10); + rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS); + if (rc < 0) + return rc; + if (rc & MII_LAN83C185_ENERGYON) + break; + }; /* Re-enable EDPD */ rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS); @@ -191,7 +198,7 @@ static struct phy_driver smsc_phy_driver[] = { /* basic functions */ .config_aneg = genphy_config_aneg, - .read_status = genphy_read_status, + .read_status = lan87xx_read_status, .config_init = smsc_phy_config_init, .soft_reset = smsc_phy_reset, |