Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 776829de authored by Igor Plyatov's avatar Igor Plyatov Committed by David S. Miller
Browse files

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: default avatarIgor Plyatov <plyatov@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a27cc68b

drivers/net/phy/smsc.c

+19 −12
Original line number Diff line number Diff line
@@ -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,