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lxt PHY: Support for the buggy LXT973 rev A2 

This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding
precautions linked to ERRATA Item 4:

Revision A2 of LXT973 chip randomly returns the contents of the previous even
register when you read a odd register regularly

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
LEROY Christophe 2012-09-24 04:00:58 +00:00 committed by David S. Miller
parent 26f7cbc0a5
commit 871d1d6b59
1 changed files with 127 additions and 0 deletions
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127
drivers/net/phy/lxt.c
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@ -122,6 +122,123 @@ static int lxt971_config_intr(struct phy_device *phydev)
return err;
}
/*
* A2 version of LXT973 chip has an ERRATA: it randomly return the contents
* of the previous even register when you read a odd register regularly
*/
static int lxt973a2_update_link(struct phy_device *phydev)
{
int status;
int control;
int retry = 8; /* we try 8 times */
/* Do a fake read */
status = phy_read(phydev, MII_BMSR);
if (status < 0)
return status;
control = phy_read(phydev, MII_BMCR);
if (control < 0)
return control;
do {
/* Read link and autonegotiation status */
status = phy_read(phydev, MII_BMSR);
} while (status >= 0 && retry-- && status == control);
if (status < 0)
return status;
if ((status & BMSR_LSTATUS) == 0)
phydev->link = 0;
else
phydev->link = 1;
return 0;
}
int lxt973a2_read_status(struct phy_device *phydev)
{
int adv;
int err;
int lpa;
int lpagb = 0;
/* Update the link, but return if there was an error */
err = lxt973a2_update_link(phydev);
if (err)
return err;
if (AUTONEG_ENABLE == phydev->autoneg) {
int retry = 1;
adv = phy_read(phydev, MII_ADVERTISE);
if (adv < 0)
return adv;
do {
lpa = phy_read(phydev, MII_LPA);
if (lpa < 0)
return lpa;
/* If both registers are equal, it is suspect but not
* impossible, hence a new try
*/
} while (lpa == adv && retry--);
lpa &= adv;
phydev->speed = SPEED_10;
phydev->duplex = DUPLEX_HALF;
phydev->pause = phydev->asym_pause = 0;
if (lpagb & (LPA_1000FULL | LPA_1000HALF)) {
phydev->speed = SPEED_1000;
if (lpagb & LPA_1000FULL)
phydev->duplex = DUPLEX_FULL;
} else if (lpa & (LPA_100FULL | LPA_100HALF)) {
phydev->speed = SPEED_100;
if (lpa & LPA_100FULL)
phydev->duplex = DUPLEX_FULL;
} else {
if (lpa & LPA_10FULL)
phydev->duplex = DUPLEX_FULL;
}
if (phydev->duplex == DUPLEX_FULL) {
phydev->pause = lpa & LPA_PAUSE_CAP ? 1 : 0;
phydev->asym_pause = lpa & LPA_PAUSE_ASYM ? 1 : 0;
}
} else {
int bmcr = phy_read(phydev, MII_BMCR);
if (bmcr < 0)
return bmcr;
if (bmcr & BMCR_FULLDPLX)
phydev->duplex = DUPLEX_FULL;
else
phydev->duplex = DUPLEX_HALF;
if (bmcr & BMCR_SPEED1000)
phydev->speed = SPEED_1000;
else if (bmcr & BMCR_SPEED100)
phydev->speed = SPEED_100;
else
phydev->speed = SPEED_10;
phydev->pause = phydev->asym_pause = 0;
}
return 0;
}
static int lxt973_probe(struct phy_device *phydev)
{
int val = phy_read(phydev, MII_LXT973_PCR);
@ -173,6 +290,16 @@ static struct phy_driver lxt97x_driver[] = {
.ack_interrupt = lxt971_ack_interrupt,
.config_intr = lxt971_config_intr,
.driver = { .owner = THIS_MODULE,},
}, {
.phy_id = 0x00137a10,
.name = "LXT973-A2",
.phy_id_mask = 0xffffffff,
.features = PHY_BASIC_FEATURES,
.flags = 0,
.probe = lxt973_probe,
.config_aneg = lxt973_config_aneg,
.read_status = lxt973a2_read_status,
.driver = { .owner = THIS_MODULE,},
}, {
.phy_id = 0x00137a10,
.name = "LXT973",