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net/phy/vitesse: Configure RGMII skew on VSC8601, if needed 

With RGMII, we need a 1.5 to 2ns skew between clock and data lines. The
VSC8601 can handle this internally. While the VSC8601 can set more
fine-grained delays, the standard skew settings work out of the box.
The same heuristic is used to determine when this skew should be enabled
as in vsc824x_config_init().

Tested on custom board with AM3352 SOC and VSC801 PHY.

Signed-off-by: Alexandru Gagniuc <alex.g@adaptrum.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alex 2016-11-16 01:02:33 -08:00 committed by David S. Miller
parent 5f00a8d8a2
commit 955e16026d
1 changed files with 33 additions and 1 deletions
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34
drivers/net/phy/vitesse.c
View File

@ -62,6 +62,10 @@
/* Vitesse Extended Page Access Register */
#define MII_VSC82X4_EXT_PAGE_ACCESS 0x1f
/* Vitesse VSC8601 Extended PHY Control Register 1 */
#define MII_VSC8601_EPHY_CTL 0x17
#define MII_VSC8601_EPHY_CTL_RGMII_SKEW (1 << 8)
#define PHY_ID_VSC8234 0x000fc620
#define PHY_ID_VSC8244 0x000fc6c0
#define PHY_ID_VSC8514 0x00070670
@ -111,6 +115,34 @@ static int vsc824x_config_init(struct phy_device *phydev)
return err;
}
/* This adds a skew for both TX and RX clocks, so the skew should only be
* applied to "rgmii-id" interfaces. It may not work as expected
* on "rgmii-txid", "rgmii-rxid" or "rgmii" interfaces. */
static int vsc8601_add_skew(struct phy_device *phydev)
{
int ret;
ret = phy_read(phydev, MII_VSC8601_EPHY_CTL);
if (ret < 0)
return ret;
ret |= MII_VSC8601_EPHY_CTL_RGMII_SKEW;
return phy_write(phydev, MII_VSC8601_EPHY_CTL, ret);
}
static int vsc8601_config_init(struct phy_device *phydev)
{
int ret = 0;
if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
ret = vsc8601_add_skew(phydev);
if (ret < 0)
return ret;
return genphy_config_init(phydev);
}
static int vsc824x_ack_interrupt(struct phy_device *phydev)
{
int err = 0;
@ -275,7 +307,7 @@ static struct phy_driver vsc82xx_driver[] = {
.phy_id_mask = 0x000ffff0,
.features = PHY_GBIT_FEATURES,
.flags = PHY_HAS_INTERRUPT,
.config_init = &genphy_config_init,
.config_init = &vsc8601_config_init,
.config_aneg = &genphy_config_aneg,
.read_status = &genphy_read_status,
.ack_interrupt = &vsc824x_ack_interrupt,