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Commit 955e1602 authored by Alex's avatar Alex Committed by David S. Miller
Browse files

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: default avatarAlexandru Gagniuc <alex.g@adaptrum.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5f00a8d8

drivers/net/phy/vitesse.c

+33 −1
Original line number Diff line number Diff line
@@ -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,