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authorAlex <alex.g@adaptrum.com>2016-11-16 12:02:33 +0300
committerDavid S. Miller <davem@davemloft.net>2016-11-17 01:53:56 +0300
commit955e16026d08a601d02b961d13b6db9d6c13c8c9 (patch)
treeb78d7f353e0323d970b39e05d20777b5cc0aecca /drivers/net/phy/vitesse.c
parent5f00a8d8a2c2fd99528ab1a3632f0e77f4d25202 (diff)
downloadlinux-955e16026d08a601d02b961d13b6db9d6c13c8c9.tar.xz
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>
Diffstat (limited to 'drivers/net/phy/vitesse.c')
-rw-r--r--drivers/net/phy/vitesse.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/net/phy/vitesse.c b/drivers/net/phy/vitesse.c
index 2e37eb337d48..24b4a09468dd 100644
--- a/drivers/net/phy/vitesse.c
+++ b/drivers/net/phy/vitesse.c
@@ -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,