The KSZ9031 erratum #2 stats:
    The 125MHz reference clock (CLK125_NDO pin) output
    has duty cycle variation when the KSZ9031 links up in
    1000Base-T Slave mode, resulting in wide variation on
    the falling clock edge.

The recommended workaround is to either only use the rising edge of
the CLK125_NDO output for PLL locking, or to

    Set KSZ9031 to always link up in 1000Base-T Master mode
    by setting register 9h, bits [12:11] to '11'.

Since we can't guarantee the former, this patch does the latter.
Original patch by Markus Niebel <[email protected]>.

Signed-off-by: Markus Niebel <[email protected]>
Signed-off-by: Philipp Zabel <[email protected]>
---
 drivers/net/phy/micrel.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index e8a566d..5227dfb 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -220,6 +220,7 @@ static int ksz9031_config_init(struct phy_device *phydev)
                "txd2-skew-ps", "txd3-skew-ps"
        };
        static const char *control_skews[2] = {"txen-skew-ps", "rxdv-skew-ps"};
+       int rc;
 
        if (!of_node && dev->parent->device_node)
                of_node = dev->parent->device_node;
@@ -242,6 +243,14 @@ static int ksz9031_config_init(struct phy_device *phydev)
                                tx_data_skews, 4);
        }
 
+       rc = phy_read(phydev, MII_CTRL1000);
+       if (rc >= 0) {
+               u16 val = rc;
+               /* Enable master mode, config & prefer master */
+               val |= (CTL1000_ENABLE_MASTER | CTL1000_AS_MASTER);
+               phy_write(phydev, MII_CTRL1000, val);
+       }
+
        return ksz9031_center_flp_timing(phydev);
 }
 
-- 
2.7.0.rc3


_______________________________________________
barebox mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/barebox

Reply via email to