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Message-ID: <20230508070019.356548-1-s-vadapalli@ti.com>
Date: Mon, 8 May 2023 12:30:19 +0530
From: Siddharth Vadapalli <s-vadapalli@...com>
To: <andrew@...n.ch>, <hkallweit1@...il.com>, <linux@...linux.org.uk>,
<davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
<pabeni@...hat.com>
CC: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <srk@...com>,
<s-vadapalli@...com>
Subject: [PATCH net] net: phy: dp83867: add w/a for packet errors seen with short cables
From: Grygorii Strashko <grygorii.strashko@...com>
Introduce the W/A for packet errors seen with short cables (<1m) between
two DP83867 PHYs.
The W/A recommended by DM requires FFE Equalizer Configuration tuning by
writing value 0x0E81 to DSP_FFE_CFG register (0x012C), surrounded by hard
and soft resets as follows:
write_reg(0x001F, 0x8000); //hard reset
write_reg(DSP_FFE_CFG, 0x0E81);
write_reg(0x001F, 0x4000); //soft reset
Since DP83867 PHY DM says "Changing this register to 0x0E81, will not
affect Long Cable performance.", enable the W/A by default.
Fixes: 2a10154abcb7 ("net: phy: dp83867: Add TI dp83867 phy")
Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@...com>
---
RFC patch at:
https://lore.kernel.org/r/20230425054429.3956535-2-s-vadapalli@ti.com/
Changes since RFC patch:
- Change patch subject to PATCH net.
- Add Fixes tag.
- Check return value of phy_write_mmd().
drivers/net/phy/dp83867.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index d75f526a20a4..4eecc9531a6b 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -44,6 +44,7 @@
#define DP83867_STRAP_STS1 0x006E
#define DP83867_STRAP_STS2 0x006f
#define DP83867_RGMIIDCTL 0x0086
+#define DP83867_DSP_FFE_CFG 0X012C
#define DP83867_RXFCFG 0x0134
#define DP83867_RXFPMD1 0x0136
#define DP83867_RXFPMD2 0x0137
@@ -941,8 +942,22 @@ static int dp83867_phy_reset(struct phy_device *phydev)
usleep_range(10, 20);
- return phy_modify(phydev, MII_DP83867_PHYCTRL,
+ err = phy_modify(phydev, MII_DP83867_PHYCTRL,
DP83867_PHYCR_FORCE_LINK_GOOD, 0);
+ if (err < 0)
+ return err;
+
+ err = phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_DSP_FFE_CFG, 0X0E81);
+ if (err < 0)
+ return err;
+
+ err = phy_write(phydev, DP83867_CTRL, DP83867_SW_RESTART);
+ if (err < 0)
+ return err;
+
+ usleep_range(10, 20);
+
+ return 0;
}
static void dp83867_link_change_notify(struct phy_device *phydev)
--
2.25.1
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