diff mbox series

[net] net: phy: dp83867: add w/a for packet errors seen with short cables

Message ID 20230508070019.356548-1-s-vadapalli@ti.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net] net: phy: dp83867: add w/a for packet errors seen with short cables | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers fail 1 blamed authors not CCed: dmurphy@ti.com; 1 maintainers not CCed: dmurphy@ti.com
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: line length of 82 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

s-vadapalli May 8, 2023, 7 a.m. UTC 
From: Grygorii Strashko <grygorii.strashko@ti.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@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.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(-)

Comments

Jakub Kicinski May 9, 2023, 2 a.m. UTC | #1 
Thanks for the patch! Some nit picks below..

On Mon, 8 May 2023 12:30:19 +0530 Siddharth Vadapalli wrote:
> +	err = phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_DSP_FFE_CFG, 0X0E81);

Pleas wrap this line at 80 characters, there's no reason for it 
to be this long.

And 0x prefix should not be in upper case, here and in the new define
you're adding.
s-vadapalli May 9, 2023, 4:42 a.m. UTC | #2 
On 09/05/23 07:30, Jakub Kicinski wrote:
> Thanks for the patch! Some nit picks below..
> 
> On Mon, 8 May 2023 12:30:19 +0530 Siddharth Vadapalli wrote:
>> +	err = phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_DSP_FFE_CFG, 0X0E81);
> 
> Pleas wrap this line at 80 characters, there's no reason for it 
> to be this long.
> 
> And 0x prefix should not be in upper case, here and in the new define
> you're adding.

Thank you for pointing out the issues. I will fix them and post the v2 patch.
diff mbox series

Patch

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)