diff mbox series

[RFC,net-next,15/22] net: dsa: mt7530: set TRGMII RD TAP if trgmii is being used

Message ID 20230421143648.87889-16-arinc.unal@arinc9.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: MT7530, MT7531, and MT7988 improvements | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -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 success CCed 16 of 16 maintainers
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 No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Arınç ÜNAL April 21, 2023, 2:36 p.m. UTC 
From: Arınç ÜNAL <arinc.unal@arinc9.com>

This code sets the Read Data (RD) TAP value to 16 for all TRGMII control
registers.

The for loop iterates over all the TRGMII control registers, and
mt7530_rmw() function is used to perform a read-modify-write operation on
each register's RD_TAP field to set its value to 16.

This operation is used to tune the timing of the read data signal in
TRGMII to match the TX signal of the link partner.

Run this if trgmii is being used. Since this code doesn't lower the
driving, there's no apparent benefit to run this if trgmii is not being
used.

Add a comment to explain the code.

Thanks to 趙皎宏 (Landen Chao) for pointing out what the code does.

Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
---
 drivers/net/dsa/mt7530.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 610828b56eac..029d3129bb8b 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -404,7 +404,7 @@  static void
 mt7530_setup_port6(struct dsa_switch *ds, phy_interface_t interface)
 {
 	struct mt7530_priv *priv = ds->priv;
-	u32 ncpo1, ssc_delta, xtal, val;
+	u32 ncpo1, ssc_delta, i, xtal, val;
 
 	val = mt7530_read(priv, MT7530_MHWTRAP);
 	val &= ~MHWTRAP_P6_DIS;
@@ -457,6 +457,11 @@  mt7530_setup_port6(struct dsa_switch *ds, phy_interface_t interface)
 
 		/* Enable the MT7530 TRGMII clocks */
 		core_set(priv, CORE_TRGMII_GSW_CLK_CG, REG_TRGMIICK_EN);
+
+		/* Set the Read Data TAP value of the MT7530 TRGMII */
+		for (i = 0; i < NUM_TRGMII_CTRL; i++)
+			mt7530_rmw(priv, MT7530_TRGMII_RD(i),
+				   RD_TAP_MASK, RD_TAP(16));
 	}
 }
 
@@ -2214,10 +2219,6 @@  mt7530_setup(struct dsa_switch *ds)
 		mt7530_write(priv, MT7530_TRGMII_TD_ODT(i),
 			     TD_DM_DRVP(8) | TD_DM_DRVN(8));
 
-	for (i = 0; i < NUM_TRGMII_CTRL; i++)
-		mt7530_rmw(priv, MT7530_TRGMII_RD(i),
-			   RD_TAP_MASK, RD_TAP(16));
-
 	/* Enable PHY access and operate in manual mode */
 	val = mt7530_read(priv, MT7530_MHWTRAP);
 	val &= ~MHWTRAP_PHY_ACCESS;