Reset the bit 12 in PHY's LRE Control register upon initialization.
According to the datasheet, this bit must be written to zero after
every device reset.

Fixes: 03ab6c244bb0 ("net: phy: bcm-phy-lib: Implement BroadR-Reach link modes")
Signed-off-by: Kamil Horák - 2N <kamilh@axis.com>
---
 drivers/net/phy/broadcom.c | 23 +++++++++++++++++++----
 include/linux/brcmphy.h    |  1 +
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 7d3b85a07b8c..9d38aa7f3b45 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -662,7 +662,7 @@ static int bcm5481x_read_abilities(struct phy_device *phydev)
 {
 	struct device_node *np = phydev->mdio.dev.of_node;
 	struct bcm54xx_phy_priv *priv = phydev->priv;
-	int i, val, err;
+	int i, val, err, aneg;

 	for (i = 0; i < ARRAY_SIZE(bcm54811_linkmodes); i++)
 		linkmode_clear_bit(bcm54811_linkmodes[i], phydev->supported);
@@ -683,9 +683,17 @@ static int bcm5481x_read_abilities(struct phy_device *phydev)
 		if (val < 0)
 			return val;

+		/* BCM54811 is not capable of LDS but the corresponding bit
+		 * in LRESR is set to 1 and marked "Ignore" in the datasheet.
+		 * So we must read the bcm54811 as unable to auto-negotiate
+		 * in BroadR-Reach mode.
+		 */
+		aneg = (BRCM_PHY_MODEL(phydev) != PHY_ID_BCM54811) ?
+			(val & LRESR_LDSABILITY) : 0;
+
 		linkmode_mod_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
 				 phydev->supported,
-				 val & LRESR_LDSABILITY);
+				 aneg);
 		linkmode_mod_bit(ETHTOOL_LINK_MODE_100baseT1_Full_BIT,
 				 phydev->supported,
 				 val & LRESR_100_1PAIR);
@@ -742,8 +750,15 @@ static int bcm54811_config_aneg(struct phy_device *phydev)

 	/* Aneg firstly. */
 	if (priv->brr_mode) {
-		/* BCM54811 is only capable of autonegotiation in IEEE mode */
-		phydev->autoneg = 0;
+		/* BCM54811 is only capable of autonegotiation in IEEE mode.
+		 * In BroadR-Reach mode, disable the Long Distance Signaling,
+		 * the BRR mode autoneg as supported in other Broadcom PHYs.
+		 * This bit is marked as "Reserved" and "Default 1, must be
+		 *  written to 0 after every device reset" in the datasheet.
+		 */
+		ret = phy_modify(phydev, MII_BCM54XX_LRECR, LRECR_LDSEN, 0);
+		if (ret < 0)
+			return ret;
 		ret = bcm_config_lre_aneg(phydev, false);
 	} else {
 		ret = genphy_config_aneg(phydev);
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 15c35655f482..115a964f3006 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -137,6 +137,7 @@

 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC			0x07
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_WIRESPEED_EN	0x0010
+#define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_RSVD		0x0060
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_RGMII_EN	0x0080
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_RGMII_SKEW_EN	0x0100
 #define MII_BCM54XX_AUXCTL_MISC_FORCE_AMDIX		0x0200
--
2.39.5

On Thu, Jun 26, 2025 at 01:56:19PM +0200, Kamil Horák - 2N wrote:
> +		/* BCM54811 is not capable of LDS but the corresponding bit
> +		 * in LRESR is set to 1 and marked "Ignore" in the datasheet.
> +		 * So we must read the bcm54811 as unable to auto-negotiate
> +		 * in BroadR-Reach mode.
> +		 */
> +		aneg = (BRCM_PHY_MODEL(phydev) != PHY_ID_BCM54811) ?
> +			(val & LRESR_LDSABILITY) : 0;

Wouldn't:

		if (BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54811)
			aneg = 0;
		else
			aneg = val & LRESR_LDSABILITY;

be more readable?

-- 
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