[PATCH] net: phy: dp83822: fix transmit amplitude if CONFIG_OF_MDIO not defined

[Dimitri Fedrau via B4 Relay]

From: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>

When CONFIG_OF_MDIO is not defined the index for selecting the transmit
amplitude voltage for 100BASE-TX is set to 0, but it should be -1, if there
is no need to modify the transmit amplitude voltage. Add a flag to make
sure there is a need to modify it.

Fixes: 4f3735e82d8a ("net: phy: dp83822: Add support for changing the transmit amplitude voltage")
Signed-off-by: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>
---
 drivers/net/phy/dp83822.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/dp83822.c b/drivers/net/phy/dp83822.c
index 3662f3905d5ade8ad933608fcaeabb714a588418..d69000cb0ceff28e8288ba24e0af1c960ea9cc97 100644
--- a/drivers/net/phy/dp83822.c
+++ b/drivers/net/phy/dp83822.c
@@ -201,6 +201,7 @@ struct dp83822_private {
 	bool set_gpio2_clk_out;
 	u32 gpio2_clk_out;
 	bool led_pin_enable[DP83822_MAX_LED_PINS];
+	bool tx_amplitude_100base_tx_modify;
 	int tx_amplitude_100base_tx_index;
 };
 
@@ -527,7 +528,7 @@ static int dp83822_config_init(struct phy_device *phydev)
 			       FIELD_PREP(DP83822_IOCTRL2_GPIO2_CLK_SRC,
 					  dp83822->gpio2_clk_out));
 
-	if (dp83822->tx_amplitude_100base_tx_index >= 0)
+	if (dp83822->tx_amplitude_100base_tx_modify)
 		phy_modify_mmd(phydev, MDIO_MMD_VEND2, MII_DP83822_LDCTRL,
 			       DP83822_100BASE_TX_LINE_DRIVER_SWING,
 			       FIELD_PREP(DP83822_100BASE_TX_LINE_DRIVER_SWING,
@@ -851,6 +852,8 @@ static int dp83822_of_init(struct phy_device *phydev)
 				   val);
 			return -EINVAL;
 		}
+
+		dp83822->tx_amplitude_100base_tx_modify = true;
 	}
 
 	return dp83822_of_init_leds(phydev);

---
base-commit: c62e6f056ea308d6382450c1cb32e41727375885
change-id: 20250307-dp83822-fix-transceiver-mdio-ae27fed80699

Best regards,
-- 
Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>