[PATCH v1] phy: fsl-imx8mq-usb: Fix PCS_TX_SWING_FULL register configuration

From: Stefano Radaelli

Date: Thu Dec 18 2025 - 12:50:09 EST


Clear the PCS_TX_SWING_FULL field mask before setting the new value
in PHY_CTRL5 register. Without clearing the mask first, the OR operation
could leave previously set bits, resulting in incorrect
register configuration.

Fixes: 63c85ad0cd81 ("phy: fsl-imx8mp-usb: add support for phy tuning")
Suggested-by: Pierluigi Passaro <pierluigi.p@xxxxxxxxxxxxx>
Signed-off-by: Stefano Radaelli <stefano.r@xxxxxxxxxxxxx>
---
drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index ad8a55012e42..9458b6e5fcf4 100644
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -504,6 +504,7 @@ static void imx8m_phy_tune(struct imx8mq_usb_phy *imx_phy)

if (imx_phy->pcs_tx_swing_full != PHY_TUNE_DEFAULT) {
value = readl(imx_phy->base + PHY_CTRL5);
+ value &= ~PHY_CTRL5_PCS_TX_SWING_FULL_MASK;
value |= FIELD_PREP(PHY_CTRL5_PCS_TX_SWING_FULL_MASK,
imx_phy->pcs_tx_swing_full);
writel(value, imx_phy->base + PHY_CTRL5);

base-commit: ea1013c1539270e372fc99854bc6e4d94eaeff66
--
2.47.3