[PATCH 6.6 035/254] phy: fsl-imx8mq-usb: Clear the PCS_TX_SWING_FULL field before using it

Greg Kroah-Hartman
2026-01-28T15:28:44Z

From: Stefano Radaelli <stefano.radaelli21@gmail.com>

[ Upstream commit 8becf9179a4b45104a1701010ed666b55bf4b3a6 ]

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: Leonid Segal <leonids@variscite.com>
Acked-by: Pierluigi Passaro <pierluigi.p@variscite.com>
Signed-off-by: Stefano Radaelli <stefano.r@variscite.com>
Reviewed-by: Xu Yang <xu.yang_2@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://patch.msgid.link/20251219160912.561431-1-stefano.r@variscite.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 f914f016b3d2c..043063699e064 100644
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -206,6 +206,7 @@ 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);
--
2.51.0