The driver currently sets bit 0 of USB_PHY_CFG1 (PLL_EN) during PHY
initialization. According to the M31 EUSB2 PHY hardware documentation,
this bit is intended only for test/debug scenarios and does not control
mission mode operation. Keeping PLL_EN asserted causes the PHY to draw
additional current during USB bus suspend. Clearing this bit results in
lower suspend power consumption without affecting normal operation.

Update the driver to leave PLL_EN cleared as recommended by the hardware
documentation.

Fixes: 9c8504861cc4 ("phy: qcom: Add M31 based eUSB2 PHY driver")
Cc: stable@vger.kernel.org
Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 drivers/phy/qualcomm/phy-qcom-m31-eusb2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-m31-eusb2.c b/drivers/phy/qualcomm/phy-qcom-m31-eusb2.c
index 95cd3175926d..68f1ba8fec4a 100644
--- a/drivers/phy/qualcomm/phy-qcom-m31-eusb2.c
+++ b/drivers/phy/qualcomm/phy-qcom-m31-eusb2.c
@@ -83,7 +83,7 @@ static const struct m31_phy_tbl_entry m31_eusb2_setup_tbl[] = {
 	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG0, UTMI_PHY_CMN_CTRL_OVERRIDE_EN, 1),
 	M31_EUSB_PHY_INIT_CFG(USB_PHY_UTMI_CTRL5, POR, 1),
 	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL_COMMON0, PHY_ENABLE, 1),
-	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG1, PLL_EN, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG1, PLL_EN, 0),
 	M31_EUSB_PHY_INIT_CFG(USB_PHY_FSEL_SEL, FSEL_SEL, 1),
 };
 
-- 
2.34.1

On Tue, 17 Feb 2026 12:11:30 -0800, Elson Serrao wrote:
> The driver currently sets bit 0 of USB_PHY_CFG1 (PLL_EN) during PHY
> initialization. According to the M31 EUSB2 PHY hardware documentation,
> this bit is intended only for test/debug scenarios and does not control
> mission mode operation. Keeping PLL_EN asserted causes the PHY to draw
> additional current during USB bus suspend. Clearing this bit results in
> lower suspend power consumption without affecting normal operation.
> 
> [...]

Applied, thanks!

[1/1] phy: qcom: m31-eusb2: clear PLL_EN during init
      commit: 520a98bdf7ae0130e22d8adced3d69a2e211b41f

Best regards,
-- 
~Vinod

On 2/17/26 9:11 PM, Elson Serrao wrote:
> The driver currently sets bit 0 of USB_PHY_CFG1 (PLL_EN) during PHY
> initialization. According to the M31 EUSB2 PHY hardware documentation,
> this bit is intended only for test/debug scenarios and does not control
> mission mode operation. Keeping PLL_EN asserted causes the PHY to draw
> additional current during USB bus suspend. Clearing this bit results in
> lower suspend power consumption without affecting normal operation.
> 
> Update the driver to leave PLL_EN cleared as recommended by the hardware
> documentation.
> 
> Fixes: 9c8504861cc4 ("phy: qcom: Add M31 based eUSB2 PHY driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad