[PATCH 1/1] phy: tegra: xusb: Explicitly configure HS_DISCON_LEVEL to 0x7
Wayne Chang
waynec at nvidia.com
Thu Dec 11 19:21:16 PST 2025
The USB2 Bias Pad Control register manages analog parameters for signal
detection. Previously, the HS_DISCON_LEVEL relied on hardware reset
values, which may lead to the detection failure.
Explicitly configure HS_DISCON_LEVEL to 0x7. This ensures the disconnect
threshold is sufficient to guarantee reliable detection.
Fixes: bbf711682cd5 ("phy: tegra: xusb: Add Tegra186 support")
Cc: stable at vger.kernel.org
Signed-off-by: Wayne Chang <waynec at nvidia.com>
---
drivers/phy/tegra/xusb-tegra186.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/phy/tegra/xusb-tegra186.c b/drivers/phy/tegra/xusb-tegra186.c
index e818f6c3980e..bec9616c4a2e 100644
--- a/drivers/phy/tegra/xusb-tegra186.c
+++ b/drivers/phy/tegra/xusb-tegra186.c
@@ -84,6 +84,7 @@
#define XUSB_PADCTL_USB2_BIAS_PAD_CTL0 0x284
#define BIAS_PAD_PD BIT(11)
#define HS_SQUELCH_LEVEL(x) (((x) & 0x7) << 0)
+#define HS_DISCON_LEVEL(x) (((x) & 0x7) << 3)
#define XUSB_PADCTL_USB2_BIAS_PAD_CTL1 0x288
#define USB2_TRK_START_TIMER(x) (((x) & 0x7f) << 12)
@@ -623,6 +624,8 @@ static void tegra186_utmi_bias_pad_power_on(struct tegra_xusb_padctl *padctl)
value &= ~BIAS_PAD_PD;
value &= ~HS_SQUELCH_LEVEL(~0);
value |= HS_SQUELCH_LEVEL(priv->calib.hs_squelch);
+ value &= ~HS_DISCON_LEVEL(~0);
+ value |= HS_DISCON_LEVEL(0x7);
padctl_writel(padctl, value, XUSB_PADCTL_USB2_BIAS_PAD_CTL0);
udelay(1);
--
2.25.1
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