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From: Wayne Chang <waynec@nvidia.com>
To: <jckuo@nvidia.com>, <vkoul@kernel.org>, <kishon@kernel.org>,
	<thierry.reding@gmail.com>, <jonathanh@nvidia.com>
Cc: <waynec@nvidia.com>, <haotienh@nvidia.com>,
	<linux-phy@lists.infradead.org>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>
Subject: [PATCH 1/1] phy: tegra: xusb: Explicitly configure HS_DISCON_LEVEL to 0x7
Date: Fri, 12 Dec 2025 11:21:16 +0800	[thread overview]
Message-ID: <20251212032116.768307-1-waynec@nvidia.com> (raw)

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@vger.kernel.org
Signed-off-by: Wayne Chang <waynec@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


             reply	other threads:[~2025-12-12  3:22 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-12  3:21 Wayne Chang [this message]
2025-12-24  7:32 ` [PATCH 1/1] phy: tegra: xusb: Explicitly configure HS_DISCON_LEVEL to 0x7 Vinod Koul

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