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Message-ID: <20250502092606.2275682-1-waynec@nvidia.com>
Date: Fri, 2 May 2025 17:26:06 +0800
From: Wayne Chang <waynec@...dia.com>
To: <waynec@...dia.com>, <jckuo@...dia.com>, <vkoul@...nel.org>,
<kishon@...nel.org>, <thierry.reding@...il.com>, <jonathanh@...dia.com>
CC: <linux-phy@...ts.infradead.org>, <linux-tegra@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>
Subject: [PATCH 1/1] phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode
When transitioning from USB_ROLE_DEVICE to USB_ROLE_NONE, the code
assumed that the regulator should be disabled. However, if the regulator
is marked as always-on, regulator_is_enabled() continues to return true,
leading to an incorrect attempt to disable a regulator which is not
enabled.
This can result in warnings such as:
[ 250.155624] WARNING: CPU: 1 PID: 7326 at drivers/regulator/core.c:3004
_regulator_disable+0xe4/0x1a0
[ 250.155652] unbalanced disables for VIN_SYS_5V0
To fix this, we move the regulator control logic into
tegra186_xusb_padctl_id_override() function since it's directly related
to the ID override state. The regulator is now only disabled when the role
transitions from USB_ROLE_HOST to USB_ROLE_NONE, by checking the VBUS_ID
register. This ensures that regulator enable/disable operations are
properly balanced and only occur when actually transitioning to/from host
mode.
Fixes: 49d46e3c7e59 ("phy: tegra: xusb: Add set_mode support for UTMI phy on Tegra186")
Cc: stable@...r.kernel.org
Signed-off-by: Wayne Chang <waynec@...dia.com>
---
drivers/phy/tegra/xusb-tegra186.c | 59 +++++++++++++++++++------------
1 file changed, 37 insertions(+), 22 deletions(-)
diff --git a/drivers/phy/tegra/xusb-tegra186.c b/drivers/phy/tegra/xusb-tegra186.c
index fae6242aa730..1b35d50821f7 100644
--- a/drivers/phy/tegra/xusb-tegra186.c
+++ b/drivers/phy/tegra/xusb-tegra186.c
@@ -774,13 +774,15 @@ static int tegra186_xusb_padctl_vbus_override(struct tegra_xusb_padctl *padctl,
}
static int tegra186_xusb_padctl_id_override(struct tegra_xusb_padctl *padctl,
- bool status)
+ struct tegra_xusb_usb2_port *port, bool status)
{
- u32 value;
+ u32 value, id_override;
+ int err = 0;
dev_dbg(padctl->dev, "%s id override\n", status ? "set" : "clear");
value = padctl_readl(padctl, USB2_VBUS_ID);
+ id_override = value & ID_OVERRIDE(~0);
if (status) {
if (value & VBUS_OVERRIDE) {
@@ -791,15 +793,35 @@ static int tegra186_xusb_padctl_id_override(struct tegra_xusb_padctl *padctl,
value = padctl_readl(padctl, USB2_VBUS_ID);
}
- value &= ~ID_OVERRIDE(~0);
- value |= ID_OVERRIDE_GROUNDED;
+ if (id_override != ID_OVERRIDE_GROUNDED) {
+ value &= ~ID_OVERRIDE(~0);
+ value |= ID_OVERRIDE_GROUNDED;
+ padctl_writel(padctl, value, USB2_VBUS_ID);
+
+ err = regulator_enable(port->supply);
+ if (err) {
+ dev_err(padctl->dev, "Failed to enable regulator: %d\n", err);
+ return err;
+ }
+ }
} else {
- value &= ~ID_OVERRIDE(~0);
- value |= ID_OVERRIDE_FLOATING;
+ if (id_override == ID_OVERRIDE_GROUNDED) {
+ /*
+ * The regulator is disabled only when the role transitions
+ * from USB_ROLE_HOST to USB_ROLE_NONE.
+ */
+ err = regulator_disable(port->supply);
+ if (err) {
+ dev_err(padctl->dev, "Failed to disable regulator: %d\n", err);
+ return err;
+ }
+
+ value &= ~ID_OVERRIDE(~0);
+ value |= ID_OVERRIDE_FLOATING;
+ padctl_writel(padctl, value, USB2_VBUS_ID);
+ }
}
- padctl_writel(padctl, value, USB2_VBUS_ID);
-
return 0;
}
@@ -818,27 +840,20 @@ static int tegra186_utmi_phy_set_mode(struct phy *phy, enum phy_mode mode,
if (mode == PHY_MODE_USB_OTG) {
if (submode == USB_ROLE_HOST) {
- tegra186_xusb_padctl_id_override(padctl, true);
-
- err = regulator_enable(port->supply);
+ err = tegra186_xusb_padctl_id_override(padctl, port, true);
+ if (err)
+ goto out;
} else if (submode == USB_ROLE_DEVICE) {
tegra186_xusb_padctl_vbus_override(padctl, true);
} else if (submode == USB_ROLE_NONE) {
- /*
- * When port is peripheral only or role transitions to
- * USB_ROLE_NONE from USB_ROLE_DEVICE, regulator is not
- * enabled.
- */
- if (regulator_is_enabled(port->supply))
- regulator_disable(port->supply);
-
- tegra186_xusb_padctl_id_override(padctl, false);
+ err = tegra186_xusb_padctl_id_override(padctl, port, false);
+ if (err)
+ goto out;
tegra186_xusb_padctl_vbus_override(padctl, false);
}
}
-
+out:
mutex_unlock(&padctl->lock);
-
return err;
}
--
2.25.1
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