Commit cefc1cae authored by Wayne Chang's avatar Wayne Chang Committed by Vinod Koul
Browse files

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: 49d46e3c ("phy: tegra: xusb: Add set_mode support for UTMI phy on Tegra186")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarWayne Chang <waynec@nvidia.com>
Reviewed-by: default avatarJon Hunter <jonathanh@nvidia.com>
Tested-by: default avatarJon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20250502092606.2275682-1-waynec@nvidia.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 7be54870

drivers/phy/tegra/xusb-tegra186.c

+37 −22
Original line number Diff line number Diff line
@@ -783,13 +783,15 @@ 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) {
@@ -800,14 +802,34 @@ static int tegra186_xusb_padctl_id_override(struct tegra_xusb_padctl *padctl, 
			value = padctl_readl(padctl, USB2_VBUS_ID);

		}



		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);

		}

	}



	return 0;

}
@@ -827,27 +849,20 @@ 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;

}