phy: tegra: xusb: reset VBUS & ID OVERRIDE

Observed VBUS_OVERRIDE & ID_OVERRIDE might be programmed
with unexpected value prior to XUSB PADCTL driver, this
could also occur in virtualization scenario.

For example, UEFI firmware programs ID_OVERRIDE=GROUNDED to set
a type-c port to host mode and keeps the value to kernel.
If the type-c port is connected a usb host, below errors can be
observed right after usb host mode driver gets probed. The errors
would keep until usb role class driver detects the type-c port
as device mode and notifies usb device mode driver to set both
ID_OVERRIDE and VBUS_OVERRIDE to correct value by XUSB PADCTL
driver.

[  173.765814] usb usb3-port2: Cannot enable. Maybe the USB cable is bad?
[  173.765837] usb usb3-port2: config error

Taking virtualization into account, asserting XUSB PADCTL
reset would break XUSB functions used by other guest OS,
hence only reset VBUS & ID OVERRIDE of the port in
utmi_phy_init.

Fixes: bbf711682cd5 ("phy: tegra: xusb: Add Tegra186 support")
Cc: stable@vger.kernel.org
Change-Id: Ic63058d4d49b4a1f8f9ab313196e20ad131cc591
Signed-off-by: BH Hsieh <bhsieh@nvidia.com>
Signed-off-by: Henry Lin <henryl@nvidia.com>
Link: https://lore.kernel.org/r/20250122105943.8057-1-henryl@nvidia.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/phy/tegra/xusb-tegra186.c b/drivers/phy/tegra/xusb-tegra186.c
index 0f60d5d1c1678d6fa1c94463b74adb7e5e3fc2b1..fae6242aa730e0deb075158f5aa1e260176d028c 100644 (file)
--- a/drivers/phy/tegra/xusb-tegra186.c
+++ b/drivers/phy/tegra/xusb-tegra186.c
@@ -928,6 +928,7 @@ static int tegra186_utmi_phy_init(struct phy *phy)
        unsigned int index = lane->index;
        struct device *dev = padctl->dev;
        int err;
+       u32 reg;
 
        port = tegra_xusb_find_usb2_port(padctl, index);
        if (!port) {
@@ -935,6 +936,16 @@ static int tegra186_utmi_phy_init(struct phy *phy)
                return -ENODEV;
        }
 
+       if (port->mode == USB_DR_MODE_OTG ||
+           port->mode == USB_DR_MODE_PERIPHERAL) {
+               /* reset VBUS&ID OVERRIDE */
+               reg = padctl_readl(padctl, USB2_VBUS_ID);
+               reg &= ~VBUS_OVERRIDE;
+               reg &= ~ID_OVERRIDE(~0);
+               reg |= ID_OVERRIDE_FLOATING;
+               padctl_writel(padctl, reg, USB2_VBUS_ID);
+       }
+
        if (port->supply && port->mode == USB_DR_MODE_HOST) {
                err = regulator_enable(port->supply);
                if (err) {