phy: tegra: xusb: Add API to retrieve the port number of phy

This patch introduces a new API, tegra_xusb_padctl_get_port_number,
to the Tegra XUSB Pad Controller driver. This API is used to identify
the USB port that is associated with a given PHY.

The function takes a PHY pointer for either a USB2 PHY or USB3 PHY as input
and returns the corresponding port number. If the PHY pointer is invalid,
it returns -ENODEV.

Cc: stable@vger.kernel.org
Signed-off-by: Wayne Chang <waynec@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20240307030328.1487748-2-waynec@nvidia.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/phy/tegra/xusb.c

@@ -1531,6 +1531,19 @@ int tegra_xusb_padctl_get_usb3_companion(struct tegra_xusb_padctl *padctl,
 }
 EXPORT_SYMBOL_GPL(tegra_xusb_padctl_get_usb3_companion);
 
+int tegra_xusb_padctl_get_port_number(struct phy *phy)
+{
+	struct tegra_xusb_lane *lane;
+
+	if (!phy)
+		return -ENODEV;
+
+	lane = phy_get_drvdata(phy);
+
+	return lane->index;
+}
+EXPORT_SYMBOL_GPL(tegra_xusb_padctl_get_port_number);
+
 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
 MODULE_DESCRIPTION("Tegra XUSB Pad Controller driver");
 MODULE_LICENSE("GPL v2");

include/linux/phy/tegra/xusb.h

@@ -26,6 +26,7 @@ void tegra_phy_xusb_utmi_pad_power_down(struct phy *phy);
 int tegra_phy_xusb_utmi_port_reset(struct phy *phy);
 int tegra_xusb_padctl_get_usb3_companion(struct tegra_xusb_padctl *padctl,
 					 unsigned int port);
+int tegra_xusb_padctl_get_port_number(struct phy *phy);
 int tegra_xusb_padctl_enable_phy_sleepwalk(struct tegra_xusb_padctl *padctl, struct phy *phy,
 					   enum usb_device_speed speed);
 int tegra_xusb_padctl_disable_phy_sleepwalk(struct tegra_xusb_padctl *padctl, struct phy *phy);