[PATCH] phy: omap-usb2: add explicit PHY comparator API

[Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>]

The existing omap_usb2_set_comparator() API locates the OMAP USB2 PHY
instance by calling usb_get_phy(USB_PHY_TYPE_USB2), assuming there is a
single USB2 PHY registered in the system.

This assumption no longer holds on systems with multiple USB2 PHY
providers. In such cases, the global lookup may return a different USB2
PHY instance, causing the OMAP driver to perform an invalid container_of()
conversion when accessing its private data.

Introduce omap_usb2_set_phy_comparator(), allowing callers to explicitly
specify the OMAP USB2 PHY instance to associate with a phy_companion.
The new helper validates that the supplied USB PHY is an OMAP USB2 PHY
before accessing its private data.

The existing omap_usb2_set_comparator() API is kept unchanged for
existing users.


Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
---
 drivers/phy/ti/phy-omap-usb2.c | 32 ++++++++++++++++++++++++++++++++
 include/linux/phy/omap_usb.h   |  7 +++++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/phy/ti/phy-omap-usb2.c b/drivers/phy/ti/phy-omap-usb2.c
index 1eb252604441..ac31b693fce7 100644
--- a/drivers/phy/ti/phy-omap-usb2.c
+++ b/drivers/phy/ti/phy-omap-usb2.c
@@ -70,6 +70,8 @@ struct omap_usb {
 
 #define	phy_to_omapusb(x)	container_of((x), struct omap_usb, phy)
 
+static int omap_usb_set_host(struct usb_otg *otg, struct usb_bus *host);
+
 struct usb_phy_data {
 	const char *label;
 	u8 flags;
@@ -113,6 +115,36 @@ int omap_usb2_set_comparator(struct phy_companion *comparator)
 }
 EXPORT_SYMBOL_GPL(omap_usb2_set_comparator);
 
+/**
+ * omap_usb2_set_phy_comparator() - associate a comparator with an OMAP USB2 PHY
+ *
+ * @omap_phy: OMAP USB2 PHY instance
+ * @comparator: companion PHY providing comparator operations
+ *
+ * The phy companion driver should call this API with the companion PHY
+ * implementation containing the callbacks required by @omap_phy.
+ *
+ * For use by phy companion drivers.
+ */
+int omap_usb2_set_phy_comparator(struct usb_phy *omap_phy,
+				 struct phy_companion *comparator)
+{
+	struct omap_usb	*phy;
+
+	if (!omap_phy)
+		return -EINVAL;
+
+	if (WARN_ON(!omap_phy->otg ||
+		    omap_phy->otg->set_host != omap_usb_set_host))
+		return -EINVAL;
+
+	phy = phy_to_omapusb(omap_phy);
+	phy->comparator = comparator;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(omap_usb2_set_phy_comparator);
+
 static int omap_usb_set_vbus(struct usb_otg *otg, bool enabled)
 {
 	struct omap_usb *phy = phy_to_omapusb(otg->usb_phy);
diff --git a/include/linux/phy/omap_usb.h b/include/linux/phy/omap_usb.h
index e23b52df93ec..96f9792c6ce6 100644
--- a/include/linux/phy/omap_usb.h
+++ b/include/linux/phy/omap_usb.h
@@ -15,11 +15,18 @@
 
 #if defined(CONFIG_OMAP_USB2) || defined(CONFIG_OMAP_USB2_MODULE)
 extern int omap_usb2_set_comparator(struct phy_companion *comparator);
+extern int omap_usb2_set_phy_comparator(struct usb_phy *omap_phy,
+					struct phy_companion *comparator);
 #else
 static inline int omap_usb2_set_comparator(struct phy_companion *comparator)
 {
 	return -ENODEV;
 }
+static inline int omap_usb2_set_phy_comparator(struct usb_phy *omap_phy,
+					       struct phy_companion *comparator)
+{
+	return -ENODEV;
+}
 #endif
 
 #endif /* __DRIVERS_OMAP_USB_H */
-- 
2.39.5