usb: phy: Introduce one extcon device into usb phy

Usually usb phy need register one extcon device to get the connection
notifications. It will remove some duplicate code if the extcon device
is registered using common code instead of each phy driver having its
own related extcon APIs. So we add one pointer of extcon device into
usb phy structure, and some other helper functions to register extcon.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/phy/Kconfig

@@ -4,6 +4,7 @@
 menu "USB Physical Layer drivers"
 
 config USB_PHY
+	select EXTCON
 	def_bool n
 
 #
@@ -109,7 +110,7 @@ config OMAP_OTG
 
 config TAHVO_USB
 	tristate "Tahvo USB transceiver driver"
-	depends on MFD_RETU && EXTCON
+	depends on MFD_RETU
 	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
@@ -141,7 +142,6 @@ config USB_MSM_OTG
 	depends on (USB || USB_GADGET) && (ARCH_QCOM || COMPILE_TEST)
 	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	depends on RESET_CONTROLLER
-	depends on EXTCON
 	select USB_PHY
 	help
 	  Enable this to support the USB OTG transceiver on Qualcomm chips. It
@@ -155,7 +155,7 @@ config USB_MSM_OTG
 config USB_QCOM_8X16_PHY
 	tristate "Qualcomm APQ8016/MSM8916 on-chip USB PHY controller support"
 	depends on ARCH_QCOM || COMPILE_TEST
-	depends on RESET_CONTROLLER && EXTCON
+	depends on RESET_CONTROLLER
 	select USB_PHY
 	select USB_ULPI_VIEWPORT
 	help

drivers/usb/phy/phy.c

@@ -100,6 +100,54 @@ static int devm_usb_phy_match(struct device *dev, void *res, void *match_data)
 	return *phy == match_data;
 }
 
+static int usb_add_extcon(struct usb_phy *x)
+{
+	int ret;
+
+	if (of_property_read_bool(x->dev->of_node, "extcon")) {
+		x->edev = extcon_get_edev_by_phandle(x->dev, 0);
+		if (IS_ERR(x->edev))
+			return PTR_ERR(x->edev);
+
+		x->id_edev = extcon_get_edev_by_phandle(x->dev, 1);
+		if (IS_ERR(x->id_edev)) {
+			x->id_edev = NULL;
+			dev_info(x->dev, "No separate ID extcon device\n");
+		}
+
+		if (x->vbus_nb.notifier_call) {
+			ret = devm_extcon_register_notifier(x->dev, x->edev,
+							    EXTCON_USB,
+							    &x->vbus_nb);
+			if (ret < 0) {
+				dev_err(x->dev,
+					"register VBUS notifier failed\n");
+				return ret;
+			}
+		}
+
+		if (x->id_nb.notifier_call) {
+			struct extcon_dev *id_ext;
+
+			if (x->id_edev)
+				id_ext = x->id_edev;
+			else
+				id_ext = x->edev;
+
+			ret = devm_extcon_register_notifier(x->dev, id_ext,
+							    EXTCON_USB_HOST,
+							    &x->id_nb);
+			if (ret < 0) {
+				dev_err(x->dev,
+					"register ID notifier failed\n");
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
 /**
  * devm_usb_get_phy - find the USB PHY
  * @dev - device that requests this phy
@@ -388,6 +436,10 @@ int usb_add_phy(struct usb_phy *x, enum usb_phy_type type)
 		return -EINVAL;
 	}
 
+	ret = usb_add_extcon(x);
+	if (ret)
+		return ret;
+
 	ATOMIC_INIT_NOTIFIER_HEAD(&x->notifier);
 
 	spin_lock_irqsave(&phy_lock, flags);
@@ -422,12 +474,17 @@ int usb_add_phy_dev(struct usb_phy *x)
 {
 	struct usb_phy_bind *phy_bind;
 	unsigned long flags;
+	int ret;
 
 	if (!x->dev) {
 		dev_err(x->dev, "no device provided for PHY\n");
 		return -EINVAL;
 	}
 
+	ret = usb_add_extcon(x);
+	if (ret)
+		return ret;
+
 	ATOMIC_INIT_NOTIFIER_HEAD(&x->notifier);
 
 	spin_lock_irqsave(&phy_lock, flags);

include/linux/usb/phy.h

@@ -9,6 +9,7 @@
 #ifndef __LINUX_USB_PHY_H
 #define __LINUX_USB_PHY_H
 
+#include <linux/extcon.h>
 #include <linux/notifier.h>
 #include <linux/usb.h>
 
@@ -85,6 +86,12 @@ struct usb_phy {
 	struct usb_phy_io_ops	*io_ops;
 	void __iomem		*io_priv;
 
+	/* to support extcon device */
+	struct extcon_dev	*edev;
+	struct extcon_dev	*id_edev;
+	struct notifier_block	vbus_nb;
+	struct notifier_block	id_nb;
+
 	/* for notification of usb_phy_events */
 	struct atomic_notifier_head	notifier;