usb: chipidea: Use extcon framework for VBUS and ID detect

On recent Qualcomm platforms VBUS and ID lines are not routed to
USB PHY LINK controller. Use extcon framework to receive connect
and disconnect ID and VBUS notification.
Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org>
Signed-off-by: Peter Chen <peter.chen@freescale.com>

Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt

@@ -46,6 +46,11 @@ Optional properties:
   (4 bytes), This register represents the maximum length of a the burst
   in 32-bit words while moving data from the USB bus to system memory,
   changing this value takes effect only the SBUSCFG.AHBBRST is 0.
+- extcon: phandles to external connector devices. First phandle should point to
+  external connector, which provide "USB" cable events, the second should point
+  to external connector device, which provide "USB-HOST" cable events. If one
+  of the external connector devices is not required, empty <0> phandle should
+  be specified.
 
 Example:
 
@@ -62,4 +67,5 @@ Example:
 		ahb-burst-config = <0x0>;
 		tx-burst-size-dword = <0x10>; /* 64 bytes */
 		rx-burst-size-dword = <0x10>;
+		extcon = <0>, <&usb_id>;
 	};

drivers/usb/chipidea/Kconfig

 config USB_CHIPIDEA
 	tristate "ChipIdea Highspeed Dual Role Controller"
 	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
+	select EXTCON
 	help
 	  Say Y here if your system has a dual role high speed USB
 	  controller based on ChipIdea silicon IP. Currently, only the

drivers/usb/chipidea/core.c

@@ -47,6 +47,7 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
+#include <linux/extcon.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/module.h>
@@ -602,9 +603,45 @@ static irqreturn_t ci_irq(int irq, void *data)
 	return ret;
 }
 
+static int ci_vbus_notifier(struct notifier_block *nb, unsigned long event,
+			    void *ptr)
+{
+	struct ci_hdrc_cable *vbus = container_of(nb, struct ci_hdrc_cable, nb);
+	struct ci_hdrc *ci = vbus->ci;
+
+	if (event)
+		vbus->state = true;
+	else
+		vbus->state = false;
+
+	vbus->changed = true;
+
+	ci_irq(ci->irq, ci);
+	return NOTIFY_DONE;
+}
+
+static int ci_id_notifier(struct notifier_block *nb, unsigned long event,
+			  void *ptr)
+{
+	struct ci_hdrc_cable *id = container_of(nb, struct ci_hdrc_cable, nb);
+	struct ci_hdrc *ci = id->ci;
+
+	if (event)
+		id->state = false;
+	else
+		id->state = true;
+
+	id->changed = true;
+
+	ci_irq(ci->irq, ci);
+	return NOTIFY_DONE;
+}
+
 static int ci_get_platdata(struct device *dev,
 		struct ci_hdrc_platform_data *platdata)
 {
+	struct extcon_dev *ext_vbus, *ext_id;
+	struct ci_hdrc_cable *cable;
 	int ret;
 
 	if (!platdata->phy_mode)
@@ -695,9 +732,91 @@ static int ci_get_platdata(struct device *dev,
 		platdata->flags |= CI_HDRC_OVERRIDE_RX_BURST;
 	}
 
+	ext_id = ERR_PTR(-ENODEV);
+	ext_vbus = ERR_PTR(-ENODEV);
+	if (of_property_read_bool(dev->of_node, "extcon")) {
+		/* Each one of them is not mandatory */
+		ext_vbus = extcon_get_edev_by_phandle(dev, 0);
+		if (IS_ERR(ext_vbus) && PTR_ERR(ext_vbus) != -ENODEV)
+			return PTR_ERR(ext_vbus);
+
+		ext_id = extcon_get_edev_by_phandle(dev, 1);
+		if (IS_ERR(ext_id) && PTR_ERR(ext_id) != -ENODEV)
+			return PTR_ERR(ext_id);
+	}
+
+	cable = &platdata->vbus_extcon;
+	cable->nb.notifier_call = ci_vbus_notifier;
+	cable->edev = ext_vbus;
+
+	if (!IS_ERR(ext_vbus)) {
+		ret = extcon_get_cable_state_(cable->edev, EXTCON_USB);
+		if (ret)
+			cable->state = true;
+		else
+			cable->state = false;
+	}
+
+	cable = &platdata->id_extcon;
+	cable->nb.notifier_call = ci_id_notifier;
+	cable->edev = ext_id;
+
+	if (!IS_ERR(ext_id)) {
+		ret = extcon_get_cable_state_(cable->edev, EXTCON_USB_HOST);
+		if (ret)
+			cable->state = false;
+		else
+			cable->state = true;
+	}
 	return 0;
 }
 
+static int ci_extcon_register(struct ci_hdrc *ci)
+{
+	struct ci_hdrc_cable *id, *vbus;
+	int ret;
+
+	id = &ci->platdata->id_extcon;
+	id->ci = ci;
+	if (!IS_ERR(id->edev)) {
+		ret = extcon_register_notifier(id->edev, EXTCON_USB_HOST,
+					       &id->nb);
+		if (ret < 0) {
+			dev_err(ci->dev, "register ID failed\n");
+			return ret;
+		}
+	}
+
+	vbus = &ci->platdata->vbus_extcon;
+	vbus->ci = ci;
+	if (!IS_ERR(vbus->edev)) {
+		ret = extcon_register_notifier(vbus->edev, EXTCON_USB,
+					       &vbus->nb);
+		if (ret < 0) {
+			extcon_unregister_notifier(id->edev, EXTCON_USB_HOST,
+						   &id->nb);
+			dev_err(ci->dev, "register VBUS failed\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void ci_extcon_unregister(struct ci_hdrc *ci)
+{
+	struct ci_hdrc_cable *cable;
+
+	cable = &ci->platdata->id_extcon;
+	if (!IS_ERR(cable->edev))
+		extcon_unregister_notifier(cable->edev, EXTCON_USB_HOST,
+					   &cable->nb);
+
+	cable = &ci->platdata->vbus_extcon;
+	if (!IS_ERR(cable->edev))
+		extcon_unregister_notifier(cable->edev, EXTCON_USB, &cable->nb);
+}
+
 static DEFINE_IDA(ci_ida);
 
 struct platform_device *ci_hdrc_add_device(struct device *dev,
@@ -921,6 +1040,10 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 	if (ret)
 		goto stop;
 
+	ret = ci_extcon_register(ci);
+	if (ret)
+		goto stop;
+
 	if (ci->supports_runtime_pm) {
 		pm_runtime_set_active(&pdev->dev);
 		pm_runtime_enable(&pdev->dev);
@@ -938,6 +1061,7 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 	if (!ret)
 		return 0;
 
+	ci_extcon_unregister(ci);
 stop:
 	ci_role_destroy(ci);
 deinit_phy:
@@ -957,6 +1081,7 @@ static int ci_hdrc_remove(struct platform_device *pdev)
 	}
 
 	dbg_remove_files(ci);
+	ci_extcon_unregister(ci);
 	ci_role_destroy(ci);
 	ci_hdrc_enter_lpm(ci, true);
 	ci_usb_phy_exit(ci);

drivers/usb/chipidea/otg.c

@@ -30,7 +30,44 @@
  */
 u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
 {
-	return hw_read(ci, OP_OTGSC, mask);
+	struct ci_hdrc_cable *cable;
+	u32 val = hw_read(ci, OP_OTGSC, mask);
+
+	/*
+	 * If using extcon framework for VBUS and/or ID signal
+	 * detection overwrite OTGSC register value
+	 */
+	cable = &ci->platdata->vbus_extcon;
+	if (!IS_ERR(cable->edev)) {
+		if (cable->changed)
+			val |= OTGSC_BSVIS;
+		else
+			val &= ~OTGSC_BSVIS;
+
+		cable->changed = false;
+
+		if (cable->state)
+			val |= OTGSC_BSV;
+		else
+			val &= ~OTGSC_BSV;
+	}
+
+	cable = &ci->platdata->id_extcon;
+	if (!IS_ERR(cable->edev)) {
+		if (cable->changed)
+			val |= OTGSC_IDIS;
+		else
+			val &= ~OTGSC_IDIS;
+
+		cable->changed = false;
+
+		if (cable->state)
+			val |= OTGSC_ID;
+		else
+			val &= ~OTGSC_ID;
+	}
+
+	return val;
 }
 
 /**

include/linux/usb/chipidea.h

@@ -5,9 +5,28 @@
 #ifndef __LINUX_USB_CHIPIDEA_H
 #define __LINUX_USB_CHIPIDEA_H
 
+#include <linux/extcon.h>
 #include <linux/usb/otg.h>
 
 struct ci_hdrc;
+
+/**
+ * struct ci_hdrc_cable - structure for external connector cable state tracking
+ * @state: current state of the line
+ * @changed: set to true when extcon event happen
+ * @edev: device which generate events
+ * @ci: driver state of the chipidea device
+ * @nb: hold event notification callback
+ * @conn: used for notification registration
+ */
+struct ci_hdrc_cable {
+	bool				state;
+	bool				changed;
+	struct extcon_dev		*edev;
+	struct ci_hdrc			*ci;
+	struct notifier_block		nb;
+};
+
 struct ci_hdrc_platform_data {
 	const char	*name;
 	/* offset of the capability registers */
@@ -48,6 +67,10 @@ struct ci_hdrc_platform_data {
 	u32			ahb_burst_config;
 	u32			tx_burst_size;
 	u32			rx_burst_size;
+
+	/* VBUS and ID signal state tracking, using extcon framework */
+	struct ci_hdrc_cable		vbus_extcon;
+	struct ci_hdrc_cable		id_extcon;
 };
 
 /* Default offset of capability registers */