usb: chipidea: add vbus interrupt handler

We add vbus interrupt handler at ci_otg_work, it uses OTGSC_BSV(at otgsc)
to know it is connect or disconnet event.
Meanwhile, we introduce two flags id_event and b_sess_valid_event to
indicate it is an id interrupt or a vbus interrupt.

Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index 3b66cbe..7f37484 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -37,13 +37,23 @@
 	return role;
 }
 
-/**
- * ci_role_work - perform role changing based on ID pin
- * @work: work struct
- */
-static void ci_role_work(struct work_struct *work)
+void ci_handle_vbus_change(struct ci_hdrc *ci)
 {
-	struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
+	u32 otgsc;
+
+	if (!ci->is_otg)
+		return;
+
+	otgsc = hw_read(ci, OP_OTGSC, ~0);
+
+	if (otgsc & OTGSC_BSV)
+		usb_gadget_vbus_connect(&ci->gadget);
+	else
+		usb_gadget_vbus_disconnect(&ci->gadget);
+}
+
+static void ci_handle_id_switch(struct ci_hdrc *ci)
+{
 	enum ci_role role = ci_otg_role(ci);
 
 	if (role != ci->role) {
@@ -53,17 +63,35 @@
 		ci_role_stop(ci);
 		ci_role_start(ci, role);
 	}
+}
+/**
+ * ci_otg_work - perform otg (vbus/id) event handle
+ * @work: work struct
+ */
+static void ci_otg_work(struct work_struct *work)
+{
+	struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
+
+	if (ci->id_event) {
+		ci->id_event = false;
+		ci_handle_id_switch(ci);
+	} else if (ci->b_sess_valid_event) {
+		ci->b_sess_valid_event = false;
+		ci_handle_vbus_change(ci);
+	} else
+		dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
 
 	enable_irq(ci->irq);
 }
 
+
 /**
  * ci_hdrc_otg_init - initialize otg struct
  * ci: the controller
  */
 int ci_hdrc_otg_init(struct ci_hdrc *ci)
 {
-	INIT_WORK(&ci->work, ci_role_work);
+	INIT_WORK(&ci->work, ci_otg_work);
 	ci->wq = create_singlethread_workqueue("ci_otg");
 	if (!ci->wq) {
 		dev_err(ci->dev, "can't create workqueue\n");