From 8595748e58885439c7e18a11a94702378bff3b02 Mon Sep 17 00:00:00 2001
From: Li Jun <jun.li@nxp.com>
Date: Sun, 27 Jan 2019 19:40:03 +0800
Subject: [PATCH] usb: dwc3: drd: add usb role switch class support for dual
 role swap

Register a usb_role_switch for dual role swap if the property
"usb-role-switch" is present.

Signed-off-by: Li Jun <jun.li@nxp.com>
---
 drivers/usb/dwc3/core.h |  2 ++
 drivers/usb/dwc3/drd.c  | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -25,6 +25,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/otg.h>
+#include <linux/usb/role.h>
 #include <linux/ulpi/interface.h>
 
 #include <linux/phy/phy.h>
@@ -1089,6 +1090,7 @@ struct dwc3 {
 	void __iomem		*regs;
 	size_t			regs_size;
 
+	struct usb_role_switch	*role_switch;
 	enum usb_dr_mode	dr_mode;
 	u32			current_dr_role;
 	u32			desired_dr_role;
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -476,6 +476,43 @@ static struct extcon_dev *dwc3_get_extco
 	return edev;
 }
 
+static int dwc3_usb_role_switch_set(struct device *dev, enum usb_role role)
+{
+	u32 mode;
+
+	switch (role) {
+	case USB_ROLE_HOST:
+		mode = DWC3_GCTL_PRTCAP_HOST;
+		break;
+	case USB_ROLE_DEVICE:
+		mode = DWC3_GCTL_PRTCAP_DEVICE;
+		break;
+	default:
+		return 0;
+	};
+
+	dwc3_set_mode(dev_get_drvdata(dev), mode);
+	return 0;
+}
+
+static enum usb_role dwc3_usb_role_switch_get(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	unsigned long flags;
+	enum usb_role role;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	role = dwc->current_dr_role;
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return role;
+}
+
+static const struct usb_role_switch_desc dwc3_role_switch = {
+	.set = dwc3_usb_role_switch_set,
+	.get = dwc3_usb_role_switch_get,
+};
+
 int dwc3_drd_init(struct dwc3 *dwc)
 {
 	int ret, irq;
@@ -484,7 +521,12 @@ int dwc3_drd_init(struct dwc3 *dwc)
 	if (IS_ERR(dwc->edev))
 		return PTR_ERR(dwc->edev);
 
-	if (dwc->edev) {
+	if (device_property_read_bool(dwc->dev, "usb-role-switch")) {
+		dwc->role_switch = usb_role_switch_register(dwc->dev,
+							    &dwc3_role_switch);
+		if (IS_ERR(dwc->role_switch))
+			return PTR_ERR(dwc->role_switch);
+	} else if (dwc->edev) {
 		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
 		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
 					       &dwc->edev_nb);
@@ -531,6 +573,9 @@ void dwc3_drd_exit(struct dwc3 *dwc)
 {
 	unsigned long flags;
 
+	if (dwc->role_switch)
+		usb_role_switch_unregister(dwc->role_switch);
+
 	if (dwc->edev)
 		extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
 					   &dwc->edev_nb);