RZ/G2E cat874 board is capable of detecting cable connect and disconnect
events. Add support for renesas_usb3 to receive connect and disconnect
events and support dual-role switch using usb-role-switch framework.

Signed-off-by: Biju Das <biju....@bp.renesas.com>
---
 V2-->V3
   * Incorporated Shimoda-san's review comment
     (https://patchwork.kernel.org/patch/10852507/)
   * Used renesas,usb-role-switch property for differentiating USB
     role switch associated with Type-C port controller driver.
 V1-->V2
   * Driver uses usb role clas for handling dual role switch and handling
     connect/disconnect events instead of extcon.
---
 drivers/usb/gadget/udc/renesas_usb3.c | 126 ++++++++++++++++++++++++++++------
 1 file changed, 104 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c 
b/drivers/usb/gadget/udc/renesas_usb3.c
index 7dc2485..efee047 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -351,6 +351,8 @@ struct renesas_usb3 {
        int disabled_count;
 
        struct usb_request *ep0_req;
+
+       enum usb_role connection_state;
        u16 test_mode;
        u8 ep0_buf[USB3_EP0_BUF_SIZE];
        bool softconnect;
@@ -359,6 +361,7 @@ struct renesas_usb3 {
        bool extcon_usb;                /* check vbus and set EXTCON_USB */
        bool forced_b_device;
        bool start_to_connect;
+       bool usb_role_switch_property;
 };
 
 #define gadget_to_renesas_usb3(_gadget)        \
@@ -644,22 +647,6 @@ static void usb3_disconnect(struct renesas_usb3 *usb3)
                usb3->driver->disconnect(&usb3->gadget);
 }
 
-static void usb3_check_vbus(struct renesas_usb3 *usb3)
-{
-       if (usb3->workaround_for_vbus) {
-               usb3_connect(usb3);
-       } else {
-               usb3->extcon_usb = !!(usb3_read(usb3, USB3_USB_STA) &
-                                                       USB_STA_VBUS_STA);
-               if (usb3->extcon_usb)
-                       usb3_connect(usb3);
-               else
-                       usb3_disconnect(usb3);
-
-               schedule_work(&usb3->extcon_work);
-       }
-}
-
 static void renesas_usb3_role_work(struct work_struct *work)
 {
        struct renesas_usb3 *usb3 =
@@ -699,8 +686,11 @@ static void usb3_mode_config(struct renesas_usb3 *usb3, 
bool host, bool a_dev)
        unsigned long flags;
 
        spin_lock_irqsave(&usb3->lock, flags);
-       usb3_set_mode_by_role_sw(usb3, host);
-       usb3_vbus_out(usb3, a_dev);
+       if (!usb3->usb_role_switch_property ||
+           usb3->connection_state != USB_ROLE_NONE) {
+               usb3_set_mode_by_role_sw(usb3, host);
+               usb3_vbus_out(usb3, a_dev);
+       }
        /* for A-Peripheral or forced B-device mode */
        if ((!host && a_dev) || usb3->start_to_connect)
                usb3_connect(usb3);
@@ -724,6 +714,28 @@ static void usb3_check_id(struct renesas_usb3 *usb3)
        schedule_work(&usb3->extcon_work);
 }
 
+static void usb3_check_vbus(struct renesas_usb3 *usb3)
+{
+       if (usb3->workaround_for_vbus) {
+               if (usb3->usb_role_switch_property) {
+                       if (usb3->connection_state == USB_ROLE_DEVICE) {
+                               usb3_mode_config(usb3, false, false);
+                               usb3_connect(usb3);
+                       }
+               } else
+                       usb3_connect(usb3);
+       } else {
+               usb3->extcon_usb = !!(usb3_read(usb3, USB3_USB_STA) &
+                                                       USB_STA_VBUS_STA);
+               if (usb3->extcon_usb)
+                       usb3_connect(usb3);
+               else
+                       usb3_disconnect(usb3);
+
+               schedule_work(&usb3->extcon_work);
+       }
+}
+
 static void renesas_usb3_init_controller(struct renesas_usb3 *usb3)
 {
        usb3_init_axi_bridge(usb3);
@@ -2343,14 +2355,65 @@ static enum usb_role 
renesas_usb3_role_switch_get(struct device *dev)
        return cur_role;
 }
 
-static int renesas_usb3_role_switch_set(struct device *dev,
-                                       enum usb_role role)
+static void handle_ext_role_switch_states(struct device *dev,
+                                           enum usb_role role)
+{
+       struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
+       struct device *host = usb3->host_dev;
+       enum usb_role cur_role = renesas_usb3_role_switch_get(dev);
+
+       switch (role) {
+       case USB_ROLE_NONE:
+               usb3->connection_state = USB_ROLE_NONE;
+               if (usb3->driver)
+                       usb3_disconnect(usb3);
+               usb3_vbus_out(usb3, false);
+               break;
+       case USB_ROLE_DEVICE:
+               if (usb3->connection_state == USB_ROLE_NONE) {
+                       usb3->connection_state = USB_ROLE_DEVICE;
+                       usb3_set_mode(usb3, false);
+                       if (usb3->driver)
+                               usb3_connect(usb3);
+               } else if (cur_role == USB_ROLE_HOST)  {
+                       device_release_driver(host);
+                       usb3_set_mode(usb3, false);
+                       if (usb3->driver)
+                               usb3_connect(usb3);
+               }
+               usb3_vbus_out(usb3, false);
+               break;
+       case USB_ROLE_HOST:
+               if (usb3->connection_state == USB_ROLE_NONE) {
+                       if (usb3->driver)
+                               usb3_disconnect(usb3);
+
+                       usb3->connection_state = USB_ROLE_HOST;
+                       usb3_set_mode(usb3, true);
+                       usb3_vbus_out(usb3, true);
+                       if (device_attach(host) < 0)
+                               dev_err(dev, "device_attach(host) failed\n");
+               } else if (cur_role == USB_ROLE_DEVICE) {
+                       usb3_disconnect(usb3);
+                       /* Must set the mode before device_attach of the host */
+                       usb3_set_mode(usb3, true);
+                       /* This device_attach() might sleep */
+                       if (device_attach(host) < 0)
+                               dev_err(dev, "device_attach(host) failed\n");
+               }
+               break;
+       default:
+               break;
+       }
+}
+
+static void handle_role_switch_states(struct device *dev,
+                                           enum usb_role role)
 {
        struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
        struct device *host = usb3->host_dev;
        enum usb_role cur_role = renesas_usb3_role_switch_get(dev);
 
-       pm_runtime_get_sync(dev);
        if (cur_role == USB_ROLE_HOST && role == USB_ROLE_DEVICE) {
                device_release_driver(host);
                usb3_set_mode(usb3, false);
@@ -2361,6 +2424,20 @@ static int renesas_usb3_role_switch_set(struct device 
*dev,
                if (device_attach(host) < 0)
                        dev_err(dev, "device_attach(host) failed\n");
        }
+}
+
+static int renesas_usb3_role_switch_set(struct device *dev,
+                                       enum usb_role role)
+{
+       struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
+
+       pm_runtime_get_sync(dev);
+
+       if (usb3->usb_role_switch_property)
+               handle_ext_role_switch_states(dev, role);
+       else
+               handle_role_switch_states(dev, role);
+
        pm_runtime_put(dev);
 
        return 0;
@@ -2650,7 +2727,7 @@ static const unsigned int renesas_usb3_cable[] = {
        EXTCON_NONE,
 };
 
-static const struct usb_role_switch_desc renesas_usb3_role_switch_desc = {
+static struct usb_role_switch_desc renesas_usb3_role_switch_desc = {
        .set = renesas_usb3_role_switch_set,
        .get = renesas_usb3_role_switch_get,
        .allow_userspace_control = true,
@@ -2741,6 +2818,11 @@ static int renesas_usb3_probe(struct platform_device 
*pdev)
        if (ret < 0)
                goto err_dev_create;
 
+       if (device_property_read_bool(&pdev->dev, "renesas,usb-role-switch")) {
+               usb3->usb_role_switch_property = true;
+               renesas_usb3_role_switch_desc.fwnode = dev_fwnode(&pdev->dev);
+       }
+
        INIT_WORK(&usb3->role_work, renesas_usb3_role_work);
        usb3->role_sw = usb_role_switch_register(&pdev->dev,
                                        &renesas_usb3_role_switch_desc);
-- 
2.7.4

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