The RZ/G2E cat874 board has a type-c connector connected to hd3ss3220 usb
type-c drp port controller. This patch adds dual role switch support for
the type-c connector using the usb role switch class framework.

Signed-off-by: Biju Das <biju....@bp.renesas.com>
---
 V5-->V6
   * Added graph api's to find the role supported by the connector.
 V4-->V5
   * Incorporated Shimoda-san's review comment
    (https://patchwork.kernel.org/patch/10902537/)
 V3-->V4
   * No Change
 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 | 121 ++++++++++++++++++++++++++++++++--
 1 file changed, 114 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c 
b/drivers/usb/gadget/udc/renesas_usb3.c
index 7dc2485..1d41998 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -24,6 +24,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/of.h>
+#include <linux/of_graph.h>
 #include <linux/usb/role.h>
 
 /* register definitions */
@@ -351,6 +352,8 @@ 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 +362,7 @@ struct renesas_usb3 {
        bool extcon_usb;                /* check vbus and set EXTCON_USB */
        bool forced_b_device;
        bool start_to_connect;
+       bool dual_role_sw;
 };
 
 #define gadget_to_renesas_usb3(_gadget)        \
@@ -699,8 +703,10 @@ 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->dual_role_sw || 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);
@@ -716,7 +722,8 @@ static void usb3_check_id(struct renesas_usb3 *usb3)
 {
        usb3->extcon_host = usb3_is_a_device(usb3);
 
-       if (usb3->extcon_host && !usb3->forced_b_device)
+       if ((!usb3->dual_role_sw && usb3->extcon_host && !usb3->forced_b_device)
+           || usb3->connection_state == USB_ROLE_HOST)
                usb3_mode_config(usb3, true, true);
        else
                usb3_mode_config(usb3, false, false);
@@ -2343,14 +2350,65 @@ 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 +2419,20 @@ 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->dual_role_sw)
+               handle_ext_role_switch_states(dev, role);
+       else
+               handle_role_switch_states(dev, role);
+
        pm_runtime_put(dev);
 
        return 0;
@@ -2650,12 +2722,41 @@ 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,
 };
 
+static bool is_usb_dual_role_switch(struct device *dev)
+{
+       struct device_node *np = dev->of_node;
+       struct device_node *parent;
+       struct device_node *child;
+       bool ret = false;
+       const char *role_type = NULL;
+
+       child = of_graph_get_endpoint_by_regs(np, -1, -1);
+       if (!child)
+               return ret;
+
+       parent = of_graph_get_remote_port_parent(child);
+       of_node_put(child);
+       child = of_get_child_by_name(parent, "connector");
+       of_node_put(parent);
+       if (!child)
+               return ret;
+
+       if (of_device_is_compatible(child, "usb-c-connector")) {
+               of_property_read_string(child, "data-role", &role_type);
+               if (role_type && (!strncmp(role_type, "dual", strlen("dual"))))
+                       ret = true;
+       }
+
+       of_node_put(child);
+       return ret;
+}
+
 static int renesas_usb3_probe(struct platform_device *pdev)
 {
        struct renesas_usb3 *usb3;
@@ -2741,6 +2842,12 @@ static int renesas_usb3_probe(struct platform_device 
*pdev)
        if (ret < 0)
                goto err_dev_create;
 
+       if (device_property_read_bool(&pdev->dev, "usb-role-switch") &&
+           is_usb_dual_role_switch(&pdev->dev)) {
+               usb3->dual_role_sw = 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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