usb: ci_udc: Add function to remove usb device

When unregister gadget driver in ci_udc, the usb device is not
removed or stop. This causes next "usb start" fails to work.

Add a new interface "usb_remove_ehci_gadget" in usb-uclass to
remove the usb device for DM driver. Using "usb_lowlevel_stop" for
non-DM driver.
Signed-off-by: NYe Li <ye.li@nxp.com>
Signed-off-by: NPeng Fan <peng.fan@nxp.com>

drivers/usb/gadget/ci_udc.c

@@ -1053,6 +1053,13 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 	free(controller.items_mem);
 	free(controller.epts);
 
+#if CONFIG_IS_ENABLED(DM_USB)
+	usb_remove_ehci_gadget(&controller.ctrl);
+#else
+	usb_lowlevel_stop(0);
+	controller.ctrl = NULL;
+#endif
+
 	return 0;
 }
 

drivers/usb/host/usb-uclass.c

@@ -411,6 +411,24 @@ int usb_setup_ehci_gadget(struct ehci_ctrl **ctlrp)
 	return 0;
 }
 
+int usb_remove_ehci_gadget(struct ehci_ctrl **ctlrp)
+{
+	struct udevice *dev;
+	int ret;
+
+	/* Find the old device and remove it */
+	ret = uclass_find_device_by_seq(UCLASS_USB, 0, true, &dev);
+	if (ret)
+		return ret;
+	ret = device_remove(dev, DM_REMOVE_NORMAL);
+	if (ret)
+		return ret;
+
+	*ctlrp = NULL;
+
+	return 0;
+}
+
 /* returns 0 if no match, 1 if match */
 static int usb_match_device(const struct usb_device_descriptor *desc,
 			    const struct usb_device_id *id)

include/usb.h

@@ -921,6 +921,15 @@ struct ehci_ctrl;
  */
 int usb_setup_ehci_gadget(struct ehci_ctrl **ctlrp);
 
+/**
+ * usb_remove_ehci_gadget() - Remove a gadget USB device
+ *
+ * TODO(sjg@chromium.org): Tidy this up when USB gadgets can use driver model
+ *
+ * This provides a way to tell a controller to remove a USB device
+ */
+int usb_remove_ehci_gadget(struct ehci_ctrl **ctlrp);
+
 /**
  * usb_stor_reset() - Prepare to scan USB storage devices
  *