subsys: usb: host: support multiple devices under hub

When hub is used, need to consider about multiple
devices are attached.

Signed-off-by: Aiden Hu <[email protected]>

Author: AidenHu

subsys/usb/host/usbh_core.c

@@ -48,6 +48,8 @@ static int usbh_event_carrier(const struct device *dev,
 static void dev_connected_handler(struct usbh_context *const ctx,
 				  const struct uhc_event *const event)
 {
+	struct usb_device *udev;
+
 	LOG_DBG("Device connected event");
 
 	udev = usbh_device_alloc(ctx);
@@ -66,7 +68,7 @@ static void dev_connected_handler(struct usbh_context *const ctx,
 
 	k_mutex_lock(&ctx->mutex, K_FOREVER);
 	sys_dlist_append(&ctx->udevs, &udev->node);
-	
+
 	if (ctx->root == NULL) {
 		ctx->root = udev;
 	}

subsys/usb/host/usbh_device.c

@@ -452,7 +452,6 @@ int usbh_device_init(struct usb_device *const udev)
 	struct usbh_context *const uhs_ctx = udev->ctx;
 	uint8_t new_addr;
 	int err;
-	sys_dnode_t *node;
 	uint8_t device_count = 0;
 
 	if (udev->state != USB_STATE_DEFAULT) {
@@ -467,8 +466,16 @@ int usbh_device_init(struct usb_device *const udev)
 	}
 
 	k_mutex_lock(&uhs_ctx->mutex, K_FOREVER);
-	SYS_DLIST_FOR_EACH_NODE(&uhs_ctx->udevs, node) {
-		device_count++;
+	device_count = sys_dlist_len(&uhs_ctx->udevs);
+	k_mutex_unlock(&uhs_ctx->mutex);
+
+	/* Only reset bus if this is the root device. */
+	if (device_count == 1U) {
+		err = uhc_bus_reset(uhs_ctx->dev);
+		if (err) {
+			LOG_ERR("Failed to signal bus reset");
+			return err;
+		}
 	}
 	k_mutex_unlock(&uhs_ctx->mutex);