subsys: usb: host: remove root member for usbh_context

add usbh_device_get_root and usbh_device_is_root
function to check root device

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

Author: AidenHu

include/zephyr/usb/usbh.h

@@ -58,8 +58,6 @@ struct usbh_context {
 	struct usbh_status status;
 	/** USB device list */
 	sys_dlist_t udevs;
-	/** USB root device */
-	struct usb_device *root;
 	/** Allocated device addresses bit array */
 	struct sys_bitarray *addr_ba;
 };

subsys/usb/host/usbh_core.c

@@ -68,30 +68,30 @@ 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;
-	}
 	k_mutex_unlock(&ctx->mutex);
 
 	if (usbh_device_init(udev)) {
 		LOG_ERR("Failed to reset new USB device");
 		sys_dlist_remove(&udev->node);
 	}
 
-	usbh_class_probe_device(ctx->root);
+	usbh_class_probe_device(usbh_device_get_root(ctx));
 }
 
 static void dev_removed_handler(struct usbh_context *const ctx)
 {
-	if (ctx->root != NULL) {
-		usbh_class_remove_all(ctx->root);
-		usbh_device_free(ctx->root);
-		ctx->root = NULL;
+	struct usb_device *udev = NULL;
+
+	udev = usbh_device_get_root(ctx);
+
+	if (udev) {
+		usbh_class_remove_all(udev);
+		usbh_device_free(udev);
 		LOG_DBG("Device removed");
 	} else {
 		LOG_DBG("Spurious device removed event");
 	}
+	/* TODO: handle remove for all of classes for the unattached device */
 }
 
 static int discard_ep_request(struct usbh_context *const ctx,

subsys/usb/host/usbh_device.c

@@ -446,6 +446,34 @@ int usbh_device_set_configuration(struct usb_device *const udev, const uint8_t n
 	return err;
 }
 
+struct usb_device *usbh_device_get_root(struct usbh_context *const ctx)
+{
+	sys_dnode_t *node;
+
+	if (ctx == NULL) {
+		return NULL;
+	}
+
+	node = sys_dlist_peek_head(&ctx->udevs);
+	if (node == NULL) {
+		/* No devices in the list */
+		return NULL;
+	}
+
+	/* Get the usb_device structure from the node */
+	return CONTAINER_OF(node, struct usb_device, node);
+}
+
+bool usbh_device_is_root(struct usbh_context *const ctx,
+			struct usb_device *const udev)
+{
+	if (ctx == NULL || udev == NULL) {
+		return false;
+	}
+
+	return sys_dlist_peek_head(&ctx->udevs) == &udev->node;
+}
+
 int usbh_device_init(struct usb_device *const udev)
 {
 	struct usbh_context *const uhs_ctx = udev->ctx;

subsys/usb/host/usbh_device.h

@@ -35,6 +35,13 @@ int usbh_device_interface_set(struct usb_device *const udev,
 			      const uint8_t iface, const uint8_t alt,
 			      const bool dry);
 
+/* Get root USB device */
+struct usb_device *usbh_device_get_root(struct usbh_context *const ctx);
+
+/* Check if USB device is root */
+bool usbh_device_is_root(struct usbh_context *const ctx,
+			struct usb_device *const udev);
+
 /* Wrappers around to avoid glue UHC calls. */
 static inline struct uhc_transfer *usbh_xfer_alloc(struct usb_device *udev,
 						   const uint8_t ep,