1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c
new file mode 100644
index 000000000..617e92569
--- /dev/null
+++ b/drivers/usb/core/of.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * of.c		The helpers for hcd device tree support
+ *
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ *	Author: Peter Chen <peter.chen@freescale.com>
+ * Copyright (C) 2017 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/usb/of.h>
+
+/**
+ * usb_of_get_device_node() - get a USB device node
+ * @hub: hub to which device is connected
+ * @port1: one-based index of port
+ *
+ * Look up the node of a USB device given its parent hub device and one-based
+ * port number.
+ *
+ * Return: A pointer to the node with incremented refcount if found, or
+ * %NULL otherwise.
+ */
+struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1)
+{
+	struct device_node *node;
+	u32 reg;
+
+	for_each_child_of_node(hub->dev.of_node, node) {
+		if (of_property_read_u32(node, "reg", &reg))
+			continue;
+
+		if (reg == port1)
+			return node;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(usb_of_get_device_node);
+
+/**
+ * usb_of_has_combined_node() - determine whether a device has a combined node
+ * @udev: USB device
+ *
+ * Determine whether a USB device has a so called combined node which is
+ * shared with its sole interface. This is the case if and only if the device
+ * has a node and its descriptors report the following:
+ *
+ *	1) bDeviceClass is 0 or 9, and
+ *	2) bNumConfigurations is 1, and
+ *	3) bNumInterfaces is 1.
+ *
+ * Return: True iff the device has a device node and its descriptors match the
+ * criteria for a combined node.
+ */
+bool usb_of_has_combined_node(struct usb_device *udev)
+{
+	struct usb_device_descriptor *ddesc = &udev->descriptor;
+	struct usb_config_descriptor *cdesc;
+
+	if (!udev->dev.of_node)
+		return false;
+
+	switch (ddesc->bDeviceClass) {
+	case USB_CLASS_PER_INTERFACE:
+	case USB_CLASS_HUB:
+		if (ddesc->bNumConfigurations == 1) {
+			cdesc = &udev->config->desc;
+			if (cdesc->bNumInterfaces == 1)
+				return true;
+		}
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(usb_of_has_combined_node);
+
+/**
+ * usb_of_get_interface_node() - get a USB interface node
+ * @udev: USB device of interface
+ * @config: configuration value
+ * @ifnum: interface number
+ *
+ * Look up the node of a USB interface given its USB device, configuration
+ * value and interface number.
+ *
+ * Return: A pointer to the node with incremented refcount if found, or
+ * %NULL otherwise.
+ */
+struct device_node *
+usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
+{
+	struct device_node *node;
+	u32 reg[2];
+
+	for_each_child_of_node(udev->dev.of_node, node) {
+		if (of_property_read_u32_array(node, "reg", reg, 2))
+			continue;
+
+		if (reg[0] == ifnum && reg[1] == config)
+			return node;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(usb_of_get_interface_node);