1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * of.c		The helpers for hcd device tree support
  4 *
  5 * Copyright (C) 2016 Freescale Semiconductor, Inc.
  6 *	Author: Peter Chen <peter.chen@freescale.com>
  7 * Copyright (C) 2017 Johan Hovold <johan@kernel.org>
  8 */
  9
 10#include <linux/of.h>
 11#include <linux/usb/of.h>
 12
 13/**
 14 * usb_of_get_device_node() - get a USB device node
 15 * @hub: hub to which device is connected
 16 * @port1: one-based index of port
 17 *
 18 * Look up the node of a USB device given its parent hub device and one-based
 19 * port number.
 20 *
 21 * Return: A pointer to the node with incremented refcount if found, or
 22 * %NULL otherwise.
 23 */
 24struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1)
 25{
 26	struct device_node *node;
 27	u32 reg;
 28
 29	for_each_child_of_node(hub->dev.of_node, node) {
 30		if (of_property_read_u32(node, "reg", &reg))
 31			continue;
 32
 33		if (reg == port1)
 34			return node;
 35	}
 36
 37	return NULL;
 38}
 39EXPORT_SYMBOL_GPL(usb_of_get_device_node);
 40
 41/**
 42 * usb_of_has_combined_node() - determine whether a device has a combined node
 43 * @udev: USB device
 44 *
 45 * Determine whether a USB device has a so called combined node which is
 46 * shared with its sole interface. This is the case if and only if the device
 47 * has a node and its descriptors report the following:
 48 *
 49 *	1) bDeviceClass is 0 or 9, and
 50 *	2) bNumConfigurations is 1, and
 51 *	3) bNumInterfaces is 1.
 52 *
 53 * Return: True iff the device has a device node and its descriptors match the
 54 * criteria for a combined node.
 55 */
 56bool usb_of_has_combined_node(struct usb_device *udev)
 57{
 58	struct usb_device_descriptor *ddesc = &udev->descriptor;
 59	struct usb_config_descriptor *cdesc;
 60
 61	if (!udev->dev.of_node)
 62		return false;
 63
 64	switch (ddesc->bDeviceClass) {
 65	case USB_CLASS_PER_INTERFACE:
 66	case USB_CLASS_HUB:
 67		if (ddesc->bNumConfigurations == 1) {
 68			cdesc = &udev->config->desc;
 69			if (cdesc->bNumInterfaces == 1)
 70				return true;
 71		}
 72	}
 73
 74	return false;
 75}
 76EXPORT_SYMBOL_GPL(usb_of_has_combined_node);
 77
 78/**
 79 * usb_of_get_interface_node() - get a USB interface node
 80 * @udev: USB device of interface
 81 * @config: configuration value
 82 * @ifnum: interface number
 83 *
 84 * Look up the node of a USB interface given its USB device, configuration
 85 * value and interface number.
 86 *
 87 * Return: A pointer to the node with incremented refcount if found, or
 88 * %NULL otherwise.
 89 */
 90struct device_node *
 91usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
 92{
 93	struct device_node *node;
 94	u32 reg[2];
 95
 96	for_each_child_of_node(udev->dev.of_node, node) {
 97		if (of_property_read_u32_array(node, "reg", reg, 2))
 98			continue;
 99
100		if (reg[0] == ifnum && reg[1] == config)
101			return node;
102	}
103
104	return NULL;
105}
106EXPORT_SYMBOL_GPL(usb_of_get_interface_node);