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/of_graph.h>
12#include <linux/usb/of.h>
13
14/**
15 * usb_of_get_device_node() - get a USB device node
16 * @hub: hub to which device is connected
17 * @port1: one-based index of port
18 *
19 * Look up the node of a USB device given its parent hub device and one-based
20 * port number.
21 *
22 * Return: A pointer to the node with incremented refcount if found, or
23 * %NULL otherwise.
24 */
25struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1)
26{
27	struct device_node *node;
28	u32 reg;
29
30	for_each_child_of_node(hub->dev.of_node, node) {
31		if (of_property_read_u32(node, "reg", &reg))
32			continue;
33
34		if (reg == port1)
35			return node;
36	}
37
38	return NULL;
39}
40EXPORT_SYMBOL_GPL(usb_of_get_device_node);
41
42/**
43 * usb_of_has_combined_node() - determine whether a device has a combined node
44 * @udev: USB device
45 *
46 * Determine whether a USB device has a so called combined node which is
47 * shared with its sole interface. This is the case if and only if the device
48 * has a node and its descriptors report the following:
49 *
50 *	1) bDeviceClass is 0 or 9, and
51 *	2) bNumConfigurations is 1, and
52 *	3) bNumInterfaces is 1.
53 *
54 * Return: True iff the device has a device node and its descriptors match the
55 * criteria for a combined node.
56 */
57bool usb_of_has_combined_node(struct usb_device *udev)
58{
59	struct usb_device_descriptor *ddesc = &udev->descriptor;
60	struct usb_config_descriptor *cdesc;
61
62	if (!udev->dev.of_node)
63		return false;
64
65	switch (ddesc->bDeviceClass) {
66	case USB_CLASS_PER_INTERFACE:
67	case USB_CLASS_HUB:
68		if (ddesc->bNumConfigurations == 1) {
69			cdesc = &udev->config->desc;
70			if (cdesc->bNumInterfaces == 1)
71				return true;
72		}
73	}
74
75	return false;
76}
77EXPORT_SYMBOL_GPL(usb_of_has_combined_node);
78
79static bool usb_of_has_devices_or_graph(const struct usb_device *hub)
80{
81	const struct device_node *np = hub->dev.of_node;
82	struct device_node *child;
83
84	if (of_graph_is_present(np))
85		return true;
86
87	for_each_child_of_node(np, child)
88		if (of_property_present(child, "reg"))
89			return true;
90
91	return false;
92}
93
94/**
95 * usb_of_get_connect_type() - get a USB hub's port connect_type
96 * @hub: hub to which port is for @port1
97 * @port1: one-based index of port
98 *
99 * Get the connect_type of @port1 based on the device node for @hub. If the
100 * port is described in the OF graph, the connect_type is "hotplug". If the
101 * @hub has a child device has with a 'reg' property equal to @port1 the
102 * connect_type is "hard-wired". If there isn't an OF graph or child node at
103 * all then the connect_type is "unknown". Otherwise, the port is considered
104 * "unused" because it isn't described at all.
105 *
106 * Return: A connect_type for @port1 based on the device node for @hub.
107 */
108enum usb_port_connect_type usb_of_get_connect_type(struct usb_device *hub, int port1)
109{
110	struct device_node *np, *child, *ep, *remote_np;
111	enum usb_port_connect_type connect_type;
112
113	/* Only set connect_type if binding has ports/hardwired devices. */
114	if (!usb_of_has_devices_or_graph(hub))
115		return USB_PORT_CONNECT_TYPE_UNKNOWN;
116
117	/* Assume port is unused if there's a graph or a child node. */
118	connect_type = USB_PORT_NOT_USED;
119
120	np = hub->dev.of_node;
121	/*
122	 * Hotplug ports are connected to an available remote node, e.g.
123	 * usb-a-connector compatible node, in the OF graph.
124	 */
125	if (of_graph_is_present(np)) {
126		ep = of_graph_get_endpoint_by_regs(np, port1, -1);
127		if (ep) {
128			remote_np = of_graph_get_remote_port_parent(ep);
129			of_node_put(ep);
130			if (of_device_is_available(remote_np))
131				connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG;
132			of_node_put(remote_np);
133		}
134	}
135
136	/*
137	 * Hard-wired ports are child nodes with a reg property corresponding
138	 * to the port number, i.e. a usb device.
139	 */
140	child = usb_of_get_device_node(hub, port1);
141	if (of_device_is_available(child))
142		connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED;
143	of_node_put(child);
144
145	return connect_type;
146}
147EXPORT_SYMBOL_GPL(usb_of_get_connect_type);
148
149/**
150 * usb_of_get_interface_node() - get a USB interface node
151 * @udev: USB device of interface
152 * @config: configuration value
153 * @ifnum: interface number
154 *
155 * Look up the node of a USB interface given its USB device, configuration
156 * value and interface number.
157 *
158 * Return: A pointer to the node with incremented refcount if found, or
159 * %NULL otherwise.
160 */
161struct device_node *
162usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
163{
164	struct device_node *node;
165	u32 reg[2];
166
167	for_each_child_of_node(udev->dev.of_node, node) {
168		if (of_property_read_u32_array(node, "reg", reg, 2))
169			continue;
170
171		if (reg[0] == ifnum && reg[1] == config)
172			return node;
173	}
174
175	return NULL;
176}
177EXPORT_SYMBOL_GPL(usb_of_get_interface_node);
178