projects/linux·blob master · refs

176 lines · 4.8 KiB

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 <[email protected]>
7 * Copyright (C) 2017 Johan Hovold <[email protected]>
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
83 if (of_graph_is_present(np))
84 return true;
85
86 for_each_child_of_node_scoped(np, child)
87 if (of_property_present(child, "reg"))
88 return true;
89
90 return false;
91}
92
93/**
94 * usb_of_get_connect_type() - get a USB hub's port connect_type
95 * @hub: hub to which port is for @port1
96 * @port1: one-based index of port
97 *
98 * Get the connect_type of @port1 based on the device node for @hub. If the
99 * port is described in the OF graph, the connect_type is "hotplug". If the
100 * @hub has a child device has with a 'reg' property equal to @port1 the
101 * connect_type is "hard-wired". If there isn't an OF graph or child node at
102 * all then the connect_type is "unknown". Otherwise, the port is considered
103 * "unused" because it isn't described at all.
104 *
105 * Return: A connect_type for @port1 based on the device node for @hub.
106 */
107enum usb_port_connect_type usb_of_get_connect_type(struct usb_device *hub, int port1)
108{
109 struct device_node *np, *child, *ep, *remote_np;
110 enum usb_port_connect_type connect_type;
111
112 /* Only set connect_type if binding has ports/hardwired devices. */
113 if (!usb_of_has_devices_or_graph(hub))
114 return USB_PORT_CONNECT_TYPE_UNKNOWN;
115
116 /* Assume port is unused if there's a graph or a child node. */
117 connect_type = USB_PORT_NOT_USED;
118
119 np = hub->dev.of_node;
120 /*
121 * Hotplug ports are connected to an available remote node, e.g.
122 * usb-a-connector compatible node, in the OF graph.
123 */
124 if (of_graph_is_present(np)) {
125 ep = of_graph_get_endpoint_by_regs(np, port1, -1);
126 if (ep) {
127 remote_np = of_graph_get_remote_port_parent(ep);
128 of_node_put(ep);
129 if (of_device_is_available(remote_np))
130 connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG;
131 of_node_put(remote_np);
132 }
133 }
134
135 /*
136 * Hard-wired ports are child nodes with a reg property corresponding
137 * to the port number, i.e. a usb device.
138 */
139 child = usb_of_get_device_node(hub, port1);
140 if (of_device_is_available(child))
141 connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED;
142 of_node_put(child);
143
144 return connect_type;
145}
146EXPORT_SYMBOL_GPL(usb_of_get_connect_type);
147
148/**
149 * usb_of_get_interface_node() - get a USB interface node
150 * @udev: USB device of interface
151 * @config: configuration value
152 * @ifnum: interface number
153 *
154 * Look up the node of a USB interface given its USB device, configuration
155 * value and interface number.
156 *
157 * Return: A pointer to the node with incremented refcount if found, or
158 * %NULL otherwise.
159 */
160struct device_node *
161usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
162{
163 struct device_node *node;
164 u32 reg[2];
165
166 for_each_child_of_node(udev->dev.of_node, node) {
167 if (of_property_read_u32_array(node, "reg", reg, 2))
168 continue;
169
170 if (reg[0] == ifnum && reg[1] == config)
171 return node;
172 }
173
174 return NULL;
175}
176EXPORT_SYMBOL_GPL(usb_of_get_interface_node);