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 | */ |
25 | struct 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(np: node, propname: "reg" , out_value: ®)) |
32 | continue; |
33 | |
34 | if (reg == port1) |
35 | return node; |
36 | } |
37 | |
38 | return NULL; |
39 | } |
40 | EXPORT_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 | */ |
57 | bool 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 | } |
77 | EXPORT_SYMBOL_GPL(usb_of_has_combined_node); |
78 | |
79 | static 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(node: np)) |
85 | return true; |
86 | |
87 | for_each_child_of_node(np, child) |
88 | if (of_property_present(np: child, propname: "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 | */ |
108 | enum 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(node: np)) { |
126 | ep = of_graph_get_endpoint_by_regs(parent: np, port_reg: port1, reg: -1); |
127 | if (ep) { |
128 | remote_np = of_graph_get_remote_port_parent(node: ep); |
129 | of_node_put(node: ep); |
130 | if (of_device_is_available(device: remote_np)) |
131 | connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG; |
132 | of_node_put(node: 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(device: child)) |
142 | connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED; |
143 | of_node_put(node: child); |
144 | |
145 | return connect_type; |
146 | } |
147 | EXPORT_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 | */ |
161 | struct device_node * |
162 | usb_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(np: node, propname: "reg" , out_values: reg, sz: 2)) |
169 | continue; |
170 | |
171 | if (reg[0] == ifnum && reg[1] == config) |
172 | return node; |
173 | } |
174 | |
175 | return NULL; |
176 | } |
177 | EXPORT_SYMBOL_GPL(usb_of_get_interface_node); |
178 | |