1 // SPDX-License-Identifier: GPL-2.0
3 * of.c The helpers for hcd device tree support
5 * Copyright (C) 2016 Freescale Semiconductor, Inc.
6 * Author: Peter Chen <peter.chen@freescale.com>
7 * Copyright (C) 2017 Johan Hovold <johan@kernel.org>
11 #include <linux/of_graph.h>
12 #include <linux/usb/of.h>
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
19 * Look up the node of a USB device given its parent hub device and one-based
22 * Return: A pointer to the node with incremented refcount if found, or
25 struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1)
27 struct device_node *node;
30 for_each_child_of_node(hub->dev.of_node, node) {
31 if (of_property_read_u32(node, "reg", ®))
40 EXPORT_SYMBOL_GPL(usb_of_get_device_node);
43 * usb_of_has_combined_node() - determine whether a device has a combined node
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:
50 * 1) bDeviceClass is 0 or 9, and
51 * 2) bNumConfigurations is 1, and
52 * 3) bNumInterfaces is 1.
54 * Return: True iff the device has a device node and its descriptors match the
55 * criteria for a combined node.
57 bool usb_of_has_combined_node(struct usb_device *udev)
59 struct usb_device_descriptor *ddesc = &udev->descriptor;
60 struct usb_config_descriptor *cdesc;
62 if (!udev->dev.of_node)
65 switch (ddesc->bDeviceClass) {
66 case USB_CLASS_PER_INTERFACE:
68 if (ddesc->bNumConfigurations == 1) {
69 cdesc = &udev->config->desc;
70 if (cdesc->bNumInterfaces == 1)
77 EXPORT_SYMBOL_GPL(usb_of_has_combined_node);
79 static bool usb_of_has_devices_or_graph(const struct usb_device *hub)
81 const struct device_node *np = hub->dev.of_node;
82 struct device_node *child;
84 if (of_graph_is_present(np))
87 for_each_child_of_node(np, child)
88 if (of_property_present(child, "reg"))
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
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.
106 * Return: A connect_type for @port1 based on the device node for @hub.
108 enum usb_port_connect_type usb_of_get_connect_type(struct usb_device *hub, int port1)
110 struct device_node *np, *child, *ep, *remote_np;
111 enum usb_port_connect_type connect_type;
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;
117 /* Assume port is unused if there's a graph or a child node. */
118 connect_type = USB_PORT_NOT_USED;
120 np = hub->dev.of_node;
122 * Hotplug ports are connected to an available remote node, e.g.
123 * usb-a-connector compatible node, in the OF graph.
125 if (of_graph_is_present(np)) {
126 ep = of_graph_get_endpoint_by_regs(np, port1, -1);
128 remote_np = of_graph_get_remote_port_parent(ep);
130 if (of_device_is_available(remote_np))
131 connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG;
132 of_node_put(remote_np);
137 * Hard-wired ports are child nodes with a reg property corresponding
138 * to the port number, i.e. a usb device.
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;
147 EXPORT_SYMBOL_GPL(usb_of_get_connect_type);
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
155 * Look up the node of a USB interface given its USB device, configuration
156 * value and interface number.
158 * Return: A pointer to the node with incremented refcount if found, or
162 usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
164 struct device_node *node;
167 for_each_child_of_node(udev->dev.of_node, node) {
168 if (of_property_read_u32_array(node, "reg", reg, 2))
171 if (reg[0] == ifnum && reg[1] == config)
177 EXPORT_SYMBOL_GPL(usb_of_get_interface_node);