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_platform.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(node, "reg", ®))
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 decriptors 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 /**
80 * usb_of_get_interface_node() - get a USB interface node
81 * @udev: USB device of interface
82 * @config: configuration value
83 * @ifnum: interface number
84 *
85 * Look up the node of a USB interface given its USB device, configuration
86 * value and interface number.
87 *
88 * Return: A pointer to the node with incremented refcount if found, or
89 * %NULL otherwise.
90 */
91 struct device_node *
92 usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
93 {
94 struct device_node *node;
95 u32 reg[2];
96
97 for_each_child_of_node(udev->dev.of_node, node) {
98 if (of_property_read_u32_array(node, "reg", reg, 2))
99 continue;
100
101 if (reg[0] == ifnum && reg[1] == config)
102 return node;
103 }
104
105 return NULL;
106 }
107 EXPORT_SYMBOL_GPL(usb_of_get_interface_node);