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  */
usb_of_get_device_node(struct usb_device * hub,int port1)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", &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 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  */
usb_of_has_combined_node(struct usb_device * udev)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 *
usb_of_get_interface_node(struct usb_device * udev,u8 config,u8 ifnum)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);
108