summaryrefslogtreecommitdiff
path: root/drivers/usb/core/of.c
blob: fd77442c2d12e1c9eba50b606d990fbb48c84e8b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
// SPDX-License-Identifier: GPL-2.0
/*
 * of.c		The helpers for hcd device tree support
 *
 * Copyright (C) 2016 Freescale Semiconductor, Inc.
 *	Author: Peter Chen <peter.chen@freescale.com>
 * Copyright (C) 2017 Johan Hovold <johan@kernel.org>
 */

#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/usb/of.h>

/**
 * usb_of_get_device_node() - get a USB device node
 * @hub: hub to which device is connected
 * @port1: one-based index of port
 *
 * Look up the node of a USB device given its parent hub device and one-based
 * port number.
 *
 * Return: A pointer to the node with incremented refcount if found, or
 * %NULL otherwise.
 */
struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1)
{
	struct device_node *node;
	u32 reg;

	for_each_child_of_node(hub->dev.of_node, node) {
		if (of_property_read_u32(node, "reg", &reg))
			continue;

		if (reg == port1)
			return node;
	}

	return NULL;
}
EXPORT_SYMBOL_GPL(usb_of_get_device_node);

/**
 * usb_of_has_combined_node() - determine whether a device has a combined node
 * @udev: USB device
 *
 * Determine whether a USB device has a so called combined node which is
 * shared with its sole interface. This is the case if and only if the device
 * has a node and its decriptors report the following:
 *
 *	1) bDeviceClass is 0 or 9, and
 *	2) bNumConfigurations is 1, and
 *	3) bNumInterfaces is 1.
 *
 * Return: True iff the device has a device node and its descriptors match the
 * criteria for a combined node.
 */
bool usb_of_has_combined_node(struct usb_device *udev)
{
	struct usb_device_descriptor *ddesc = &udev->descriptor;
	struct usb_config_descriptor *cdesc;

	if (!udev->dev.of_node)
		return false;

	switch (ddesc->bDeviceClass) {
	case USB_CLASS_PER_INTERFACE:
	case USB_CLASS_HUB:
		if (ddesc->bNumConfigurations == 1) {
			cdesc = &udev->config->desc;
			if (cdesc->bNumInterfaces == 1)
				return true;
		}
	}

	return false;
}
EXPORT_SYMBOL_GPL(usb_of_has_combined_node);

/**
 * usb_of_get_interface_node() - get a USB interface node
 * @udev: USB device of interface
 * @config: configuration value
 * @ifnum: interface number
 *
 * Look up the node of a USB interface given its USB device, configuration
 * value and interface number.
 *
 * Return: A pointer to the node with incremented refcount if found, or
 * %NULL otherwise.
 */
struct device_node *
usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
{
	struct device_node *node;
	u32 reg[2];

	for_each_child_of_node(udev->dev.of_node, node) {
		if (of_property_read_u32_array(node, "reg", reg, 2))
			continue;

		if (reg[0] == ifnum && reg[1] == config)
			return node;
	}

	return NULL;
}
EXPORT_SYMBOL_GPL(usb_of_get_interface_node);

/**
 * usb_of_get_companion_dev - Find the companion device
 * @dev: the device pointer to find a companion
 *
 * Find the companion device from platform bus.
 *
 * Takes a reference to the returned struct device which needs to be dropped
 * after use.
 *
 * Return: On success, a pointer to the companion device, %NULL on failure.
 */
struct device *usb_of_get_companion_dev(struct device *dev)
{
	struct device_node *node;
	struct platform_device *pdev = NULL;

	node = of_parse_phandle(dev->of_node, "companion", 0);
	if (node)
		pdev = of_find_device_by_node(node);

	of_node_put(node);

	return pdev ? &pdev->dev : NULL;
}
EXPORT_SYMBOL_GPL(usb_of_get_companion_dev);