1/*
2 * otg.c -- USB OTG utility code
3 *
4 * Copyright (C) 2004 Texas Instruments
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12#include <linux/kernel.h>
13#include <linux/export.h>
14#include <linux/device.h>
15
16#include <linux/usb/otg.h>
17
18static struct usb_phy *phy;
19
20/**
21 * usb_get_transceiver - find the (single) USB transceiver
22 *
23 * Returns the transceiver driver, after getting a refcount to it; or
24 * null if there is no such transceiver.  The caller is responsible for
25 * calling usb_put_transceiver() to release that count.
26 *
27 * For use by USB host and peripheral drivers.
28 */
29struct usb_phy *usb_get_transceiver(void)
30{
31	if (phy)
32		get_device(phy->dev);
33	return phy;
34}
35EXPORT_SYMBOL(usb_get_transceiver);
36
37/**
38 * usb_put_transceiver - release the (single) USB transceiver
39 * @x: the transceiver returned by usb_get_transceiver()
40 *
41 * Releases a refcount the caller received from usb_get_transceiver().
42 *
43 * For use by USB host and peripheral drivers.
44 */
45void usb_put_transceiver(struct usb_phy *x)
46{
47	if (x)
48		put_device(x->dev);
49}
50EXPORT_SYMBOL(usb_put_transceiver);
51
52/**
53 * usb_set_transceiver - declare the (single) USB transceiver
54 * @x: the USB transceiver to be used; or NULL
55 *
56 * This call is exclusively for use by transceiver drivers, which
57 * coordinate the activities of drivers for host and peripheral
58 * controllers, and in some cases for VBUS current regulation.
59 */
60int usb_set_transceiver(struct usb_phy *x)
61{
62	if (phy && x)
63		return -EBUSY;
64	phy = x;
65	return 0;
66}
67EXPORT_SYMBOL(usb_set_transceiver);
68
69const char *otg_state_string(enum usb_otg_state state)
70{
71	switch (state) {
72	case OTG_STATE_A_IDLE:
73		return "a_idle";
74	case OTG_STATE_A_WAIT_VRISE:
75		return "a_wait_vrise";
76	case OTG_STATE_A_WAIT_BCON:
77		return "a_wait_bcon";
78	case OTG_STATE_A_HOST:
79		return "a_host";
80	case OTG_STATE_A_SUSPEND:
81		return "a_suspend";
82	case OTG_STATE_A_PERIPHERAL:
83		return "a_peripheral";
84	case OTG_STATE_A_WAIT_VFALL:
85		return "a_wait_vfall";
86	case OTG_STATE_A_VBUS_ERR:
87		return "a_vbus_err";
88	case OTG_STATE_B_IDLE:
89		return "b_idle";
90	case OTG_STATE_B_SRP_INIT:
91		return "b_srp_init";
92	case OTG_STATE_B_PERIPHERAL:
93		return "b_peripheral";
94	case OTG_STATE_B_WAIT_ACON:
95		return "b_wait_acon";
96	case OTG_STATE_B_HOST:
97		return "b_host";
98	default:
99		return "UNDEFINED";
100	}
101}
102EXPORT_SYMBOL(otg_state_string);
103