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);