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/device.h>
 14
 15#include <linux/usb/otg.h>
 16
 17static struct otg_transceiver *xceiv;
 18
 19/**
 20 * otg_get_transceiver - find the (single) OTG transceiver
 21 *
 22 * Returns the transceiver driver, after getting a refcount to it; or
 23 * null if there is no such transceiver.  The caller is responsible for
 24 * calling otg_put_transceiver() to release that count.
 25 *
 26 * For use by USB host and peripheral drivers.
 27 */
 28struct otg_transceiver *otg_get_transceiver(void)
 29{
 30	if (xceiv)
 31		get_device(xceiv->dev);
 32	return xceiv;
 33}
 34EXPORT_SYMBOL(otg_get_transceiver);
 35
 36/**
 37 * otg_put_transceiver - release the (single) OTG transceiver
 38 * @x: the transceiver returned by otg_get_transceiver()
 39 *
 40 * Releases a refcount the caller received from otg_get_transceiver().
 41 *
 42 * For use by USB host and peripheral drivers.
 43 */
 44void otg_put_transceiver(struct otg_transceiver *x)
 45{
 46	if (x)
 47		put_device(x->dev);
 48}
 49EXPORT_SYMBOL(otg_put_transceiver);
 50
 51/**
 52 * otg_set_transceiver - declare the (single) OTG transceiver
 53 * @x: the USB OTG transceiver to be used; or NULL
 54 *
 55 * This call is exclusively for use by transceiver drivers, which
 56 * coordinate the activities of drivers for host and peripheral
 57 * controllers, and in some cases for VBUS current regulation.
 58 */
 59int otg_set_transceiver(struct otg_transceiver *x)
 60{
 61	if (xceiv && x)
 62		return -EBUSY;
 63	xceiv = x;
 64	return 0;
 65}
 66EXPORT_SYMBOL(otg_set_transceiver);
 67
 68const char *otg_state_string(enum usb_otg_state state)
 69{
 70	switch (state) {
 71	case OTG_STATE_A_IDLE:
 72		return "a_idle";
 73	case OTG_STATE_A_WAIT_VRISE:
 74		return "a_wait_vrise";
 75	case OTG_STATE_A_WAIT_BCON:
 76		return "a_wait_bcon";
 77	case OTG_STATE_A_HOST:
 78		return "a_host";
 79	case OTG_STATE_A_SUSPEND:
 80		return "a_suspend";
 81	case OTG_STATE_A_PERIPHERAL:
 82		return "a_peripheral";
 83	case OTG_STATE_A_WAIT_VFALL:
 84		return "a_wait_vfall";
 85	case OTG_STATE_A_VBUS_ERR:
 86		return "a_vbus_err";
 87	case OTG_STATE_B_IDLE:
 88		return "b_idle";
 89	case OTG_STATE_B_SRP_INIT:
 90		return "b_srp_init";
 91	case OTG_STATE_B_PERIPHERAL:
 92		return "b_peripheral";
 93	case OTG_STATE_B_WAIT_ACON:
 94		return "b_wait_acon";
 95	case OTG_STATE_B_HOST:
 96		return "b_host";
 97	default:
 98		return "UNDEFINED";
 99	}
100}
101EXPORT_SYMBOL(otg_state_string);