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