drivers/usb/otg/otg.c

   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
  17 static 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  */
  28 struct otg_transceiver *otg_get_transceiver(void)
  29 {
  30         if (xceiv)
  31                 get_device(xceiv->dev);
  32         return xceiv;
  33 }
  34 EXPORT_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  */
  44 void otg_put_transceiver(struct otg_transceiver *x)
  45 {
  46         if (x)
  47                 put_device(x->dev);
  48 }
  49 EXPORT_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  */
  59 int otg_set_transceiver(struct otg_transceiver *x)
  60 {
  61         if (xceiv && x)
  62                 return -EBUSY;
  63         xceiv = x;
  64         return 0;
  65 }
  66 EXPORT_SYMBOL(otg_set_transceiver);
  67
  68 const 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 }
 101 EXPORT_SYMBOL(otg_state_string);