66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/*
|
|
* otg.c -- USB OTG utility code
|
|
*
|
|
* Copyright (C) 2004 Texas Instruments
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/device.h>
|
|
|
|
#include <linux/usb/otg.h>
|
|
|
|
static struct otg_transceiver *xceiv;
|
|
|
|
/**
|
|
* otg_get_transceiver - find the (single) OTG transceiver
|
|
*
|
|
* Returns the transceiver driver, after getting a refcount to it; or
|
|
* null if there is no such transceiver. The caller is responsible for
|
|
* calling otg_put_transceiver() to release that count.
|
|
*
|
|
* For use by USB host and peripheral drivers.
|
|
*/
|
|
struct otg_transceiver *otg_get_transceiver(void)
|
|
{
|
|
if (xceiv)
|
|
get_device(xceiv->dev);
|
|
return xceiv;
|
|
}
|
|
EXPORT_SYMBOL(otg_get_transceiver);
|
|
|
|
/**
|
|
* otg_put_transceiver - release the (single) OTG transceiver
|
|
* @x: the transceiver returned by otg_get_transceiver()
|
|
*
|
|
* Releases a refcount the caller received from otg_get_transceiver().
|
|
*
|
|
* For use by USB host and peripheral drivers.
|
|
*/
|
|
void otg_put_transceiver(struct otg_transceiver *x)
|
|
{
|
|
put_device(x->dev);
|
|
}
|
|
EXPORT_SYMBOL(otg_put_transceiver);
|
|
|
|
/**
|
|
* otg_set_transceiver - declare the (single) OTG transceiver
|
|
* @x: the USB OTG transceiver to be used; or NULL
|
|
*
|
|
* This call is exclusively for use by transceiver drivers, which
|
|
* coordinate the activities of drivers for host and peripheral
|
|
* controllers, and in some cases for VBUS current regulation.
|
|
*/
|
|
int otg_set_transceiver(struct otg_transceiver *x)
|
|
{
|
|
if (xceiv && x)
|
|
return -EBUSY;
|
|
xceiv = x;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(otg_set_transceiver);
|