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