| Tony Lindgren | 3cb22d6 | 2008-11-24 12:02:21 -0800 | [diff] [blame] | 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 | put_device(x->dev); |
| 47 | } |
| 48 | EXPORT_SYMBOL(otg_put_transceiver); |
| 49 | |
| 50 | /** |
| 51 | * otg_set_transceiver - declare the (single) OTG transceiver |
| 52 | * @x: the USB OTG transceiver to be used; or NULL |
| 53 | * |
| 54 | * This call is exclusively for use by transceiver drivers, which |
| 55 | * coordinate the activities of drivers for host and peripheral |
| 56 | * controllers, and in some cases for VBUS current regulation. |
| 57 | */ |
| 58 | int otg_set_transceiver(struct otg_transceiver *x) |
| 59 | { |
| 60 | if (xceiv && x) |
| 61 | return -EBUSY; |
| 62 | xceiv = x; |
| 63 | return 0; |
| 64 | } |
| 65 | EXPORT_SYMBOL(otg_set_transceiver); |