| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [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/export.h> |
| 14 | #include <linux/device.h> |
| 15 | |
| 16 | #include <linux/usb/otg.h> |
| 17 | |
| 18 | static 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 | */ |
| 29 | struct usb_phy *usb_get_transceiver(void) |
| 30 | { |
| 31 | if (phy) |
| 32 | get_device(phy->dev); |
| 33 | return phy; |
| 34 | } |
| 35 | EXPORT_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 | */ |
| 45 | void usb_put_transceiver(struct usb_phy *x) |
| 46 | { |
| 47 | if (x) |
| 48 | put_device(x->dev); |
| 49 | } |
| 50 | EXPORT_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 | */ |
| 60 | int usb_set_transceiver(struct usb_phy *x) |
| 61 | { |
| 62 | if (phy && x) |
| 63 | return -EBUSY; |
| 64 | phy = x; |
| 65 | return 0; |
| 66 | } |
| 67 | EXPORT_SYMBOL(usb_set_transceiver); |
| 68 | |
| 69 | const 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 | } |
| 102 | EXPORT_SYMBOL(otg_state_string); |