drivers/usb/otg/nop-usb-xceiv.c

   1 /*
   2  * drivers/usb/otg/nop-usb-xceiv.c
   3  *
   4  * NOP USB transceiver for all USB transceiver which are either built-in
   5  * into USB IP or which are mostly autonomous.
   6  *
   7  * Copyright (C) 2009 Texas Instruments Inc
   8  * Author: Ajay Kumar Gupta <ajay.gupta@ti.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23  *
  24  * Current status:
  25  *      This provides a "nop" transceiver for PHYs which are
  26  *      autonomous such as isp1504, isp1707, etc.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/dma-mapping.h>
  32 #include <linux/usb/otg.h>
  33
  34 struct nop_usb_xceiv {
  35         struct otg_transceiver  otg;
  36         struct device           *dev;
  37 };
  38
  39 static struct platform_device *pd;
  40
  41 void usb_nop_xceiv_register(void)
  42 {
  43         if (pd)
  44                 return;
  45         pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
  46         if (!pd) {
  47                 printk(KERN_ERR "Unable to register usb nop transceiver\n");
  48                 return;
  49         }
  50 }
  51 EXPORT_SYMBOL(usb_nop_xceiv_register);
  52
  53 void usb_nop_xceiv_unregister(void)
  54 {
  55         platform_device_unregister(pd);
  56 }
  57 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  58
  59 static inline struct nop_usb_xceiv *xceiv_to_nop(struct otg_transceiver *x)
  60 {
  61         return container_of(x, struct nop_usb_xceiv, otg);
  62 }
  63
  64 static int nop_set_suspend(struct otg_transceiver *x, int suspend)
  65 {
  66         return 0;
  67 }
  68
  69 static int nop_set_peripheral(struct otg_transceiver *x,
  70                 struct usb_gadget *gadget)
  71 {
  72         struct nop_usb_xceiv *nop;
  73
  74         if (!x)
  75                 return -ENODEV;
  76
  77         nop = xceiv_to_nop(x);
  78
  79         if (!gadget) {
  80                 nop->otg.gadget = NULL;
  81                 return -ENODEV;
  82         }
  83
  84         nop->otg.gadget = gadget;
  85         nop->otg.state = OTG_STATE_B_IDLE;
  86         return 0;
  87 }
  88
  89 static int nop_set_host(struct otg_transceiver *x, struct usb_bus *host)
  90 {
  91         struct nop_usb_xceiv *nop;
  92
  93         if (!x)
  94                 return -ENODEV;
  95
  96         nop = xceiv_to_nop(x);
  97
  98         if (!host) {
  99                 nop->otg.host = NULL;
 100                 return -ENODEV;
 101         }
 102
 103         nop->otg.host = host;
 104         return 0;
 105 }
 106
 107 static int __devinit nop_usb_xceiv_probe(struct platform_device *pdev)
 108 {
 109         struct nop_usb_xceiv    *nop;
 110         int err;
 111
 112         nop = kzalloc(sizeof *nop, GFP_KERNEL);
 113         if (!nop)
 114                 return -ENOMEM;
 115
 116         nop->dev                = &pdev->dev;
 117         nop->otg.dev            = nop->dev;
 118         nop->otg.label          = "nop-xceiv";
 119         nop->otg.state          = OTG_STATE_UNDEFINED;
 120         nop->otg.set_host       = nop_set_host;
 121         nop->otg.set_peripheral = nop_set_peripheral;
 122         nop->otg.set_suspend    = nop_set_suspend;
 123
 124         err = otg_set_transceiver(&nop->otg);
 125         if (err) {
 126                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 127                         err);
 128                 goto exit;
 129         }
 130
 131         platform_set_drvdata(pdev, nop);
 132
 133         return 0;
 134 exit:
 135         kfree(nop);
 136         return err;
 137 }
 138
 139 static int __devexit nop_usb_xceiv_remove(struct platform_device *pdev)
 140 {
 141         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 142
 143         otg_set_transceiver(NULL);
 144
 145         platform_set_drvdata(pdev, NULL);
 146         kfree(nop);
 147
 148         return 0;
 149 }
 150
 151 static struct platform_driver nop_usb_xceiv_driver = {
 152         .probe          = nop_usb_xceiv_probe,
 153         .remove         = __devexit_p(nop_usb_xceiv_remove),
 154         .driver         = {
 155                 .name   = "nop_usb_xceiv",
 156                 .owner  = THIS_MODULE,
 157         },
 158 };
 159
 160 static int __init nop_usb_xceiv_init(void)
 161 {
 162         return platform_driver_register(&nop_usb_xceiv_driver);
 163 }
 164 subsys_initcall(nop_usb_xceiv_init);
 165
 166 static void __exit nop_usb_xceiv_exit(void)
 167 {
 168         platform_driver_unregister(&nop_usb_xceiv_driver);
 169 }
 170 module_exit(nop_usb_xceiv_exit);
 171
 172 MODULE_ALIAS("platform:nop_usb_xceiv");
 173 MODULE_AUTHOR("Texas Instruments Inc");
 174 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 175 MODULE_LICENSE("GPL");