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         pd = NULL;
  57 }
  58 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  59
  60 static inline struct nop_usb_xceiv *xceiv_to_nop(struct otg_transceiver *x)
  61 {
  62         return container_of(x, struct nop_usb_xceiv, otg);
  63 }
  64
  65 static int nop_set_suspend(struct otg_transceiver *x, int suspend)
  66 {
  67         return 0;
  68 }
  69
  70 static int nop_set_peripheral(struct otg_transceiver *x,
  71                 struct usb_gadget *gadget)
  72 {
  73         struct nop_usb_xceiv *nop;
  74
  75         if (!x)
  76                 return -ENODEV;
  77
  78         nop = xceiv_to_nop(x);
  79
  80         if (!gadget) {
  81                 nop->otg.gadget = NULL;
  82                 return -ENODEV;
  83         }
  84
  85         nop->otg.gadget = gadget;
  86         nop->otg.state = OTG_STATE_B_IDLE;
  87         return 0;
  88 }
  89
  90 static int nop_set_host(struct otg_transceiver *x, struct usb_bus *host)
  91 {
  92         struct nop_usb_xceiv *nop;
  93
  94         if (!x)
  95                 return -ENODEV;
  96
  97         nop = xceiv_to_nop(x);
  98
  99         if (!host) {
 100                 nop->otg.host = NULL;
 101                 return -ENODEV;
 102         }
 103
 104         nop->otg.host = host;
 105         return 0;
 106 }
 107
 108 static int __devinit nop_usb_xceiv_probe(struct platform_device *pdev)
 109 {
 110         struct nop_usb_xceiv    *nop;
 111         int err;
 112
 113         nop = kzalloc(sizeof *nop, GFP_KERNEL);
 114         if (!nop)
 115                 return -ENOMEM;
 116
 117         nop->dev                = &pdev->dev;
 118         nop->otg.dev            = nop->dev;
 119         nop->otg.label          = "nop-xceiv";
 120         nop->otg.state          = OTG_STATE_UNDEFINED;
 121         nop->otg.set_host       = nop_set_host;
 122         nop->otg.set_peripheral = nop_set_peripheral;
 123         nop->otg.set_suspend    = nop_set_suspend;
 124
 125         err = otg_set_transceiver(&nop->otg);
 126         if (err) {
 127                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 128                         err);
 129                 goto exit;
 130         }
 131
 132         platform_set_drvdata(pdev, nop);
 133
 134         return 0;
 135 exit:
 136         kfree(nop);
 137         return err;
 138 }
 139
 140 static int __devexit nop_usb_xceiv_remove(struct platform_device *pdev)
 141 {
 142         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 143
 144         otg_set_transceiver(NULL);
 145
 146         platform_set_drvdata(pdev, NULL);
 147         kfree(nop);
 148
 149         return 0;
 150 }
 151
 152 static struct platform_driver nop_usb_xceiv_driver = {
 153         .probe          = nop_usb_xceiv_probe,
 154         .remove         = __devexit_p(nop_usb_xceiv_remove),
 155         .driver         = {
 156                 .name   = "nop_usb_xceiv",
 157                 .owner  = THIS_MODULE,
 158         },
 159 };
 160
 161 static int __init nop_usb_xceiv_init(void)
 162 {
 163         return platform_driver_register(&nop_usb_xceiv_driver);
 164 }
 165 subsys_initcall(nop_usb_xceiv_init);
 166
 167 static void __exit nop_usb_xceiv_exit(void)
 168 {
 169         platform_driver_unregister(&nop_usb_xceiv_driver);
 170 }
 171 module_exit(nop_usb_xceiv_exit);
 172
 173 MODULE_ALIAS("platform:nop_usb_xceiv");
 174 MODULE_AUTHOR("Texas Instruments Inc");
 175 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 176 MODULE_LICENSE("GPL");