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 #include <linux/slab.h>
  34
  35 struct nop_usb_xceiv {
  36         struct otg_transceiver  otg;
  37         struct device           *dev;
  38 };
  39
  40 static struct platform_device *pd;
  41
  42 void usb_nop_xceiv_register(void)
  43 {
  44         if (pd)
  45                 return;
  46         pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
  47         if (!pd) {
  48                 printk(KERN_ERR "Unable to register usb nop transceiver\n");
  49                 return;
  50         }
  51 }
  52 EXPORT_SYMBOL(usb_nop_xceiv_register);
  53
  54 void usb_nop_xceiv_unregister(void)
  55 {
  56         platform_device_unregister(pd);
  57         pd = NULL;
  58 }
  59 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  60
  61 static inline struct nop_usb_xceiv *xceiv_to_nop(struct otg_transceiver *x)
  62 {
  63         return container_of(x, struct nop_usb_xceiv, otg);
  64 }
  65
  66 static int nop_set_suspend(struct otg_transceiver *x, int suspend)
  67 {
  68         return 0;
  69 }
  70
  71 static int nop_set_peripheral(struct otg_transceiver *x,
  72                 struct usb_gadget *gadget)
  73 {
  74         struct nop_usb_xceiv *nop;
  75
  76         if (!x)
  77                 return -ENODEV;
  78
  79         nop = xceiv_to_nop(x);
  80
  81         if (!gadget) {
  82                 nop->otg.gadget = NULL;
  83                 return -ENODEV;
  84         }
  85
  86         nop->otg.gadget = gadget;
  87         nop->otg.state = OTG_STATE_B_IDLE;
  88         return 0;
  89 }
  90
  91 static int nop_set_host(struct otg_transceiver *x, struct usb_bus *host)
  92 {
  93         struct nop_usb_xceiv *nop;
  94
  95         if (!x)
  96                 return -ENODEV;
  97
  98         nop = xceiv_to_nop(x);
  99
 100         if (!host) {
 101                 nop->otg.host = NULL;
 102                 return -ENODEV;
 103         }
 104
 105         nop->otg.host = host;
 106         return 0;
 107 }
 108
 109 static int __devinit nop_usb_xceiv_probe(struct platform_device *pdev)
 110 {
 111         struct nop_usb_xceiv    *nop;
 112         int err;
 113
 114         nop = kzalloc(sizeof *nop, GFP_KERNEL);
 115         if (!nop)
 116                 return -ENOMEM;
 117
 118         nop->dev                = &pdev->dev;
 119         nop->otg.dev            = nop->dev;
 120         nop->otg.label          = "nop-xceiv";
 121         nop->otg.state          = OTG_STATE_UNDEFINED;
 122         nop->otg.set_host       = nop_set_host;
 123         nop->otg.set_peripheral = nop_set_peripheral;
 124         nop->otg.set_suspend    = nop_set_suspend;
 125
 126         err = otg_set_transceiver(&nop->otg);
 127         if (err) {
 128                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 129                         err);
 130                 goto exit;
 131         }
 132
 133         platform_set_drvdata(pdev, nop);
 134
 135         ATOMIC_INIT_NOTIFIER_HEAD(&nop->otg.notifier);
 136
 137         return 0;
 138 exit:
 139         kfree(nop);
 140         return err;
 141 }
 142
 143 static int __devexit nop_usb_xceiv_remove(struct platform_device *pdev)
 144 {
 145         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 146
 147         otg_set_transceiver(NULL);
 148
 149         platform_set_drvdata(pdev, NULL);
 150         kfree(nop);
 151
 152         return 0;
 153 }
 154
 155 static struct platform_driver nop_usb_xceiv_driver = {
 156         .probe          = nop_usb_xceiv_probe,
 157         .remove         = __devexit_p(nop_usb_xceiv_remove),
 158         .driver         = {
 159                 .name   = "nop_usb_xceiv",
 160                 .owner  = THIS_MODULE,
 161         },
 162 };
 163
 164 static int __init nop_usb_xceiv_init(void)
 165 {
 166         return platform_driver_register(&nop_usb_xceiv_driver);
 167 }
 168 subsys_initcall(nop_usb_xceiv_init);
 169
 170 static void __exit nop_usb_xceiv_exit(void)
 171 {
 172         platform_driver_unregister(&nop_usb_xceiv_driver);
 173 }
 174 module_exit(nop_usb_xceiv_exit);
 175
 176 MODULE_ALIAS("platform:nop_usb_xceiv");
 177 MODULE_AUTHOR("Texas Instruments Inc");
 178 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 179 MODULE_LICENSE("GPL");