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/usb/nop-usb-xceiv.h>
  34 #include <linux/slab.h>
  35 #include <linux/clk.h>
  36
  37 struct nop_usb_xceiv {
  38         struct usb_phy          phy;
  39         struct device           *dev;
  40         struct clk              *clk;
  41 };
  42
  43 static struct platform_device *pd;
  44
  45 void usb_nop_xceiv_register(void)
  46 {
  47         if (pd)
  48                 return;
  49         pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
  50         if (!pd) {
  51                 printk(KERN_ERR "Unable to register usb nop transceiver\n");
  52                 return;
  53         }
  54 }
  55 EXPORT_SYMBOL(usb_nop_xceiv_register);
  56
  57 void usb_nop_xceiv_unregister(void)
  58 {
  59         platform_device_unregister(pd);
  60         pd = NULL;
  61 }
  62 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  63
  64 static int nop_set_suspend(struct usb_phy *x, int suspend)
  65 {
  66         return 0;
  67 }
  68
  69 static int nop_init(struct usb_phy *phy)
  70 {
  71         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  72
  73         if (!IS_ERR(nop->clk))
  74                 clk_enable(nop->clk);
  75
  76         return 0;
  77 }
  78
  79 static void nop_shutdown(struct usb_phy *phy)
  80 {
  81         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  82
  83         if (!IS_ERR(nop->clk))
  84                 clk_disable(nop->clk);
  85 }
  86
  87 static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
  88 {
  89         if (!otg)
  90                 return -ENODEV;
  91
  92         if (!gadget) {
  93                 otg->gadget = NULL;
  94                 return -ENODEV;
  95         }
  96
  97         otg->gadget = gadget;
  98         otg->phy->state = OTG_STATE_B_IDLE;
  99         return 0;
 100 }
 101
 102 static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
 103 {
 104         if (!otg)
 105                 return -ENODEV;
 106
 107         if (!host) {
 108                 otg->host = NULL;
 109                 return -ENODEV;
 110         }
 111
 112         otg->host = host;
 113         return 0;
 114 }
 115
 116 static int nop_usb_xceiv_probe(struct platform_device *pdev)
 117 {
 118         struct nop_usb_xceiv_platform_data *pdata = pdev->dev.platform_data;
 119         struct nop_usb_xceiv    *nop;
 120         enum usb_phy_type       type = USB_PHY_TYPE_USB2;
 121         int err;
 122
 123         nop = devm_kzalloc(&pdev->dev, sizeof(*nop), GFP_KERNEL);
 124         if (!nop)
 125                 return -ENOMEM;
 126
 127         nop->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*nop->phy.otg),
 128                                                         GFP_KERNEL);
 129         if (!nop->phy.otg)
 130                 return -ENOMEM;
 131
 132         if (pdata)
 133                 type = pdata->type;
 134
 135         nop->clk = devm_clk_get(&pdev->dev, "main_clk");
 136         if (IS_ERR(nop->clk)) {
 137                 dev_dbg(&pdev->dev, "Can't get phy clock: %ld\n",
 138                                         PTR_ERR(nop->clk));
 139         }
 140
 141         if (!IS_ERR(nop->clk) && pdata && pdata->clk_rate) {
 142                 err = clk_set_rate(nop->clk, pdata->clk_rate);
 143                 if (err) {
 144                         dev_err(&pdev->dev, "Error setting clock rate\n");
 145                         return err;
 146                 }
 147         }
 148
 149         if (!IS_ERR(nop->clk)) {
 150                 err = clk_prepare(nop->clk);
 151                 if (err) {
 152                         dev_err(&pdev->dev, "Error preparing clock\n");
 153                         return err;
 154                 }
 155         }
 156
 157         nop->dev                = &pdev->dev;
 158         nop->phy.dev            = nop->dev;
 159         nop->phy.label          = "nop-xceiv";
 160         nop->phy.set_suspend    = nop_set_suspend;
 161         nop->phy.init           = nop_init;
 162         nop->phy.shutdown       = nop_shutdown;
 163         nop->phy.state          = OTG_STATE_UNDEFINED;
 164
 165         nop->phy.otg->phy               = &nop->phy;
 166         nop->phy.otg->set_host          = nop_set_host;
 167         nop->phy.otg->set_peripheral    = nop_set_peripheral;
 168
 169         err = usb_add_phy(&nop->phy, type);
 170         if (err) {
 171                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 172                         err);
 173                 goto err_add;
 174         }
 175
 176         platform_set_drvdata(pdev, nop);
 177
 178         ATOMIC_INIT_NOTIFIER_HEAD(&nop->phy.notifier);
 179
 180         return 0;
 181
 182 err_add:
 183         if (!IS_ERR(nop->clk))
 184                 clk_unprepare(nop->clk);
 185         return err;
 186 }
 187
 188 static int nop_usb_xceiv_remove(struct platform_device *pdev)
 189 {
 190         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 191
 192         if (!IS_ERR(nop->clk))
 193                 clk_unprepare(nop->clk);
 194
 195         usb_remove_phy(&nop->phy);
 196
 197         platform_set_drvdata(pdev, NULL);
 198
 199         return 0;
 200 }
 201
 202 static struct platform_driver nop_usb_xceiv_driver = {
 203         .probe          = nop_usb_xceiv_probe,
 204         .remove         = nop_usb_xceiv_remove,
 205         .driver         = {
 206                 .name   = "nop_usb_xceiv",
 207                 .owner  = THIS_MODULE,
 208         },
 209 };
 210
 211 static int __init nop_usb_xceiv_init(void)
 212 {
 213         return platform_driver_register(&nop_usb_xceiv_driver);
 214 }
 215 subsys_initcall(nop_usb_xceiv_init);
 216
 217 static void __exit nop_usb_xceiv_exit(void)
 218 {
 219         platform_driver_unregister(&nop_usb_xceiv_driver);
 220 }
 221 module_exit(nop_usb_xceiv_exit);
 222
 223 MODULE_ALIAS("platform:nop_usb_xceiv");
 224 MODULE_AUTHOR("Texas Instruments Inc");
 225 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 226 MODULE_LICENSE("GPL");