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 #include <linux/regulator/consumer.h>
  37
  38 struct nop_usb_xceiv {
  39         struct usb_phy          phy;
  40         struct device           *dev;
  41         struct clk              *clk;
  42         struct regulator        *vcc;
  43         struct regulator        *reset;
  44 };
  45
  46 static struct platform_device *pd;
  47
  48 void usb_nop_xceiv_register(void)
  49 {
  50         if (pd)
  51                 return;
  52         pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
  53         if (!pd) {
  54                 printk(KERN_ERR "Unable to register usb nop transceiver\n");
  55                 return;
  56         }
  57 }
  58 EXPORT_SYMBOL(usb_nop_xceiv_register);
  59
  60 void usb_nop_xceiv_unregister(void)
  61 {
  62         platform_device_unregister(pd);
  63         pd = NULL;
  64 }
  65 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  66
  67 static int nop_set_suspend(struct usb_phy *x, int suspend)
  68 {
  69         return 0;
  70 }
  71
  72 static int nop_init(struct usb_phy *phy)
  73 {
  74         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  75
  76         if (!IS_ERR(nop->vcc)) {
  77                 if (regulator_enable(nop->vcc))
  78                         dev_err(phy->dev, "Failed to enable power\n");
  79         }
  80
  81         if (!IS_ERR(nop->clk))
  82                 clk_enable(nop->clk);
  83
  84         if (!IS_ERR(nop->reset)) {
  85                 /* De-assert RESET */
  86                 if (regulator_enable(nop->reset))
  87                         dev_err(phy->dev, "Failed to de-assert reset\n");
  88         }
  89
  90         return 0;
  91 }
  92
  93 static void nop_shutdown(struct usb_phy *phy)
  94 {
  95         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  96
  97         if (!IS_ERR(nop->reset)) {
  98                 /* Assert RESET */
  99                 if (regulator_disable(nop->reset))
 100                         dev_err(phy->dev, "Failed to assert reset\n");
 101         }
 102
 103         if (!IS_ERR(nop->clk))
 104                 clk_disable(nop->clk);
 105
 106         if (!IS_ERR(nop->vcc)) {
 107                 if (regulator_disable(nop->vcc))
 108                         dev_err(phy->dev, "Failed to disable power\n");
 109         }
 110 }
 111
 112 static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
 113 {
 114         if (!otg)
 115                 return -ENODEV;
 116
 117         if (!gadget) {
 118                 otg->gadget = NULL;
 119                 return -ENODEV;
 120         }
 121
 122         otg->gadget = gadget;
 123         otg->phy->state = OTG_STATE_B_IDLE;
 124         return 0;
 125 }
 126
 127 static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
 128 {
 129         if (!otg)
 130                 return -ENODEV;
 131
 132         if (!host) {
 133                 otg->host = NULL;
 134                 return -ENODEV;
 135         }
 136
 137         otg->host = host;
 138         return 0;
 139 }
 140
 141 static int nop_usb_xceiv_probe(struct platform_device *pdev)
 142 {
 143         struct nop_usb_xceiv_platform_data *pdata = pdev->dev.platform_data;
 144         struct nop_usb_xceiv    *nop;
 145         enum usb_phy_type       type = USB_PHY_TYPE_USB2;
 146         int err;
 147
 148         nop = devm_kzalloc(&pdev->dev, sizeof(*nop), GFP_KERNEL);
 149         if (!nop)
 150                 return -ENOMEM;
 151
 152         nop->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*nop->phy.otg),
 153                                                         GFP_KERNEL);
 154         if (!nop->phy.otg)
 155                 return -ENOMEM;
 156
 157         if (pdata)
 158                 type = pdata->type;
 159
 160         nop->clk = devm_clk_get(&pdev->dev, "main_clk");
 161         if (IS_ERR(nop->clk)) {
 162                 dev_dbg(&pdev->dev, "Can't get phy clock: %ld\n",
 163                                         PTR_ERR(nop->clk));
 164         }
 165
 166         if (!IS_ERR(nop->clk) && pdata && pdata->clk_rate) {
 167                 err = clk_set_rate(nop->clk, pdata->clk_rate);
 168                 if (err) {
 169                         dev_err(&pdev->dev, "Error setting clock rate\n");
 170                         return err;
 171                 }
 172         }
 173
 174         if (!IS_ERR(nop->clk)) {
 175                 err = clk_prepare(nop->clk);
 176                 if (err) {
 177                         dev_err(&pdev->dev, "Error preparing clock\n");
 178                         return err;
 179                 }
 180         }
 181
 182         nop->vcc = devm_regulator_get(&pdev->dev, "vcc");
 183         if (IS_ERR(nop->vcc)) {
 184                 dev_dbg(&pdev->dev, "Error getting vcc regulator: %ld\n",
 185                                         PTR_ERR(nop->vcc));
 186         }
 187
 188         nop->reset = devm_regulator_get(&pdev->dev, "reset");
 189         if (IS_ERR(nop->reset)) {
 190                 dev_dbg(&pdev->dev, "Error getting reset regulator: %ld\n",
 191                                         PTR_ERR(nop->reset));
 192         }
 193
 194         nop->dev                = &pdev->dev;
 195         nop->phy.dev            = nop->dev;
 196         nop->phy.label          = "nop-xceiv";
 197         nop->phy.set_suspend    = nop_set_suspend;
 198         nop->phy.init           = nop_init;
 199         nop->phy.shutdown       = nop_shutdown;
 200         nop->phy.state          = OTG_STATE_UNDEFINED;
 201
 202         nop->phy.otg->phy               = &nop->phy;
 203         nop->phy.otg->set_host          = nop_set_host;
 204         nop->phy.otg->set_peripheral    = nop_set_peripheral;
 205
 206         err = usb_add_phy(&nop->phy, type);
 207         if (err) {
 208                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 209                         err);
 210                 goto err_add;
 211         }
 212
 213         platform_set_drvdata(pdev, nop);
 214
 215         ATOMIC_INIT_NOTIFIER_HEAD(&nop->phy.notifier);
 216
 217         return 0;
 218
 219 err_add:
 220         if (!IS_ERR(nop->clk))
 221                 clk_unprepare(nop->clk);
 222         return err;
 223 }
 224
 225 static int nop_usb_xceiv_remove(struct platform_device *pdev)
 226 {
 227         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 228
 229         if (!IS_ERR(nop->clk))
 230                 clk_unprepare(nop->clk);
 231
 232         usb_remove_phy(&nop->phy);
 233
 234         platform_set_drvdata(pdev, NULL);
 235
 236         return 0;
 237 }
 238
 239 static struct platform_driver nop_usb_xceiv_driver = {
 240         .probe          = nop_usb_xceiv_probe,
 241         .remove         = nop_usb_xceiv_remove,
 242         .driver         = {
 243                 .name   = "nop_usb_xceiv",
 244                 .owner  = THIS_MODULE,
 245         },
 246 };
 247
 248 static int __init nop_usb_xceiv_init(void)
 249 {
 250         return platform_driver_register(&nop_usb_xceiv_driver);
 251 }
 252 subsys_initcall(nop_usb_xceiv_init);
 253
 254 static void __exit nop_usb_xceiv_exit(void)
 255 {
 256         platform_driver_unregister(&nop_usb_xceiv_driver);
 257 }
 258 module_exit(nop_usb_xceiv_exit);
 259
 260 MODULE_ALIAS("platform:nop_usb_xceiv");
 261 MODULE_AUTHOR("Texas Instruments Inc");
 262 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 263 MODULE_LICENSE("GPL");