drivers/usb/phy/phy-nop.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 #include <linux/of.h>
  38
  39 struct nop_usb_xceiv {
  40         struct usb_phy phy;
  41         struct device *dev;
  42         struct clk *clk;
  43         struct regulator *vcc;
  44         struct regulator *reset;
  45 };
  46
  47 static struct platform_device *pd;
  48
  49 void usb_nop_xceiv_register(void)
  50 {
  51         if (pd)
  52                 return;
  53         pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
  54         if (!pd) {
  55                 printk(KERN_ERR "Unable to register usb nop transceiver\n");
  56                 return;
  57         }
  58 }
  59 EXPORT_SYMBOL(usb_nop_xceiv_register);
  60
  61 void usb_nop_xceiv_unregister(void)
  62 {
  63         platform_device_unregister(pd);
  64         pd = NULL;
  65 }
  66 EXPORT_SYMBOL(usb_nop_xceiv_unregister);
  67
  68 static int nop_set_suspend(struct usb_phy *x, int suspend)
  69 {
  70         return 0;
  71 }
  72
  73 static int nop_init(struct usb_phy *phy)
  74 {
  75         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  76
  77         if (!IS_ERR(nop->vcc)) {
  78                 if (regulator_enable(nop->vcc))
  79                         dev_err(phy->dev, "Failed to enable power\n");
  80         }
  81
  82         if (!IS_ERR(nop->clk))
  83                 clk_enable(nop->clk);
  84
  85         if (!IS_ERR(nop->reset)) {
  86                 /* De-assert RESET */
  87                 if (regulator_enable(nop->reset))
  88                         dev_err(phy->dev, "Failed to de-assert reset\n");
  89         }
  90
  91         return 0;
  92 }
  93
  94 static void nop_shutdown(struct usb_phy *phy)
  95 {
  96         struct nop_usb_xceiv *nop = dev_get_drvdata(phy->dev);
  97
  98         if (!IS_ERR(nop->reset)) {
  99                 /* Assert RESET */
 100                 if (regulator_disable(nop->reset))
 101                         dev_err(phy->dev, "Failed to assert reset\n");
 102         }
 103
 104         if (!IS_ERR(nop->clk))
 105                 clk_disable(nop->clk);
 106
 107         if (!IS_ERR(nop->vcc)) {
 108                 if (regulator_disable(nop->vcc))
 109                         dev_err(phy->dev, "Failed to disable power\n");
 110         }
 111 }
 112
 113 static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
 114 {
 115         if (!otg)
 116                 return -ENODEV;
 117
 118         if (!gadget) {
 119                 otg->gadget = NULL;
 120                 return -ENODEV;
 121         }
 122
 123         otg->gadget = gadget;
 124         otg->phy->state = OTG_STATE_B_IDLE;
 125         return 0;
 126 }
 127
 128 static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
 129 {
 130         if (!otg)
 131                 return -ENODEV;
 132
 133         if (!host) {
 134                 otg->host = NULL;
 135                 return -ENODEV;
 136         }
 137
 138         otg->host = host;
 139         return 0;
 140 }
 141
 142 static int nop_usb_xceiv_probe(struct platform_device *pdev)
 143 {
 144         struct device *dev = &pdev->dev;
 145         struct nop_usb_xceiv_platform_data *pdata = pdev->dev.platform_data;
 146         struct nop_usb_xceiv    *nop;
 147         enum usb_phy_type       type = USB_PHY_TYPE_USB2;
 148         int err;
 149         u32 clk_rate = 0;
 150         bool needs_vcc = false;
 151         bool needs_reset = false;
 152
 153         nop = devm_kzalloc(&pdev->dev, sizeof(*nop), GFP_KERNEL);
 154         if (!nop)
 155                 return -ENOMEM;
 156
 157         nop->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*nop->phy.otg),
 158                                                         GFP_KERNEL);
 159         if (!nop->phy.otg)
 160                 return -ENOMEM;
 161
 162         if (dev->of_node) {
 163                 struct device_node *node = dev->of_node;
 164
 165                 if (of_property_read_u32(node, "clock-frequency", &clk_rate))
 166                         clk_rate = 0;
 167
 168                 needs_vcc = of_property_read_bool(node, "vcc-supply");
 169                 needs_reset = of_property_read_bool(node, "reset-supply");
 170
 171         } else if (pdata) {
 172                 type = pdata->type;
 173                 clk_rate = pdata->clk_rate;
 174                 needs_vcc = pdata->needs_vcc;
 175                 needs_reset = pdata->needs_reset;
 176         }
 177
 178         nop->clk = devm_clk_get(&pdev->dev, "main_clk");
 179         if (IS_ERR(nop->clk)) {
 180                 dev_dbg(&pdev->dev, "Can't get phy clock: %ld\n",
 181                                         PTR_ERR(nop->clk));
 182         }
 183
 184         if (!IS_ERR(nop->clk) && clk_rate) {
 185                 err = clk_set_rate(nop->clk, clk_rate);
 186                 if (err) {
 187                         dev_err(&pdev->dev, "Error setting clock rate\n");
 188                         return err;
 189                 }
 190         }
 191
 192         if (!IS_ERR(nop->clk)) {
 193                 err = clk_prepare(nop->clk);
 194                 if (err) {
 195                         dev_err(&pdev->dev, "Error preparing clock\n");
 196                         return err;
 197                 }
 198         }
 199
 200         nop->vcc = devm_regulator_get(&pdev->dev, "vcc");
 201         if (IS_ERR(nop->vcc)) {
 202                 dev_dbg(&pdev->dev, "Error getting vcc regulator: %ld\n",
 203                                         PTR_ERR(nop->vcc));
 204                 if (needs_vcc)
 205                         return -EPROBE_DEFER;
 206         }
 207
 208         nop->reset = devm_regulator_get(&pdev->dev, "reset");
 209         if (IS_ERR(nop->reset)) {
 210                 dev_dbg(&pdev->dev, "Error getting reset regulator: %ld\n",
 211                                         PTR_ERR(nop->reset));
 212                 if (needs_reset)
 213                         return -EPROBE_DEFER;
 214         }
 215
 216         nop->dev                = &pdev->dev;
 217         nop->phy.dev            = nop->dev;
 218         nop->phy.label          = "nop-xceiv";
 219         nop->phy.set_suspend    = nop_set_suspend;
 220         nop->phy.init           = nop_init;
 221         nop->phy.shutdown       = nop_shutdown;
 222         nop->phy.state          = OTG_STATE_UNDEFINED;
 223         nop->phy.type           = type;
 224
 225         nop->phy.otg->phy               = &nop->phy;
 226         nop->phy.otg->set_host          = nop_set_host;
 227         nop->phy.otg->set_peripheral    = nop_set_peripheral;
 228
 229         err = usb_add_phy_dev(&nop->phy);
 230         if (err) {
 231                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 232                         err);
 233                 goto err_add;
 234         }
 235
 236         platform_set_drvdata(pdev, nop);
 237
 238         ATOMIC_INIT_NOTIFIER_HEAD(&nop->phy.notifier);
 239
 240         return 0;
 241
 242 err_add:
 243         if (!IS_ERR(nop->clk))
 244                 clk_unprepare(nop->clk);
 245         return err;
 246 }
 247
 248 static int nop_usb_xceiv_remove(struct platform_device *pdev)
 249 {
 250         struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
 251
 252         if (!IS_ERR(nop->clk))
 253                 clk_unprepare(nop->clk);
 254
 255         usb_remove_phy(&nop->phy);
 256
 257         platform_set_drvdata(pdev, NULL);
 258
 259         return 0;
 260 }
 261
 262 static const struct of_device_id nop_xceiv_dt_ids[] = {
 263         { .compatible = "usb-nop-xceiv" },
 264         { }
 265 };
 266
 267 MODULE_DEVICE_TABLE(of, nop_xceiv_dt_ids);
 268
 269 static struct platform_driver nop_usb_xceiv_driver = {
 270         .probe          = nop_usb_xceiv_probe,
 271         .remove         = nop_usb_xceiv_remove,
 272         .driver         = {
 273                 .name   = "nop_usb_xceiv",
 274                 .owner  = THIS_MODULE,
 275                 .of_match_table = of_match_ptr(nop_xceiv_dt_ids),
 276         },
 277 };
 278
 279 static int __init nop_usb_xceiv_init(void)
 280 {
 281         return platform_driver_register(&nop_usb_xceiv_driver);
 282 }
 283 subsys_initcall(nop_usb_xceiv_init);
 284
 285 static void __exit nop_usb_xceiv_exit(void)
 286 {
 287         platform_driver_unregister(&nop_usb_xceiv_driver);
 288 }
 289 module_exit(nop_usb_xceiv_exit);
 290
 291 MODULE_ALIAS("platform:nop_usb_xceiv");
 292 MODULE_AUTHOR("Texas Instruments Inc");
 293 MODULE_DESCRIPTION("NOP USB Transceiver driver");
 294 MODULE_LICENSE("GPL");