drivers/usb/phy/phy-gpio-vbus-usb.c

   1 /*
   2  * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
   3  *
   4  * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/gpio.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/usb.h>
  18 #include <linux/workqueue.h>
  19
  20 #include <linux/regulator/consumer.h>
  21
  22 #include <linux/usb/gadget.h>
  23 #include <linux/usb/gpio_vbus.h>
  24 #include <linux/usb/otg.h>
  25
  26
  27 /*
  28  * A simple GPIO VBUS sensing driver for B peripheral only devices
  29  * with internal transceivers. It can control a D+ pullup GPIO and
  30  * a regulator to limit the current drawn from VBUS.
  31  *
  32  * Needs to be loaded before the UDC driver that will use it.
  33  */
  34 struct gpio_vbus_data {
  35         struct usb_phy          phy;
  36         struct device          *dev;
  37         struct regulator       *vbus_draw;
  38         int                     vbus_draw_enabled;
  39         unsigned                mA;
  40         struct delayed_work     work;
  41         int                     vbus;
  42         int                     irq;
  43 };
  44
  45
  46 /*
  47  * This driver relies on "both edges" triggering.  VBUS has 100 msec to
  48  * stabilize, so the peripheral controller driver may need to cope with
  49  * some bouncing due to current surges (e.g. charging local capacitance)
  50  * and contact chatter.
  51  *
  52  * REVISIT in desperate straits, toggling between rising and falling
  53  * edges might be workable.
  54  */
  55 #define VBUS_IRQ_FLAGS \
  56         (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
  57
  58
  59 /* interface to regulator framework */
  60 static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
  61 {
  62         struct regulator *vbus_draw = gpio_vbus->vbus_draw;
  63         int enabled;
  64         int ret;
  65
  66         if (!vbus_draw)
  67                 return;
  68
  69         enabled = gpio_vbus->vbus_draw_enabled;
  70         if (mA) {
  71                 regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
  72                 if (!enabled) {
  73                         ret = regulator_enable(vbus_draw);
  74                         if (ret < 0)
  75                                 return;
  76                         gpio_vbus->vbus_draw_enabled = 1;
  77                 }
  78         } else {
  79                 if (enabled) {
  80                         ret = regulator_disable(vbus_draw);
  81                         if (ret < 0)
  82                                 return;
  83                         gpio_vbus->vbus_draw_enabled = 0;
  84                 }
  85         }
  86         gpio_vbus->mA = mA;
  87 }
  88
  89 static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
  90 {
  91         int vbus;
  92
  93         vbus = gpio_get_value(pdata->gpio_vbus);
  94         if (pdata->gpio_vbus_inverted)
  95                 vbus = !vbus;
  96
  97         return vbus;
  98 }
  99
 100 static void gpio_vbus_work(struct work_struct *work)
 101 {
 102         struct gpio_vbus_data *gpio_vbus =
 103                 container_of(work, struct gpio_vbus_data, work.work);
 104         struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
 105         int gpio, status, vbus;
 106
 107         if (!gpio_vbus->phy.otg->gadget)
 108                 return;
 109
 110         vbus = is_vbus_powered(pdata);
 111         if ((vbus ^ gpio_vbus->vbus) == 0)
 112                 return;
 113         gpio_vbus->vbus = vbus;
 114
 115         /* Peripheral controllers which manage the pullup themselves won't have
 116          * gpio_pullup configured here.  If it's configured here, we'll do what
 117          * isp1301_omap::b_peripheral() does and enable the pullup here... although
 118          * that may complicate usb_gadget_{,dis}connect() support.
 119          */
 120         gpio = pdata->gpio_pullup;
 121
 122         if (vbus) {
 123                 status = USB_EVENT_VBUS;
 124                 gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
 125                 gpio_vbus->phy.last_event = status;
 126                 usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
 127
 128                 /* drawing a "unit load" is *always* OK, except for OTG */
 129                 set_vbus_draw(gpio_vbus, 100);
 130
 131                 /* optionally enable D+ pullup */
 132                 if (gpio_is_valid(gpio))
 133                         gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
 134
 135                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
 136                                            status, gpio_vbus->phy.otg->gadget);
 137         } else {
 138                 /* optionally disable D+ pullup */
 139                 if (gpio_is_valid(gpio))
 140                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 141
 142                 set_vbus_draw(gpio_vbus, 0);
 143
 144                 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
 145                 status = USB_EVENT_NONE;
 146                 gpio_vbus->phy.state = OTG_STATE_B_IDLE;
 147                 gpio_vbus->phy.last_event = status;
 148
 149                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
 150                                            status, gpio_vbus->phy.otg->gadget);
 151         }
 152 }
 153
 154 /* VBUS change IRQ handler */
 155 static irqreturn_t gpio_vbus_irq(int irq, void *data)
 156 {
 157         struct platform_device *pdev = data;
 158         struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
 159         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 160         struct usb_otg *otg = gpio_vbus->phy.otg;
 161
 162         dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
 163                 is_vbus_powered(pdata) ? "supplied" : "inactive",
 164                 otg->gadget ? otg->gadget->name : "none");
 165
 166         if (otg->gadget)
 167                 schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
 168
 169         return IRQ_HANDLED;
 170 }
 171
 172 /* OTG transceiver interface */
 173
 174 /* bind/unbind the peripheral controller */
 175 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
 176                                         struct usb_gadget *gadget)
 177 {
 178         struct gpio_vbus_data *gpio_vbus;
 179         struct gpio_vbus_mach_info *pdata;
 180         struct platform_device *pdev;
 181         int gpio;
 182
 183         gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
 184         pdev = to_platform_device(gpio_vbus->dev);
 185         pdata = gpio_vbus->dev->platform_data;
 186         gpio = pdata->gpio_pullup;
 187
 188         if (!gadget) {
 189                 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
 190                         otg->gadget->name);
 191
 192                 /* optionally disable D+ pullup */
 193                 if (gpio_is_valid(gpio))
 194                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 195
 196                 set_vbus_draw(gpio_vbus, 0);
 197
 198                 usb_gadget_vbus_disconnect(otg->gadget);
 199                 otg->phy->state = OTG_STATE_UNDEFINED;
 200
 201                 otg->gadget = NULL;
 202                 return 0;
 203         }
 204
 205         otg->gadget = gadget;
 206         dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
 207
 208         /* initialize connection state */
 209         gpio_vbus->vbus = 0; /* start with disconnected */
 210         gpio_vbus_irq(gpio_vbus->irq, pdev);
 211         return 0;
 212 }
 213
 214 /* effective for B devices, ignored for A-peripheral */
 215 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
 216 {
 217         struct gpio_vbus_data *gpio_vbus;
 218
 219         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 220
 221         if (phy->state == OTG_STATE_B_PERIPHERAL)
 222                 set_vbus_draw(gpio_vbus, mA);
 223         return 0;
 224 }
 225
 226 /* for non-OTG B devices: set/clear transceiver suspend mode */
 227 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
 228 {
 229         struct gpio_vbus_data *gpio_vbus;
 230
 231         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 232
 233         /* draw max 0 mA from vbus in suspend mode; or the previously
 234          * recorded amount of current if not suspended
 235          *
 236          * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
 237          * if they're wake-enabled ... we don't handle that yet.
 238          */
 239         return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
 240 }
 241
 242 /* platform driver interface */
 243
 244 static int __init gpio_vbus_probe(struct platform_device *pdev)
 245 {
 246         struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
 247         struct gpio_vbus_data *gpio_vbus;
 248         struct resource *res;
 249         int err, gpio, irq;
 250         unsigned long irqflags;
 251
 252         if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
 253                 return -EINVAL;
 254         gpio = pdata->gpio_vbus;
 255
 256         gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
 257         if (!gpio_vbus)
 258                 return -ENOMEM;
 259
 260         gpio_vbus->phy.otg = kzalloc(sizeof(struct usb_otg), GFP_KERNEL);
 261         if (!gpio_vbus->phy.otg) {
 262                 kfree(gpio_vbus);
 263                 return -ENOMEM;
 264         }
 265
 266         platform_set_drvdata(pdev, gpio_vbus);
 267         gpio_vbus->dev = &pdev->dev;
 268         gpio_vbus->phy.label = "gpio-vbus";
 269         gpio_vbus->phy.dev = gpio_vbus->dev;
 270         gpio_vbus->phy.set_power = gpio_vbus_set_power;
 271         gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
 272         gpio_vbus->phy.state = OTG_STATE_UNDEFINED;
 273
 274         gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
 275         gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
 276
 277         err = gpio_request(gpio, "vbus_detect");
 278         if (err) {
 279                 dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
 280                         gpio, err);
 281                 goto err_gpio;
 282         }
 283         gpio_direction_input(gpio);
 284
 285         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 286         if (res) {
 287                 irq = res->start;
 288                 irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
 289         } else {
 290                 irq = gpio_to_irq(gpio);
 291                 irqflags = VBUS_IRQ_FLAGS;
 292         }
 293
 294         gpio_vbus->irq = irq;
 295
 296         /* if data line pullup is in use, initialize it to "not pulling up" */
 297         gpio = pdata->gpio_pullup;
 298         if (gpio_is_valid(gpio)) {
 299                 err = gpio_request(gpio, "udc_pullup");
 300                 if (err) {
 301                         dev_err(&pdev->dev,
 302                                 "can't request pullup gpio %d, err: %d\n",
 303                                 gpio, err);
 304                         gpio_free(pdata->gpio_vbus);
 305                         goto err_gpio;
 306                 }
 307                 gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
 308         }
 309
 310         err = request_irq(irq, gpio_vbus_irq, irqflags, "vbus_detect", pdev);
 311         if (err) {
 312                 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
 313                         irq, err);
 314                 goto err_irq;
 315         }
 316
 317         ATOMIC_INIT_NOTIFIER_HEAD(&gpio_vbus->phy.notifier);
 318
 319         INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
 320
 321         gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
 322         if (IS_ERR(gpio_vbus->vbus_draw)) {
 323                 dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
 324                         PTR_ERR(gpio_vbus->vbus_draw));
 325                 gpio_vbus->vbus_draw = NULL;
 326         }
 327
 328         /* only active when a gadget is registered */
 329         err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
 330         if (err) {
 331                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 332                         err);
 333                 goto err_otg;
 334         }
 335
 336         device_init_wakeup(&pdev->dev, pdata->wakeup);
 337
 338         return 0;
 339 err_otg:
 340         regulator_put(gpio_vbus->vbus_draw);
 341         free_irq(irq, pdev);
 342 err_irq:
 343         if (gpio_is_valid(pdata->gpio_pullup))
 344                 gpio_free(pdata->gpio_pullup);
 345         gpio_free(pdata->gpio_vbus);
 346 err_gpio:
 347         kfree(gpio_vbus->phy.otg);
 348         kfree(gpio_vbus);
 349         return err;
 350 }
 351
 352 static int __exit gpio_vbus_remove(struct platform_device *pdev)
 353 {
 354         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 355         struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
 356         int gpio = pdata->gpio_vbus;
 357
 358         device_init_wakeup(&pdev->dev, 0);
 359         cancel_delayed_work_sync(&gpio_vbus->work);
 360         regulator_put(gpio_vbus->vbus_draw);
 361
 362         usb_remove_phy(&gpio_vbus->phy);
 363
 364         free_irq(gpio_vbus->irq, pdev);
 365         if (gpio_is_valid(pdata->gpio_pullup))
 366                 gpio_free(pdata->gpio_pullup);
 367         gpio_free(gpio);
 368         kfree(gpio_vbus->phy.otg);
 369         kfree(gpio_vbus);
 370
 371         return 0;
 372 }
 373
 374 #ifdef CONFIG_PM
 375 static int gpio_vbus_pm_suspend(struct device *dev)
 376 {
 377         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 378
 379         if (device_may_wakeup(dev))
 380                 enable_irq_wake(gpio_vbus->irq);
 381
 382         return 0;
 383 }
 384
 385 static int gpio_vbus_pm_resume(struct device *dev)
 386 {
 387         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 388
 389         if (device_may_wakeup(dev))
 390                 disable_irq_wake(gpio_vbus->irq);
 391
 392         return 0;
 393 }
 394
 395 static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
 396         .suspend        = gpio_vbus_pm_suspend,
 397         .resume         = gpio_vbus_pm_resume,
 398 };
 399 #endif
 400
 401 /* NOTE:  the gpio-vbus device may *NOT* be hotplugged */
 402
 403 MODULE_ALIAS("platform:gpio-vbus");
 404
 405 static struct platform_driver gpio_vbus_driver = {
 406         .driver = {
 407                 .name  = "gpio-vbus",
 408                 .owner = THIS_MODULE,
 409 #ifdef CONFIG_PM
 410                 .pm = &gpio_vbus_dev_pm_ops,
 411 #endif
 412         },
 413         .remove  = __exit_p(gpio_vbus_remove),
 414 };
 415
 416 module_platform_driver_probe(gpio_vbus_driver, gpio_vbus_probe);
 417
 418 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
 419 MODULE_AUTHOR("Philipp Zabel");
 420 MODULE_LICENSE("GPL");