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 = dev_get_platdata(gpio_vbus->dev);
 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.otg->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                 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
 138         } else {
 139                 /* optionally disable D+ pullup */
 140                 if (gpio_is_valid(gpio))
 141                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 142
 143                 set_vbus_draw(gpio_vbus, 0);
 144
 145                 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
 146                 status = USB_EVENT_NONE;
 147                 gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
 148                 gpio_vbus->phy.last_event = status;
 149
 150                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
 151                                            status, gpio_vbus->phy.otg->gadget);
 152                 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
 153         }
 154 }
 155
 156 /* VBUS change IRQ handler */
 157 static irqreturn_t gpio_vbus_irq(int irq, void *data)
 158 {
 159         struct platform_device *pdev = data;
 160         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
 161         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 162         struct usb_otg *otg = gpio_vbus->phy.otg;
 163
 164         dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
 165                 is_vbus_powered(pdata) ? "supplied" : "inactive",
 166                 otg->gadget ? otg->gadget->name : "none");
 167
 168         if (otg->gadget)
 169                 schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
 170
 171         return IRQ_HANDLED;
 172 }
 173
 174 /* OTG transceiver interface */
 175
 176 /* bind/unbind the peripheral controller */
 177 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
 178                                         struct usb_gadget *gadget)
 179 {
 180         struct gpio_vbus_data *gpio_vbus;
 181         struct gpio_vbus_mach_info *pdata;
 182         struct platform_device *pdev;
 183         int gpio;
 184
 185         gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
 186         pdev = to_platform_device(gpio_vbus->dev);
 187         pdata = dev_get_platdata(gpio_vbus->dev);
 188         gpio = pdata->gpio_pullup;
 189
 190         if (!gadget) {
 191                 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
 192                         otg->gadget->name);
 193
 194                 /* optionally disable D+ pullup */
 195                 if (gpio_is_valid(gpio))
 196                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 197
 198                 set_vbus_draw(gpio_vbus, 0);
 199
 200                 usb_gadget_vbus_disconnect(otg->gadget);
 201                 otg->state = OTG_STATE_UNDEFINED;
 202
 203                 otg->gadget = NULL;
 204                 return 0;
 205         }
 206
 207         otg->gadget = gadget;
 208         dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
 209
 210         /* initialize connection state */
 211         gpio_vbus->vbus = 0; /* start with disconnected */
 212         gpio_vbus_irq(gpio_vbus->irq, pdev);
 213         return 0;
 214 }
 215
 216 /* effective for B devices, ignored for A-peripheral */
 217 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
 218 {
 219         struct gpio_vbus_data *gpio_vbus;
 220
 221         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 222
 223         if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
 224                 set_vbus_draw(gpio_vbus, mA);
 225         return 0;
 226 }
 227
 228 /* for non-OTG B devices: set/clear transceiver suspend mode */
 229 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
 230 {
 231         struct gpio_vbus_data *gpio_vbus;
 232
 233         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 234
 235         /* draw max 0 mA from vbus in suspend mode; or the previously
 236          * recorded amount of current if not suspended
 237          *
 238          * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
 239          * if they're wake-enabled ... we don't handle that yet.
 240          */
 241         return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
 242 }
 243
 244 /* platform driver interface */
 245
 246 static int gpio_vbus_probe(struct platform_device *pdev)
 247 {
 248         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
 249         struct gpio_vbus_data *gpio_vbus;
 250         struct resource *res;
 251         int err, gpio, irq;
 252         unsigned long irqflags;
 253
 254         if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
 255                 return -EINVAL;
 256         gpio = pdata->gpio_vbus;
 257
 258         gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
 259                                  GFP_KERNEL);
 260         if (!gpio_vbus)
 261                 return -ENOMEM;
 262
 263         gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
 264                                           GFP_KERNEL);
 265         if (!gpio_vbus->phy.otg)
 266                 return -ENOMEM;
 267
 268         platform_set_drvdata(pdev, gpio_vbus);
 269         gpio_vbus->dev = &pdev->dev;
 270         gpio_vbus->phy.label = "gpio-vbus";
 271         gpio_vbus->phy.dev = gpio_vbus->dev;
 272         gpio_vbus->phy.set_power = gpio_vbus_set_power;
 273         gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
 274
 275         gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
 276         gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
 277         gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
 278
 279         err = devm_gpio_request(&pdev->dev, gpio, "vbus_detect");
 280         if (err) {
 281                 dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
 282                         gpio, err);
 283                 return err;
 284         }
 285         gpio_direction_input(gpio);
 286
 287         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 288         if (res) {
 289                 irq = res->start;
 290                 irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
 291         } else {
 292                 irq = gpio_to_irq(gpio);
 293                 irqflags = VBUS_IRQ_FLAGS;
 294         }
 295
 296         gpio_vbus->irq = irq;
 297
 298         /* if data line pullup is in use, initialize it to "not pulling up" */
 299         gpio = pdata->gpio_pullup;
 300         if (gpio_is_valid(gpio)) {
 301                 err = devm_gpio_request(&pdev->dev, gpio, "udc_pullup");
 302                 if (err) {
 303                         dev_err(&pdev->dev,
 304                                 "can't request pullup gpio %d, err: %d\n",
 305                                 gpio, err);
 306                         return err;
 307                 }
 308                 gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
 309         }
 310
 311         err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
 312                                "vbus_detect", pdev);
 313         if (err) {
 314                 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
 315                         irq, err);
 316                 return err;
 317         }
 318
 319         INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
 320
 321         gpio_vbus->vbus_draw = devm_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                 return err;
 334         }
 335
 336         device_init_wakeup(&pdev->dev, pdata->wakeup);
 337
 338         return 0;
 339 }
 340
 341 static int gpio_vbus_remove(struct platform_device *pdev)
 342 {
 343         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 344
 345         device_init_wakeup(&pdev->dev, 0);
 346         cancel_delayed_work_sync(&gpio_vbus->work);
 347
 348         usb_remove_phy(&gpio_vbus->phy);
 349
 350         return 0;
 351 }
 352
 353 #ifdef CONFIG_PM
 354 static int gpio_vbus_pm_suspend(struct device *dev)
 355 {
 356         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 357
 358         if (device_may_wakeup(dev))
 359                 enable_irq_wake(gpio_vbus->irq);
 360
 361         return 0;
 362 }
 363
 364 static int gpio_vbus_pm_resume(struct device *dev)
 365 {
 366         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 367
 368         if (device_may_wakeup(dev))
 369                 disable_irq_wake(gpio_vbus->irq);
 370
 371         return 0;
 372 }
 373
 374 static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
 375         .suspend        = gpio_vbus_pm_suspend,
 376         .resume         = gpio_vbus_pm_resume,
 377 };
 378 #endif
 379
 380 MODULE_ALIAS("platform:gpio-vbus");
 381
 382 static struct platform_driver gpio_vbus_driver = {
 383         .driver = {
 384                 .name  = "gpio-vbus",
 385 #ifdef CONFIG_PM
 386                 .pm = &gpio_vbus_dev_pm_ops,
 387 #endif
 388         },
 389         .probe          = gpio_vbus_probe,
 390         .remove         = gpio_vbus_remove,
 391 };
 392
 393 module_platform_driver(gpio_vbus_driver);
 394
 395 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
 396 MODULE_AUTHOR("Philipp Zabel");
 397 MODULE_LICENSE("GPL");