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

DEFINITIONS

1. set_vbus_draw
2. is_vbus_powered
3. gpio_vbus_work
4. gpio_vbus_irq
5. gpio_vbus_set_peripheral
6. gpio_vbus_set_power
7. gpio_vbus_set_suspend
8. gpio_vbus_probe
9. gpio_vbus_remove
10. gpio_vbus_pm_suspend
11. gpio_vbus_pm_resume

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
   4  *
   5  * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
   6  */
   7 
   8 #include <linux/kernel.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/gpio.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/usb.h>
  15 #include <linux/workqueue.h>
  16 
  17 #include <linux/regulator/consumer.h>
  18 
  19 #include <linux/usb/gadget.h>
  20 #include <linux/usb/gpio_vbus.h>
  21 #include <linux/usb/otg.h>
  22 
  23 
  24 /*
  25  * A simple GPIO VBUS sensing driver for B peripheral only devices
  26  * with internal transceivers. It can control a D+ pullup GPIO and
  27  * a regulator to limit the current drawn from VBUS.
  28  *
  29  * Needs to be loaded before the UDC driver that will use it.
  30  */
  31 struct gpio_vbus_data {
  32         struct usb_phy          phy;
  33         struct device          *dev;
  34         struct regulator       *vbus_draw;
  35         int                     vbus_draw_enabled;
  36         unsigned                mA;
  37         struct delayed_work     work;
  38         int                     vbus;
  39         int                     irq;
  40 };
  41 
  42 
  43 /*
  44  * This driver relies on "both edges" triggering.  VBUS has 100 msec to
  45  * stabilize, so the peripheral controller driver may need to cope with
  46  * some bouncing due to current surges (e.g. charging local capacitance)
  47  * and contact chatter.
  48  *
  49  * REVISIT in desperate straits, toggling between rising and falling
  50  * edges might be workable.
  51  */
  52 #define VBUS_IRQ_FLAGS \
  53         (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
  54 
  55 
  56 /* interface to regulator framework */
  57 static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
  58 {
  59         struct regulator *vbus_draw = gpio_vbus->vbus_draw;
  60         int enabled;
  61         int ret;
  62 
  63         if (!vbus_draw)
  64                 return;
  65 
  66         enabled = gpio_vbus->vbus_draw_enabled;
  67         if (mA) {
  68                 regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
  69                 if (!enabled) {
  70                         ret = regulator_enable(vbus_draw);
  71                         if (ret < 0)
  72                                 return;
  73                         gpio_vbus->vbus_draw_enabled = 1;
  74                 }
  75         } else {
  76                 if (enabled) {
  77                         ret = regulator_disable(vbus_draw);
  78                         if (ret < 0)
  79                                 return;
  80                         gpio_vbus->vbus_draw_enabled = 0;
  81                 }
  82         }
  83         gpio_vbus->mA = mA;
  84 }
  85 
  86 static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
  87 {
  88         int vbus;
  89 
  90         vbus = gpio_get_value(pdata->gpio_vbus);
  91         if (pdata->gpio_vbus_inverted)
  92                 vbus = !vbus;
  93 
  94         return vbus;
  95 }
  96 
  97 static void gpio_vbus_work(struct work_struct *work)
  98 {
  99         struct gpio_vbus_data *gpio_vbus =
 100                 container_of(work, struct gpio_vbus_data, work.work);
 101         struct gpio_vbus_mach_info *pdata = dev_get_platdata(gpio_vbus->dev);
 102         int gpio, status, vbus;
 103 
 104         if (!gpio_vbus->phy.otg->gadget)
 105                 return;
 106 
 107         vbus = is_vbus_powered(pdata);
 108         if ((vbus ^ gpio_vbus->vbus) == 0)
 109                 return;
 110         gpio_vbus->vbus = vbus;
 111 
 112         /* Peripheral controllers which manage the pullup themselves won't have
 113          * gpio_pullup configured here.  If it's configured here, we'll do what
 114          * isp1301_omap::b_peripheral() does and enable the pullup here... although
 115          * that may complicate usb_gadget_{,dis}connect() support.
 116          */
 117         gpio = pdata->gpio_pullup;
 118 
 119         if (vbus) {
 120                 status = USB_EVENT_VBUS;
 121                 gpio_vbus->phy.otg->state = OTG_STATE_B_PERIPHERAL;
 122                 gpio_vbus->phy.last_event = status;
 123                 usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
 124 
 125                 /* drawing a "unit load" is *always* OK, except for OTG */
 126                 set_vbus_draw(gpio_vbus, 100);
 127 
 128                 /* optionally enable D+ pullup */
 129                 if (gpio_is_valid(gpio))
 130                         gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
 131 
 132                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
 133                                            status, gpio_vbus->phy.otg->gadget);
 134                 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
 135         } else {
 136                 /* optionally disable D+ pullup */
 137                 if (gpio_is_valid(gpio))
 138                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 139 
 140                 set_vbus_draw(gpio_vbus, 0);
 141 
 142                 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
 143                 status = USB_EVENT_NONE;
 144                 gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
 145                 gpio_vbus->phy.last_event = status;
 146 
 147                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
 148                                            status, gpio_vbus->phy.otg->gadget);
 149                 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
 150         }
 151 }
 152 
 153 /* VBUS change IRQ handler */
 154 static irqreturn_t gpio_vbus_irq(int irq, void *data)
 155 {
 156         struct platform_device *pdev = data;
 157         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
 158         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 159         struct usb_otg *otg = gpio_vbus->phy.otg;
 160 
 161         dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
 162                 is_vbus_powered(pdata) ? "supplied" : "inactive",
 163                 otg->gadget ? otg->gadget->name : "none");
 164 
 165         if (otg->gadget)
 166                 schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
 167 
 168         return IRQ_HANDLED;
 169 }
 170 
 171 /* OTG transceiver interface */
 172 
 173 /* bind/unbind the peripheral controller */
 174 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
 175                                         struct usb_gadget *gadget)
 176 {
 177         struct gpio_vbus_data *gpio_vbus;
 178         struct gpio_vbus_mach_info *pdata;
 179         struct platform_device *pdev;
 180         int gpio;
 181 
 182         gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
 183         pdev = to_platform_device(gpio_vbus->dev);
 184         pdata = dev_get_platdata(gpio_vbus->dev);
 185         gpio = pdata->gpio_pullup;
 186 
 187         if (!gadget) {
 188                 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
 189                         otg->gadget->name);
 190 
 191                 /* optionally disable D+ pullup */
 192                 if (gpio_is_valid(gpio))
 193                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
 194 
 195                 set_vbus_draw(gpio_vbus, 0);
 196 
 197                 usb_gadget_vbus_disconnect(otg->gadget);
 198                 otg->state = OTG_STATE_UNDEFINED;
 199 
 200                 otg->gadget = NULL;
 201                 return 0;
 202         }
 203 
 204         otg->gadget = gadget;
 205         dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
 206 
 207         /* initialize connection state */
 208         gpio_vbus->vbus = 0; /* start with disconnected */
 209         gpio_vbus_irq(gpio_vbus->irq, pdev);
 210         return 0;
 211 }
 212 
 213 /* effective for B devices, ignored for A-peripheral */
 214 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
 215 {
 216         struct gpio_vbus_data *gpio_vbus;
 217 
 218         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 219 
 220         if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
 221                 set_vbus_draw(gpio_vbus, mA);
 222         return 0;
 223 }
 224 
 225 /* for non-OTG B devices: set/clear transceiver suspend mode */
 226 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
 227 {
 228         struct gpio_vbus_data *gpio_vbus;
 229 
 230         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
 231 
 232         /* draw max 0 mA from vbus in suspend mode; or the previously
 233          * recorded amount of current if not suspended
 234          *
 235          * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
 236          * if they're wake-enabled ... we don't handle that yet.
 237          */
 238         return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
 239 }
 240 
 241 /* platform driver interface */
 242 
 243 static int gpio_vbus_probe(struct platform_device *pdev)
 244 {
 245         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
 246         struct gpio_vbus_data *gpio_vbus;
 247         struct resource *res;
 248         int err, gpio, irq;
 249         unsigned long irqflags;
 250 
 251         if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
 252                 return -EINVAL;
 253         gpio = pdata->gpio_vbus;
 254 
 255         gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
 256                                  GFP_KERNEL);
 257         if (!gpio_vbus)
 258                 return -ENOMEM;
 259 
 260         gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
 261                                           GFP_KERNEL);
 262         if (!gpio_vbus->phy.otg)
 263                 return -ENOMEM;
 264 
 265         platform_set_drvdata(pdev, gpio_vbus);
 266         gpio_vbus->dev = &pdev->dev;
 267         gpio_vbus->phy.label = "gpio-vbus";
 268         gpio_vbus->phy.dev = gpio_vbus->dev;
 269         gpio_vbus->phy.set_power = gpio_vbus_set_power;
 270         gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
 271 
 272         gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
 273         gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
 274         gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
 275 
 276         err = devm_gpio_request(&pdev->dev, gpio, "vbus_detect");
 277         if (err) {
 278                 dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
 279                         gpio, err);
 280                 return err;
 281         }
 282         gpio_direction_input(gpio);
 283 
 284         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 285         if (res) {
 286                 irq = res->start;
 287                 irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
 288         } else {
 289                 irq = gpio_to_irq(gpio);
 290                 irqflags = VBUS_IRQ_FLAGS;
 291         }
 292 
 293         gpio_vbus->irq = irq;
 294 
 295         /* if data line pullup is in use, initialize it to "not pulling up" */
 296         gpio = pdata->gpio_pullup;
 297         if (gpio_is_valid(gpio)) {
 298                 err = devm_gpio_request(&pdev->dev, gpio, "udc_pullup");
 299                 if (err) {
 300                         dev_err(&pdev->dev,
 301                                 "can't request pullup gpio %d, err: %d\n",
 302                                 gpio, err);
 303                         return err;
 304                 }
 305                 gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
 306         }
 307 
 308         err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
 309                                "vbus_detect", pdev);
 310         if (err) {
 311                 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
 312                         irq, err);
 313                 return err;
 314         }
 315 
 316         INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
 317 
 318         gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
 319         if (IS_ERR(gpio_vbus->vbus_draw)) {
 320                 dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
 321                         PTR_ERR(gpio_vbus->vbus_draw));
 322                 gpio_vbus->vbus_draw = NULL;
 323         }
 324 
 325         /* only active when a gadget is registered */
 326         err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
 327         if (err) {
 328                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
 329                         err);
 330                 return err;
 331         }
 332 
 333         device_init_wakeup(&pdev->dev, pdata->wakeup);
 334 
 335         return 0;
 336 }
 337 
 338 static int gpio_vbus_remove(struct platform_device *pdev)
 339 {
 340         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
 341 
 342         device_init_wakeup(&pdev->dev, 0);
 343         cancel_delayed_work_sync(&gpio_vbus->work);
 344 
 345         usb_remove_phy(&gpio_vbus->phy);
 346 
 347         return 0;
 348 }
 349 
 350 #ifdef CONFIG_PM
 351 static int gpio_vbus_pm_suspend(struct device *dev)
 352 {
 353         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 354 
 355         if (device_may_wakeup(dev))
 356                 enable_irq_wake(gpio_vbus->irq);
 357 
 358         return 0;
 359 }
 360 
 361 static int gpio_vbus_pm_resume(struct device *dev)
 362 {
 363         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
 364 
 365         if (device_may_wakeup(dev))
 366                 disable_irq_wake(gpio_vbus->irq);
 367 
 368         return 0;
 369 }
 370 
 371 static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
 372         .suspend        = gpio_vbus_pm_suspend,
 373         .resume         = gpio_vbus_pm_resume,
 374 };
 375 #endif
 376 
 377 MODULE_ALIAS("platform:gpio-vbus");
 378 
 379 static struct platform_driver gpio_vbus_driver = {
 380         .driver = {
 381                 .name  = "gpio-vbus",
 382 #ifdef CONFIG_PM
 383                 .pm = &gpio_vbus_dev_pm_ops,
 384 #endif
 385         },
 386         .probe          = gpio_vbus_probe,
 387         .remove         = gpio_vbus_remove,
 388 };
 389 
 390 module_platform_driver(gpio_vbus_driver);
 391 
 392 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
 393 MODULE_AUTHOR("Philipp Zabel");
 394 MODULE_LICENSE("GPL");