LXR linux/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 */
  34struct 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 */
  60static 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
  89static 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
 100static 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 */
 157static 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 */
 177static 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 */
 217static 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 */
 229static 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
 246static 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
 341static 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
 354static 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
 364static 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
 374static 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
 380MODULE_ALIAS("platform:gpio-vbus");
 381
 382static 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
 393module_platform_driver(gpio_vbus_driver);
 394
 395MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
 396MODULE_AUTHOR("Philipp Zabel");
 397MODULE_LICENSE("GPL");
 398