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 = 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 */
 155static 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 */
 175static 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 */
 215static 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 */
 227static 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
 244static 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;
 339err_otg:
 340        regulator_put(gpio_vbus->vbus_draw);
 341        free_irq(irq, pdev);
 342err_irq:
 343        if (gpio_is_valid(pdata->gpio_pullup))
 344                gpio_free(pdata->gpio_pullup);
 345        gpio_free(pdata->gpio_vbus);
 346err_gpio:
 347        kfree(gpio_vbus->phy.otg);
 348        kfree(gpio_vbus);
 349        return err;
 350}
 351
 352static 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
 375static 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
 385static 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
 395static 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
 403MODULE_ALIAS("platform:gpio-vbus");
 404
 405static 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
 416module_platform_driver_probe(gpio_vbus_driver, gpio_vbus_probe);
 417
 418MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
 419MODULE_AUTHOR("Philipp Zabel");
 420MODULE_LICENSE("GPL");
 421