package/kernel/gpio-button-hotplug/src/gpio-button-hotplug.c

   1 /*
   2  *  GPIO Button Hotplug driver
   3  *
   4  *  Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   5  *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
   6  *
   7  *  Based on the diag.c - GPIO interface driver for Broadcom boards
   8  *    Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
   9  *    Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
  10  *    Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify it
  13  *  under the terms of the GNU General Public License version 2 as published
  14  *  by the Free Software Foundation.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/version.h>
  19 #include <linux/kmod.h>
  20
  21 #include <linux/workqueue.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/netlink.h>
  24 #include <linux/kobject.h>
  25 #include <linux/input.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/of_gpio.h>
  29 #include <linux/gpio_keys.h>
  30
  31 #define DRV_NAME        "gpio-keys"
  32
  33 #define BH_SKB_SIZE     2048
  34
  35 #define PFX     DRV_NAME ": "
  36
  37 #undef BH_DEBUG
  38
  39 #ifdef BH_DEBUG
  40 #define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
  41 #else
  42 #define BH_DBG(fmt, args...) do {} while (0)
  43 #endif
  44
  45 #define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
  46
  47 struct bh_priv {
  48         unsigned long           seen;
  49 };
  50
  51 struct bh_event {
  52         const char              *name;
  53         unsigned int            type;
  54         char                    *action;
  55         unsigned long           seen;
  56
  57         struct sk_buff          *skb;
  58         struct work_struct      work;
  59 };
  60
  61 struct bh_map {
  62         unsigned int    code;
  63         const char      *name;
  64 };
  65
  66 struct gpio_keys_button_data {
  67         struct delayed_work work;
  68         struct bh_priv bh;
  69         int last_state;
  70         int count;
  71         int threshold;
  72         int can_sleep;
  73         struct gpio_keys_button *b;
  74 };
  75
  76 extern u64 uevent_next_seqnum(void);
  77
  78 #define BH_MAP(_code, _name)            \
  79         {                               \
  80                 .code = (_code),        \
  81                 .name = (_name),        \
  82         }
  83
  84 static struct bh_map button_map[] = {
  85         BH_MAP(BTN_0,           "BTN_0"),
  86         BH_MAP(BTN_1,           "BTN_1"),
  87         BH_MAP(BTN_2,           "BTN_2"),
  88         BH_MAP(BTN_3,           "BTN_3"),
  89         BH_MAP(BTN_4,           "BTN_4"),
  90         BH_MAP(BTN_5,           "BTN_5"),
  91         BH_MAP(BTN_6,           "BTN_6"),
  92         BH_MAP(BTN_7,           "BTN_7"),
  93         BH_MAP(BTN_8,           "BTN_8"),
  94         BH_MAP(BTN_9,           "BTN_9"),
  95         BH_MAP(KEY_POWER,       "power"),
  96         BH_MAP(KEY_RESTART,     "reset"),
  97         BH_MAP(KEY_RFKILL,      "rfkill"),
  98         BH_MAP(KEY_WPS_BUTTON,  "wps"),
  99 };
 100
 101 /* -------------------------------------------------------------------------*/
 102
 103 static int bh_event_add_var(struct bh_event *event, int argv,
 104                 const char *format, ...)
 105 {
 106         static char buf[128];
 107         char *s;
 108         va_list args;
 109         int len;
 110
 111         if (argv)
 112                 return 0;
 113
 114         va_start(args, format);
 115         len = vsnprintf(buf, sizeof(buf), format, args);
 116         va_end(args);
 117
 118         if (len >= sizeof(buf)) {
 119                 BH_ERR("buffer size too small\n");
 120                 WARN_ON(1);
 121                 return -ENOMEM;
 122         }
 123
 124         s = skb_put(event->skb, len + 1);
 125         strcpy(s, buf);
 126
 127         BH_DBG("added variable '%s'\n", s);
 128
 129         return 0;
 130 }
 131
 132 static int button_hotplug_fill_event(struct bh_event *event)
 133 {
 134         int ret;
 135
 136         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 137         if (ret)
 138                 return ret;
 139
 140         ret = bh_event_add_var(event, 0, "PATH=%s",
 141                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 142         if (ret)
 143                 return ret;
 144
 145         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 146         if (ret)
 147                 return ret;
 148
 149         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 150         if (ret)
 151                 return ret;
 152
 153         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 154         if (ret)
 155                 return ret;
 156
 157         if (event->type == EV_SW) {
 158                 ret = bh_event_add_var(event, 0, "TYPE=%s", "switch");
 159                 if (ret)
 160                         return ret;
 161         }
 162
 163         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 164         if (ret)
 165                 return ret;
 166
 167         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 168
 169         return ret;
 170 }
 171
 172 static void button_hotplug_work(struct work_struct *work)
 173 {
 174         struct bh_event *event = container_of(work, struct bh_event, work);
 175         int ret = 0;
 176
 177         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 178         if (!event->skb)
 179                 goto out_free_event;
 180
 181         ret = bh_event_add_var(event, 0, "%s@", event->action);
 182         if (ret)
 183                 goto out_free_skb;
 184
 185         ret = button_hotplug_fill_event(event);
 186         if (ret)
 187                 goto out_free_skb;
 188
 189         NETLINK_CB(event->skb).dst_group = 1;
 190         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 191
 192  out_free_skb:
 193         if (ret) {
 194                 BH_ERR("work error %d\n", ret);
 195                 kfree_skb(event->skb);
 196         }
 197  out_free_event:
 198         kfree(event);
 199 }
 200
 201 static int button_hotplug_create_event(const char *name, unsigned int type,
 202                 unsigned long seen, int pressed)
 203 {
 204         struct bh_event *event;
 205
 206         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 207                 name, seen, pressed);
 208
 209         event = kzalloc(sizeof(*event), GFP_KERNEL);
 210         if (!event)
 211                 return -ENOMEM;
 212
 213         event->name = name;
 214         event->type = type;
 215         event->seen = seen;
 216         event->action = pressed ? "pressed" : "released";
 217
 218         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 219         schedule_work(&event->work);
 220
 221         return 0;
 222 }
 223
 224 /* -------------------------------------------------------------------------*/
 225
 226 #ifdef  CONFIG_HOTPLUG
 227 static int button_get_index(unsigned int code)
 228 {
 229         int i;
 230
 231         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 232                 if (button_map[i].code == code)
 233                         return i;
 234
 235         return -1;
 236 }
 237
 238 static void button_hotplug_event(struct gpio_keys_button_data *data,
 239                            unsigned int type, int value)
 240 {
 241         struct bh_priv *priv = &data->bh;
 242         unsigned long seen = jiffies;
 243         int btn;
 244
 245         BH_DBG("event type=%u, code=%u, value=%d\n", type, data->b->code, value);
 246
 247         if ((type != EV_KEY) && (type != EV_SW))
 248                 return;
 249
 250         btn = button_get_index(data->b->code);
 251         if (btn < 0)
 252                 return;
 253
 254         button_hotplug_create_event(button_map[btn].name, type,
 255                         (seen - priv->seen) / HZ, value);
 256         priv->seen = seen;
 257 }
 258 #else
 259 static void button_hotplug_event(struct gpio_keys_button_data *data,
 260                            unsigned int type, int value)
 261 {
 262 }
 263 #endif  /* CONFIG_HOTPLUG */
 264
 265 struct gpio_keys_button_dev {
 266         int polled;
 267         struct delayed_work work;
 268
 269         struct device *dev;
 270         struct gpio_keys_platform_data *pdata;
 271         struct gpio_keys_button_data data[0];
 272 };
 273
 274 static int gpio_button_get_value(struct gpio_keys_button_data *bdata)
 275 {
 276         int val;
 277
 278         if (bdata->can_sleep)
 279                 val = !!gpio_get_value_cansleep(bdata->b->gpio);
 280         else
 281                 val = !!gpio_get_value(bdata->b->gpio);
 282
 283         return val ^ bdata->b->active_low;
 284 }
 285
 286 static void gpio_keys_polled_check_state(struct gpio_keys_button_data *bdata)
 287 {
 288         int state = gpio_button_get_value(bdata);
 289
 290         if (state != bdata->last_state) {
 291                 unsigned int type = bdata->b->type ?: EV_KEY;
 292
 293                 if (bdata->count < bdata->threshold) {
 294                         bdata->count++;
 295                         return;
 296                 }
 297
 298                 if ((bdata->last_state != -1) || (type == EV_SW))
 299                         button_hotplug_event(bdata, type, state);
 300
 301                 bdata->last_state = state;
 302         }
 303
 304         bdata->count = 0;
 305 }
 306
 307 static void gpio_keys_polled_queue_work(struct gpio_keys_button_dev *bdev)
 308 {
 309         struct gpio_keys_platform_data *pdata = bdev->pdata;
 310         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 311
 312         if (delay >= HZ)
 313                 delay = round_jiffies_relative(delay);
 314         schedule_delayed_work(&bdev->work, delay);
 315 }
 316
 317 static void gpio_keys_polled_poll(struct work_struct *work)
 318 {
 319         struct gpio_keys_button_dev *bdev =
 320                 container_of(work, struct gpio_keys_button_dev, work.work);
 321         int i;
 322
 323         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 324                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 325                 gpio_keys_polled_check_state(bdata);
 326         }
 327         gpio_keys_polled_queue_work(bdev);
 328 }
 329
 330 static void gpio_keys_polled_close(struct gpio_keys_button_dev *bdev)
 331 {
 332         struct gpio_keys_platform_data *pdata = bdev->pdata;
 333
 334         cancel_delayed_work_sync(&bdev->work);
 335
 336         if (pdata->disable)
 337                 pdata->disable(bdev->dev);
 338 }
 339
 340 static irqreturn_t button_handle_irq(int irq, void *_bdata)
 341 {
 342         struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *) _bdata;
 343
 344         button_hotplug_event(bdata, bdata->b->type ?: EV_KEY, gpio_button_get_value(bdata));
 345
 346         return IRQ_HANDLED;
 347 }
 348
 349 #ifdef CONFIG_OF
 350 static struct gpio_keys_platform_data *
 351 gpio_keys_get_devtree_pdata(struct device *dev)
 352 {
 353         struct device_node *node, *pp;
 354         struct gpio_keys_platform_data *pdata;
 355         struct gpio_keys_button *button;
 356         int error;
 357         int nbuttons;
 358         int i = 0;
 359
 360         node = dev->of_node;
 361         if (!node)
 362                 return NULL;
 363
 364         nbuttons = of_get_child_count(node);
 365         if (nbuttons == 0)
 366                 return NULL;
 367
 368         pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * (sizeof *button),
 369                 GFP_KERNEL);
 370         if (!pdata) {
 371                 error = -ENOMEM;
 372                 goto err_out;
 373         }
 374
 375         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 376         pdata->nbuttons = nbuttons;
 377
 378         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 379         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 380
 381         for_each_child_of_node(node, pp) {
 382                 enum of_gpio_flags flags;
 383
 384                 if (!of_find_property(pp, "gpios", NULL)) {
 385                         pdata->nbuttons--;
 386                         dev_warn(dev, "Found button without gpios\n");
 387                         continue;
 388                 }
 389
 390                 button = &pdata->buttons[i++];
 391
 392                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 393                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 394
 395                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 396                         dev_err(dev, "Button without keycode: 0x%x\n",
 397                                 button->gpio);
 398                         error = -EINVAL;
 399                         goto err_out;
 400                 }
 401
 402                 button->desc = of_get_property(pp, "label", NULL);
 403
 404                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 405                         button->type = EV_KEY;
 406
 407                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 408
 409                 if (of_property_read_u32(pp, "debounce-interval",
 410                                         &button->debounce_interval))
 411                         button->debounce_interval = 5;
 412         }
 413
 414         if (pdata->nbuttons == 0) {
 415                 error = -EINVAL;
 416                 goto err_out;
 417         }
 418
 419         return pdata;
 420
 421 err_out:
 422         return ERR_PTR(error);
 423 }
 424
 425 static struct of_device_id gpio_keys_of_match[] = {
 426         { .compatible = "gpio-keys", },
 427         { },
 428 };
 429 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
 430
 431 static struct of_device_id gpio_keys_polled_of_match[] = {
 432         { .compatible = "gpio-keys-polled", },
 433         { },
 434 };
 435 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 436
 437 #else
 438
 439 static inline struct gpio_keys_platform_data *
 440 gpio_keys_get_devtree_pdata(struct device *dev)
 441 {
 442         return NULL;
 443 }
 444 #endif
 445
 446 static int gpio_keys_button_probe(struct platform_device *pdev,
 447                 struct gpio_keys_button_dev **_bdev, int polled)
 448 {
 449         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 450         struct device *dev = &pdev->dev;
 451         struct gpio_keys_button_dev *bdev;
 452         struct gpio_keys_button *buttons;
 453         int error;
 454         int i;
 455
 456         if (!pdata) {
 457                 pdata = gpio_keys_get_devtree_pdata(dev);
 458                 if (IS_ERR(pdata))
 459                         return PTR_ERR(pdata);
 460                 if (!pdata) {
 461                         dev_err(dev, "missing platform data\n");
 462                         return -EINVAL;
 463                 }
 464                 pdev->dev.platform_data = pdata;
 465         }
 466
 467         if (polled && !pdata->poll_interval) {
 468                 dev_err(dev, "missing poll_interval value\n");
 469                 return -EINVAL;
 470         }
 471
 472         buttons = devm_kzalloc(dev, pdata->nbuttons * sizeof(struct gpio_keys_button),
 473                        GFP_KERNEL);
 474         if (!buttons) {
 475                 dev_err(dev, "no memory for button data\n");
 476                 return -ENOMEM;
 477         }
 478         memcpy(buttons, pdata->buttons, pdata->nbuttons * sizeof(struct gpio_keys_button));
 479
 480         bdev = devm_kzalloc(dev, sizeof(struct gpio_keys_button_dev) +
 481                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 482                        GFP_KERNEL);
 483         if (!bdev) {
 484                 dev_err(dev, "no memory for private data\n");
 485                 return -ENOMEM;
 486         }
 487
 488         bdev->polled = polled;
 489
 490         for (i = 0; i < pdata->nbuttons; i++) {
 491                 struct gpio_keys_button *button = &buttons[i];
 492                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 493                 unsigned int gpio = button->gpio;
 494
 495                 if (button->wakeup) {
 496                         dev_err(dev, DRV_NAME "does not support wakeup\n");
 497                         return -EINVAL;
 498                 }
 499
 500                 error = devm_gpio_request(dev, gpio,
 501                                      button->desc ? button->desc : DRV_NAME);
 502                 if (error) {
 503                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 504                                 gpio, error);
 505                         return error;
 506                 }
 507
 508                 error = gpio_direction_input(gpio);
 509                 if (error) {
 510                         dev_err(dev,
 511                                 "unable to set direction on gpio %u, err=%d\n",
 512                                 gpio, error);
 513                         return error;
 514                 }
 515
 516                 bdata->can_sleep = gpio_cansleep(gpio);
 517                 bdata->last_state = -1;
 518
 519                 if (bdev->polled)
 520                         bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 521                                                 pdata->poll_interval);
 522                 else
 523                         bdata->threshold = 1;
 524
 525                 bdata->b = &pdata->buttons[i];
 526         }
 527
 528         bdev->dev = &pdev->dev;
 529         bdev->pdata = pdata;
 530         platform_set_drvdata(pdev, bdev);
 531
 532         *_bdev = bdev;
 533
 534         return 0;
 535 }
 536
 537 static int gpio_keys_probe(struct platform_device *pdev)
 538 {
 539         struct gpio_keys_platform_data *pdata;
 540         struct gpio_keys_button_dev *bdev;
 541         int ret, i;
 542
 543
 544         ret = gpio_keys_button_probe(pdev, &bdev, 0);
 545
 546         if (ret)
 547                 return ret;
 548
 549         pdata = pdev->dev.platform_data;
 550         for (i = 0; i < pdata->nbuttons; i++) {
 551                 struct gpio_keys_button *button = &pdata->buttons[i];
 552                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 553
 554                 if (bdata->can_sleep) {
 555                         dev_err(&pdev->dev, "skipping gpio:%d, it can sleep\n", button->gpio);
 556                         continue;
 557                 }
 558                 if (!button->irq)
 559                         button->irq = gpio_to_irq(button->gpio);
 560                 if (button->irq < 0) {
 561                         dev_err(&pdev->dev, "failed to get irq for gpio:%d\n", button->gpio);
 562                         continue;
 563                 }
 564                 ret = devm_request_irq(&pdev->dev, button->irq, button_handle_irq,
 565                                         IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 566                                         dev_name(&pdev->dev), bdata);
 567                 if (ret)
 568                         dev_err(&pdev->dev, "failed to request irq:%d for gpio:%d\n", button->irq, button->gpio);
 569                 else
 570                         dev_dbg(&pdev->dev, "gpio:%d has irq:%d\n", button->gpio, button->irq);
 571
 572                 if (bdata->b->type == EV_SW)
 573                         button_hotplug_event(bdata, EV_SW, gpio_button_get_value(bdata));
 574         }
 575
 576         return 0;
 577 }
 578
 579 static int gpio_keys_polled_probe(struct platform_device *pdev)
 580 {
 581         struct gpio_keys_platform_data *pdata;
 582         struct gpio_keys_button_dev *bdev;
 583         int ret;
 584         int i;
 585
 586         ret = gpio_keys_button_probe(pdev, &bdev, 1);
 587
 588         if (ret)
 589                 return ret;
 590
 591         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 592
 593         pdata = bdev->pdata;
 594
 595         if (pdata->enable)
 596                 pdata->enable(bdev->dev);
 597
 598         for (i = 0; i < pdata->nbuttons; i++)
 599                 gpio_keys_polled_check_state(&bdev->data[i]);
 600
 601         gpio_keys_polled_queue_work(bdev);
 602
 603         return ret;
 604 }
 605
 606 static int gpio_keys_remove(struct platform_device *pdev)
 607 {
 608         struct gpio_keys_button_dev *bdev = platform_get_drvdata(pdev);
 609
 610         platform_set_drvdata(pdev, NULL);
 611
 612         if (bdev->polled)
 613                 gpio_keys_polled_close(bdev);
 614
 615         return gpio_keys_remove(pdev);
 616 }
 617
 618 static struct platform_driver gpio_keys_driver = {
 619         .probe  = gpio_keys_probe,
 620         .remove = gpio_keys_remove,
 621         .driver = {
 622                 .name   = "gpio-keys",
 623                 .owner  = THIS_MODULE,
 624                 .of_match_table = of_match_ptr(gpio_keys_of_match),
 625         },
 626 };
 627
 628 static struct platform_driver gpio_keys_polled_driver = {
 629         .probe  = gpio_keys_polled_probe,
 630         .remove = gpio_keys_remove,
 631         .driver = {
 632                 .name   = "gpio-keys-polled",
 633                 .owner  = THIS_MODULE,
 634                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 635         },
 636 };
 637
 638 static int __init gpio_button_init(void)
 639 {
 640         int ret;
 641
 642         ret = platform_driver_register(&gpio_keys_driver);
 643         if (ret)
 644                 return ret;
 645
 646         ret = platform_driver_register(&gpio_keys_polled_driver);
 647         if (ret)
 648                 platform_driver_unregister(&gpio_keys_driver);
 649
 650         return ret;
 651 }
 652
 653 static void __exit gpio_button_exit(void)
 654 {
 655         platform_driver_unregister(&gpio_keys_driver);
 656         platform_driver_unregister(&gpio_keys_polled_driver);
 657 }
 658
 659 module_init(gpio_button_init);
 660 module_exit(gpio_button_exit);
 661
 662 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 663 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 664 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 665 MODULE_LICENSE("GPL v2");
 666 MODULE_ALIAS("platform:" DRV_NAME);