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

   1 /*
   2  *  GPIO Button Hotplug driver
   3  *
   4  *  Copyright (C) 2012 Felix Fietkau <nbd@nbd.name>
   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@nbd.name>
  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         BH_MAP(KEY_WIMAX,       "wwan"),
 100 };
 101
 102 /* -------------------------------------------------------------------------*/
 103
 104 static __printf(3, 4)
 105 int bh_event_add_var(struct bh_event *event, int argv, const char *format, ...)
 106 {
 107         static char buf[128];
 108         char *s;
 109         va_list args;
 110         int len;
 111
 112         if (argv)
 113                 return 0;
 114
 115         va_start(args, format);
 116         len = vsnprintf(buf, sizeof(buf), format, args);
 117         va_end(args);
 118
 119         if (len >= sizeof(buf)) {
 120                 WARN(1, "buffer size too small");
 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 static int button_get_index(unsigned int code)
 227 {
 228         int i;
 229
 230         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 231                 if (button_map[i].code == code)
 232                         return i;
 233
 234         return -1;
 235 }
 236
 237 static void button_hotplug_event(struct gpio_keys_button_data *data,
 238                            unsigned int type, int value)
 239 {
 240         struct bh_priv *priv = &data->bh;
 241         unsigned long seen = jiffies;
 242         int btn;
 243
 244         BH_DBG("event type=%u, code=%u, value=%d\n", type, data->b->code, value);
 245
 246         if ((type != EV_KEY) && (type != EV_SW))
 247                 return;
 248
 249         btn = button_get_index(data->b->code);
 250         if (btn < 0)
 251                 return;
 252
 253         button_hotplug_create_event(button_map[btn].name, type,
 254                         (seen - priv->seen) / HZ, value);
 255         priv->seen = seen;
 256 }
 257
 258 struct gpio_keys_button_dev {
 259         int polled;
 260         struct delayed_work work;
 261
 262         struct device *dev;
 263         struct gpio_keys_platform_data *pdata;
 264         struct gpio_keys_button_data data[0];
 265 };
 266
 267 static int gpio_button_get_value(struct gpio_keys_button_data *bdata)
 268 {
 269         int val;
 270
 271         if (bdata->can_sleep)
 272                 val = !!gpio_get_value_cansleep(bdata->b->gpio);
 273         else
 274                 val = !!gpio_get_value(bdata->b->gpio);
 275
 276         return val ^ bdata->b->active_low;
 277 }
 278
 279 static void gpio_keys_polled_check_state(struct gpio_keys_button_data *bdata)
 280 {
 281         int state = gpio_button_get_value(bdata);
 282
 283         if (state != bdata->last_state) {
 284                 unsigned int type = bdata->b->type ?: EV_KEY;
 285
 286                 if (bdata->count < bdata->threshold) {
 287                         bdata->count++;
 288                         return;
 289                 }
 290
 291                 if ((bdata->last_state != -1) || (type == EV_SW))
 292                         button_hotplug_event(bdata, type, state);
 293
 294                 bdata->last_state = state;
 295         }
 296
 297         bdata->count = 0;
 298 }
 299
 300 static void gpio_keys_polled_queue_work(struct gpio_keys_button_dev *bdev)
 301 {
 302         struct gpio_keys_platform_data *pdata = bdev->pdata;
 303         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 304
 305         if (delay >= HZ)
 306                 delay = round_jiffies_relative(delay);
 307         schedule_delayed_work(&bdev->work, delay);
 308 }
 309
 310 static void gpio_keys_polled_poll(struct work_struct *work)
 311 {
 312         struct gpio_keys_button_dev *bdev =
 313                 container_of(work, struct gpio_keys_button_dev, work.work);
 314         int i;
 315
 316         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 317                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 318                 gpio_keys_polled_check_state(bdata);
 319         }
 320         gpio_keys_polled_queue_work(bdev);
 321 }
 322
 323 static void gpio_keys_polled_close(struct gpio_keys_button_dev *bdev)
 324 {
 325         struct gpio_keys_platform_data *pdata = bdev->pdata;
 326
 327         cancel_delayed_work_sync(&bdev->work);
 328
 329         if (pdata->disable)
 330                 pdata->disable(bdev->dev);
 331 }
 332
 333 static irqreturn_t button_handle_irq(int irq, void *_bdata)
 334 {
 335         struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *) _bdata;
 336
 337         button_hotplug_event(bdata, bdata->b->type ?: EV_KEY, gpio_button_get_value(bdata));
 338
 339         return IRQ_HANDLED;
 340 }
 341
 342 #ifdef CONFIG_OF
 343 static struct gpio_keys_platform_data *
 344 gpio_keys_get_devtree_pdata(struct device *dev)
 345 {
 346         struct device_node *node, *pp;
 347         struct gpio_keys_platform_data *pdata;
 348         struct gpio_keys_button *button;
 349         int error;
 350         int nbuttons;
 351         int i = 0;
 352
 353         node = dev->of_node;
 354         if (!node)
 355                 return NULL;
 356
 357         nbuttons = of_get_child_count(node);
 358         if (nbuttons == 0)
 359                 return NULL;
 360
 361         pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * (sizeof *button),
 362                 GFP_KERNEL);
 363         if (!pdata) {
 364                 error = -ENOMEM;
 365                 goto err_out;
 366         }
 367
 368         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 369         pdata->nbuttons = nbuttons;
 370
 371         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 372         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 373
 374         for_each_child_of_node(node, pp) {
 375                 enum of_gpio_flags flags;
 376
 377                 if (!of_find_property(pp, "gpios", NULL)) {
 378                         pdata->nbuttons--;
 379                         dev_warn(dev, "Found button without gpios\n");
 380                         continue;
 381                 }
 382
 383                 button = &pdata->buttons[i++];
 384
 385                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 386                 if (button->gpio < 0) {
 387                         error = button->gpio;
 388                         if (error != -ENOENT) {
 389                                 if (error != -EPROBE_DEFER)
 390                                         dev_err(dev,
 391                                                 "Failed to get gpio flags, error: %d\n",
 392                                                 error);
 393                                 return ERR_PTR(error);
 394                         }
 395                 } else {
 396                         button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 397                 }
 398
 399                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 400                         dev_err(dev, "Button without keycode: 0x%x\n",
 401                                 button->gpio);
 402                         error = -EINVAL;
 403                         goto err_out;
 404                 }
 405
 406                 button->desc = of_get_property(pp, "label", NULL);
 407
 408                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 409                         button->type = EV_KEY;
 410
 411                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 412
 413                 if (of_property_read_u32(pp, "debounce-interval",
 414                                         &button->debounce_interval))
 415                         button->debounce_interval = 5;
 416         }
 417
 418         if (pdata->nbuttons == 0) {
 419                 error = -EINVAL;
 420                 goto err_out;
 421         }
 422
 423         return pdata;
 424
 425 err_out:
 426         return ERR_PTR(error);
 427 }
 428
 429 static struct of_device_id gpio_keys_of_match[] = {
 430         { .compatible = "gpio-keys", },
 431         { },
 432 };
 433 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
 434
 435 static struct of_device_id gpio_keys_polled_of_match[] = {
 436         { .compatible = "gpio-keys-polled", },
 437         { },
 438 };
 439 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 440
 441 #else
 442
 443 static inline struct gpio_keys_platform_data *
 444 gpio_keys_get_devtree_pdata(struct device *dev)
 445 {
 446         return NULL;
 447 }
 448 #endif
 449
 450 static int gpio_keys_button_probe(struct platform_device *pdev,
 451                 struct gpio_keys_button_dev **_bdev, int polled)
 452 {
 453         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 454         struct device *dev = &pdev->dev;
 455         struct gpio_keys_button_dev *bdev;
 456         struct gpio_keys_button *buttons;
 457         int error;
 458         int i;
 459
 460         if (!pdata) {
 461                 pdata = gpio_keys_get_devtree_pdata(dev);
 462                 if (IS_ERR(pdata))
 463                         return PTR_ERR(pdata);
 464                 if (!pdata) {
 465                         dev_err(dev, "missing platform data\n");
 466                         return -EINVAL;
 467                 }
 468                 pdev->dev.platform_data = pdata;
 469         }
 470
 471         if (polled && !pdata->poll_interval) {
 472                 dev_err(dev, "missing poll_interval value\n");
 473                 return -EINVAL;
 474         }
 475
 476         buttons = devm_kzalloc(dev, pdata->nbuttons * sizeof(struct gpio_keys_button),
 477                        GFP_KERNEL);
 478         if (!buttons) {
 479                 dev_err(dev, "no memory for button data\n");
 480                 return -ENOMEM;
 481         }
 482         memcpy(buttons, pdata->buttons, pdata->nbuttons * sizeof(struct gpio_keys_button));
 483
 484         bdev = devm_kzalloc(dev, sizeof(struct gpio_keys_button_dev) +
 485                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 486                        GFP_KERNEL);
 487         if (!bdev) {
 488                 dev_err(dev, "no memory for private data\n");
 489                 return -ENOMEM;
 490         }
 491
 492         bdev->polled = polled;
 493
 494         for (i = 0; i < pdata->nbuttons; i++) {
 495                 struct gpio_keys_button *button = &buttons[i];
 496                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 497                 unsigned int gpio = button->gpio;
 498
 499                 if (button->wakeup) {
 500                         dev_err(dev, DRV_NAME "does not support wakeup\n");
 501                         return -EINVAL;
 502                 }
 503
 504                 error = devm_gpio_request(dev, gpio,
 505                                      button->desc ? button->desc : DRV_NAME);
 506                 if (error) {
 507                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 508                                 gpio, error);
 509                         return error;
 510                 }
 511
 512                 error = gpio_direction_input(gpio);
 513                 if (error) {
 514                         dev_err(dev,
 515                                 "unable to set direction on gpio %u, err=%d\n",
 516                                 gpio, error);
 517                         return error;
 518                 }
 519
 520                 bdata->can_sleep = gpio_cansleep(gpio);
 521                 bdata->last_state = -1;
 522
 523                 if (bdev->polled)
 524                         bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 525                                                 pdata->poll_interval);
 526                 else
 527                         bdata->threshold = 1;
 528
 529                 bdata->b = &pdata->buttons[i];
 530         }
 531
 532         bdev->dev = &pdev->dev;
 533         bdev->pdata = pdata;
 534         platform_set_drvdata(pdev, bdev);
 535
 536         *_bdev = bdev;
 537
 538         return 0;
 539 }
 540
 541 static int gpio_keys_probe(struct platform_device *pdev)
 542 {
 543         struct gpio_keys_platform_data *pdata;
 544         struct gpio_keys_button_dev *bdev;
 545         int ret, i;
 546
 547
 548         ret = gpio_keys_button_probe(pdev, &bdev, 0);
 549
 550         if (ret)
 551                 return ret;
 552
 553         pdata = pdev->dev.platform_data;
 554         for (i = 0; i < pdata->nbuttons; i++) {
 555                 struct gpio_keys_button *button = &pdata->buttons[i];
 556                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 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
 565                 ret = devm_request_threaded_irq(&pdev->dev, button->irq, NULL, button_handle_irq,
 566                                                 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 567                                                 dev_name(&pdev->dev), bdata);
 568                 if (ret < 0)
 569                         dev_err(&pdev->dev, "failed to request irq:%d for gpio:%d\n", button->irq, button->gpio);
 570                 else
 571                         dev_dbg(&pdev->dev, "gpio:%d has irq:%d\n", button->gpio, button->irq);
 572
 573                 if (bdata->b->type == EV_SW)
 574                         button_hotplug_event(bdata, EV_SW, gpio_button_get_value(bdata));
 575         }
 576
 577         return 0;
 578 }
 579
 580 static int gpio_keys_polled_probe(struct platform_device *pdev)
 581 {
 582         struct gpio_keys_platform_data *pdata;
 583         struct gpio_keys_button_dev *bdev;
 584         int ret;
 585         int i;
 586
 587         ret = gpio_keys_button_probe(pdev, &bdev, 1);
 588
 589         if (ret)
 590                 return ret;
 591
 592         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 593
 594         pdata = bdev->pdata;
 595
 596         if (pdata->enable)
 597                 pdata->enable(bdev->dev);
 598
 599         for (i = 0; i < pdata->nbuttons; i++)
 600                 gpio_keys_polled_check_state(&bdev->data[i]);
 601
 602         gpio_keys_polled_queue_work(bdev);
 603
 604         return ret;
 605 }
 606
 607 static int gpio_keys_remove(struct platform_device *pdev)
 608 {
 609         struct gpio_keys_button_dev *bdev = platform_get_drvdata(pdev);
 610
 611         platform_set_drvdata(pdev, NULL);
 612
 613         if (bdev->polled)
 614                 gpio_keys_polled_close(bdev);
 615
 616         return 0;
 617 }
 618
 619 static struct platform_driver gpio_keys_driver = {
 620         .probe  = gpio_keys_probe,
 621         .remove = gpio_keys_remove,
 622         .driver = {
 623                 .name   = "gpio-keys",
 624                 .owner  = THIS_MODULE,
 625                 .of_match_table = of_match_ptr(gpio_keys_of_match),
 626         },
 627 };
 628
 629 static struct platform_driver gpio_keys_polled_driver = {
 630         .probe  = gpio_keys_polled_probe,
 631         .remove = gpio_keys_remove,
 632         .driver = {
 633                 .name   = "gpio-keys-polled",
 634                 .owner  = THIS_MODULE,
 635                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 636         },
 637 };
 638
 639 static int __init gpio_button_init(void)
 640 {
 641         int ret;
 642
 643         ret = platform_driver_register(&gpio_keys_driver);
 644         if (ret)
 645                 return ret;
 646
 647         ret = platform_driver_register(&gpio_keys_polled_driver);
 648         if (ret)
 649                 platform_driver_unregister(&gpio_keys_driver);
 650
 651         return ret;
 652 }
 653
 654 static void __exit gpio_button_exit(void)
 655 {
 656         platform_driver_unregister(&gpio_keys_driver);
 657         platform_driver_unregister(&gpio_keys_polled_driver);
 658 }
 659
 660 module_init(gpio_button_init);
 661 module_exit(gpio_button_exit);
 662
 663 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 664 MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
 665 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 666 MODULE_LICENSE("GPL v2");
 667 MODULE_ALIAS("platform:" DRV_NAME);