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         BH_MAP(KEY_WIMAX,       "wwan"),
 100 };
 101
 102 /* -------------------------------------------------------------------------*/
 103
 104 static int bh_event_add_var(struct bh_event *event, int argv,
 105                 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                 BH_ERR("buffer size too small\n");
 121                 WARN_ON(1);
 122                 return -ENOMEM;
 123         }
 124
 125         s = skb_put(event->skb, len + 1);
 126         strcpy(s, buf);
 127
 128         BH_DBG("added variable '%s'\n", s);
 129
 130         return 0;
 131 }
 132
 133 static int button_hotplug_fill_event(struct bh_event *event)
 134 {
 135         int ret;
 136
 137         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 138         if (ret)
 139                 return ret;
 140
 141         ret = bh_event_add_var(event, 0, "PATH=%s",
 142                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 143         if (ret)
 144                 return ret;
 145
 146         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 147         if (ret)
 148                 return ret;
 149
 150         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 151         if (ret)
 152                 return ret;
 153
 154         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 155         if (ret)
 156                 return ret;
 157
 158         if (event->type == EV_SW) {
 159                 ret = bh_event_add_var(event, 0, "TYPE=%s", "switch");
 160                 if (ret)
 161                         return ret;
 162         }
 163
 164         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 165         if (ret)
 166                 return ret;
 167
 168         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 169
 170         return ret;
 171 }
 172
 173 static void button_hotplug_work(struct work_struct *work)
 174 {
 175         struct bh_event *event = container_of(work, struct bh_event, work);
 176         int ret = 0;
 177
 178         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 179         if (!event->skb)
 180                 goto out_free_event;
 181
 182         ret = bh_event_add_var(event, 0, "%s@", event->action);
 183         if (ret)
 184                 goto out_free_skb;
 185
 186         ret = button_hotplug_fill_event(event);
 187         if (ret)
 188                 goto out_free_skb;
 189
 190         NETLINK_CB(event->skb).dst_group = 1;
 191         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 192
 193  out_free_skb:
 194         if (ret) {
 195                 BH_ERR("work error %d\n", ret);
 196                 kfree_skb(event->skb);
 197         }
 198  out_free_event:
 199         kfree(event);
 200 }
 201
 202 static int button_hotplug_create_event(const char *name, unsigned int type,
 203                 unsigned long seen, int pressed)
 204 {
 205         struct bh_event *event;
 206
 207         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 208                 name, seen, pressed);
 209
 210         event = kzalloc(sizeof(*event), GFP_KERNEL);
 211         if (!event)
 212                 return -ENOMEM;
 213
 214         event->name = name;
 215         event->type = type;
 216         event->seen = seen;
 217         event->action = pressed ? "pressed" : "released";
 218
 219         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 220         schedule_work(&event->work);
 221
 222         return 0;
 223 }
 224
 225 /* -------------------------------------------------------------------------*/
 226
 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
 259 struct gpio_keys_button_dev {
 260         int polled;
 261         struct delayed_work work;
 262
 263         struct device *dev;
 264         struct gpio_keys_platform_data *pdata;
 265         struct gpio_keys_button_data data[0];
 266 };
 267
 268 static int gpio_button_get_value(struct gpio_keys_button_data *bdata)
 269 {
 270         int val;
 271
 272         if (bdata->can_sleep)
 273                 val = !!gpio_get_value_cansleep(bdata->b->gpio);
 274         else
 275                 val = !!gpio_get_value(bdata->b->gpio);
 276
 277         return val ^ bdata->b->active_low;
 278 }
 279
 280 static void gpio_keys_polled_check_state(struct gpio_keys_button_data *bdata)
 281 {
 282         int state = gpio_button_get_value(bdata);
 283
 284         if (state != bdata->last_state) {
 285                 unsigned int type = bdata->b->type ?: EV_KEY;
 286
 287                 if (bdata->count < bdata->threshold) {
 288                         bdata->count++;
 289                         return;
 290                 }
 291
 292                 if ((bdata->last_state != -1) || (type == EV_SW))
 293                         button_hotplug_event(bdata, type, state);
 294
 295                 bdata->last_state = state;
 296         }
 297
 298         bdata->count = 0;
 299 }
 300
 301 static void gpio_keys_polled_queue_work(struct gpio_keys_button_dev *bdev)
 302 {
 303         struct gpio_keys_platform_data *pdata = bdev->pdata;
 304         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 305
 306         if (delay >= HZ)
 307                 delay = round_jiffies_relative(delay);
 308         schedule_delayed_work(&bdev->work, delay);
 309 }
 310
 311 static void gpio_keys_polled_poll(struct work_struct *work)
 312 {
 313         struct gpio_keys_button_dev *bdev =
 314                 container_of(work, struct gpio_keys_button_dev, work.work);
 315         int i;
 316
 317         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 318                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 319                 gpio_keys_polled_check_state(bdata);
 320         }
 321         gpio_keys_polled_queue_work(bdev);
 322 }
 323
 324 static void gpio_keys_polled_close(struct gpio_keys_button_dev *bdev)
 325 {
 326         struct gpio_keys_platform_data *pdata = bdev->pdata;
 327
 328         cancel_delayed_work_sync(&bdev->work);
 329
 330         if (pdata->disable)
 331                 pdata->disable(bdev->dev);
 332 }
 333
 334 static irqreturn_t button_handle_irq(int irq, void *_bdata)
 335 {
 336         struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *) _bdata;
 337
 338         button_hotplug_event(bdata, bdata->b->type ?: EV_KEY, gpio_button_get_value(bdata));
 339
 340         return IRQ_HANDLED;
 341 }
 342
 343 #ifdef CONFIG_OF
 344 static struct gpio_keys_platform_data *
 345 gpio_keys_get_devtree_pdata(struct device *dev)
 346 {
 347         struct device_node *node, *pp;
 348         struct gpio_keys_platform_data *pdata;
 349         struct gpio_keys_button *button;
 350         int error;
 351         int nbuttons;
 352         int i = 0;
 353
 354         node = dev->of_node;
 355         if (!node)
 356                 return NULL;
 357
 358         nbuttons = of_get_child_count(node);
 359         if (nbuttons == 0)
 360                 return NULL;
 361
 362         pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * (sizeof *button),
 363                 GFP_KERNEL);
 364         if (!pdata) {
 365                 error = -ENOMEM;
 366                 goto err_out;
 367         }
 368
 369         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 370         pdata->nbuttons = nbuttons;
 371
 372         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 373         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 374
 375         for_each_child_of_node(node, pp) {
 376                 enum of_gpio_flags flags;
 377
 378                 if (!of_find_property(pp, "gpios", NULL)) {
 379                         pdata->nbuttons--;
 380                         dev_warn(dev, "Found button without gpios\n");
 381                         continue;
 382                 }
 383
 384                 button = &pdata->buttons[i++];
 385
 386                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 387                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 388
 389                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 390                         dev_err(dev, "Button without keycode: 0x%x\n",
 391                                 button->gpio);
 392                         error = -EINVAL;
 393                         goto err_out;
 394                 }
 395
 396                 button->desc = of_get_property(pp, "label", NULL);
 397
 398                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 399                         button->type = EV_KEY;
 400
 401                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 402
 403                 if (of_property_read_u32(pp, "debounce-interval",
 404                                         &button->debounce_interval))
 405                         button->debounce_interval = 5;
 406         }
 407
 408         if (pdata->nbuttons == 0) {
 409                 error = -EINVAL;
 410                 goto err_out;
 411         }
 412
 413         return pdata;
 414
 415 err_out:
 416         return ERR_PTR(error);
 417 }
 418
 419 static struct of_device_id gpio_keys_of_match[] = {
 420         { .compatible = "gpio-keys", },
 421         { },
 422 };
 423 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
 424
 425 static struct of_device_id gpio_keys_polled_of_match[] = {
 426         { .compatible = "gpio-keys-polled", },
 427         { },
 428 };
 429 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 430
 431 #else
 432
 433 static inline struct gpio_keys_platform_data *
 434 gpio_keys_get_devtree_pdata(struct device *dev)
 435 {
 436         return NULL;
 437 }
 438 #endif
 439
 440 static int gpio_keys_button_probe(struct platform_device *pdev,
 441                 struct gpio_keys_button_dev **_bdev, int polled)
 442 {
 443         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 444         struct device *dev = &pdev->dev;
 445         struct gpio_keys_button_dev *bdev;
 446         struct gpio_keys_button *buttons;
 447         int error;
 448         int i;
 449
 450         if (!pdata) {
 451                 pdata = gpio_keys_get_devtree_pdata(dev);
 452                 if (IS_ERR(pdata))
 453                         return PTR_ERR(pdata);
 454                 if (!pdata) {
 455                         dev_err(dev, "missing platform data\n");
 456                         return -EINVAL;
 457                 }
 458                 pdev->dev.platform_data = pdata;
 459         }
 460
 461         if (polled && !pdata->poll_interval) {
 462                 dev_err(dev, "missing poll_interval value\n");
 463                 return -EINVAL;
 464         }
 465
 466         buttons = devm_kzalloc(dev, pdata->nbuttons * sizeof(struct gpio_keys_button),
 467                        GFP_KERNEL);
 468         if (!buttons) {
 469                 dev_err(dev, "no memory for button data\n");
 470                 return -ENOMEM;
 471         }
 472         memcpy(buttons, pdata->buttons, pdata->nbuttons * sizeof(struct gpio_keys_button));
 473
 474         bdev = devm_kzalloc(dev, sizeof(struct gpio_keys_button_dev) +
 475                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 476                        GFP_KERNEL);
 477         if (!bdev) {
 478                 dev_err(dev, "no memory for private data\n");
 479                 return -ENOMEM;
 480         }
 481
 482         bdev->polled = polled;
 483
 484         for (i = 0; i < pdata->nbuttons; i++) {
 485                 struct gpio_keys_button *button = &buttons[i];
 486                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 487                 unsigned int gpio = button->gpio;
 488
 489                 if (button->wakeup) {
 490                         dev_err(dev, DRV_NAME "does not support wakeup\n");
 491                         return -EINVAL;
 492                 }
 493
 494                 error = devm_gpio_request(dev, gpio,
 495                                      button->desc ? button->desc : DRV_NAME);
 496                 if (error) {
 497                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 498                                 gpio, error);
 499                         return error;
 500                 }
 501
 502                 error = gpio_direction_input(gpio);
 503                 if (error) {
 504                         dev_err(dev,
 505                                 "unable to set direction on gpio %u, err=%d\n",
 506                                 gpio, error);
 507                         return error;
 508                 }
 509
 510                 bdata->can_sleep = gpio_cansleep(gpio);
 511                 bdata->last_state = -1;
 512
 513                 if (bdev->polled)
 514                         bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 515                                                 pdata->poll_interval);
 516                 else
 517                         bdata->threshold = 1;
 518
 519                 bdata->b = &pdata->buttons[i];
 520         }
 521
 522         bdev->dev = &pdev->dev;
 523         bdev->pdata = pdata;
 524         platform_set_drvdata(pdev, bdev);
 525
 526         *_bdev = bdev;
 527
 528         return 0;
 529 }
 530
 531 static int gpio_keys_probe(struct platform_device *pdev)
 532 {
 533         struct gpio_keys_platform_data *pdata;
 534         struct gpio_keys_button_dev *bdev;
 535         int ret, i;
 536
 537
 538         ret = gpio_keys_button_probe(pdev, &bdev, 0);
 539
 540         if (ret)
 541                 return ret;
 542
 543         pdata = pdev->dev.platform_data;
 544         for (i = 0; i < pdata->nbuttons; i++) {
 545                 struct gpio_keys_button *button = &pdata->buttons[i];
 546                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 547
 548                 if (bdata->can_sleep) {
 549                         dev_err(&pdev->dev, "skipping gpio:%d, it can sleep\n", button->gpio);
 550                         continue;
 551                 }
 552                 if (!button->irq)
 553                         button->irq = gpio_to_irq(button->gpio);
 554                 if (button->irq < 0) {
 555                         dev_err(&pdev->dev, "failed to get irq for gpio:%d\n", button->gpio);
 556                         continue;
 557                 }
 558                 ret = devm_request_irq(&pdev->dev, button->irq, button_handle_irq,
 559                                         IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 560                                         dev_name(&pdev->dev), bdata);
 561                 if (ret)
 562                         dev_err(&pdev->dev, "failed to request irq:%d for gpio:%d\n", button->irq, button->gpio);
 563                 else
 564                         dev_dbg(&pdev->dev, "gpio:%d has irq:%d\n", button->gpio, button->irq);
 565
 566                 if (bdata->b->type == EV_SW)
 567                         button_hotplug_event(bdata, EV_SW, gpio_button_get_value(bdata));
 568         }
 569
 570         return 0;
 571 }
 572
 573 static int gpio_keys_polled_probe(struct platform_device *pdev)
 574 {
 575         struct gpio_keys_platform_data *pdata;
 576         struct gpio_keys_button_dev *bdev;
 577         int ret;
 578         int i;
 579
 580         ret = gpio_keys_button_probe(pdev, &bdev, 1);
 581
 582         if (ret)
 583                 return ret;
 584
 585         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 586
 587         pdata = bdev->pdata;
 588
 589         if (pdata->enable)
 590                 pdata->enable(bdev->dev);
 591
 592         for (i = 0; i < pdata->nbuttons; i++)
 593                 gpio_keys_polled_check_state(&bdev->data[i]);
 594
 595         gpio_keys_polled_queue_work(bdev);
 596
 597         return ret;
 598 }
 599
 600 static int gpio_keys_remove(struct platform_device *pdev)
 601 {
 602         struct gpio_keys_button_dev *bdev = platform_get_drvdata(pdev);
 603
 604         platform_set_drvdata(pdev, NULL);
 605
 606         if (bdev->polled)
 607                 gpio_keys_polled_close(bdev);
 608
 609         return 0;
 610 }
 611
 612 static struct platform_driver gpio_keys_driver = {
 613         .probe  = gpio_keys_probe,
 614         .remove = gpio_keys_remove,
 615         .driver = {
 616                 .name   = "gpio-keys",
 617                 .owner  = THIS_MODULE,
 618                 .of_match_table = of_match_ptr(gpio_keys_of_match),
 619         },
 620 };
 621
 622 static struct platform_driver gpio_keys_polled_driver = {
 623         .probe  = gpio_keys_polled_probe,
 624         .remove = gpio_keys_remove,
 625         .driver = {
 626                 .name   = "gpio-keys-polled",
 627                 .owner  = THIS_MODULE,
 628                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 629         },
 630 };
 631
 632 static int __init gpio_button_init(void)
 633 {
 634         int ret;
 635
 636         ret = platform_driver_register(&gpio_keys_driver);
 637         if (ret)
 638                 return ret;
 639
 640         ret = platform_driver_register(&gpio_keys_polled_driver);
 641         if (ret)
 642                 platform_driver_unregister(&gpio_keys_driver);
 643
 644         return ret;
 645 }
 646
 647 static void __exit gpio_button_exit(void)
 648 {
 649         platform_driver_unregister(&gpio_keys_driver);
 650         platform_driver_unregister(&gpio_keys_polled_driver);
 651 }
 652
 653 module_init(gpio_button_init);
 654 module_exit(gpio_button_exit);
 655
 656 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 657 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 658 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 659 MODULE_LICENSE("GPL v2");
 660 MODULE_ALIAS("platform:" DRV_NAME);